The Implementation of the NUD Process - dfrsolutions.com DfR Conference/Presentation... · NUD Electronic Example 23 • Cell Phone − Next years model, what has changed. NUD RISK

9000 Virginia Manor Rd Ste 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

The Implementation of the NUD Process

How it is used to develop reliable products such as the Lennox S30 thermostat

26 March 2019 | Joe Powell


Copyright of DfR Solutions 2019

Agenda

02 NUDS and FMEA

Why and what is NUDS01

06 Questions

03 The NUDS Process

04 Lennox S30 and NUDs

05 Summary

2



Why

• Tool that is part of our DFR process.

• In use for over 10 years.

• Identify risks.

• Begin mitigation sooner, with higher confidence of product success.

• NUDS

3



What is NUDs

• New: an adjective referring to something recently made, discovered, or created.

• Unique: a state or condition wherein something is unlike anything else.

• Difficult: requiring much work or skill to do or make.

4



What is NUDs

• New: Just as it implies, anything that is new. − First time using a material, component or technology.

› Switch, motor or LCD display never used before.

› Plastic material change.

› Newly implemented process.

− First time use in the present design.

› Used in xyz product, now used in abc product but same use and environment profile.

5



What is NUDs

• Unique: − Different use of material or component, with different use or environmental profile.

› What was used as an evaporator motor in a furnace, now is used as condenser motor in an outdoor unit.

• Different ambient temperature, humidity, vibration, dust.

› Same refrigerant pressure switch used in walk-in coolers, now is used in commercial HVAC.

• Also different ambient temperature and humidity, as well as duty cycles and use profile.

6



What is NUDs

• Difficult: requiring much work or skill to do or make.

− Challenging agency or government regulation requirement.

› Fuel efficiency improvement 20% by 2020 for automobile.

› Phase out of ozone-depleting refrigerants.

7



NUDs and FMEA

• Supportive and helpful for FMEA and design process, not a replacement.• Why do we need an alternative?

• FMEA NEVER GETS COMPLETED SOON ENOUGH!!!

Why not? − People are too busy. Schedule driven.

− FMEA is boring, design is more fun.

− Difficult to get all members to attend.

− Paperwork check box.

− Design engineer not skilled in preparing FMEA.

8



NUDs and FMEA

• FMEA Output:− Systematic identification of potential failures modes, and cause mechanisms.

− Manage risks.

− Recommend alternative solutions.

• All important for identifying tests to insure that the product meets all targeted performance criteria, but especially reliability objectives.

• NUDs can provide the same and sooner.

9



NUDs and FMEA

10

Concept DFMEA

PrototypeDesign VerifyPre-

productionProduction

Specification Design

Ideal development process with DFMEA





NUDs and FMEA

11

Concept DFMEASpecification Design

What really happens with design DFMEA

THIS DOES NOT WORK FOR RELIABILITY ENGINEERS

DFMEA



NUDs and FMEA

12

Concept

PrototypeDesign Verify

ProductionPre-

Production

Specification

Ideal development process with DFMEA, PFMEA AND S&IFMEA

PFMEAS&IFMEA

DFMEA Design



NUDs and FMEA

Concept


ProductionPre-

Production

Specification

What really happens with PFMEA and S&IFMEA

PFMEA and S&IFMEA

THIS DOES NOT WORK FOR ANYONE

DFMEA Design

13



HOW DOES NUDs IMPROVE THIS?

14



NUDs and FMEA

15

Concept DFMEA



Specification Design

NUDs for design

NUDs

RELIABILITY ENGINEERS CAN BEGIN TEST PLAN ON

HIGH RISK, SPECIAL REQUIREMENT ELEMENTS



NUDs and FMEA

16

Concept


ProductionPre-

Production

Specification

NUDs for Process and Service and Installation

PFMEAS&IFMEA

THIS WORKS FOR P AND S&I FMEAs

DFMEA DesignNUDs



Summary to this Point

• New concept, NUDs.− New

− Unique

− Difficult

• Gets to high risks issues of change quickly.

• Helps reliability engineer develop risks mitigation sooner.

• Not a FMEA replacement.

• Efficient utilization of resources.

17



NUDs Process

18

Block Diagram

Failure Mode

Worksheet

Interface

MatrixDFMEA Form

P-Diagram

FMEA Diagram



NUDs Process

• Utilizes a portion of DFMEA process.

Block Diagram: Describes system relationships.

P-Diagram: Describes external factors.

