Techniques for Measurement of Threaded Hole Position Hole Location Study - Sandia Natl Lab.pdf ·...

Techniques for Measurement of Threaded Hole Position

Tony BryceSandia National Laboratories

Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company,for the United States Department of Energy under contract DE-AC04-94AL85000.

“The funny part of metrology is that we're never right, we just have to tell people how wrong we are, and hope the wrong part is right enough!”

Joseph CeremugaSandia National Laboratories (Livermore, CA)

How should the position be established?

� ANSI Y14.5M-1994• Section 2.9

– “Each tolerance of orientation or position and datum reference specified for a screw thread applies to the axis of the thread derived from the pitch cylinder.”

• Figure 5-6 – “Note that the length of the tolerance zone is equal to

the length of the feature, unless otherwise specified on the drawing.”

• Projected tolerance zone applications

To comply with ANSI Y14.5M� Measure the feature or gage –

• as a cylinder • in multiple circle sections

– Line generated between circle centers serves as the axis

� Axis is used to determine pierce points at ends of feature or evaluation length• Zeiss UMESS UX will evaluate these

points as L1 & L2 for TP calculations and report worst case deviation

CMM Methods� Direct probing of the thread form

• Issues– Chips, burrs– Establishing pitch cylinder

• Not able to probe pitch diameter directly

� Probing a threaded/cylinder gage• Issues

– $ - Cost of gage– Inconvenience of installing (time = money $)– Establishing pitch cylinder

• Various gages each using a different method to locate the pitch cylinder

How did we get interested in this?

Threaded Holes on a Curved Surface

Threaded Holes on a Curved Surface

Threaded Holes on a Curved Surface

Off-Line CMM Programming� Silma CimStation Inspection

Curved Surface Issue� Standard threaded/cylinder gage does

not seat properly?

Rocking Motion

Technique is needed that is not influenced by the surface the hole is on!

What to do?� Evaluate techniques � Perform R & R tests using various

techniques on a flat surface• Test pieces having a 2 inch outside

diameter with ¼”-20 thread in center– Aluminum part

• Diameter and face turned on lathe • Drill and tap hole

– Steel part• Gage quality lapped thread with outside diameter

and face ground to pitch diameter axis

Test Piece Datum’s• Datum A = Top surface • Datum B = 2” outside diameter• Datum C = 0.25” through hole• Establish DRF - ABC

Threaded / Cylinder Gages� Obtain all available types on the market

• Jo-Plug – Cylinder with straight thread and shoulder face

perpendicular to axis• Tru-Pos

– Tapered thread for interference fit• CL Flex Plug

– Split thread for compliance fit• Multi-Ball Gage

– Expanding balls fit to pitch diameter

Jo-Plug (Spence Industries Inc.)

CL Flex Plug (Glastonbury/Southern Gage)

Tru-Pos Locator (LaVezzi Precision Inc. )

Multi-Ball (True Precision Corp. )

R&R Test Parameters for Threaded / Cylinder gages

� Using UMESS UX with PCM routines, probe a total of 32 points* on the cylinder• 8 equally spaced points at 4 different

levels over the length of the cylinder

– * 24 points (8 equally spaced points at 3 levels) used on CL Flex Gage due to short cylinder length

R&R Test Parameters

� Establish pierce points of cylinder axis with Datum A (top surface) and at –0.5” below Datum A

� Record X & Y position at both pierce points• Should show repeatability of not just

Datum A location, but of the cylinder orientation (tilt).

Jo-Plug (Spence Industries Inc.)

CL Flex Plug (Glastonbury/Southern Gage)

Tru-Pos Locator (LaVezzi Precision Inc. )

Tru-Pos Locator (LaVezzi Precision Inc. )

Multi-Ball (True Precision Corp.)

