Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
1
Author: Kotyk, Brian, K Title: Metrology Equipment Selection for Measuring the Material Thickness of
Company XYZ’s Next Generation JB3 Titanium Cathode Material The accompanying research report is submitted to the University of Wisconsin-Stout, Graduate School in partial
completion of the requirements for the
Graduate Degree/ Major: MS Technology Management
Research Adviser: Diane Olson, Ph.D.
Submission Term/Year: Fall, 2011
Number of Pages: 72
Style Manual Used: American Psychological Association, 6th edition
I understand that this research report must be officially approved by the Graduate School and that an electronic copy of the approved version will be made available through the University Library website
I attest that the research report is my original work (that any copyrightable materials have been used with the permission of the original authors), and as such, it is automatically protected by the laws, rules, and regulations of the U.S. Copyright Office.
STUDENT’S NAME: Brian Kotyk
STUDENT’S SIGNATURE: ______________________ DATE: Dec 19, 2011
ADVISER’S NAME Dr. Diane Olson
ADVISER’S SIGNATURE: ____ ______________________ DATE: Dec 20, 2011
--------------------------------------------------------------------------------------------------------------------------------- This section to be completed by the Graduate School This final research report has been approved by the Graduate School.
___________________________________________________ ___________________________
(Director, Office of Graduate Studies) (Date)
2
Kotyk, Brian K. Metrology Equipment Selection for Measuring the Material Thickness of
Company XYZ’s Next Generation JB3 Titanium Cathode Material
Abstract
The purpose of this study is to identify a measurement device and process that is capable
of accurately measuring the overall thickness of thin metal foils with high surface finishes.
Company XYZ has specified the JB3 titanium cathode material which is grade two titanium and
.0009 +/- .0002” in thickness with a 23 Ra (roughness average) minimum. This foil had never
been manufactured prior to Company XYZ contracting to have Ullegheny who is a world leader
in titanium foil manufacturing. Ullegheny currently does not have the capability to measure the
JB3 titanium cathode overall thickness per Company XYZ’s specifications because their current
measurement system does not have the capability. In this study two devices will be evaluated as
well as Ullegheny’s current measurement device. The evaluations will consist of a Gage
Repeatability and Reproducibility, capability study, and measurement characteristic analysis to
determine the optimal device for Ullegheny to implement to measure the JB3 titanium cathode
material thickness.
3
The Graduate School University of Wisconsin Stout
Menomonie, WI
Acknowledgments
I would like to thank everybody at Company XYZ for being supportive of my research
project and assisting me through the process. I would also like to thank Ullegheny for assisting
me with the testing at their facility. My instructor Dr. Diane Olson did a wonderful job
mentoring me through the research paper and I could not thank her more. Last but not least I
would like to thank my wonderful girlfriend Marissa for keeping me motivated throughout the
long process of research and the writing process.
4
Table of Contents
.................................................................................................................................................... Page
Abstract ............................................................................................................................................2
List of Tables ...................................................................................................................................6
List of Figures ..................................................................................................................................7
Chapter I: Introduction ....................................................................................................................8
Statement of the Problem ...................................................................................................11
Purpose of the Study ..........................................................................................................12
Assumptions of the Study ..................................................................................................12
Definition of Terms............................................................................................................12
Limitations of the Study.....................................................................................................16
Methodology ......................................................................................................................16
Chapter II: Literature Review ........................................................................................................17
Quality Costs ......................................................................................................................17
Measurement Devices ........................................................................................................18
Measurement Process.........................................................................................................21
Measurement Variation ......................................................................................................23
Concept of Gage R&R Study .............................................................................................29
Process Capability, Control Charts, and Statistical Tools .................................................31
Chapter III: Methodology ..............................................................................................................33
Measurement Device Selection and Descriptions ..............................................................33
Titanium Cathode Subject Selection and Description .......................................................39
Gage Reproducibility and Repeatability Test Description ................................................40
5
Capability Study Description .............................................................................................40
Gage R&R and Capability Study Data Analysis ...............................................................41
Quantitative Analysis of the Measurement System ...........................................................42
Limitations .........................................................................................................................43
Chapter IV: Results ........................................................................................................................44
Statistical Analysis: Gage R&R and Capability Study .....................................................44
Quantitative Analysis of the Measurement System Results .............................................47
Chapter V: Discussion ...................................................................................................................53
Measurement Device Selection .........................................................................................54
Limitations ........................................................................................................................55
Conclusions ........................................................................................................................55
References ......................................................................................................................................57
Appendix A: An Introduction to APA Style. Research Paper FAQS; Provided here
for your reference only; don’t include in your paper ......................................................58
Appendix B: Gage R&R Raw and Analysis Data .........................................................................61
Appendix C: Heidenhain work instructions for Ullegheny Ludlum for measuring the JB3
Company XYZ titanium cathode material thickness ......................................................67
6
List of Tables Table 1: Statistical Analysis Studies – Gage R&R and Capability Study……………………42
Table 2: Quantitative Analysis of the Measurement System……………………….…………43
Table 3: Statistical Analysis Studies – Gage R&R and Capability Study Results……………45
Table 4: Quantitative Analysis Results of the Measurement Systems………………………...47
7
List of Figures
Figure 1: Digital hand micrometer from Company XYZ’s Corlab…………………..….19
Figure 2: Direct Computer Controlled Coordinate Measuring Machine …………….….20
Figure 3: Heidenhain CT6001 precision height measurement system at Ullegheny.……21
Figure 4: The relationship between total, process and measuring variation.………….…24
Figure 5: Measurement Bias.…………………………………………………….………25
Figure 6: Measurement Stability.……………………..………………………….……...26
Figure 7: Measurement Linearity.……………………..………………………….…..…27
Figure 8: Measurement repeatability.……………………..………………………..……28
Figure 9: Measurement reproducibility.……………………..……………………..….…29
Figure 10: Breakdown of overall variation.……………………..……………..…..….…30
Figure 11: This figure is showing the percent tolerance calculation. .……………….…30
Figure 12: Pp and Ppk formulas.……………………..………………………….…….…31
Figure 13: Vollmer VMF1000 Measurement System at Ullegheny……………….…….34
Figure 14: Vollmer VMF1000 contact sphere points……………….…………………....35
Figure 15: Fowler THV Measurement system at Company XYZ’s Corlab….………..…36
Figure 16: Fowler THV Flat Anvil Contact Surfaces……………………..….………..…37
Figure 17: Heidenhain CT6001 Measurement system.…………………….……………..38
Figure 18: Heidenhain CT6001 Flat Anvil Contact Surface.……………………………..39
Figure 19: Capability study for the three measurement devices evaluated.…….….……..46
Figure 20: Capability study deviation chart for each of the measurement systems..……...46
8
Chapter I: Introduction
Company XYZ is an industry leader in producing human implantable defibrillators.
Implantable defibrillators are small battery powered pulse generator devices that deliver therapy
to the heart when it senses abnormal activity. The device is programmed to monitor heart rate
for rhythm abnormalities and when they occur the device delivers therapy. The device consists
of a pulse generator which holds the computer board, battery, and capacitors. Connecting the
pulse generator to the heart are the lead wires, which transfer the energy and signals to and from
the pulse generator unit. When therapy is needed the battery charges up the capacitors and the
energy jolt is delivered through the leads to the heart. The jolt resynchronizes the heart to a
normal beat. There are two forms of implantable defibrillators on the market today which treat
heart complications. The CRT-D (Cardiac Resynchronization Therapy Defibrillator) device
treats patients with heart failure and need biventricular pacing. The ICD (Implantable
Cardioverter Defibrillator) device treats patients with sudden cardiac arrest due to ventricular
fibrillation and ventricular tachycardia.
One of the main components in the defibrillator that facilitates the delivery of the therapy
is the pair of capacitors in the pulse generator device. Company XYZ designs and manufactures
the capacitors at their Minnesota campus. There are two main materials in the capacitor which
are the aluminum anode and titanium cathode foils. Both materials are rolled to the desired
thickness at Ullegheny, which is a metal rolling supplier for Company XYZ. Ullegheny uses a
Z-Mill to roll the material to the specified thickness, width, and finish. The Z-Mill is a metal
rolling machine that operates with very small diameter work rolls with high pressure to reduce
the metal material thickness with pressure and tension. Once the processing of the material has
been completed the metal is spooled on a coil and shipped to Company XYZ. Once Company
9
XYZ receives the material at the capacitor manufacturing facility, the spools of metal are utilized
in a metal stamping press to produce the anode and cathode coupons which make up the
capacitor.
With each device generation, the capacitor requirements are to be smaller and deliver the
same or better energy output as the previous generation. Therefore, the tolerances of all the
components in the pulse generator tighten with each new generation. The layers of anodes,
cathodes, and paper insulators in the capacitor are held to a very tight tolerance because the
capacitor tolerance stack up does not allow excessive variation. If there is too much material
variation and the layers stack height is too tall, the can lid will not close. If the layers are not
thick enough, usually the capacitance requirement will not be met. The titanium cathode
function in the capacitor is to hold the energy with capacitance based off the total surface area.
The current generation capacitor is called the JB2 and the cathode has an overall thickness
specification of .0009 +/- .0002” with a surface finish of 10 +/- 2 Ra.
Company XYZ’s next generation capacitor called the JB3 which is smaller in volume but
still has the same capacitance as the current JB2. To achieve this requirement the engineers at
Company XYZ increased the JB3 titanium cathode surface area without increasing the overall
thickness. Through prototype testing the optimal JB3 titanium cathode specification was
determined to have a thickness of .0009 +/- .0002” with a surface finish of 23 Ra minimum. The
increased Ra specification from the JB2 to the JB3 significantly increased the surface area which
helps achieve the capacitance requirement. The JB2 titanium cathode material with a surface
finish of 10 Ra has high sheen. The JB3 is a very dull textured surface when viewed under a
microscope.
10
In the early development of the JB3 material, there was a correlation issue of the material
thickness between Company XYZ and Ullegheny who supplied the titanium cathode material.
