CMSC 2011

Phoenix Arizona

Measurement

Measurement Study 2011

CMSC 2011

Phoenix Arizona

Thanks

CMS Executive Committee

Bertrand Metrologic

Nathalie Metrologic

Mark Metrologic

Dennis Metrologic

Charlie BMW

Trevor Coventry University

Ben NPL

Preston ATT Metrology

Lucas East coast Metrology

Jason Prolink

All of you

CMSC 2011

Phoenix Arizona

Measurement study

2010

CMSC 2011

Phoenix Arizona

Open measurement workshop inviting conference delegates

to participate in a measurement study

• Subject: First principle measurement study based on a variety of‘hand tools’ used in dimensional measurement

• Objectives:To look at the importance of

• core measurement principles

• instilling the right measurement strategy

• observing behaviours when dealing with measurements

• instilling questioning

2010 measurement study

CMSC 2011

Phoenix Arizona

Measurement tasks

Image taken from NPL Training materials

CMSC 2011

Phoenix Arizona

Activity

• The measurement studies were to be undertaken over 2 days in 2 separate areas using various defined first principle tasks.

• The criteria of the tasks was modified to allow for various training & assessments techniques to be undertaken such as:

– Assessment of prior learning and experience

– Questioning techniques

– Practical task monitoring

– Demonstration

CMSC 2011

Phoenix Arizona

Profile• Varied industries ranging from

– Aerospace

– Nuclear

– Automotive

– Science

– Woodworking

• Varied job roles

– Quality

– Scientist

– Management

– Measurement

– Supplier Experience

• Measurement experience

– Ranging from newcomer to in excess of 15 years experience

CMSC 2011

Phoenix Arizona

Observations

– Checked jaws for parallelism

– Checked calibration status

– Used gauge block to check vernier

– Cleaned before using

– Made multiple measurements

– Made multiple re-zero’s

– Checked vernier zero

– Cleaned jaws

– Misunderstanding of scale and units

– Check for damageImage taken from NPL Training materials – courtesy Hexagon Metrology

CMSC 2011

Phoenix Arizona

Observations

– Locked jaws using thumbscrew

– Measured with jaws not parallel to the workpiece

– Used internal jaws for depth measurement

– Used depth bar and checked zero

– Spent effort to find minimum value

– Used gauge block as a comparator

– Poor lighting didn’t help reading scale

Images taken from NPL Training materials – courtesy Hexagon Metrology

CMSC 2011

Phoenix Arizona

Observations

– Cleaned the artefact

– Checked the zero

– Felt for dirt on the surface table

– Used without zeroing – difference between 2 values

– Base upwards/ part downwards

– Cleaned surface plate

– Checked using gauge block

– Used direct comparison against gauge block

Image taken from NPL Training materials – courtesy Hexagon Metrology

CMSC 2011

Phoenix Arizona

4 measurement tasks with and without instruction covering diameters,

length, depths and gauge block wringing

• Task 1: Without procedures 55 readings ranged from 0,155 to 0,191mm

• Task 2: Without procedures 43 readings ranged from 0.0015 to 1.21 inches

• Task 3: With procedures 39 readings ranged from 0,009 to 0,057mm

• Task 4: Without procedures 28 readings varied by 0.0045 inches

• Key observations and behaviours across a wide range of expertise

Data

CMSC 2011

Phoenix Arizona

Summary

CMSC 2011

Phoenix Arizona

Summary

• Key areas • Standards

• Traceabilty

• Calibration

• Measurement uncertainty

• Understanding design requirements

• Repeatability and reproducibility

• Questioning

• Attitudes and behaviours

CMSC 2011

Phoenix Arizona

Measurement study

2011

CMSC 2011

Phoenix Arizona

Open measurement workshop inviting conference delegates to participate

in a 3D co-ordinate measurement study on ‘How behaviours impact your

Measurement’

Objectives: Over a 3 day period of the conference participants are

• Days 1 & 2: Invited to undertake 3D co-ordinate measurements by a variety of methods whilst looking at underpinning measurement core principles and behaviours.

• Day 3: Invited to the measurement study workshop where the findings of the study will be presented by the study group.

