I hope this is in the right forum, if not, i apologize.

Having issues in our Final QC area. We have gone through 7 pairs of calipers in one years time in this area. Everytime it seems to be "grinding" and "squeeking" when opening and closing the calipers.

I just put a new pair down there 2 weeks ago, and already this is happening.
I do not have any backed reasoning, only my opinions. I feel the rate of inspection is to high for calipers to handle on repeated use. I have tried to train and "slow" the inspection process some, but it's hard to get operators to slow down when there supervisors are telling them to hurry and get the lot out.

We have been through SPI, Mitutoyo, Starrett and Fowler. We get the same results on all, but only in this area. No other area has similar problems.
Clean environment as well.
Does anyone have some suggestions on where to turn as far as testing, training or anything else I could use at this point??:blowup:

Are operators using any lubricant, compressed air :bonk:, or any other substance to remove contaminants?

Observe, and you'll know....

Stijloor.

Have you had comrehensive training? Have you performed any gauge R&R studies? Does this group measure material different than other groups?

It's possible this group is placing entirely too much pressure on the caliper when taking measurements.

Do the calibration values on these look adequate prior to retiring them?

Just my opinion, but I would not sacrifice sampling rates (if they are appropriately calculated) simply due to wearing out calipers. I am in an organization where calipers are used several times a day, and they have had them for 10+ years. I'm thinking there is something else going on with the group.

I would approach this as a matter of root cause, and not "going after" the QC inspectors.:D I'm pretty sure you would not do that, but if they felt they were being singled out, they might 'clam up', and you would not get any information out of them.

fortyfour73,

Have you considered non-contact measurement devices? The devices do not wear-out from contact with the product but their measurements are often sensitive to contamination on the product surfaces. The initial cost for them is considerable but there are benefits to their long term investment. First and foremost is precision and accuracy, next I would say is speed of measurement and ease of data collection, then repeatability and reproducibility among users. There are many different types of devices and their costs vary considerably depending upon their sophistication, volumetric capacity, and precision. A simple search of “non contact measurement devices” will reveal many types, applications and sources for these tools.

When I worked as an STA liaison I encouraged some of our suppliers of precision ground spool valves to consider laser micrometers for their OD measurements. The devices are so precise that they had to angle the axis of the valves with respect to the ribbon-like laser beam otherwise their readings would vary with the peaks and valleys of the surface finish. Naturally where center-less grinding was employed precautions were established to detect circularity (odd-lobbing) to insure that the (2-point) measurements reflected the effective size. Attached is an example of the device they used.

Paul

Grinding? Squeeking? I used to handle calipers a lot, and I don't feel familiar with these handling issues. Are we dealing with a bunch of Popeyes?

If the issue is sprinking the jaws, operators can be trained - and should be, because springing the jaws can bring error into the reading.

Supervisors should not be allowed to overly influence inspector behavior - doing a good job with inspection usually involves a studied approach. That doesn't mean they should move in slow motion, but jerking the tools about can't possibly be adding value to the inspection step...

Are these tight tolerance, critical measurements, or can a jig be set up to make quick checks?

My only other idea is to use vernier calipers. But then you have another problem: what my dad used to call "inchitis..." reading off by .01, or .1 inch.

A similar issue I had. After going to the gemba, observing and asking, I found that there were some major issues in comprehension, lack of the right tools and no visual controls. Not at all a suitable environment for a lab! Not at all anyone that could be called a QC Inspector, or Tech.
The solution was first control of who used, reducing if needed (start small), second training that deals with respecting the equipment and why, then continuous training and auditing to the standards and training. During this, implement visual controls and written standards. After gains, you can increase the who, if needed.

If the proper leading and accountability is done, and over time there are a few bruits, you may have to move people out of such a responsibility, should be a rare thing though.

I may have some documentation that may help, but I would need more specifics as to what equipment you are using. PM me, and I will see if I can find anything.

Are your operators not loosening the little screw on the top of the set that can hold the calipers in place? That would be the only way I could see a pair of calipers 'squeaking' or grinding.

I hope this is in the right forum, if not, i apologize.

Having issues in our Final QC area. We have gone through 7 pairs of calipers in one years time in this area. Everytime it seems to be "grinding" and "squeeking" when opening and closing the calipers.

I just put a new pair down there 2 weeks ago, and already this is happening.
I do not have any backed reasoning, only my opinions. I feel the rate of inspection is to high for calipers to handle on repeated use. I have tried to train and "slow" the inspection process some, but it's hard to get operators to slow down when there supervisors are telling them to hurry and get the lot out.

We have been through SPI, Mitutoyo, Starrett and Fowler. We get the same results on all, but only in this area. No other area has similar problems.
Clean environment as well.
Does anyone have some suggestions on where to turn as far as testing, training or anything else I could use at this point??:blowup:

Hello,

Have your issues with the calipers been resolved? If not, please let us know.

Stijloor, Forum Moderator.

I was also going to suggest looking at the little screw on top to see if it is tightened - obvious I know, but like in most problem solving situations, look for the simple obvious stuff first before investing in new equipment.

Another thing in that area could be abusive handling. Dropping them or tossing them around will cause the tetth to break and cause what you are describing.

Rather than guessing, I would send a notably bad pair to a calibration laboratory that is also qualified for repair, and have them fix it and tell you specifically what is happening to the gage.

Rather than guessing, I would send a notably bad pair to a calibration laboratory that is also qualified for repair, and have them fix it and tell you specifically what is happening to the gage.

Why Bob, that is a devilishy tricky but brilliant idea!:D:agree1:

That's also a good method to check and see if your calibration lab is truly checking everything-adjust the instrument out (to a known value) and send to the calibration house. :D

Why Bob, that is a devilishy tricky but brilliant idea!:D:agree1:

It wasn't meant to be tricky...but I'll take brilliant. :cool: Point is, you need to have a person trained and qualified to tear down a device in order to seek its problem, replace and repair, an give a meaningful report. Of course, your PO should specify that report of failure mode and repair, or they will just give you a cert. Now THAT is tricky....and brilliant, I must say.....:cool:

Try transferring the employees to a different part of plant. If calipers wear out there as well you know you have a bunch of dummies in one sector.