Ullegheny was measuring the JB3 material thickness with the same measurement device and
following the same procedure to measuring the JB2 material but Company XYZ noticed a
significant measurement shift. Ullegheny is currently using a Vollmer VMF 1000 precision
height gauge to measure the material thickness. The Vollmer device is a vertical precision
measurement system that has two .500” spheres as the contact points to measure the material
thickness. The industry standard for measuring sheet metal material thickness at sheet metal
manufactures is the Vollmer contact and X-ray measurement devices.
Company XYZ’s Corlab (Corporate Laboratory) has a Fowler THV horizontal precision
measurement system. This is the system engineers use to measure the JB3 titanium cathode in
development. It has two flat anvil .250” diameter posts that contact the material to measure the
overall thickness. The major difference between the Fowler THV and the Heidenhain CT6001 is
that the Vollmer has spheres that contact the surface and the Fowler has round flat surfaces.
With the JB2 material Company XYZ and Ullegheny didn’t have correlation issues because the
material is extremely flat and has a very smooth high sheen finish. The JB3 material has a very
high surface finish which is very dull with an orange peel effect. The orange peel effect gives
the material a slight texture which is inherent from the high finish application. The correlation
issue comes from the two different measurement methods of sphere and flat contact methods.
When measuring the JB3 titanium material with the Vollmer it measures the base material
thickness and the Fowler measures the overall thickness and accounts for the material texture.
Thus the Vollmer measurements compared to the Fowler are consistently thinner.
11
Since Company XYZ is concerned with the overall material thickness, the Vollmer in its
current configuration cannot accurately measure thickness to the specified requirement. Also,
the sphere contact points on the Vollmer measurement device are not removable, which would
have been ideal to insert flat anvils to replicate the THV measurement contact surfaces. For
Ullegheny to accurately produce the JB3 titanium cathode per Company XYZ’s requirements
they needed to implement a measurement device capable of measuring the overall thickness
specification.
Two measurement systems were identified that would be able to measure the JB3
titanium cathode material thickness accurately and with a degree of repeatability. The two
systems identified are the Heidenhain CT6001 and the Fowler THV measurement devices.
These systems were designed to measure heights to a very high resolution which would
encompass the JB3 material thickness specification callout. According to the manufacturer
specifications the three measurement devices are accurate enough to measure the JB3 material
thickness’ total tolerance of .0004”.
Statement of the Problem
The problem is the industry standard measurement devices for measuring material
thicknesses at sheet metal manufacturers do not have the accuracy to measure extremely thin,
high surface finish, and tight tolerance metals. This study will evaluate different measurement
devices and establish a technique to accurately measure the thin metal materials.
12
Purpose of the Study
The titanium cathode in the next generation JB3 capacitor at Company XYZ has a
thickness specification of .0009 +/- .0002” with a surface finish of 23 Ra minimum. Ullegheny
has the current industry standard measurement device, which is not capable of accurately
measuring the overall thickness of the JB3 titanium cathode material. The purpose of the study
is to identify a metrology device and method to measure thin metal material with extremely tight
tolerances.
Assumptions of the Study
1. The metrology equipment was calibrated to its manufactures’ standards.
2. The data was measured by an engineer that is trained on the measurement device.
3. The data is collected in an environment that was constant to limit the variables
such as temperature and humidity.
4. The devices that are to be evaluated need to be affordable for a raw material
supplier, and the method of measurement needs to be efficient for manufacturing.
5. The only contributions to measurement variation are the operator and the
measurement device.
Definition of Terms
Accuracy - The closeness of agreement between an observation value and the accepted
reference value (MSA, 2010).
Bias - The difference between the observed average of measurements (trials under
repeatability conditions) and a reference value; historically referred to as accuracy. Bias is
evaluated and expressed at a single point within the operating range of the measurement system.
This also can be systematic error favoring a particular result (MSA, 2010).
13
Calibration – A set of operations that establish, under specified conditions, the
relationship between a measuring device and a traceable standard of known reference value and
uncertainty. Calibration may also include steps to detect, correlate, report, or eliminate by
adjusting any discrepency in accuracy of the measuring device being compared (MSA, 2010).
Capability – An estimate of the combined variation of measurement errors (random and
systematic) based on short-term assessment of the measurement system (MSA, 2010).
Cathode – Electrode through which electric current flows out of a polarized electrical
device.
Control Chart – A graph of process characterstics, based on sample measurements in
time order, used to display the behavior of a process, identify patterns of process variation, assess
stability, and indicate process direction (MSA, 2010).
Data – A collection of observations under a set of conditions that may be variable (a
quantified value and unit of measure) or discrete (attribute or counted data such as Pass/Fail or
Good/Bad) (MSA, 2010).
Drift – The actual change in the measurement value when the same characteristic is
measured under the same conditions, same operator, at different points in time. Drift indicates
how often a measurement needs recalibration (MSA, 2010).
Gage Repeatability and Reproducibility – An estimate of the combined variation of
repeatability and reproducabiilty for a measurement system. The Gage R&R variance is equal to
the sum of within-system and between-system variances (MSA, 2010).
Linearity – The difference in bias errors over the expected operating range of the
measurement system. In other terms, linearity expresses the correlation of multiple and
independent bias errors over the operating range (MSA, 2010).
14
Measurement System – A collection of instruments or gages, standards, operations,
methods, fixtures, software, personnel, environment, and assumptions used to quantify a unit of
measure or fix assessment to the feature characteristic being measured; the complete process
used to obtain measurements (MSA, 2010).
Measurement System Error – The combined variation due to gage bias, repeatability,
reproducability, stability and linearity (MSA, 2010).
Metrology – The science of measurement (MSA, 2010).
Out-of-Control – State of a process when it exhibits chaotic, assignable, or special cause
variation. A process that is out of control is statistacally unstable (MSA, 2010).
Part Variation – related to measurement systems analysis, part variation represents the
expected part-to-part and time-to-time variation for a stable process (MSA, 2010).
Performance – An estimate of the combined variation of measurement errors based on a
long-term assessment of the measurement system; includes all significant and determinable
sources of variation over time (MSA, 2010).
Pp – Process Performance. A simple and straightforward indicator of process
performance (MSA, 2010).
Ppk – Process Performance Index. Adjustment of Pp for the effect of non-centered
distribution (MSA, 2010).
Precision – The net effect of discrimination, sensitivity and repeatability over the
operating range of the measurement system (MSA, 2010).
Process Control – Operational state when the purpose of measurement and decision
criteria applies to the real-time production to assess process stability and the measurement or
15
feature to the natural process variation; the measurement result indicated the process is either
stable or “in-control” or “out-of-control” (MSA, 2010).
Process Capability – compares the output of an in-control process to the specification
limits by using capability indices (MSA, 2010)
Repeatability – The common cause, random variation resulting from successive trials
under defined conditions of measurement. Often referred to as equipment variation, although
this is misleading. The best term for repeatability is within-system variation when the conditions
of the measurement are fixed and defined – fixed part, instrument, standard, method, operator,
environment, and assumptions. (MSA, 2010)
Reproducibility - The variation in the average of measurements caused by a normal
condition of change in the measurement process. Typically, it has been defined as the variation
in average measurements of the same part between different appraisers using the same measuring
instrument and method in a stable environment. This is often true for manual instruments
influenced by the skill of the operator. It is not true, however, for measurement processes where
the operator is not a major source of variation. For this reason, reproducibility is referred to as
the average variation between-systems or between-conditions of measurement (MSA, 2010).
Resolution – The capability of the measurement system to detect and faithfully indicate
even small changes of the measured characteristic.
Sensitivity – Smallest input signal that results in a detectable output signal for a
measurement device.
Specification – explicit set of requirements to be satisfied (Benbow, 2002).
Stability – Measurement stability addresses the necessary conformance to the
measurement standard or reference over the operating life of the measurement system.
16
Tolerance – Allowable deviation from a standard or nominal value that maintains fit,
form, and fuction (MSA, 2010).
Limitations of the Study
In this study, the measurement devices tested were limited to two devices that are capable
of meeting the JB3 material thickness specification. There may be more accurate measurement
devices on the market but the ones chosen to be tested in this study are industry proven devices.
The measurement devices also had to be economical because at the end of the study, Ullegheny
is to purchase and implement the optimal device and price is a concern. Also, the measurement
devices that were selected to be tested didn’t need any abnormal environmental controls.
Methodology
This study is to evaluate two different metrology devices to accurately measure the JB3
titanium cathode material per Company XYZ’s design specifications. The devices will be
analyzed with their measurement error characteristics, the cost, ease of use, and calibration
requirements. The quantitative analysis consists of performing a Gage Repeatability and
Reproducibility study, process capability analysis, and range deviation analysis of a standard
material.
17
Chapter II: Literature Review
Continuous improvement is one of the core parts of quality in manufacturing. When it
comes to metrology engineering it is a continuous battle to limit the gauge variation, which will
in turn reveal a more accurate manufacturing process capability.
Quality Costs
The benefits of quality are endless and some of the main drivers are cost savings,
throughput efficiency, yield savings, and customer satisfaction and confidence. To achieve the
most effective quality improvements, management needs to ensure the organization has an
understanding of the importance of quality and its benefits. Quality cost reports can be used to
point out the strengths and weaknesses in a quality organization. With this information
identified, it can be used as leverage to make improvements across an organization. Any
reduction in quality costs will have a direct impact on the bottom line margins and is an
important issue to an organization (Benbow, 2002).
Quality costs are a measure of the costs specifically associated with the achievement or
non-achievement of a product or service. Quality costs are broken down into four different
categories:
Prevention costs are the costs of all activities specifically designed to prevent poor
quality in products or services
Appraisal costs are the costs associated with measuring, evaluating, or auditing
products or services to assure conformance to quality standards and performance
requirements.
Failure costs are those costs resulting from products or services not conforming to
requirements or customer needs
18
Total quality costs are the sum of these costs: prevention, plus appraisal, plus failure.
It represents the different between the actual cost of a product or service and what
the reduced cost would be if there weren’t any failures of product or quality defects.