2011 CMSC measurement study

Sponsored By Metrologic

CMSC 2011

Phoenix Arizona

Activity:

– Day 1 (Tuesday): 3D measurement tasks with little or no instruction where the

participant will need to determine the requirements to take measurements or

instruct the operator as to the measurements needed. The resultant data will

be stored in an appropriate system

– Day 2 (Wednesday): 3D measurement tasks with instructions or procedures

where the participant will be required to take measurements or instruct the

operator as to the method to collect the measurements needed. The resultant

data will be stored in an appropriate system

– Day 3 (Thursday – PM): Workshop presentation of the observations and data

from the measurement study.

The criteria of the tasks will allow for various training & assessments techniques

to be undertaken such as: Assessment of prior learning and experience,

questioning techniques, practical task monitoring and demonstration

2011 CMSC measurement study

Sponsored By Metrologic

CMSC 2011

Phoenix Arizona

Study Criteria

• Study categories

– Pre- Measurement

– Measurement planning

– Measurement

– Post Measurement

• Participants

– Beginner to measurement

– Beginner to portable measurement

– Some experience of portable measurement

– Experienced

CMSC 2011

Phoenix Arizona

Tasks

CMSC 2011

Phoenix Arizona

Profile

• Varied industries ranging from

– Aerospace

– Nuclear

– Science

• Varied job roles

– Quality

– Scientist

– Management

– Measurement

CMSC 2011

Phoenix Arizona

Profile

• Industry

– 80% aerospace

– 15% Other

– 5% Nuclear

• Job

– 40% engineer

– 38% metrologist

– 8% management

– 8% other

– 6% scientist

CMSC 2011

Phoenix Arizona

• Department

– 60% quality

– 12% design

– 12% manufacturing

– 16% other

• Experience

– 40% 0-3 years

– 10% 3-7 years

– 50% 7 years & above

Profile

CMSC 2011

Phoenix Arizona

Profile

• Frequency of measurement activity

– 30% daily

– 40% occasionally or never

– 30% weekly

• Undertook CMSC 2010 workshop

– 25% Yes

– 75% No

CMSC 2011

Phoenix Arizona

Participant

Observations

CMSC 2011

Phoenix Arizona

Day 1 Articulated Arm

• Pre Measurement

– 6% Temperature

– 6% Carpet

– 19% calibration

– 19% calibration of hemisphere

– 13% Accuracy

– 6% Repeatability

– 13% What is purpose of the measurement

• Planning

– 13% What are tolerances on alignment

– 13% Is CAD the reference

CMSC 2011

Phoenix Arizona

Day 1 Articulated Arm• Measurement Process

– 19% different reference features to be measured

– 50% Lack of guidance of the probe tip resulting in large form errors

– 12% asked to re-probe due to form error

– 6% Fixturing – is that sitting in fixture right

– 94% Best fit

– 6% Weighted fit

CMSC 2011

Phoenix Arizona

Day 1 Articulated Arm

Analysis

– 31% Asked what was the tolerance

– 6% Vector deviation from the reference system

– 6% What you going to do with data

– 13% Requested repeat of measurements due to form

errors

– 13% Asked if wanted to repeat measurements – said no

– 6% Asked about functionality of the features being measured

CMSC 2011

Phoenix Arizona

Day 1 Laser Tracker

• Pre Measurement

– 6% Is there a Temperature sensor

– 6% Temperature better in hall than outside

– 20% Stability of part

– Carpet

– 65% Alignment - buttons

– 5% Alignment planes with projected point

– 8% put SMR in hole directly offset to datum

– Ad-hoc choice or probing strategy for planes with 3, 4, 5 points

– Scanned multiple points and asked for form errors

– 5% people asked about certification of reflector

– 5% asked to checked certificate

– 20% mentioned the state of the SMR

– Hemisphere – several noticed they were sloppy but nobody attempted to measure or put it in the context of the tolerance

CMSC 2011

Phoenix Arizona

Day 1 Laser Tracker• Buttons – wide variety for number points. – 1 used a formula for

spacing of points

• 7% scanned 205 points

• 7% Asked for 250 points

• 7% knocked part after aligning and carried on

• 7% person cleaned the part

• 7% asked if tracker calibrated

• 7% scanned around top of hemisphere

• 7% Variable speed

• Wanted 200 points at 0.075 spacing generic points and spacing

• Scanned round the hole and tried to scan the centre area of the hole but repeated after realising

