Counterbore

[cmmspm]

Good afternoon,

Has anyone ran into a problem where when they write a program with a series of counterbored holes, and the next time the program is run (the next day after everthing has been shut down and restarted) the stylus is not contacting some of the the counterbores because its trying to check it above the counterbore?

John

[rebeldude]

No. I use sample hits so that it finds the top of the part everytime.

[#2#]

Are you trying to measure the diameter of the counterbore or the depth of the counterbore?

It sounds to me that you are looking for the diameters. Do the hits for some of the bores fall in the correct place but not for other bores? Or, is it off for all bores and some of them hit because of the depth of the counterbore? If it is the second case I would suspect and alignment issue.

[bw_bob]

Not running 4.0, but here are some suggestions

1 Are you doing auto circles with sample hits and depth
2 Is the same probe being used
3 Could the parts have changed or set up differently.

[\v/inston]

are you using an auto circle with sample hits and a set depth? if you are then like GL said sound like an alignment problem or a check distance issue.

[#2#]

I would try re-calibrating the probe tip also. Could be that if you are talking missing by just a little bit. If you are missing by .25 inch then probably not going to help.

[cmmspm]

It's missing them but just a small amount. And it's not missing all of them it checked 10 c'bores and then on the 11th it started missing. I haven't tried any past the 11th hole. I re-calibrated, it didn't help. But, thinkgin back, I don't think I calibrated before I satrted programming the part. I guess this could be the problem?

Thanks you.

[Wes Cisco]

What kind of surface are these counterbores on? A plane? A cylinder? Is it level? Is it bowed? How did you align? I would guess that either the alignment or the straightness/flatness is the problem. I check counterbores fairly often and prefer to use auto cone when I have enough land to work with. I often use a pretty small tip to do this. (.5 to 1.5mm). HTH

[#2#]

It's missing them but just a small amount. And it's not missing all of them it checked 10 c'bores and then on the 11th it started missing. I haven't tried any past the 11th hole. I re-calibrated, it didn't help. But, thinkgin back, I don't think I calibrated before I satrted programming the part. I guess this could be the problem?

Thanks you.

Depending on your program you may need to only adjust that 11th counterbore's location. I would make a copy of your program before you start changing anything. That way if everything goes all wonky you won't have to start from scratch! So, then I would take the copy and try adjusting the 11th counterbore and see what happens. Run it slow though - don't want any fishhooks!

[bw_bob]

But, thinkgin back, I don't think I calibrated before I satrted programming the part. I guess this could be the problem?

Thanks you.

Depending on the difference in ball size and difference in length you might be whats called.

"nuts & bolts..nuts & bolts..i've been screwed".......sorry

[cmmspm]

re-calibrated - didn't help.
re-aligned - worked.

Thanks for all your info.

[email protected] bob.. i was using the same stylus. But I'm not sure how much of a differance it would make if it's not calibrated every day. Like when the machine is shut down over night.

[Matthew D. Hoedeman]

Shutting down the machine has NO effect on the probe calibration, it WILL change your machine home position slightly, so after a re-home, you MUST re-align anything you are working on and you MUST tell Pcdmis that the calibration tool is in a NEW location the first time you go to calibrate tips.

[#2#]

re-calibrated - didn't help.
re-aligned - worked.

Thanks for all your info.

[email protected] bob.. i was using the same stylus. But I'm not sure how much of a differance it would make if it's not calibrated every day. Like when the machine is shut down over night.

It shouldn't make much difference as long as no one crashed or messed with the probe.

I ALWAYS calibrate the probe before running a batch of parts through a program as I figure it is much easier to do that than to go back and re-measure parts.

[Wes Cisco]

Depending on your program you may need to only adjust that 11th counterbore's location. I would make a copy of your program before you start changing anything. That way if everything goes all wonky you won't have to start from scratch! So, then I would take the copy and try adjusting the 11th counterbore and see what happens. Run it slow though - don't want any fishhooks!

That must the be technical term. You say "fishhooks" like they are undesireable or something. I would investigate the alignment and part straightness before I adjusted a single feature because if the part is bent and you adjust the feature then the next part is not bent you are back to digging worms to cover your booboo with! Do you want to fix it now and get it right and be done with it, or do you want to tweak the program for each individual part that comes along?

So, I got busy and you solved the problem while I was away, and I come back and finish my post without checking first. Glad you found the problem.

[Sean Harris]

If the probe set up was not tampered with ( taken apart , bent, chipped ,or loaded up ) you could in theory never cal it again. Shutting the machine down would not necessarily change your probe file. That being said it could be corrupted, not saved correctly etc etc, but shutting the system down would not normally affect your .prb file.