(Benbow, 2002)
Measurement Devices
The measurement device selection is the most important aspect of measurement system
analysis. The quality of the measurement system is based on the statistical properties of the data
it produces over time (MSA, 2010). Identifying the sensitivity or accuracy of the device is
important and there is a common practice to determine this requirement. The commonly known
Rule of Tens states that measurement instrument discrimination should divide the total tolerance
or process variation into ten parts or more (MSA, 2010).
Common industry standards to measure sheet metal are hand tools such as calipers,
digital micrometers, and drop indicators. In each of the hand tool categories they range from
analog to highly sophisticated digital pressure sensing devices. Depending on the device type,
some of these hand tools can be very accurate, however the inspector can introduce a lot of
variation due to the manual measurement technique. For instance, a digital micrometer is screw
driven and depending on how tight the screw is applied to a thin metal material can significantly
change the readout value. Most hand tool measurement devices are relatively cheap compared to
other fixed metrology devices. Hand tool measurements are usually very simple to use and
commonly found in the sheet metal manufacturing industry. Hand tools, such as the one
depicted in Figure 1, are used to give a quick reference to the material thickness but are known
not to be accurate enough for final verification.
19
Figure 1. Digital hand micrometer from Company XYZ’s Corlab
Coordinate Measuring Machines (CMM) are very accurate vision or touch probe
metrology machines. Usually CMMs are either user controlled or computer controlled systems.
Measurements are taken as individual points by a touch probe, optically, or with a laser. They
can be programmed manually, then operated in DCC (Direct Computer Controlled) mode which
is very repeatable and takes out the human error of interaction. There is little human interaction
besides loading the part onto a fixture or location on the machine. Once the part is loaded on the
CMM an automated program measures the part. Although a CMM, such as the one pictured in
Figure 2, would be a great way to measure the material thickness of sheet metal, they are not
commonly used because of cost and programming complexities. Also a measurement system
20
like this would be overkill because there are other measurement systems which are much smaller
and require less stringent environmental requirements.
Figure 2. Direct Computer Controlled Coordinate Measuring Machine
The industry standard for measuring the thin metal foils is precision height gauges.
These machines are very similar to a digital height indicators but are more accurate and
repeatable. Some of these devices are manually operated, where some have electronic actuators
to regulate the pressure applied to a material. Most systems come complete with a granite base,
plunger actuator, and a digital readout display. Some systems have a plunger that meets a granite
base and some have two contacts that read the material thickness between. Depending on the
application and measurement, the different contact methods need to be evaluated. The precision
21
height gauges are more expensive than the typical hand tool, but less expensive than a CMM.
Like hand tools, the precision height gauges like that shown in Figure 3 are very easy to operate
and have less stringent temperature and humidity requirements.
Figure 3. Heidenhain CT6001 precision height measurement system at Ullegheny
Measurement Process
A measurement process is a repeated application of a test method with a measurement
system. A robust test apparatus and well defined work instruction are essential. A measuring
system should be able to provide accuracy capabilities that will assure the reliability of a
measurement. (MSA, 2010)
22
Readout
Readouts consist of indicators, digital readout, and recordings to display the measurement
value. Adequate resolution is the degree to which small increments of the measured quantity can
be discriminated in the instrument output. This is one very important element to evaluate when
trying to identify a measurement system. A typical rule is one digit greater than the least
significant digit of the specification.
Error in Measurement
The difference between the indicated value and the actual value of a measurement quality
is error in measurement. Systematic errors are those not usually detected by repetition of the
measurement system. It is very important to understand all known sources of error in a
measurement system. The requirement of precision measuring devices is that it should be able to
represent, as accurately as possible, the dimension it measures. There may be small
measurement error but that is why the 10:1 rule is highly recommended when selecting a
measurement device (Benbow, 2002).
Accuracy
Accuracy is the degree of agreement about individual or group measurements with an
accepted reference or master value. “Measurement science encompasses two basic approaches
for determining conformity to measurement accuracy objectives: (1) an engineering analysis to
determine all causes of error; (2) a statistical evaluation of data after stripping or eliminating the
errors revealed by the engineering analysis” (Benbow, 2002, p. 144).
23
Precision
Precision is the degree of mutual agreement between an individual measurement made
under prescribed conditions or how well identically performed measurement agrees with each
other.
“This concept applies to a process or a set of measurements, not to a single measurement,
because in any set of measurements, the individual results will scatter about the mean.
Since the means of the results from groups of measurement tend to scatter less about the
overall mean the individual results, reference is commonly made to the precision of a
single measurement as contrasted with the precision of groups of measurements, but this
is a misuse of the term. What is really meant is the precision of a set of single
measurements or the precision of a set of groups of measurements.” (Benbow, 2002, p.
185)
Consistency
Consistency of the rading on the instrument scale when the same dimension is being
measured is necessary. This can easily be tested with any measurement device by making sure
the device is at its zeroed state. Then move the scales to its maximum extent and return it back
to the zero location. This may be repeated as needed but each time the device is returned to it’s
zero location the readout should read excactly the same each time (Benbow, 2002).
Measurement Variation
Measurement system analysis is one overlooked characteristic in many organizations.
Assumptions that a system is capable of measuring a certain feature can lead to inaccurate
analysis and conclusions when making data driven decisions. When inspectors measure a part
inconsistently they may be rejecting good parts and accepting bad parts which are a quality and
24
business risk. Inadequate measurement system performance can make the process capability
analysis less satisfactory because of the measurement variation induced, shown in Figure 4.
“Measurement system analysis assesses the statistical properties of repeatability, reproducibility,
bias, stability, and linearity. Collectively, these techniques are sometimes referred to as Gage
R&R (repeatability and reproducibility)” (Breyfogle, 1999, p. 205).
Figure 4. The relationship between total, process and measuring variation (MSA, 2010)
Bias, shown in Figure 5, is the difference between the true value and the observed
average of measurements on the same characteristic on the same part. It is a measure of the
systematic error of the measurement system and is the main concept of a Gage R&R study. “The
contribution to the total error comprised of the combined effects of all sources of variation,
known or unknown, contributes to the total error and tends to offset consistently. Predictably all
results of repeated applications are of the same measurement process at the time of the
measurements.” (MSA, 2010, p. 206)
Possible causes for induced bias are:
Instrument needs calibration
Worn instrument, equipment, or fixture
Worn or damaged master gage can lead to error in master gage
Product/Process
Variation
+
Measurement Variation
=
Observed
Variation
25
Improper calibration or use of the setting master
Poor quality instrument due to inadequate design
Linearity error
Wrong gage for the application
Different measurement method such as setup, loading, clamping, technique
Measuring the wrong characteristic
Distortion (gage or part)
Environment concerns such as temperature, humidity, vibration, cleanliness
Violation of an assumption, error in an applied constant
Application such as part size, position, operator skill, fatigue, observation error
(MSA, 2010)
Figure 5. Measurement bias (MSA, 2010)
Stability, or drift, depicted in Figure 6, is the total variation in the measurements
observed with a measurement system on the same parts when measured over an
extended period of time (MSA, 2010). Stability is one of the areas of concern when
26
measuring a feature in manufacturing. If the measurement system was drifting not the
process it can create a lot of confusion to solve the drifting process which was really the
measurement system.
Possible causes for induced bias are:
Instrument needs calibration, reduce the calibration interval
Worn instrument, equipment or fixture
Normal aging or obsolescence
Poor maintenance – air, power, hydraulic, filters, corrosion, rust, cleanliness
Distortion
Figure 6. Measurement Stability (MSA, 2010)
Linearity, as shown in Figure 7, is the difference of bias through the expected operating
range of the equipment. Linearity can be thought of as a change of bias with respect to size
(MSA, 2010). The measurement system may be accurate at measuring a small range but its
important to test the linearity by measuring the device at the maximum and minimum ranges of
the feature you’re trying to analyze.
27
Possible causes for linearity error include:
Instruments that need calibration
Worn instrument, equipment or fixture
Worn or damaged master gage or error in master gage
Distortion changes with the part size (MSA, 2010)
Figure 7. Measurement linearity (MSA, 2010)
Repeatability, demonstrated in Figure 8, refers to the variability within the appraiser. It
is also the variation in measurements obtained with one measurement instrument when used
several times by one appraiser while measuring an identical characteristic on the part. The
repeatability is within the system variability and this is analyzed with a fixed part and appraiser
(MSA, 2010).
Possible causes for poor repeatability include:
Within-part: form, position, surface finish, taper, sample consistency
Within-instrument: repair; wear, equipment or fixture failure, poor quality or
maintenance
28
Within-standard: quality, class, wear
Within-method: variation in setup, technique, zeroing, holding
Within-appraiser: technique, position, lack of experience, manipulation skill or
training, feel, fatigue
Within-environment: short-cycle, fluctuations in temperature, humidity, vibration,
lighting, cleanliness
Wrong gage for the application (MSA, 2010)
Figure 8. Measurement repeatability (MSA, 2010)
Reproducibility is referred to as the variability between the appraisers, pictured in
Figure 9. Reproducibility is typically defined as the variation in the average of the
measurements made by different appraisers using the same measurement instrument when
measuring the identical feature on the same part (MSA, 2010). For automated measurement
systems often the operator is the main source of variation.
Potential sources of reproducibility error include:
Between parts: average difference when measuring types of parts A, B, C, etc.,
using the same instrument, operators, and method.
29
Between instruments: average difference using instruments A, B, C, etc., for the
same parts, operators, and environment.
Between standards: average influence of different setting standards in the
measurement process.
Between methods: average difference caused by changing point densities, manual
versus automated systems, zeroing, holding or clamping methods.
Between appraisers: average difference between appraisers A, B, C, etc., caused
by training, technique, skill and experience.
Between environment: average difference in measurements over time 1, 2, 3 etc.,
caused by environmental cycles (MSA, 2010)
Figure 9. Measurement reproducibility (MSA, 2010)
Concept of Gage R&R Study
A Gage Repeatability and Reproducibility study is an estimate of the combined variation
of repeatability and reproducibility. This in another way is the variance equal to the sum of
within system and between system variances. A Gage R&R test can be performed to identify the
root cause of the problem in a process, and a breakdown of that data can be seen in an example
30
in Figure 10. Measurement system variation can be described by location and width or spread
variation (Benbow, 2002).
