Process Validation on Vision Inspection System

Nancylove

Starting to get Involved
I have a question about validation vs. calibration of measuring equipment for a medical device company. A recent internal audit reported that we haven?t performed OQ/PQ on our vision inspection system for inspecting mechanical parts. This confuses me. This equipment is calibrated. I didn?t understand why measuring equipment that is calibrated also needs to have process validation. If process validation is required for measuring equipment such as a vision inspection system, is it required for all measurement equipment? Looking at 2 extremes: the vision inspection system and a digital caliper: Would process validation be required for both pieces of equipment after calibration has been performed?

Thank you much.
 

somashekar

Leader
Admin
Nancy ~~~
Welcome to the COVE.

Does your Vision inspection system gives out a measurement or it decides the Pass / Fail status of a part based on what you learn into the system.
 

Nancylove

Starting to get Involved
Nancy ~~~
Welcome to the COVE.

Does your Vision inspection system gives out a measurement or it decides the Pass / Fail status of a part based on what you learn into the system.
If you create a part program, part of the process is to enter the dimensions and tolerances. Then, when inspecting a part, the system will give you all of the measurement results and indicate all passing and failing characteristics.
 

Kales Veggie

People: The Vital Few
If you create a part program, part of the process is to enter the dimensions and tolerances. Then, when inspecting a part, the system will give you all of the measurement results and indicate all passing and failing characteristics.

The simple question is:

How do you know the results are valid? How do you know the equipment is set-up correctly? Has the equipment been maintained properly? How do you know the software is correct and/or recently updated without effecting the results? Programmer made a change to the program, are the results still valid?

A calibration, maybe every 6 months, will not tell you this.

You need to validate the equipment before use.

(Caliper vs. Optical system: complexity, a lot more variables that can effect the final results).
 

somashekar

Leader
Admin
If you create a part program, part of the process is to enter the dimensions and tolerances. Then, when inspecting a part, the system will give you all of the measurement results and indicate all passing and failing characteristics.
So it is a contactless optical (Vision) measuring equipment.
This is calibrated.
So if you have measures that safeguard the equipment from adjustments without authorization, protected from damage during use, maintenance and storage...
and the required equipment installation is done per the recommended guidelines aka IQ., you must be good.
The software used is not for a specified requirement, but the software that runs the equipment is the company provided equipment firmware that is necessary to use the measuring system.
I guess you are good and your internal audit just needs better process validation understanding.
 

bobdoering

Stop X-bar/R Madness!!
Trusted Information Resource
OQ/PQ has always been a painful concept to me, even when I was in medical (see posts on frustration with people tring to OQ/PQ bagging machines.)

But, let me put the issue in the simplest terms. There is gage error and measurement error. Two vastly different things. Gage error is the intrinsic error of the gage - it simply can't do any better. Measurement error is taking a perfectly good gage and using it incorrectly. You need to ensure they are both statistically insignificant for your requirements.
 

Nancylove

Starting to get Involved
Kees, Someshekar, Bob Doering,

Thank you much for your responses. I think you all had input that validated my thoughts.

In my opinion, the equipment itself does not require OQ/PQ like Someshekar mentioned, but it does require IQ and PM. However, a test program and test setup should be validated. A vision inspection system is prone to measurement variations due to variations in part reflectiveness, part roughness, features related to or near the feature of interest, and anything else that can affect the lighting and imagery. This can affect the effectiveness of a program/setup validation.

Do you agree with my thinking?

Best regards,
Nancylove
 

sowmya

Involved - Posts
Hello Nancy

I agree, for each lot there may be a variation due to reflection, part roughness and features related to that. we use optical character verification as a tool for programming. what you are talking is a true call or false call.

how do you ensure that your programming is correct? the tolerances given while programming is within the boundary of screening good and bad parts?
what we do is, after each program, we do 100 % Visual inspection after AOI for first 100 parts. we also mix process indicators and confirm whether the programming is done correctly. This is for program qualification. for all batch productions, you have to fine tune the program for parameters like reflection, brightness...etc to reduce the false call. first 5 boards of each lot will be sent five times through AOI to confirm that it is producing same results every time.

The above process is developed in line with our own requirements. hope it helps
 

bobdoering

Stop X-bar/R Madness!!
Trusted Information Resource
A vision inspection system is prone to measurement variations due to variations in part reflectiveness, part roughness, features related to or near the feature of interest, and anything else that can affect the lighting and imagery. This can affect the effectiveness of a program/setup validation.

This is true, and the set-up of the lighting is a huge impact on the repeatability of teh measureemnt. Vision systems prefer lighting a bit darker than a visual observer. So, the technique for both locating points and features, and the setting and control of the lighting will be critical to its effectiveness.
 

Florent73

Registered
Hello Everyone,

I am more or less facing the same issue. We are currently manufacturing metal parts for the medical device industry. The shape/dimensions of the parts are 100% visually controlled through online camera. So far we haven't performed any qualification of the equipment. We are in a process of seeking ISO 13485 certification. I was simply wondering whether you could suggest references/books/standards on how to perform a proper qualification of such vision measurement system both on line (100% visual inspection) and of line (metrology laboratory for QC).
Many thanks,
Florent
 
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