Should Air Screwdrivers be Calibrated?

[lmamao]

Hello all, hope you can help me with this. We are an ISO/TS 16949 certified company, in our process we use a lot of pneumatic torque guns, Air Screwdrivers, etc.

Some of this tools we say we calibrate them because they are adjusted to a certain torque range, here's where the question is, Do you think 7.6 applies to this type of tools?

I don't think so because is not a monitoring or a measuring equipment.

Do you agree?

Thanks,

Luis

 

[hogheavenfarm]

Re: Air Screwdrivers Calibrated??

We have had to calibrate the gages (air pressure) supplying these devices. This was due to air rivet guns needing a specific range of pressure to operate with the proper torque. For normal air ratchets and wrenches, if torque is not a specified requirement then no, no calibration, or you may also provide a final check later in production using calibrated equipment.

 

[somashekar]

I don't think so because is not a monitoring or a measuring equipment.

If you use a Air screwdriver and you are supposed to be operating at xx torque for the application, your screwdriver is understood to be monitoring and driving the screw at xx torque, to which it is set. Here you need to have some sort of acceptable verification, where you can check periodically or before use.

 

[BoardGuy]

As noted earlier if you are using these air drivers to apply a specific torque to a screw then calibration is required under 7.6. If you use then as an assembly aid and then torque then to the requirement with a calibrated torque wrench, then no.

Calibrating air drivers requires a little deferent calibration setup then just using a torque calibrator. The system used must allow running torque (similar to screwing the screw in) to set torque that matches the specified requirement.

 

[lmamao]

Well is not an specific torque, it's a range (since we are a remanufacturing company, there are a lot of variables in the process) for example for a process of a pulley assembly we have a range of 65-85 ft/lbs, and we do daily process inspection with a calibrated torque and verify that torque range.

 

[Sidney Vianna]

...snip... We are an ISO/TS 16949 certified company, snip... Do you think 7.6 applies to this type of tools?

I don't think so because is not a monitoring or a measuring equipment.

Do you agree?

Yes, I agree with you. These tools are NOT covered under 7.6. The torque-meter used to verify the torque, on the other hand, is.

snip (since we are a remanufacturing company, there are a lot of variables in the process)

I thought the eligibility requirements for ISO/TS-16949 certification did not allow remanufacturing plants to be certified, but I may be wrong.

 

[BoardGuy]

Well is not an specific torque, it's a range (since we are a remanufacturing company, there are a lot of variables in the process) for example for a process of a pulley assembly we have a range of 65-85 ft/lbs, and we do daily process inspection with a calibrated torque and verify that torque range.

[FONT=&quot]So your nominal is 65 +/- 10 ft/lb more or less. Rule of thumb would be to calibrate them at appropriate points between 60 to 90 ft/lb. [/FONT]
[FONT=&quot]Even if process is overhaul fasteners require specific torques to prevent failure.[/FONT]

 

[gpainter]

Most definitely. I would look at your air system for issues, as they are about 5% efficient at best. Leaks, leaks, leaks. Consider using rechargeable tools as compared to air. Total cost will be less

 

[qpappa31]

I am running into the same issue at my plant now. We are an ISO/TS 16949 manufacturing company. During our last TS Audit, the auditor asked about our pneumatic torque tool calibration. We have about 60 air tools in house and we send them out for repair when needed but never actually perform a calibration on them. We do verify the torque at the start of the shift using a Norbar Torque Meter & Transducer. All of our process have a torque range (ex: 6-9 Nm). We verify the torque tool by running it down on our transducer at the start of every shift as I said and if its out we adjust the tool or replace it.

Our auditor told us that this is not sufficient and that the tools need to be actually calibrated. I've had this position for 10 years and this is first time any auditor told me this so now I am stuck trying to figure out what to do. I thought the audit at each shift would be sufficient but apparently not.

I am not sure what calibrating the torque tools will actually accomplish. If the tool has a range of 5-12 Nm but my target range in my process is 6-9 Nm what added benefit am I getting out of the torque tool being calibrated when I am verifying the gun at the start of each shift. I guess what I'm asking is what are they actually doing during a calibration of the torque tool.

 

[gpainter]

That is strange. I would think as long as you are verifying the torque with a traceable instrument that it would be good. Has someone else ran into this? Talk to your auditor.