SBS - The Best Value in QMS software

Contact vs Non-Contact Measurement

E

Eric

#1
#1
In my place of business there is currently a debate about the value of contact measurement (i.e. CMMs, pin gages) vs non-contact measurement(i.e. optical measurement)to verify the dimensions of machined parts. Is there any general consesus in the metrology industry on which type of measurement is more accurate or acceptable over the other? If so, why?
 
Standard Work Instruction Software by Dozuki
Elsmar Forum Sponsor
J

Jim Biz

#2
#2
My opinion only - Opticals (if we are talking shadow graph optical here) are "subject to light distortion" in varing degree .. contact should in theroy at least prove to be more accurate.

Regards
Jim
 
Jerry Eldred

Jerry Eldred

Forum Moderator
Super Moderator
#3
#3
I am not a guru in this area. I took a few moments to ask one of our mechanical people an opinion, and came up with none.

I don't think there is a single answer to the question. I understand laser micrometers and certain optical measurement instruments to be very good. But bottom line (I underscore I am not a guru in this one), it comes back to comparison of the measurement and its variables and the appropriate tool. Even in the semiconductor industry use of laser (6328 Angstrom) to measure film thickness has long been one of the industry standards. But as films get thinner, X-ray becomes more desirable, and ultimately, perhaps measurement of electrical parameters on the thin films may replace the laser (i.e.: first contact, then non-contact, then back to non-contact).

In larger dimensional measurements (machined parts), some of that may also apply. Contact vs non-contact temperature measurement - some applications one is better, some, the other.

I think you have to intelligently evaluate your application, and be familiar with the state of the art tools available to measure it.

------------------
 
Claes Gefvenberg

Claes Gefvenberg

Admin
#4
#4
Hi Erik,

Interesting question, but nigh on impossible to answer...

It all depends on what and how many objects you are measuring, what accuracy and speed of operation you need, etc...

Optical can be very good when you measure flexible materials for instance, but if you're measuring something with very generous tolerances it may still be "overkill". It's all down to the application..

/Claes
 
E

Eric

#5
#5
Thank you for your replies thus far. The particular application that is receiving the most argument is measuring a .104" thru hole in stainless steel with a tolerance of +/- .001". Our Quality department is verifying the dimension on a machine vision system using profile lighting and automatic edge detection and measurement software(stated linear accuracy +/- .00025"). Our machine shop is using pin gages (class ZZ) and has a severe distrust of the vision system. I guess I am looking for a strong argument that can support one department's method of measurement over the other's to help mediate a solution. Speed is not critical in this issue, but accuracy is. Again, thank you for any help you can give me.
 
S

Steven Truchon

#6
#6
Jim hit the major flaw in optical measurement, but it is manageable. Unfortunately most people will adjust light intensity to suit the image on the monitor which more often than not, is too bright causing the distortion that Jim mentioned. I have learned not to trust my eyes for optical parameters on a CMM. Once the optical measurement parameters are "proven" via other measurement methods, the optical method is reliable and very fast. My last experience with optical measurement was an OGP SmartScope and the only aspect that I didnt like was even though I could take one hundred plus points on a diameter, if the hole was not perfectly round I would not get the virtual diameter or the maximum inscribed circle which is what you'll get with .0001 increment gage pins for instance. For a thru hole of .104 +/-.001 diameter, I would always hard gage with pins whether I measured the part optically, or with a contact CMM or otherwise. Beyond that, air gaging is always an option but not cost effective for a .002 total tolerance.
I hope this helps