Overall Variation
Measurement
System Variation
Variation due to
Gage
REPEATABILITY
Variation due to
Operators
REPRODUCIBILITY
Operator
Operator by Part
Part-to-Part
Variation
Figure 10. Breakdown of overall variation (MSA, 2010)
The total variation for the Gage R&R study is calculated by summing the square of both
the repeatability and reproducibility (R&R) variation and the part-to-part variation and taking the
square root. The Gage R&R formula used across the industry is the ANOVA method, shown in
Figure 11. This method is a standard statistical technique and it can be used to analyze
measurement error and other sources of variability of data in a measurement system. The
analysis can be broken down into four categories parts, appraisers, interaction between
appraisers, and replication error due to the gage (MSA, 2010).
100LSLUSL
*15.5Tolerance% MS
I I
I I
I I I
I I
I I
31
Figure 11. This figure is showing the percent tolerance calculation. Note the 5.15 standard
deviations accounts for 99% of measurement system variation (MSA, 2010)
Gage R&R studies are very common in the manufacturing industry to prove whether a
measurement system is capable of measuring a specification. Typically Gage R&R studies are
performed in the early development of a component to verify they pass the specified
requirements. If the Gage R&R passes the requirements, it helps prove that the parts measured
are more representative of the manufacturing process and not due to measurement variation
introduced which could skew the values.
Process Capability, Control Charts, and Statistical Tools
The process capability or performance study is how a process is assessed in respect of the
specifications. Process capability is analyzed a few different ways and is very sensitive to the
input value for the standard deviation. Also, depending on how the data was collected, it needs
to be analyzed in a certain manner. There are ways of analyzing a process to itself, and also the
process to a given specification. Pp and Ppk outputs, shown in Figure 12, are medical device
industry standards for analyzing a process. The Pp is the process capability and the Ppk is the
process capability with respect to how centered the process is to the tolerance specification.
Figure 12. Pp and Ppk formulas. σ = stdev(Xi) (MSA, 2010)
32
Process capability is a way of analyzing a process to determine whether it is in control.
Instead of measuring each part manufactured with a statistical sample and analyzing the Pp and
Ppk, the entire lot can be accurately depicted.
Today there are many statistical tools to analyze the process capability such as software
programs like QC Cal and Minitab. These tools are used to make data driven decisions so
internal validation testing can be performed. These tools are widely used in the manufacturing
industry today to determine the process capability, which is very beneficial to the supplier and
customer. The supplier can benefit from seeing a process shift and fixing or adjusting the
process before the product goes out of control. If the product goes out of control there will be
scrapped material and time wasted. The supplier can also better predict machine wear and
preventative maintenance.
33
Chapter III: Methodology
The problem is the industry standard measurement devices for measuring material
thicknesses at sheet metal manufactures do not have the accuracy to measure extremely thin,
high surface finish, and tight tolerance metals. There will be two systems evaluated that are
benchmarked to the current Vollmer measurement system. First, a Gage R&R will be performed
on each system to prove that it’s capable of holding the necessary tolerance. Second, a capability
analysis will be performed to show the measurement shift and to see the difference between the
systems. Finally, a quantitative analysis about the measurement system’s characteristics based
on cost, ease of use, and calibration requirements. These tests will help identify the
measurement system that is needed to properly measure the JB3 titanium cathode material at
Ullegheny.
Measurement Device Selection and Descriptions
Vollmer VMF1000. The Vollmer VMF1000, which is the current thickness
measurement device at Ullegheny, has been in service over fifteen years. Even though the
device is relatively old, it still is an accurate measurement system. According to Vollmer, the
accuracy of the VMF1000 is .00001” which is accurate enough to measure the JB3 titanium
cathode thickness. (America, 2002) As stated earlier in the paper, this device is not optimal
because of the two .500” spheres it has for contact points to measure the material thickness.
These contact spheres are not able to be replaced with flat anvil contacts which are required to
accurately measure the overall material thickness.
Measuring the foil thickness is relatively easy with the Vollmer system pictured in Figure
13. The two contact spheres, shown in Figure 14, have a constant spring load to mate them. A
supplied tool is used to spread the contact points. Once the contact points are spread, a foil
34
sample can be inserted between the points and the contact points can be gently lowered to the
surface of the material. If the contact points are slammed onto the surface it can leave a dent and
also give false readings. As long as the contact points are lowered slowly onto the material
surface, the Vollmer gives very repeatable results. The measurement taken is then shown on a
digital readout display which has a resolution to .00001”. (America, 2002).
Figure 13. Vollmer VMF1000 measurement system at Ullegheny
35
Figure 14. Notice the Vollmer VMF1000 sphere contact points circled in the image
Fowler THV. The Fowler THV shown in Figure 15 is a horizontal precision
measurement system that has two flat anvil .250” in diameter posts, shown in Figure 16, that
contact the material to measure the overall thickness. This is the current thickness measuring
device at Company XYZ’s Corlab. Company XYZ chose this device for calibrating gauge
blocks, gauge pins, and measuring precision lengths. The THV is a very versatile measuring
device that is capable of measuring the JB3 titanium cathode thickness with an accuracy rating of
.000005”.
Measuring the material thickness with the THV can be somewhat complicated because of
the setup requirement. Since the contact points can be switched out to measure different
36
characteristics, the system is very versatile. A setscrew on each of the anvils holds the posts in
place, and it is essential that the setscrew is tight so posts do not move while measuring. When
measuring the JB3 titanium cathode the .250” diameter flat anvil posts must be used. Since there
are two contact surfaces meeting each other, the calibration of how the two surfaces meet up is
very critical to the accuracy of the machine. The calibration company inscribes lines on the
posts which need to perfectly line up when setting up the machine.
Once the machine is set up, the force of the contact points can be adjusted. It has been
determined that ten foot pounds of force is necessary. To open and shut the contact surfaces a
round wheel is simply turned and a piece of material can be inserted between the surfaces. The
measurement taken is then shown on a digital readout display which has a resolution to .000010”
(Fowler, 2011).
37
Figure 15. Fowler THV measurement system at Company XYZ’s Corlab
Figure 16. The Fowler THV’s two .250” diameter flat anvil contact surfaces
Heidenhain CT600. The Heidenhain CT6001 pictured in Figure 17 is a precision length
gauge that uses a plunger actuator in the vertical direction that contacts a granite surface, shown
in Figure 18. This system is very similar to the THV but instead of being horizontal it is a
vertical measurement system. The Heidenhain CT6001 was chosen to be in this study because it
was recommended by Company XYZ’s calibration company as an alternative to the THV
system. The Heidenhain can also be used for calibrating gauge blocks, gauge pins, and
measuring precision heights. The Heidenhain CT6001 has an accuracy of .000004” which is
very capable of measuring the JB3 titanium material thickness specification.
The Heidenhain has the versatility of changing out the contact points but it is very simple
because the anvils are threaded. When measuring the JB3 titanium cathode material thickness
38
the .250” flat anvil must be utilized. The controller is used to raise and lower the plunger
actuator and it needs to be set at the ten foot pounds of force mode. To measure the foil, simply
place the foil on the granite surface and using the controller lower the anvil until it contacts the
material. The measurement taken is then shown on a digital readout display which has a
resolution to .00001” (Heidenhain, 2011).
Figure 17. The Heidenhain CT6001 measurement system at Ullegheny
39
Figure 18. The Heidenhain .250” diameter flat anvil utilized to measure the JB3 titanium cathode
material thickness.
Titanium Cathode Subject Selection and Description
The titanium foil samples that were selected for the Gage R&R and the capability study
were of grade two titanium of different thicknesses. The ten Gage R&R samples needed to
represent normal process variation and also have passing and failing parts. The samples ranged
from .0006” to .0014” in thickness to span the entire tolerance band and outside the tolerance
band to ensure the measurement system can accurately depict the thickness. The surface finishes
for all the samples were 30 Ra minimum, which is representative of the production JB3 titanium
cathode material. The thirty samples for the capability study were the best effort JB3 titanium
cathode material produced by Ullegheny. Ullegheny cannot define the manufacturing rolling
process until a measurement system is identified and implemented. Once the manufacturing
rolling process is set, Ullegheny will be able to produce production equivalent material. All of
40
the titanium cathode samples will be of the production width which is 1.000” and cut to a length
of 4.000”.
Gage Reproducibility and Repeatability Test Description
The gage reproducibility and repeatability test was performed per Company XYZ’s
internal procedure, which complied with ISO 13485 and the FDA regulations. The Gage R&R
test was performed on the Heidenhain CT6001, Vollmer VMF1000, and the Fowler THV
measurement systems. There were ten separate titanium cathode strips, measured by three
operators (A, B, and C). Each operator measured each sample three separate times in a blind
study. A blind sequence means the operator does know what the part number being sampled but
the instructor viewing the Gage R&R does. The operators were trained at the same time with the
same procedure.
Capability Study Description
The capability study was performed after the chosen measurement system was
implemented at Ullegheny to show the difference in measurement shift with variation induced.
Thirty samples were measured to show the process capability of Ullegheny’s Z-Mill
manufacturing equipment.
41
Gage R&R and Capability Study Data Analysis
For both the Gage R&R test and the capability study, MINITAB Version 15 statistical
software will be used to evaluate the data. Minitab is a statistical analysis software that has been
validated by Company XYZ. The analysis of this software will help make the recommendations
for the measurement system through data driven decisions.
Gage R&R Data Analysis. Per Company XYZ’s variable Gage R&R procedure, the
raw data measured by the three operators will be analyzed in Minitab. The Gage R&R
(ANOVA) Crossed function in the Minitab software is the Company XYZ specified analysis
tool. The crossed formula assumes that the master samples can be selected such that each
operator can measure multiple parts from each master sample. Once the analysis has been
performed, the results will appear in the Minitab session window. The value that needs to be
reviewed is the Total Gage R&R percent tolerance (Study Variation/Tolerance). This value per
Company XYZ’s standard procedure needs to be lower than 30%, and the lower the value the
less measurement variation will be induced. Refer to Figure 11 for the Gage R&R percent
tolerance formula to be used.