• No point in measuring not accurate enough

CMSC 2011

Phoenix Arizona

Day 1 Laser Tracker• 50% noticed Large hole had burrs

• 7% Measured by missing burrs using artefact obtained

• 7% Checked drift by checking one of the alignment points at the end of the measurement

• 7% Big hole with burrs what is functionality

• 7% Wanted to move tracker closer 4 wanted to repeat measurement of scanned need hole based on didn’t feel right

• 7% person concerned about deviations form nominal but didn’t do anything about it

CMSC 2011

Phoenix Arizona

Day 1 Laser Tracker Tprobe, Tscan• Pre- measurement

– 25% discussed temperature

– 20% Stability and carpet

– 30% calibration and set up

– 50% discussed the measurement

• Measurement Planning

– 30% discussed specification and reference system

– 25% planning process – What do I do!!

– 15% probing compensation and strategy

– 15% discussed orientation, handling and stability measurement and part

– 15% good alignment needed

– 10% drift

– 40% guided through the whole measurement process

• 90% were new to the combination of equipment

CMSC 2011

Phoenix Arizona

Day 1 Laser Tracker Tprobe, Tscan

• Measurement and Post Measurement operations

– 70% asked about CAD, tolerance requirements or alignment

– 30% asked about analysis decision making and data

– 15% asked about analysis of alignment system

– 15% asked How well did I do?

– 20% discussed repeating measurement

• Other observations

– 15% discussed operator mistakes

– 15% had fun

CMSC 2011

Phoenix Arizona

Day 2 Articulated Arm

• Pre Measurement

– 60% Temperature and air

– 86% Carpet and people (busy traffic)

– 75% calibration

– 30% Part stability

• Planning

– 18% Format of CAD

– 36% orientation of probing methods

– 60% target adaptors accuracy

– 80% Part location and height

– 30% arm location

CMSC 2011

Phoenix Arizona

Day 2 Articulated Arm

• Measurement Process

– 50% wanted to discussed alignments

– 30% discussed form of buttons

– 10% noticed missed location of button

• Post measurement

– 6% round probe for slot – consider different probe

– 20% should have been higher

– 6% Validate the probe qualification after (field checks)

– 12% didn’t like using hemispheres

CMSC 2011

Phoenix Arizona

Day 2 Laser Tracker

• Pre measurement

– 80% temperature, carpet

– 80% height and access

– 50% equipment certification and calibration

– 20% difficult

• Measurement Planning, Measurement and analysis

– 80% wanted part raised

– 30% wanted to move tracker square to part

– 3% wanted the part end on to tracker

– 12% discussed result requirements

– 6% repeated measurements

– 3% did a drift measurement (repeated a reference point)

CMSC 2011

Phoenix Arizona

Day 2 Laser Tracker, Tprobe, Tscan

• Pre measurement

– 60% temperature,

– 90% carpet

– 40% area too busy

– 65% equipment certification and calibration

• Measurement Planning, Measurement and analysis

– 40% discussed measurement strategy

– 50% talked about location

– 8% asked about appropriateness of measurement to needs or application

CMSC 2011

Phoenix Arizona

Day 2 Laser Tracker, Tprobe, Tscan

– 40% easier because of procedure

– 10% asked about cleaning equipment

– 10% asked about model validation

– 20% discussed the outcomes in detail

– 10% mentioned carpet after completing measurement process

– 10% repeated some of the measurements

– 5% requested a drift measurement

CMSC 2011

Phoenix Arizona

Results

CMSC 2011

Phoenix Arizona

Door

Day 1 Day 2

CMSC 2011

Phoenix Arizona

Vehicle

Day 1 Day 2

CMSC 2011

Phoenix Arizona

Motor compartment

• Consistency in results from day 1 to day 2 changed as the alignment routine was chosen and more functional.

• Day 1 option of using adaptors

• Day 2 adaptors were used in the programme

• Twice as many people completed the task on day 2

CMSC 2011

Phoenix Arizona

Summary

CMSC 2011

Phoenix Arizona

Summary

• Key areas• Number of measurements

• Day 1 - 54

• Day 2 - 94

CMSC 2011

Phoenix Arizona

Summary

• Key areas• Standards

• Traceabilty

• Calibration

• Measurement uncertainty

• Understanding design requirements

• Repeatability and reproducibility

• Questioning

• Attitudes and behaviours

CMSC 2011

Phoenix Arizona

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