19



NUDs Process

20

Block Diagram

Failure Mode

Worksheet

Interface

MatrixDFMEA Form

P-Diagram

NUDs

NUDs Diagram



NUDs Development Example

21

XYZ

Control

HW

FW

Detect ckt 1

Detect ckt 3

Detect ckt 2

Pump Drive

Regulator Drive

3.3V regulator circuit

Output Drive 1

CPU function

GV Drive

Power Supply

Input Detection

Relay Driver

LED

K5

PCB

R49

R46

R44

C4

D12

D13

R48

Input 1 Input 2 Output 1

24V Rectifier/

Regulator circuit

Block Diagram Step



NUDs Development Example

22

XYZ Control: Noise

Factors

System Factors New/Unique/Difficult

Input 1 Yes

Input 2 No

Output 1 No

User Factors New/Unique/Difficult

Voltage Surges No

Number of cycles Yes

Wiring Yes

Environmental Factors New/Unique/Difficult

Temperature No

Humidity No

Vibration No

XYZ ControlINPUTS

Signal Factors

Response/Ideal

Function

OUTPUTS

P-Diagram Step



NUD Electronic Example

23

• Cell Phone− Next years model, what has changed.

NUD RISK MITIGATION

Table with

Headers

Display/touchscreen

Different button supplier

and increased count of

presses.

Breaking of glass.

Scratch resistance.

Touch sensitivity.

Meet lifetime button

presses.

Perform standard drop test.

Perform standard scratch

test.

Perform touch sensitivity test.

Perform standard button press

life test with increased number of

cycles.

Identify and

Record NUDs

Identify and

Record Risk

List Mitigation

Method

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&ved=0ahUKEwi699Olv-PLAhUll4MKHWJtCZcQjRwIBw&url=http://www.overstock.com/Electronics/Unnecto-Primo-Unlocked-GSM-3G-Dual-SIM-Cell-Phone/10072185/product.html&psig=AFQjCNHIvaYRBW_ChXGiRPPk9APKz-Kmtg&ust=1459255198100536



NUDs Development, NUD Worksheet Step

24

• Simple:

Pump efficiency > 20 % Fuel economy Redesign -valve size and

shape

Insufficient torque Improve pump flow

List the NUD

Identify the

associated

risk.

List the test,

analysis, method

you will use to

mitigate that risk.

NUD RISK MITIGATION



NUDs Development

• Two reasons to develop NUD list:− Type 1: Existing product change, upgrade etc.

− Type 2: New product development.

25



NUDs Development

26

What has

changed?

What is

different about

use?

Anything

different about

environment?

What worries

you?

New Parts?

ABC Control

KEEP ASKING QUESTIONS!! INTERACTIVE DIALOGUE

Type 1: Existing Product Change



NUDs Development

27

New

Processor?

Different p/s

design?

More cycles

over lifetime,

different relay?

What wakes

you up at night?

What have we

never done

before?

XYZ Control

KEEP ASKING QUESTIONS!! INTERACTIVE DIALOGUE

Type 2: New Product



Summary

• NUDs process is straight forward table.

• Uses block diagram and p-diagram of FMEA process to focus thinking.

• Interactive dialogue with designer is important.

28



How was NUDS used for S30 Testing

29



NUDs and S30

30

What is S30



NUDs and S30

31

Over 250 parts Over 135 parts

HD Display

Over 500 parts

Device DFMEA Lines No. of Man Hours

HD Display 290 110

Mag Mount 218 60

Smart Hub 274 73

Total 782 243



NUDs and S30

32

NUD Risk Mitigation

Display Touchscreen

Breakage for use or droppingPackaging drop test

Drop test without packaging

Scratch resistance Test to be developed.

Capacitive TouchElectronic qualification test, touch

sensitivity test

Chemical SusceptibilityChemical exposure with environmental

stresses.

UV susceptibility UV testing

Backlight life Analytics for backlighting life.

Viewing angle, brightness and contrast Display testing

Battery

LifeCombination of analytics and testing

under adverse conditions.

Fire Fire test

ESD susceptibility of regulator failure allowing

battery to thermally runaway.Electronic qualification test

Electronics EMI and Environmental Electronic qualification test

Plastic Housing Environmental susceptibility UV testing, thermal shock,

Durability and mounting strength. FEA, Plastic

Microphone and speaker

Durability (household chemicals) Durability test to be developed

Loudness of speaker Test to be developed.

Sensitivity of microphone Test to be developed.

PC Board Thermal/mechanical stresses FEA, HALT, Thermal Shock.