Capability Study Data Analysis. The process capability analysis will be calculated in
Minitab using the Process Capability Sixpack function. This function looks at the raw data
provided and the upper specification and lower specification limits. The output results to be
analyzed are the Pp value and the normality per Company XYZ’s procedure. Per Company
XYZ’s process capability procedure, the Pp needs to exceed 1.00 and the Anderson Darling
normality needs to be above .05. If the normality is under .05 it means the data set isn’t a normal
distribution. Refer to Figure 12 for the formula to calculate Pp. Pp is being analyzed and not
Ppk, because Ppk is the process capability with respect to the specification limits. Since one
42
manufacturing lot will be evaluated with the measurement systems, there would be bias if a Ppk
was evaluated. The Pp analyzes the process capability with respect to the tolerance range. If
Ullegheny can hold a tight distribution, it will be simple to move the mean to the specification.
Also being evaluated is the range deviation to show how much deviation is present in the
measurement systems over fifteen samples. For the capability study evaluation, fifteen samples
from one manufacturing lot will be evaluated, and the measurements for all three systems will be
taken from the same location on the titanium coupon to eliminate variation between systems.
Table 1 Statistical Analysis Studies – Gage R&R and Capability Study
Total Gage R&R Value
Needs to be under 30%
Rankin
g
Capability Study Range Deviation -
Inches
Rankin
g
Capability Study Ppk Value - Normality
Pass/Fail
Rankin
g
Overall Ranking
for Statistical Testing
Vollmer
Fowler THV
Heidenhain
Quantitative Analysis of the Measurement System
A quantitative analysis is necessary for this study and is based on the measurement
system cost, ease of use, setup requirements, and calibration requirement. Ullegheny is very
sensitive to the measurement system cost because they have already invested in the Vollmer, so
implementing another device needs to be cost effective. In addition, the measurement system
that will be utilized will need to be as easy as the Vollmer or easier because of time constraints,
and it cannot require a special technician to operate the device. The setup of the Vollmer system
43
is very simple so the new system implemented will need to have a fast setup. The calibration
requirements for the next system need to have a semi-annual or annual expiration, which would
correlate with the rest of Ullegheny’s measurement equipment.
Table 2 Quantitative Analysis of the Measurement System
Measurement System
Cost
Rankin
g
Setup Requirements Rating 1-10 (1 being the
easiest)
Rankin
g
Inspection Difficulty Rating 1-
10 (1 being
the easiest)
Rankin
g
Calibration Requirements Rating 1-10 (1 being the
same as Ullegheny's
current system, 10 being on a different
calibration schedule)
Rankin
g
Overall Ranking for
the quantitative
analysis
Vollmer
Fowler THV
Heidenhain
Limitations
The measurement systems evaluated are limited to two systems besides the Vollmer
currently being utilized by Ullegheny. In an ideal world, hundreds of systems could be evaluated
but it is not practical for this study. The two best systems that met the cost and accuracy
requirements were chosen. The samples being measured by the operators are under strict
conditions of not using bias or coaching to drive the results. The limitations of the statistical
analysis were per Company XYZ’s procedure and only the Minitab software was utilized.
44
Chapter IV: Results
The purpose of this study was to identify a measurement system to accurately measure
the next generation JB3 titanium cathode thickness at Ullegheny. Two measurement systems
were identified to be evaluated in the study, as well as the current Vollmer which is utilized to
measure the current generation JB3 titanium cathode material thickness. A statistical analysis
consisting of a Gage R&R, capability study, and a capability range deviation analysis was
performed. In conjunction with the statistical analysis, a quantitative analysis was performed on
each of the systems to see how the different key aspects compare to each other.
Statistical Analysis: Gage R&R and Capability Study
The Gage R&R and capability studies were performed on the Heidenhain, Vollmer, and
Fowler THV measurement devices with the trained individuals. The two systems that were to be
evaluated for implementation at Ullegheny were the Fowler THV and the Heidenhain systems.
The Vollmer measurement device was included to benchmark against the two systems to be
evaluated for implementation. Both systems passed the Gage R&R test with total percent
tolerances below thirty, but the THV was very close to the specification limits. The Heidenhain
had better reproducibility and repeatability values than the THV, but only by four percent, which
in percent tolerance variation is a very close deviation. The Gage R&R results were higher than
anticipated.
45
Table 3 Statistical Analysis Studies – Gage R&R and Capability Study Results
Measurement System
Cost
Rankin
g
Setup Requirements Rating 1-10 (1
being the easiest)
Rankin
g
Inspection Difficulty
Rating 1-10 (1 being the
easiest)
Rankin
g
Calibration Requirements Rating 1-10 (1 being the same as Ullegheny's current system, 10 being on a
different calibration schedule)
Rankin
g
Overall Ranking for
the quantitative
analysis
Vollmer $33,000 3 2 1 2 1 1 1 1
Fowler THV $22,000 2 6 2 4 2 1 1 1
Heidenhain $12,000 1 8 3 7 3 1 1 1
The capability study measurements exemplified in Figure 19 were taken from fifteen
samples from one manufacturing lot. The two systems evaluated and the benchmark
measurement system measured from the same location to eliminate variation and to see the
difference in the range deviation between the systems, shown in the graph in Figure 20. The
Heidenhain had the least range deviation with .00003”, .00005” with the Vollmer, and finally
.000051” with the THV. The range deviations proved to show a high capability with all the
systems but once again, the measurements were taken from one manufacturing lot so there was
no thickness or surface roughness variation introduced. All three systems surpassed the Pp
requirement of 1.0 with the systems having extremely high values. When Pp values are in the
range of 3.58-5.95 for all three systems it is showing an extremely high process capability
without respect to the specification mean value.
46
Figure 19. Capability study for the three measurement devices evaluated
Figure 20. Capability study deviation chart for each of the measurement systems.
47
The statistical analysis testing proved the Heidenhain and THV systems were acceptable
systems to implement at Ullegheny by passing Company XYZ’s requirements. The Heidenhain
had virtually the same results than the THV measurement system for the capability range
analysis with .000050” and .000051” respectively. The Vollmer system failed the Gage R&R
with 37.45% total variation and thus the reason for implementing a more accurate measurement
device at Ullegheny.
Quantitative Analysis of the Measurement System Results
A quantitative analysis was performed on each of the systems based on the measurement
system cost, setup requirements, inspection difficulty, and calibration requirements. Since
Ullegheny already had the Vollmer measurement system in service, which was a costly device to
begin with and has semi-annual calibrations, another measurement system cannot be
overburdening.
Table 4 Quantitative Analysis Results of the Measurement Systems
Measurement System
Cost
Rankin
g
Setup Requirements Rating 1-10 (1 being the
easiest)
Rankin
g
Inspection Difficulty
Rating 1-10 (1 being the
easiest)
Rankin
g
Calibration Requirements Rating 1-10 (1
being the same as Ullegheny's
current system, 10 being on a different
calibration schedule)
Rankin
g
Overall Ranking for
the quantitative
analysis
Vollmer $33,000 3 2 1 2 1 1 1 1
Fowler THV $22,000 2 6 2 4 2 1 1 1
Heidenhain $12,000 1 8 3 7 3 1 1 1
48
Measurement System Cost. The benchmark for the cost comparison was the Vollmer
VMF 1000 measurement system at Ullegheny. The Vollmer VMF 1000 system is $43,000 and
comes with a digital readout and the measurement device, which are separate from one another.
The Vollmer system is rather expensive compared to the THV and Heidenhain systems, but in
the precision measurement industry it’s priced fairly. Even though Ullegheny has had this
system in operation for roughly fifteen years, Vollmer still makes this system and it is readily
available (America, 2002).
The Fowler THV system retails for $22,600 and comes with a Heidenhain digital readout
display and the measurement system. The machine is very versatile so different contact tips are
also included in the price of the system. The specified contact surfaces, which are the dual .250”
diameter flat anvil posts were supplied with the measurement system for the quoted price. The
THV system lead time is roughly six to eight weeks because the manufacture builds them to suit
the customer needs (Fowler, 2011).
The Heidenhain CT6001 measurement system is the cheapest and most accurate out of
the three systems evaluated. The complete system cost is $11,500 which includes the digital
readout, CT6001 length gauge, granite table with post, switch box, and anvil tip. The price of
this system is rather a bargain in the metrology industry but the Heidenhain is limited to only
measuring lengths, compared to the THV which can measure an assortment of features
(Heidenhain, 2011).
49
Setup Requirements. The setup requirements were based upon starting the machine up
from its powered off state to being ready to measure samples of the JB3 titanium cathode
material thickness. This is a very important aspect because each time Ullegheny manufactures
the JB3 titanium; a quality technician will need to prepare the measurement device.
The Vollmer system was by far the easiest of the three systems to get from its powered
down state to being ready to measure. Simply turn the machine on and take a lint free cloth and
slide it under the contact points. Once the contact points are clear of any debris the machine can
be set to zero and it is ready to measure. The Vollmer system is very popular with the quality
and manufacturing technicians as it is easy to operate.
Ranking second out of the three machines was the Fowler THV system. The THV setup
was pretty straight forward from turning on the digital readout, inserting the .250” cylindrical
posts, cleaning the anvils, and then zeroing the machine. Since the anvil contact posts are
removable in the THV the flatness between the contact surfaces are extremely important. In the
calibration process lines are inscribed on the anvil posts because they need to be lined up when
setting up the machine. In the setup process, when the posts are inserted into the machine it is
critical the lines match up or the contact surfaces won’t be flat to each other as the calibration
company intended. A setscrew holds the anvil posts into the machine, and if the post is not fully
seated or the screws are not tight the anvil posts can slip while taking measurements. The setup
process can be somewhat tedious to make sure everything is lined up and tightened to ensure the
system will be accurate.