Multi-Ball (True Precision Corp. )

Multi-Ball (True Precision Corp. )

Direct Probing of Thread

� Use Zeiss PCM thread routine• Measure circles at both ends of threaded

hole. (8 equally spaced points)• Construct a line through the centers of

both circles• Establish pierce points at Datum A (top

surface) and at –0.5” below Datum A

PCM Measurement

PCM Measurement

PCM Measurement

� Many CAD models show threaded holes as plain cylinders (minor diameter) and could be programmed in a helical path to establish pitch cylinder

� Use pass through commands via Silma Cim Station Inspection

Off-Line CMM Programming

Test Parameters

� CNC Program written to measure datum features and establish W-Pos

� Measure position using each of the five techniques

� Loop program for a total of 10 runs• Loop includes establishing W-Pos

� Run the CNC program on 3 different CMM’s

CMM’s Used & Specifications� Prismo (9/12/7)

• 1D = 2.2 microns + L / 300• 3D = 2.7 microns + L / 300

� Contura (7/10/6)• 1D = 2.0 microns + L / 300• 3D = 2.3 microns + L / 300

� UPMC 550 (CAA)• 1D = 0.9 microns + L / 400• 3D = 1.3 microns + L / 300

– L = Length in millimeters

CMM Software

� UMESS UX• Version 8.7

Prismo

Contura

UPMC 550

Test Results –Steel Test Piece

Jo-Plug Position Std. Dev. Position Std. Dev.X -0.00009 0.00003 -0.00019 0.00001Y -0.00012 0.00002 -0.00020 0.00001

Tru-PosX -0.00016 0.00002 0.00050 0.00003Y -0.00002 0.00001 -0.00015 0.00003

CL FlexX -0.00002 0.00019 -0.00033 0.00019Y -0.00014 0.00014 -0.00054 0.00014

Multi-BallX 0.00002 0.00006 0.00041 0.00002Y -0.00019 0.00003 0.00012 0.00008

PCMX -0.00015 0.00002 0.00060 0.00001Y -0.00015 0.00002 0.00060 0.00001

Datum A Projected -0.5"

Contura

Results In Inches

Test Results – ConturaSteel Test Piece

0.0013 TP

Results In Inches

0.0017 TP

Gages PCM

Test Results –Steel Test Piece

Jo-Plug Position Std. Dev. Position Std. Dev.X -0.00013 0.00005 -0.00013 0.00002Y -0.00010 0.00002 -0.00010 0.00004

Tru-PosX -0.00014 0.00002 -0.00014 0.00001Y -0.00003 0.00002 -0.00003 0.00003

CL FlexX -0.00022 0.00014 -0.00021 0.00022Y -0.00002 0.00015 -0.00002 0.00024

Multi-BallX 0.00005 0.00008 0.00004 0.00003Y -0.00024 0.00004 -0.00025 0.00006

PCMX 0.00162 0.00001 0.00162 0.00001Y -0.00017 0.00001 -0.00018 0.00017

Prismo

Datum A Projected -0.5"Results In Inches

Test Results – PrismoSteel Test Piece

Results In Inches

0.0005 TP 0.0033 TP

Gages PCM

Test Results –Steel Test Piece

Jo-Plug Position Std. Dev. Position Std. DevX -0.00011 0.00002 -0.00019 0.00001Y -0.00012 0.00002 -0.00020 0.00001

Tru-PosX -0.00017 0.00001 0.00050 0.00003Y 0.00001 0.00001 -0.00015 0.00003

CL FlexX -0.00026 0.00009 -0.00033 0.00019Y -0.00014 0.00007 -0.00054 0.00014

Multi-BallX 0.00004 0.00006 0.00041 0.00002Y -0.00014 0.00003 0.00012 0.00008

PCMX -0.00018 0.00001 0.00060 0.00001Y -0.00018 0.00001 0.00060 0.00001

UPMC 550

Projected -0.5"Datum AResults In Inches

Test Results – UPMC550Steel Test Piece

Results In Inches

0.0012 TP 0.0017 TP

Gages PCM

Test Results –Steel Test Piece

Jo-Plug Position Std. Dev. Position Std. DevX -0.00011 0.00002 -0.00017 0.00003Y -0.00011 0.00001 -0.00017 0.00006

Tru-PosX -0.00016 0.00002 0.00029 0.00037Y -0.00001 0.00002 -0.00011 0.00007

CL FlexX -0.00017 0.00013 -0.00029 0.00007Y -0.00010 0.00007 -0.00037 0.00030

Multi-BallX 0.00004 0.00002 0.00029 0.00021Y -0.00019 0.00005 -0.00001 0.00021

PCMX 0.00043 0.00103 0.00094 0.00059Y -0.00017 0.00001 0.00034 0.00045

Datum A Projected -0.5"

