Calibration of Temperature, Pressure Displays of Molding Machines

[galcantar]

I am working in a wiring harness factory wher we do a little molding operation - mostly as a way to pretect- cover ring terminlas- flag teminals and other ends, we are ISO/TS certified and since the beggining we are paying an external lab to come and verify- calibrate all these displays ( 4 molding machines), two weeks ago an external auditor mentioned that these displays don't need to be part of the calibration program. Iam wondering if somebody have a similar experience and or let me know how can I support any of the decisions - or we continue doing it or we just move- includ ethis operation as a part of the normal preventive maintenace. thanks in advance for the feedback you can provide

[BradM]

Well.... are the gauges used for anything in the process? Are the values written down? If one of the gauges were off (even by a lot) would it affect any of your process activities? If the answers are no, then you don't need to calibrate them.

Injection molding machines are famous for having 102 pressure gauges on them. They are used as aides when performing maintenance, but IMHO, they don't need to calibrate them (unless you answered yes to the other questions).

Now during maintenance activities, some of the gauge readings may be important; and they made need calibration.

So, figure out if the readings matter. If they don't, then skip the calibration.

[Marc]

To add to Brad's info, make sure you can explain to an auditor why you do, or do not, calibrate each gage, especially if you calibrate some of the gages and not others.

[Jeff Frost]

If the gauges are used to control the process to specified requirements then they must be calibrated.

[galcantar]

Thanks for your input I will check your suggestions.

[Marc]

Originally Posted by Jeff Frost

If the gauges are used to control the process to specified requirements then they must be calibrated.

Exactly, or if there are 20 gages and 8 of them are part of the process control aspect, those 8 must be calibrated.

[arios]

Going to the basics. The text form the ISO standard says:

"7.6 .....Where necessary to ensure valid results, measuring equipment shall
a) be calibrated or verified..."

If by the use of the displays you need to ensure a "valid result" then proceed with the calibration.

[Hershal]

Simple answer: If the gauges do not matter enough to require calibration, remove them from the machine. Then you avoid questions from the auditor.

If they are important enough in providing information that they are necessary for the machine, calibrate them.

Hope this helps.