The Heidenhain setup process is very similar to the other systems evaluated in this study.
The digital readout needs to be powered on, granite and .250” diameter anvil surface cleaned,
and the plunger actuator lowered to the granite surface to be set at zero. The .250” diameter
50
anvil is threaded into the plunger actuator post so it is important this is tightened before setting
the machine to zero.
Inspection Difficulty. The Vollmer system was very easy to use by simply spreading the
contact points and inserting the titanium cathode material. The biggest complaint for the
Vollmer system was if the user would open the contact points and release them too fast, the
points would slam together and give a false readout. Since the Vollmer has contact points and
not surfaces like the other two systems, when the points are slammed they penetrate into the
material. It is very apparent when a user has slammed the anvils into the material because the
value can be off significantly. When operating this system, if the user is gentle and measuring
with care, the false readout issue isn’t systemic. This system is able to take measurements very
quick with high confidence. It is recommended to clean the contact points if the machine doesn’t
come back to the zero location after measuring a few samples.
The THV system proved to be almost as simple as the Vollmer to use. To measure a
sample the round wheel on the THV is turned to open the anvils, and then the wheel can be
rotated the opposite direction to close the anvils onto the material. Like the Vollmer system, the
THV anvils can be slammed into one another if the user isn’t taking care. Since there are two
.250” diameter anvils with the THV, the surfaces don’t penetrate the titanium material but can
compress it slightly. Since it’s not as apparent in the readout between a sample that had been
slammed or not slammed, this is a concern. The users were instructed to carefully bring the
contact surfaces to the titanium and thus the Gage R&R values were acceptable. The THV can
measure samples quickly but cleaning the anvils is essential. To clean the anvils a lint free tissue
is inserted between the anvils and the contacts surfaces are released to compress the tissue. Then
the tissue is to be pulled out. Since the JB43 titanium cathode material is very rough, the peaks
51
of the material break off and can stick to the anvils. If the surface particulates build up from not
being cleaned it will give false readings.
The Heidenhain measurement system was well received by the users in the Gage R&R
and capability study. The controller used to raise and lower the plunger actuator and needs to be
set at the ten foot pounds of force mode. To measure a sample, place the titanium on the granite
surface and, using the controller, lower the anvil until it contacts the material. Just like the THV
system, the anvil and granite need to be cleaned after each sample is measured to remove surface
particulates on the anvil. Particulate buildup was an issue in preliminary testing but solved with
the cleaning step prior to each measurement. The Heidenhain was more sensitive than the THV
with the particulate buildup, but since the machine is slightly more accurate, this may be why.
Particulate buildup can slow the measurement process up by cleaning the anvil each time, but it
is essential for accurate measurements.
Calibration Requirements
The Heidenhain, Fowler THV, and Vollmer measurement systems are to be calibrated
on a semi-annual basis. The calibration company that currently calibrates the Vollmer
measurement system at Ullegheny is able to calibrate the Heidenhain and THV system. The
calibration is very similar for the three systems so it will not be overburdening to implement the
THV or Heidenhain system. Calibrations typically take two-to-three hours depending on how
much time the technician needs to spend tweaking the device.
Overall Ranking for the Quantitative Analysis
The Vollmer was a great benchmarking system to the Fowler THV and Heidenhain
systems to baseline what Ullegheny is currently using to what they will be using to measure the
JB3 titanium cathode material thickness. In every aspect, the Vollmer was an easier device to
52
use, but not as accurate as the THV or Heidenhain systems. The THV and Heidenhain were very
similar with the setup and measurement ease of use but the Heidenhain was more sensitive to
surface particulate buildup.
53
Chapter V: Discussion
Company XYZ is an industry leader of producing human implantable defibrillators. The
most important components of the defibrillator are the capacitors. The capacitors are charged via
the power supply from the battery and then a jolt is delivered through the leads to the heart. The
materials that make up the capacitor are the paper insulators, anodes, and cathodes. The next
generation defibrillator at Company XYZ needs to be smaller in volume than the current
generation but deliver the same amount of energy. The next generation capacitor is called the
JB3 and this research paper focuses on the titanium cathode material.
Ullegheny is a titanium metal rolling supplier for Company XYZ and makes the current
JB3 titanium cathode material. The challenge with the JB3 compared to the JB2 titanium
cathode is the roughened titanium material. The overall material thickness of .0009 +/- .0002” is
the same on both materials but their surface finish requirement is dramatically different. The
JB2 has a surface finish of 10 +/- 2 Ra and the JB3 has a 23 Ra minimum. The JB2 material has
a very smooth high finish where the JB3 is a rough textured material. Since the JB3 capacitor
has less volume than the JB2 material, the added material surface roughness is how Company
XYZ is increasing the surface area.
The measurement specification required measuring the overall material thickness, and the
current JB2 method of measurement did not translate well to the JB3 material. Ullegheny uses a
Vollmer measurement system to measure the JB2 titanium cathode material and the anvil tips are
spherical shaped. With a very smooth surface finish the spherical shaped anvils can accurately
measure the material thickness. When the Vollmer attempted to measure the JB3 titanium
cathode, it could not capture the overall material thickness because it measures a point and not a
specific area. This prompted the research study to find a measurement device that could measure
54
the overall JB3 titanium cathode material thickness and pass the Company XYZ evaluation
requirements.
The two measurement devices evaluated were the Heidenhain CT6001 and the Fowler
THV. These systems were chosen because they are standard measurement devices in the
medical device industry. The study was to evaluate both devices and select one to be
implemented at Ullegheny to measure the JB3 Company XYZ titanium cathode material
thickness. A statistical analysis and quantitative analysis were performed on the system with a
comparison to the baseline Vollmer VMF1000, which currently measures the JB2 material
thickness.
Measurement Device Selection
The Heidenhain CT6001 device was chosen to be implemented at Ullegheny to measure
the JB3 titanium cathode thickness. The Heidenhain had better statistical evaluation results,
which were the most important area to be evaluated in this study. The Gage R&R yielded a total
percent tolerance value at 25.5%, where the Company XYZ specification maximum was 30%.
The THV’s Gage R&R value was extremely close to the 30% limit and this was a concern. Also,
the Heidenhain’s capability study proved to have less range deviation than the THV. The Pp
value from the Heidenhain was a very tight distribution while the THV was not as concentrated.
One of the key advantages of the Heidenhain system when compared to the THV is cost.
The Heidenhain was over ten thousand dollars cheaper while being more accurate. Although the
THV is a more versatile measurement device Ullegheny’s plans are to only use the implemented
measurement device to measure the JB3 titanium cathode material thickness. The setup and
inspection difficulties are very similar between both the systems, with the Heidenhain needing
more setup time. Since the Heidenhain device is more accurate, it’s understandable that the
55
setup and inspection technique can be cumbersome at times. Since the Vollmer system is very
easy to use it will be only a slight change for the Ullegheny technicians to start using the
Heidenhain measurement system.
With the medical device industry pushing for smaller and less invasive devices, quality
constraints for suppliers will continue to increase. Suppliers such as Ullegheny will have to
accept that it may be more time consuming using the Heidenhain measurement system compared
to the Vollmer, but the accuracy results are a priority. With material tolerances tightening with
each product generation the statistical quality requirements still need to be met.
Limitations
In this study, the measurement devices tested were limited to two devices that are capable
of meeting the JB3 material thickness specification. There may be more accurate measurement
devices on the market but the ones chosen to be tested in this study are industry proven devices.
The measurement devices also had to be economical because at the end of the study, Ullegheny
was to purchase and implement the optimal device and price is a concern. Also the measurement
devices that were selected to be tested didn’t need any abnormal environmental controls because
Ullegheny’s quality lab only meets ISO 9001 requirements.
Conclusions
This study was very beneficial for Company XYZ because development on the JB3
titanium cathode was halted until a measurement device that could be implemented at Ullegheny
to measure the material thickness. Prior to the study, without having an accurate measurement
device and procedure to measure the JB3 material thickness, there was no reason to move ahead
with the development. Once the Heidenhain measurement system was implemented at
56
Ullegheny, the manufacturing and processing improved, to provide JB3 titanium cathode
material to Company XYZ.
57
References
America, V. (2002). VMF brochure . Retrieved from Vollmer America:
www.vollmeramerica.com
Benbow, D. W. (2002). The certified quality engineer handbook. Milwaukee: American Society
for Quality.
Breyfogle, F. W. (1999). Implementing six sigma. Austin, TX: Wiley-Interscience Publication.
Fowler. (2011). Fowler/Trimos THV System. Retrieved from Fowler:
http://www.fvfowler.com/thv.html
Heidenhain. (2011). Heidenhain encoders CT6001. Retrieved from Heidenhain Encoders:
http://www.heidenhainencoders.co.uk/heidenhain-ct6001-60mmmeasuringrange_74
MSA. (2010). Measurement systems analysis reference manual, 4th Ed.,. Chrysler Corp., Ford
Motor Corp., General Motors Corp.,.
58
Appendix A: Capability Study Raw and Analysis Data
CAPABILITY STUDY OF THE DEVICES
Equipment Used: THV Pressure Micrometer
Settings: .28 Ft/Lb Applied, .250 Flat Diameter Anvil
Location: BSC Qual Lab
.0009 +/- .002"
Sample NumberFowler THV Measurement Data
1 0.001009
2 0.001006
3 0.001005
4 0.001010
5 0.001051
6 0.001048
7 0.001056
8 0.001056
9 0.001042
10 0.001043
11 0.001049
12 0.001046
13 0.001034
14 0.001032
15 0.001026
Min 0.001005
Max 0.001056
Avg 0.001034
Range 0.000051
Heidenhain Measurement Data
1 0.00096
2 0.00096
3 0.00099
4 0.00097
5 0.00098
6 0.00099
7 0.00097
8 0.00098
9 0.00097
10 0.00098
11 0.00097
12 0.00099
13 0.00096
14 0.00098
15 0.00099
Min 0.000960
Max 0.000990
Avg 0.000976
Range 0.000030
Vollmer Measurement Data
1 0.00084
2 0.00087
3 0.00086
4 0.00086
5 0.00087
6 0.00089
7 0.00086
8 0.00087
9 0.00085
10 0.00086
11 0.00089
12 0.00085
13 0.00084
14 0.00088
15 0.00087
Min 0.000840
Max 0.000890
Avg 0.000864
Range 0.000050
Vollm
er
Pre
cis
ion S
uper
Mic
rom
ete
r
Accura
cy:
???