Average All CMM's

Results In Inches

Test Results – Average of all CMM’sSteel Test Piece

Results In Inches

0.0009 TP 0.0019 TP

Gages PCM

Test Results –Aluminum Test Piece

Jo-Plug Position Std. Dev. Position Std. Dev.X -0.00084 0.00016 -0.00088 0.00010Y 0.00107 0.00005 0.00107 0.00002

Tru-PosX -0.00022 0.00005 -0.00094 0.00008Y 0.00137 0.00005 0.00149 0.00027

CL FlexX -0.00046 0.00025 -0.00140 0.00028Y 0.00098 0.00026 0.00101 0.00034

Multi-BallX 0.00011 0.00020 -0.00089 0.00016Y 0.00112 0.00010 0.00138 0.00008

PCMX 0.00085 0.00002 -0.00033 0.00002Y -0.00006 0.00001 0.00032 0.00001

Datum A Projected -0.5"

Contura

Results In Inches

Test Results – ConturaAluminum Test Piece

Results In Inches

0.0035 TP 0.0017 TP

Gages PCM

Test Results –Aluminum Test Piece

Jo-Plug Position Std. Dev. Position Std. Dev.X -0.00082 0.00007 -0.00082 0.00007Y 0.00111 0.00006 0.00214 0.00007

Tru-PosX -0.00018 0.00003 -0.00018 0.00012Y 0.00129 0.00005 0.00129 0.00012

CL FlexX -0.00043 0.00037 -0.00045 0.00044Y 0.00133 0.00029 0.00135 0.00041

Multi-BallX 0.00037 0.00019 0.00036 0.00014Y 0.00116 0.00013 0.00118 0.00011

PCMX 0.00075 0.00002 0.00075 0.00001Y 0.00003 0.00005 0.00004 0.00008

Datum A Projected -0.5"

Prismo

Results In Inches

Test Results – PrismoAluminum Test Piece

Results In Inches

0.0046 TP 0.0015 TP

Gages PCM

Test Results –Aluminum Test Piece

Jo-Plug Position Std. Dev. Position Std. DevX -0.00081 0.00017 -0.00095 0.00007Y 0.00112 0.00013 0.00101 0.00005

Tru-PosX -0.00013 0.00009 -0.00071 0.00006Y 0.00128 0.00005 0.00140 0.00006

CL FlexX -0.00051 0.00027 -0.00134 0.00027Y 0.00107 0.00033 0.00101 0.00040

Multi-BallX 0.00041 0.00017 -0.00131 0.00013Y 0.00124 0.00014 0.00106 0.00016

PCMX 0.00079 0.00003 -0.00037 0.00001Y 0.00015 0.00009 0.00005 0.00004

Datum A Projected -0.5"

UPMC 550

Results In Inches

Test Results – UPMC550Aluminum Test Piece

Results In Inches

0.0034 TP 0.0016 TP

Gages PCM

Test Results –Aluminum Test Piece

Jo-Plug Position Std. Dev. Position Std. DevX -0.00082 0.00002 -0.00088 0.00007Y 0.00110 0.00002 0.00141 0.00063

Tru-PosX -0.00018 0.00004 -0.00061 0.00039Y 0.00132 0.00005 0.00140 0.00010

CL FlexX -0.00047 0.00004 -0.00106 0.00053Y 0.00113 0.00018 0.00112 0.00019

Multi-BallX 0.00029 0.00016 -0.00061 0.00087Y 0.00117 0.00006 0.00120 0.00016

PCMX 0.00080 0.00005 0.00002 0.00064Y 0.00004 0.00010 0.00014 0.00015

Datum A Projected -0.5"

Average All CMM's

Results In Inches

Test Results – All CMM’sAluminum Test Piece

Results In Inches

0.0033 TP 0.0016 TP

Gages PCM

Test Result Summary

Manufacturer’s

� Jo – Plug• Spence Industries Inc.

– 800-991-1396– http:// www.jo-plug.com

� Multi – Ball • True Precision Corporation

– 317-899-0899– http://www.trueprecisioncorp.com

Manufacturer’s

� CL Flex Plug• Glastonbury / Southern Gage

– 800-229-4243– http://www.gsgage.com

� Tru-Pos• LaVezzi Precision Inc.

– 800-323-1772– http://www.lavezzi.com

Questions?