New FirmwareUnintended operation or not meeting

specificationFirmware test

Temperature Sensor Location Poor temperature control Temperature test

Proximiity Detector False triggering Proximity test

9 NUDs

Display NUD list



NUDs and S30

33

NUD Risk Mitigation

Magnetic support for display Loss of strength over time.Analytics. Test to be

developed.

Magcon ConnectorCorrosion, connection reliability Corrosion test

Maintain spring tension Test to be developed.

Communication Bus EMI Electronic qualification test

2 screw wall mount with sheetrock

anchors

Holding strength to wall versus removal

strength of display

Analytics. Testing to be

developed.

Humidity SensorEMI Electronic qualification test

Accuracy Humidity sensor test

Plastic HousingEnvironmental susceptibility UV testing, thermal shock,

Durability and mounting strength. FEA, Plastic

METZ Connector Corrosion, connection reliability Corrosion/connector test

Life Meet Lennox life requirements ALT


Power supplyEMI

Electronic qualification testHandle range of input voltage

New processor EMI/Environmental/LifeElectronic qualification test and

ALT

Communication protocol to HD Display EMI/Environmental/Life Electronic qualification test

New firmwareUnintended operation or not meeting

specificationFirmware test

13 NUDs

Mag-Mount NUD list



NUDs and S30

34

Smart-Hub NUD listNUD Risk Mitigation

Pushbutton Switch

Meet # of pushes Analytics, testing if necessary.

Meet push force Analytics, testing if necessary.

2 wifi antennaESD Electronic qualification test

Gimbal Testing to be developed.

Plastic HousingEnvironmental susceptibility UV testing, thermal shock,

Durability and mounting strength. FEA

Linux operating system Intended and reliable functionality Firmware Testing

METZ Connector Corrosion, connection reliability LR-805

Power Sequencer Failure to process correctly during EMI. Electronic qualification test

WIFI RadioEMI, environment Electronic qualification test

Meet distance requirements Testing to be developed.

LED Meet brightness requirements Half Life calculation

Clear Plastic Lens Clear becomes cloudy over time. UV testing, thermal shock,

SD Card Holder Application SD card becomes dislodged. Package testing, HALT

Life Meet Lennox life requirements ALT


12 NUDs



NUDs and S30

35

Comparison

Device FMEA Lines (man

hrs)

NUDs (man hrs)

HD Display 290 (110) 9 (2.5)

Mag Mount 218 (60) 13 (1)

Smart Hub 274 (73) 12 (2)

Total 782 (243) 34 (5.5)

Quicker than FMEA, higher confidence of reliability, early.

• Brought to market 1 month earlier with higher confidence of reliability.

• Warranty rate is lower than predecessor.

• No warranty claims due to high risk items.

• Identified unique manufacturing issues, magnet orientation.



NUDs

36

Pros/Cons of NUDs Method

• Pros:− Quicker path to identifying critical issues/components.

− Efficient utilization of engineering and manufacturing resources.

− Fewer team members to reach critical point.

− Help guide engineering team to prioritize corrective actions.

− Helps focus and prioritize FMEA process.

− Actions underway on addressing high risk items at start of FMEA.

− Help to reduce the time of project life cycle.

− Identify risks at the beginning when costs of change are low.

− Scales to scope of the project.

• Cons:− Not 100% coverage as FMEA.

− Doesn’t necessarily include historical failure history data.

− There is a chance failure modes can be missed.



Summary

37

• NUDs: New, Unique, Difficult.

• Uses block diagram, p-diagram.

• Does not replace FMEA.

• Identifies high risk issues at beginning of project with mitigation.

• Efficient use of resources, (S30 3% of FMEA man hours).

• Use for DFMEA, PFMEA, S&IFMEA.

• Quicker to market, higher confidence of reliability.



Speaker Bio

Joe Powell, Reliability Engineer, Fellow

Lennox International

Joe has been with Lennox for 31 years in various positions of design and management of electronic

controls and has spent the last 10 years in electronic control reliability. Previous to Lennox he worked in

electronic design at Ranco Electronics, Luminator, Northern Telecom. Joe holds an Associate and Bachelors

degree in Electrical Engineering and holds 8 patents.

Contact

214-460-3966

[email protected]

38



Questions?

39

Documents

The Implementation of the NUD Process - dfrsolutions.com DfR Conference/Presentation... · NUD Electronic Example 23 • Cell Phone − Next years model, what has changed. NUD RISK