Steve
 
You must log in or register to reply here.
Thread starter Similar threads Forum Replies Date
optomist1 Recommend Primer Details of Non-Contact White/Blue Light Scanning General Measurement Device and Calibration Topics 0
C Biocompatibility Test for a Non Contact Medical Device US Food and Drug Administration (FDA) 11
D Actual Definition of Non-Contact for ISO 10993 Other Medical Device Related Standards 1
A Non-Contact Measuring Equipment Recommendations wanted General Measurement Device and Calibration Topics 4
R Non Food Contact Packaging cGMP's US Food and Drug Administration (FDA) 1
N Infrared Tachometer vs. Laser Non-Contact Tachometer vs. Stroboscope - Differences Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
E How do you classify Contact Lenses ? Non-invasive, Invasive or Surgically Invasive? Other US Medical Device Regulations 1
L FDA GMP requirement: Avoid Non contact with floor? 21 CFR Part 110 US Food and Drug Administration (FDA) 1
V Is spray painting allowed for non-blood contact medical devices? ISO 13485:2016 - Medical Device Quality Management Systems 3
F Non Contact OD Measurements of Ceramic Coated Rods Inspection, Prints (Drawings), Testing, Sampling and Related Topics 4
J FDA regulation on decorative contact lenses Medical Device and FDA Regulations and Standards News 5
Ed Panek IFU Contact Requirements - FDA and MDD/MDR US Food and Drug Administration (FDA) 1
P FDA Approved Product Contact Parts ISO 13485:2016 - Medical Device Quality Management Systems 6
L FDA Biocompatibility Requirements - Transitory Contact Other US Medical Device Regulations 1
G Saline solution change for soft contact lens potting CE Marking (Conformité Européene) / CB Scheme 0
P Induction hardened part in contact with product EU Medical Device Regulations 3
M Authorised Representative Contact Information EU Medical Device Regulations 3
I Food Contact Materials Declaration of Compliance Inquiry - (EC) 1935/2004 Food Safety - ISO 22000, HACCP (21 CFR 120) 4
T Type BF or CF (Direct conductive contact with the heart) IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
R Electrical contact resistance testing in MIL-DTL-5541 AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 3
I Process compressed air and contact with the product (ISO 8573-1:2010) Qualification and Validation (including 21 CFR Part 11) 0
Sidney Vianna ISO 18295 - Requirements for Call Centers (Customer Contact Centres) - 2017 Other ISO and International Standards and European Regulations 0
M Can a Consultant be the main contact for a Medical Device Company? Other Medical Device and Orthopedic Related Topics 6
R Disinfectant for Contact Lenses CE Marking (Conformité Européene) / CB Scheme 1
T Single Point Contact / DoC CE Marking (Conformité Européene) / CB Scheme 2
S Korea - MFDS (South Korea Ministry of Food and Drug Safety) Contact? Other Medical Device Regulations World-Wide 4
V Tie-wrap pull test to verify contact retention Manufacturing and Related Processes 6
J Change of contact person Other US Medical Device Regulations 3
M List of Contact Info for Asian Regulatory Authorities Other Medical Device Regulations World-Wide 0
L Canadian Users of ISO 14001 please contact me ISO 14001:2015 Specific Discussions 4
A 21CFR807.25 (d) Owner-Operator Contact question 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 1
J Plastic Compatibility tests with the contact of mucous membranes Other Medical Device Regulations World-Wide 3
B What is the safe Temperature Limit for Medical Device with blood contact ? IEC 60601 - Medical Electrical Equipment Safety Standards Series 3
G Clean Room Classification for Contact Lens Packaging ISO 13485:2016 - Medical Device Quality Management Systems 4
W Depth Gage Spindle moved when changing Contact Point Calibration and Metrology Software and Hardware 6
D Contact Retention Tools Question General Measurement Device and Calibration Topics 3
I Microbiological Monitoring for Surfaces - Switching from Swab to Contact Plates Other Medical Device Related Standards 2
Ajit Basrur Google?s smart contact lens: What it does and how it works Coffee Break and Water Cooler Discussions 9
F Where does Contact begin for Biocompatability? EU Medical Device Regulations 5
C Compressed Air coming into contact with Class II Medical Device Design and Development of Products and Processes 10
C Casual Contact With Exposed Metal - Infusion Pump - Type CF Medical Device IEC 60601 - Medical Electrical Equipment Safety Standards Series 6
P Food Contact Surfaces presentation # 2 Training - Internal, External, Online and Distance Learning 1
P Food Contact Surfaces Presentation Training - Internal, External, Online and Distance Learning 0
A Contact Resistance issue - Gold plating on PCB Manufacturing and Related Processes 3
J Testing data for Special 510k and contact person Other US Medical Device Regulations 4
M Copper Potassium Crystals forming on Switch Contact Silver Plating Manufacturing and Related Processes 2
F HACCP Certification for Single Use Disposable Food Contact Grade Gloves Food Safety - ISO 22000, HACCP (21 CFR 120) 1
S Suppliers of ISO 10993 compliant Material for Skin Contact Other ISO and International Standards and European Regulations 3
R Registration of Ophthalmic Optics Devices (Contact Lens) in China China Medical Device Regulations 2
F Class III Medical Device (Contact Lenses) Registration Timescale in Japan Japan Medical Device Regulations 4

Similar threads

Top Bottom