Alle
gheny's
Measure
ment
Gauge
TH
V S
uper
Mic
rom
ete
r
Accura
cy:
.000020"
Heid
enhain
Pre
cis
ion L
ength
Gauge
Accura
cy:
.000002"
59
151413121110987654321
0.00090
0.00085
0.00080
In
div
idu
al V
alu
e
_X=0.000864
UCL=0.0009153
LCL=0.0008127
151413121110987654321
0.000050
0.000025
0.000000
Mo
vin
g R
an
ge
__MR=0.00001929
UCL=0.00006301
LCL=0
15105
0.00088
0.00086
0.00084
Observation
Va
lue
s
0.00
108
0.0010
2
0.00
096
0.00
090
0.00
084
0.0007
8
0.00
072
LSL USL
LSL 0.0007
USL 0.0011
Specifications
0.000920.000880.000840.00080
Within
Overall
Specs
StDev 1.70973e-005
C p 3.9
C pk 3.2
Within
StDev 1.54919e-005
Pp 4.3
Ppk 3.53
C pm *
O v erall
Process Capability Sixpack of Vollmer Measurement Data
I Chart
Moving Range Chart
Last 15 Observations
Capability Histogram
Normal Prob PlotA D: 0.366, P: 0.387
Capability Plot
151413121110987654321
0.001000
0.000975
0.000950
In
div
idu
al V
alu
e
_X=0.000976
UCL=0.00101589
LCL=0.00093611
151413121110987654321
0.00004
0.00002
0.00000
Mo
vin
g R
an
ge
__MR=0.000015
UCL=0.00004901
LCL=0
15105
0.000990
0.000975
0.000960
Observation
Va
lue
s
0.00
108
0.0010
2
0.00
096
0.00
090
0.00
084
0.0007
8
0.00
072
LSL USL
LSL 0.0007
USL 0.0011
Specifications
0.001000.000980.000960.00094
Within
Overall
Specs
StDev 1.32979e-005
C p 5.01
C pk 3.11
Within
StDev 1.12122e-005
Pp 5.95
Ppk 3.69
C pm *
O v erall
Process Capability Sixpack of Heidenhain Measurement Data
I Chart
Moving Range Chart
Last 15 Observations
Capability Histogram
Normal Prob PlotA D: 0.671, P: 0.063
Capability Plot
1~=~:~1 1. >z7t061
• • • • • • • • • • • • • • •
~~~::::=:::1 1. t;;:;~ : : ::::1 l .. · · ~ · ··· ~ · · .· ]
I! Jl ID i '
}---}---} --t-~ - i I I I ---'1"-- t"- . I I ---1-
1 I
I! l iD I I I M M I I I I I e I I --r--r--T--,.- - , · r --r-1 I I I I I
. -t- - t- - t' - ~ - -1- --t- -- .... --I I I I
.-- I - I +- :--+--L R ft R f
CJ:
60
151413121110987654321
0.00104
0.00102
0.00100
In
div
idu
al V
alu
e
_X=0.0010342
UCL=0.00105415
LCL=0.00101425
151413121110987654321
0.00004
0.00002
0.00000
Mo
vin
g R
an
ge
__MR=0.0000075
UCL=0.00002450
LCL=0
15105
0.00104
0.00102
0.00100
Observation
Va
lue
s
0.00
108
0.0010
2
0.00
096
0.00
090
0.00
084
0.0007
8
0.00
072
LSL USL
LSL 0.0007
USL 0.0011
Specifications
0.001100.001050.00100
Within
Overall
Specs
StDev 6.64894e-006
C p 10.03
C pk 3.3
Within
StDev 1.86325e-005
Pp 3.58
Ppk 1.18
C pm *
O v erall
11
111
1
1
Process Capability Sixpack of Fowler THV Measurement Data
I Chart
Moving Range Chart
Last 15 Observations
Capability Histogram
Normal Prob PlotA D: 0.711, P: 0.050
Capability Plot
('"'?':~ ~
L .... .. · ·. · · · ·I I I I
I! _l iD ' I I I --r ---1----T
I
~~~ ~----~----r - L ___ .J ___ L
. I I
"
61
Appendix B: Gage R&R Raw and Analysis Data
Part
Fowler THV
Brian Trial
1
Fowler THV
Brian Trial
2
Fowler THV
Brian Trial
3
Fowler THV
Tom Trial
1
Fowler THV
Tom Trial
2
Fowler THV
Tom Trial
3
Fowler THV
Tony Trial
1
Fowler THV
Tony Trial
2
Fowler THV
Tony Trial
3 Deviation
1 0.00064 0.00065 0.00062 0.00063 0.00063 0.00065 0.00063 0.00066 0.00066 0.00004
2 0.00098 0.00094 0.00094 0.00093 0.00097 0.00093 0.00096 0.00097 0.00092 0.00006
3 0.00076 0.00065 0.00067 0.00066 0.00062 0.00064 0.00066 0.00068 0.00063 0.00014
4 0.00133 0.00135 0.00136 0.00132 0.00134 0.00135 0.00134 0.00134 0.00136 0.00004
5 0.00127 0.00131 0.00127 0.00130 0.00130 0.00130 0.00130 0.00127 0.00128 0.00004
6 0.00136 0.00133 0.00138 0.00137 0.00138 0.00136 0.00134 0.00135 0.00132 0.00006
7 0.00133 0.00136 0.00135 0.00133 0.00135 0.00132 0.00131 0.00131 0.00135 0.00005
8 0.00096 0.00095 0.00096 0.00094 0.00092 0.00093 0.00097 0.00095 0.00093 0.00005
9 0.00097 0.00097 0.00098 0.00095 0.00095 0.00095 0.00104 0.00094 0.00100 0.00010
10 0.00090 0.00093 0.00088 0.00088 0.00087 0.00090 0.00086 0.00091 0.00089 0.00007
Fowler THV Gage R&R Raw Data
Part-to-PartReprodRepeatGage R&R
400
200
0
Perc
ent
% Contribution
% Study Var
% Tolerance
0.00010
0.00005
0.00000
Sam
ple
Range
_R=0.0000357
UCL=0.0000918
LCL=0
Brian Tom Tony
0.0012
0.0009
0.0006
Sam
ple
Mean
__X=0.0010383UCL=0.0010748LCL=0.0010018
Brian Tom Tony
10987654321
0.0012
0.0009
0.0006
Parts
TonyTomBrian
0.0012
0.0009
0.0006
Operators
10 9 8 7 6 5 4 3 2 1
0.0012
0.0009
0.0006
Parts
Avera
ge
Brian
Tom
Tony
Operators
Gage name:
Date of study : 11/1/2011
Reported by : Brian Koty k
Tolerance:
Misc:
Components of Variation
R Chart by Operators
Xbar Chart by Operators
Results by Parts
Results by Operators
Operators * Parts Interaction
THV Gage R&R .0009 +/- .0002" Ti Cathode Thickness
Welcome to Minitab, press F1 for help.
Gage R&R for Results
Gage R&R Study - ANOVA Method Gage R&R for Results
62
Gage name:
Date of study: 11/1/2011
Reported by: Brian Kotyk
Tolerance:
Misc:
Two-Way ANOVA Table With Interaction Source DF SS MS F P
Parts 9 0.0000062 0.0000007 1175.13 0.000
Operators 2 0.0000000 0.0000000 2.08 0.154
Parts * Operators 18 0.0000000 0.0000000 1.18 0.308
Repeatability 60 0.0000000 0.0000000
Total 89 0.0000062
Alpha to remove interaction term = 0.25
Two-Way ANOVA Table Without Interaction Source DF SS MS F P
Parts 9 0.0000062 0.0000007 1329.70 0.000
Operators 2 0.0000000 0.0000000 2.36 0.101
Repeatability 78 0.0000000 0.0000000
Total 89 0.0000062
Gage R&R %Contribution
Source VarComp (of VarComp)
Total Gage R&R 0.0000000 0.70
Repeatability 0.0000000 0.67
Reproducibility 0.0000000 0.03
Operators 0.0000000 0.03
Part-To-Part 0.0000001 99.30
Total Variation 0.0000001 100.00
Process tolerance = 0.0004
Study Var %Study Var %Tolerance
Source StdDev (SD) (5.15 * SD) (%SV) (SV/Toler)
Total Gage R&R 0.0000232 0.0001195 8.38 29.86
Repeatability 0.0000227 0.0001168 8.20 29.21
Reproducibility 0.0000048 0.0000249 1.74 6.21
Operators 0.0000048 0.0000249 1.74 6.21
Part-To-Part 0.0002757 0.0014197 99.65 354.93
Total Variation 0.0002766 0.0014247 100.00 356.18
Number of Distinct Categories = 16
Gage R&R for Results
______________________________________________________________________________
63
Part
Heidenhain
Brian Trial
1
Heidenhain
Brian Trial
2
Heidenhain
Brian Trial
3
Heidenhain
Tom Trial
1
Heidenhain
Tom Trial
2
Heidenhain
Tom Trial
3
Heidenhain
Tony Trial
1
Heidenhain
Tony Trial
2
Heidenhain
Tony Trial
3 Deviation
1 0.00068 0.00069 0.00068 0.00069 0.00069 0.00068 0.00070 0.00069 0.00070 0.00002
2 0.00102 0.00100 0.00100 0.00099 0.00100 0.00100 0.00099 0.00101 0.00099 0.00003
3 0.00082 0.00071 0.00073 0.00069 0.00069 0.00067 0.00070 0.00072 0.00070 0.00015
4 0.00139 0.00141 0.00139 0.00139 0.00137 0.00139 0.00138 0.00138 0.00139 0.00004
5 0.00133 0.00134 0.00134 0.00133 0.00134 0.00134 0.00134 0.00133 0.00132 0.00002
6 0.00139 0.00140 0.00141 0.00141 0.00142 0.00140 0.00140 0.00141 0.00139 0.00003
7 0.00140 0.00139 0.00139 0.00137 0.00139 0.00138 0.00137 0.00137 0.00138 0.00003
8 0.00099 0.00099 0.00100 0.00098 0.00098 0.00099 0.00103 0.00098 0.00097 0.00006
9 0.00101 0.00101 0.00102 0.00101 0.00101 0.00101 0.00107 0.00101 0.00107 0.00006
10 0.00094 0.00097 0.00094 0.00094 0.00093 0.00093 0.00093 0.00094 0.00095 0.00004
Heidenhain Gage R&R Raw Data
Part-to-PartReprodRepeatGage R&R
400
200
0
Perc
ent
% Contribution
% Study Var
% Tolerance
0.00010
0.00005
0.00000
Sam
ple
Range
_R=0.000021
UCL=0.0000541
LCL=0
Brian Tom Tony
0.0012
0.0009
0.0006
Sam
ple
Mean
__X=0.0010867UCL=0.0011082LCL=0.0010652
Brian Tom Tony
10987654321
0.0012
0.0009
0.0006
Parts
TonyTomBrian
0.0012
0.0009
0.0006
Operators
10 9 8 7 6 5 4 3 2 1
0.0012
0.0009
0.0006
Parts
Avera
ge
Brian
Tom
Tony
Operators
Gage name:
Date of study :
Reported by :
Tolerance:
Misc:
Components of Variation
R Chart by Operators
Xbar Chart by Operators
Results by Parts
Results by Operators
Operators * Parts Interaction
Heidenhain Gage R&R Study for .0009 +/- .002" Ti Cathode
Welcome to Minitab, press F1 for help.
