Diameters measurement with 3D touch machine like a CMM

#1
Dear all,

I'd like to solve and clear some doubts about diameters measurements like in the thread title:

when you measure with a CMM e.g. a diameter of a piece, usually is used the best-fit algorithm to get the best approximated diameter value and the roundness error to evaluate the circle form.
Then, but could not be useful to get the minimum circumscribed and the maximum inscribed circles, referred to the roundness error and not only the roundness error?
And more, for a coupling analysis with another part, should not be more indicated the minimum and maximum diameters got from the circle form construction? (that is different from roundness error that considers the circle center, instead of singles and separates diameters, that has the barycentre translating)
 
Elsmar Forum Sponsor

John Predmore

Trusted Information Resource
#3
The best-fit circle is not always the best choice, the answer depends on what information you want and what you will do with the information. If you measure the outside diameter of a shaft which will be inserted into a hole, the minimum circumscribed circle could be better to predict how the shaft will fit in the hole. I think you know this. What is your question?
 

Ron Rompen

Trusted Information Resource
#4
Most CMM software that I have used in the past few years has the option of reporting Min circumscribed/Max inscribed/Average (least squares) diameters. If your CMM doesn't give you these options, then perhaps you should investigate a software upgrade.
 
#5
The best-fit circle is not always the best choice, the answer depends on what information you want and what you will do with the information. If you measure the outside diameter of a shaft which will be inserted into a hole, the minimum circumscribed circle could be better to predict how the shaft will fit in the hole. I think you know this. What is your question?
You're right John, it depends which application is intended for that diameter.
However, what I want to clarify then is that max inscribed and minimum circumscribed diameters, could and usually have different center than the minimum and maximum diameters got to evaluate the roundness value with the least-squares actual diameter calculation, isn't it?
Another question: why is not considered with GD&T to give out the information of those min. and max. diameters got with least-squares calculation, instead of only roundness value, that could be positioned in different ways compared to the actual diameter got?
 
Thread starter Similar threads Forum Replies Date
C Measurement System to measure Hole Diameters, True Positions, Surface Profiles, etc General Measurement Device and Calibration Topics 4
M Measuring FIM (TIR) - Two inside diameters - Conflicting readings between inspectors Manufacturing and Related Processes 1
M Dimensioning diameters Inspection, Prints (Drawings), Testing, Sampling and Related Topics 2
M Laser Micrometer Suggestion (if any) for diameters that are +/-.0001 inch General Measurement Device and Calibration Topics 1
S How to check runout on Id to ID diameters Inspection, Prints (Drawings), Testing, Sampling and Related Topics 2
A Concentricity of two ID's (Inside Diameters) Inspection, Prints (Drawings), Testing, Sampling and Related Topics 7
L Inspection Equipment Accuracy - Measuring the diameters of small holes Measurement Uncertainty (MU) 5
C Measurements of Major Diameters of plug thread gages General Measurement Device and Calibration Topics 12
E Floor Gaging for Internal Thread Major Diameters Inspection, Prints (Drawings), Testing, Sampling and Related Topics 6
F SPC Data Analysis - Excel Spreadsheet I can use for Diameters and Perpendicularity Capability, Accuracy and Stability - Processes, Machines, etc. 6
G Tolerance for Cpk purposes on certain diameters Capability, Accuracy and Stability - Processes, Machines, etc. 10
H Measuring Diameters in Coordinate Measuring Machine (CMM) Inspection, Prints (Drawings), Testing, Sampling and Related Topics 11
R Inspection of Diameters on a CMM (Coordinate Measuring Machine) Inspection, Prints (Drawings), Testing, Sampling and Related Topics 13
T Deviation of shaft and housing bore diameters? Manufacturing and Related Processes 3
C SPC presentation - How to convince someone to use SPC - Grind diameters Statistical Analysis Tools, Techniques and SPC 6
Wayne Screw Thread Major and Minor Diameters - Parts vs. Gages Inspection, Prints (Drawings), Testing, Sampling and Related Topics 9
R SPC for Diameters - Parts not Perfectly round so charts are useless Statistical Analysis Tools, Techniques and SPC 28
P Gauge R&R of automeasuring machine for checking the crankshaft diameters Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
J Conducting Gage R&R - 300 plug gauges - Different diameters - One for each plug gage? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 10
J Finding a Radius - How to measure diameters that are not a full diameter Registered Visitor Articles Archive 19
N Drawing tolerance vs. Measurement device General Measurement Device and Calibration Topics 6
Ron Rompen MSA on automated measurement system - Multiple Step Vision System Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
P Thermo-Hygrometer - Measurement of 10DegC @10%RH ISO 17025 related Discussions 4
hogheavenfarm GDT Flatness measurement question Inspection, Prints (Drawings), Testing, Sampling and Related Topics 10
K Software Validation for Measurement Tools used in Process Validation ISO 13485:2016 - Medical Device Quality Management Systems 2
K Best Measurement Systems Demos in California? General Measurement Device and Calibration Topics 1
M Measurement Error - How to determine what is acceptable? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
K Process Mapping - Inputs/Outputs/Detail Activities/Control points/Measurement? Process Maps, Process Mapping and Turtle Diagrams 4
B IEC 60601-2-10 - Accuracy of Pulse Parameters - Required Measurement Uncertainty IEC 60601 - Medical Electrical Equipment Safety Standards Series 3
N Program or application for standard time measurement in industry from video surveillance? Human Factors and Ergonomics in Engineering 1
M Defining frequency of measurement tools callibration Calibration and Metrology Software and Hardware 3
T How to “validate/qualify” a new measurement equipment? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
Bev D Verification and Validation of Measurement Systems Misc. Quality Assurance and Business Systems Related Topics 0
F How do you add accuracies for tools with different measurement devices? General Measurement Device and Calibration Topics 1
M Viable count Measurement ISO Standard Other Medical Device Related Standards 1
J Gauge R&R on a torque measurement Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 11
W Air Quality Measurement Hardware and Software General Measurement Device and Calibration Topics 11
O Dimension Measurement Tool Recommendation General Measurement Device and Calibration Topics 21
G Does pitch/increment/resolution of a ruled scale apply to measurement uncertainty as line item? Measurement Uncertainty (MU) 10
Marco Bernardi Plane measurement with a 3D touch machine like a CMM. Calibration and Metrology Software and Hardware 3
R Uncertainty in measurement larger than tolerance Measurement Uncertainty (MU) 2
R Measurement Uncertainties Budget for Thermometer Measurement Uncertainty (MU) 6
O Performance Measurement ISO 9001: 2015 ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 2
O Monitoring performance - How do I determine performance measurement basis within my organization? Misc. Quality Assurance and Business Systems Related Topics 4
G What information to put on measurement Dimensional Results APQP and PPAP 7
D O Ring capability and measurement - What is the automotive 'norm' for capability studies on O Rings? General Measurement Device and Calibration Topics 3
F Electrical Metrology (Source/Generation and Measurement) General Measurement Device and Calibration Topics 1
G Gauge R&R on multiple dimensions using 3D measurement system Capability, Accuracy and Stability - Processes, Machines, etc. 6
F Measurement Audit and ILC for ISO 17025 Clause 7.7.2 - Comparison with results of other laboratories ISO 17025 related Discussions 0
Emran.mi Measurement system analysis - Can you help me about implementation MSA for CMM device Manufacturing and Related Processes 2

Similar threads

Top Bottom