Automated internal thread gaging 1

[wmdn]

I have recently quoted a high production job for the automotive industry. One of the part features is an internal M10 x 1.5 thread that requires 100% inspection of Major, minor, and pitch diameters, as well as lead error. The gage must also be capable of outputting the dimensions electronically. Does anyone know of a gage that can check all these characteristics, and, hopefully be adaptable to automated checking. We will be running these parts on a twin spindle turn/mill center with gantry part loading and unloading. We can program the gantry to stop and place the piece on a fixture, or drop the piece on a shuttle to be carried to the gage if necessary. Upon completion of the inspection the gantry would pick up the piece and carry it to the conveyor.

Thank you for any and all responses to this thread.

 

[PSE]

Ugh, You have me stumped . Not much room there to work with at all. About the only thing I could think of would be to try to take a cast impression of the threaded hole, remove the form and measure that. I am not sure of a good material for that purpose and it would likely loose a lot of accuracy as it got turned out of the hole. Not to mention the possibility of plugging the hole or leaving material behind when removed.

Is it possible for the design to change to a stud so that you could have external threads to work with? I shudder to think at what happens if the internal threads are wrong. Especially if it is a key feature to the part (sounds like it is given the 100% inspection requirement). Would the whole thing get scrapped or would it be reworkable?

Good luck, hopefully others will have better ideas.

 

[wmdn]

Unfortunately, the assembly design will not allow this thread to be external. Even if it could , it would only transfer the quality requirements of the internal threads to another component. I am still not sure how to accomplish this task without additional direct labor input, (a potential deal killer for us), however i am looking at methods that would reduce the labor content to an acceptable level.

I am going to look more closely at Johnson Gage, as it seems to have at least most of what we require, and looks like it may be relatively quick to check the part if properly fixtured. From the pics on their website, it looks as though it is fitted with dial indicators. If it can be fitted with digital indicators, and output to spc, it may satisfy our customers requirements.

Thank you for your response, and if anyone else has any ideas I would appreciate hearing from you.

 

[rhodie]

This is probably a stupid thing to say, but can't you just perform your inspection on the cutter after every part, and determine whether or not the parts produced are satisfactory?

 

[wmdn]

Rhodie,

No, I don't think it is a stupid thing. It's something I hadn't thought of. I will have to give it some though to see if it is feasible to inspect the tool. It may be diificult, as the cutting tool is either a carbide tap, or forming tap (haven't decided yet).

Thanks for your input. I have to study that one a while.

 

[wmdn]

Rhodie,

I don't think it is a thing to say. It is certainly something I hadn't thought of. I will have to do a little studying to see if it is feasible to check the tool. It may be difficult as the cutting tool is either a carbide tap, or forming tap, (haven't decided yet) and not a lot of available time within the manufacturing cycle.

Thanks for your input.

 

[mscatoloni]

Your best bet for internal thread measurement is to look at either Johnson Gages or Bowers/Fowler Gages. I am in the aerospace hydraulic fitting industry where we manufacture 1000's of threaded parts (internal and external threads per AS8879)and use SPC controls to monitor Pitch Dia, Functional Dia (ie. Lead), & Minor Dia, using these gages and output measurement data via RS232 connection.

 

[SteveMeisel]

I am not sure if this will work but it is worth a try:

http://www.ndttechinc.com/20_ghp2x.htm

They use a probe that measures the eddy currents to measure the threads. We have several of them in house.

 

[wmdn]

Thanks to all for your response. Though we were not awarded this job, I believe the information will be helpful in other applications. Thanks again.

 

[dskarupa]

I just went to Cutler-Hammer seminar and they make a programmable proximity sensor that could detect that the hole had been tapped but could not measure the pitch.