Retrieving project from file: 'C:\DOCUMENTS AND
SETTINGS\G044904\DESKTOP\MEASUREMENT SYSTEM SELECTION\GRR TEST
DATA\HEIDENHAIN GRR TEST.MPJ'
Gage R&R Study - ANOVA Method
Two-Way ANOVA Table With Interaction Source DF SS MS F P
Parts 9 0.0000061 0.0000007 1144.53 0.000
Operators 2 0.0000000 0.0000000 1.93 0.174
Parts * Operators 18 0.0000000 0.0000000 2.28 0.009
Repeatability 60 0.0000000 0.0000000
Total 89 0.0000061
j .. = Jl18 I ~~~
~I li: ~I
V[L~~~I 111:':::1°
64
Alpha to remove interaction term = 0.25
Gage R&R %Contribution
Source VarComp (of VarComp)
Total Gage R&R 0.0000000 0.51
Repeatability 0.0000000 0.34
Reproducibility 0.0000000 0.17
Operators 0.0000000 0.02
Operators*Parts 0.0000000 0.15
Part-To-Part 0.0000001 99.49
Total Variation 0.0000001 100.00
Process tolerance = 0.0004
Study Var %Study Var %Tolerance
Source StdDev (SD) (5.15 * SD) (%SV) (SV/Toler)
Total Gage R&R 0.0000197 0.0001016 7.17 25.40
Repeatability 0.0000161 0.0000830 5.86 20.76
Reproducibility 0.0000114 0.0000586 4.13 14.64
Operators 0.0000043 0.0000221 1.56 5.52
Operators*Parts 0.0000105 0.0000542 3.83 13.56
Part-To-Part 0.0002744 0.0014133 99.74 353.32
Total Variation 0.0002751 0.0014169 100.00 354.24
Number of Distinct Categories = 19
Gage R&R for Results
______________________________________________________________________________
Part
Vollmer
Brian Trial
1
Vollmer
Brian Trial
2
Vollmer
Brian Trial
3
Vollmer
Tom Trial
1
Vollmer
Tom Trial
2
Vollmer
Tom Trial
3
Vollmer
Tony Trial
1
Vollmer
Tony Trial
2
Vollmer
Tony Trial
3 Deviation
1 0.00060 0.00063 0.00058 0.00054 0.00053 0.00055 0.00058 0.00057 0.00054 0.00010
2 0.00090 0.00092 0.00091 0.00087 0.00089 0.00090 0.00089 0.00089 0.00088 0.00005
3 0.00040 0.00041 0.00039 0.00039 0.00037 0.00039 0.00037 0.00037 0.00039 0.00004
4 0.00115 0.00119 0.00115 0.00116 0.00122 0.00117 0.00115 0.00114 0.00114 0.00008
5 0.00114 0.00118 0.00109 0.00115 0.00118 0.00119 0.00112 0.00113 0.00116 0.00010
6 0.00117 0.00117 0.00117 0.00115 0.00116 0.00119 0.00111 0.00117 0.00115 0.00008
7 0.00116 0.00115 0.00117 0.00116 0.00114 0.00116 0.00106 0.00114 0.00111 0.00011
8 0.00098 0.00091 0.00091 0.00096 0.00093 0.00094 0.00093 0.00092 0.00093 0.00007
9 0.00106 0.00097 0.00096 0.00096 0.00095 0.00097 0.00096 0.00095 0.00094 0.00012
10 0.00074 0.00074 0.00078 0.00081 0.00079 0.00079 0.00082 0.00082 0.00080 0.00008
Vollmer Gage R&R Raw Data
65
Part-to-PartReprodRepeatGage R&R
300
150
0
Perc
ent
% Contribution
% Study Var
% Tolerance
0.00010
0.00005
0.00000
Sam
ple
Range
_R=0.0000353
UCL=0.0000910
LCL=0
Brian Tom Tony
0.00100
0.00075
0.00050Sam
ple
Mean __
X=0.0009152UCL=0.0009514LCL=0.0008791
Brian Tom Tony
10987654321
0.0012
0.0008
0.0004
Parts
TonyTomBrian
0.0012
0.0008
0.0004
Operators
10 9 8 7 6 5 4 3 2 1
0.00100
0.00075
0.00050
PartsA
vera
ge
Brian
Tom
Tony
Operators
Gage name:
Date of study :
Reported by :
Tolerance:
Misc:
Components of Variation
R Chart by Operators
Xbar Chart by Operators
Results by Parts
Results by Operators
Operators * Parts Interaction
Vollmer Gage R&R Study .0009 +/- .0002" Ti Cathode Thickness
Welcome to Minitab, press F1 for help.
Gage R&R Study - ANOVA Method
Two-Way ANOVA Table With Interaction Source DF SS MS F P
Parts 9 0.0000058 0.0000006 475.164 0.000
Operators 2 0.0000000 0.0000000 2.053 0.157
Parts * Operators 18 0.0000000 0.0000000 2.617 0.003
Repeatability 60 0.0000000 0.0000000
Total 89 0.0000059
Alpha to remove interaction term = 0.25
Gage R&R %Contribution
Source VarComp (of VarComp)
Total Gage R&R 0.0000000 1.17
Repeatability 0.0000000 0.72
Reproducibility 0.0000000 0.45
Operators 0.0000000 0.07
Operators*Parts 0.0000000 0.39
Part-To-Part 0.0000001 98.83
Total Variation 0.0000001 100.00
66
Process tolerance = 0.0004
Study Var %Study Var %Tolerance
Source StdDev (SD) (5.15 * SD) (%SV) (SV/Toler)
Total Gage R&R 0.0000291 0.0001498 10.81 37.45
Repeatability 0.0000228 0.0001173 8.47 29.33
Reproducibility 0.0000181 0.0000932 6.72 23.30
Operators 0.0000069 0.0000356 2.57 8.89
Operators*Parts 0.0000167 0.0000861 6.22 21.53
Part-To-Part 0.0002675 0.0013776 99.41 344.40
Total Variation 0.0002691 0.0013857 100.00 346.43
Number of Distinct Categories = 12
Gage R&R for Results
67
Appendix C: Heidenhain work instructions for Ullegheny Ludlum for measuring
the JB3 Company XYZ titanium cathode material thickness.
Heidenhain Length Gauge Work Instructions for Ullegheny Ludlum
These work instructions are intended for measuring the Company XYZ JB3
titanium cathode material thickness
A - Setting up the Heidenhain – ID No 31415092F
1) Power the Heidenhain ND 287 readout to the On position – The power switch is on the back of the unit.
68
2) Press any key to get the readout screen to appear 3) With switch box move the length gauge slightly down until the reference mark is crossed.
This will produce a live readout
4) Make sure the force is set to “3” which is the maximum Newton’s force applied by the
Heidenhain
69
5) Clean the System –
- With lint free wipes and alcohol clean wipe the granite base, flat anvil, and .005” Master block.
- Lower the indicator onto a lint free wipe then pull it out. This will help clean any residue off of the surfaces. Make sure no small pieces of lint are trapped between the indicator and granite surface. *** This step is essential for the machine to produce accurate measurements ***
70
6) Master the machine – Lower the indicator until it touches the granite base. Press “0” into the readout and hit enter. Move the indicator up and down a few times to verify it consistently reads out 0.0000” when the anvil is contacting the granite base. *** This is a very important step ***
7) Measure the cleaned .005” gauge block to verify the system has been mastered correctly.
.005” Master Gauge Block
71
B - Measuring the Raw Material
1) Place pristine wrinkle free material under the indicator. Lower the indicator until the digital readout stops descending in value. This will be the measured thickness to record.
2) Before each measurement is taken lower the indicator until it contacts the surface. Verify
the readout is at 0.0000” and if it isn’t there is debris on the indicator or granite surface. Refer to section A4 to clean the contacts and re-zero the device. This is very important because if you don’t verify it’s zeroing out before each measurement you will get false readings.
72
C – Shutting down the Heidenhain.
1) Raise the indicator until it reaches the upper stop point. (Do not leave the indicator in the lowered position!)
2) Turn power button on the readout display to the off position.