Hi Covers,

I have a few ultrasonic welders that we use to weld products together during a recent calibration process audit we found that they were not calibrated.

My question is should these welders be calibrated i.e. Weld time, Power output, Force, Pressure they are used to assemble deliverable product so how do you know you're getting the right pressure, etc to get a good weld?

The manufacturing manager is having a fit because of the cost to calibrate the machines and says we've used them for years without calibration so why now?

Thanks,

Al40

The welders simply do not need calibrated. You verify the output of the welding operation by the integrity of the product produced. It’s no different than any other piece of manufacturing equipment. (God forbid I would have to calibrate 50 CNC Lathes…..). :mad:

This is really a calibration frequency issue, if anything.

There is also the issue of the need to calibrate. I would think that if you can show you have used the machines "...for years without calibration..." and there was no indication that they need calibration (no incidents where calibration of the equipment played a part in nonconforming product, for example) one could justify not calibrating the equipment.

I have seen this in a number of processes. One involved soldering irons where the auditor insisted the company calibrate their soldering irons (and that the operators be qualified). It could be shown that there had been no nonconformances due to soldering the component going back a number of years, and there was no customer requirement for calibration. The auditor finally had to 'give in'. It is not up to an auditor to tell you what to calibrate, but it is up to you to be ready to show/explain why there is no need to calibrate the equipment.

You would only need to calibrate the welders if you did not somehow check the weld or the product after it is welded. Remember you only calibrate gages and your gages accept or reject product. Are the welders listed as gages on your control plans or do you have real gages listed?

Prove to your auditors that you check the product after welding and it makes no difference what you did to the parts before that check (provided the parts are acceptable of course). Worked when we were audited to QS 9000 back in the day. Guess that arguement is still valid.

We have around 20 ultrasonic welders located throughout the Injection Molding Department and we do not calibrate any of the welders. The assembled product is inspected for TIR, securement (check torque), leaks, etc. We have no certifications however we pretend to be !SO 9000 compliant.

Hope this helps
Ramona