z-zeroing

[lutchman]

hey all,
our machine is not zeroing properly, sometimes it zeros exactly on the top of the material (as it should) and most time it zeros about .01-.005 of an inch (sometimes more)above the material. the zeroing is always inconsistent. i am sure its not the vacuum and the hold-down that is causing this inconsistency, is there anyone with another suggestion?

[jerry_stanek]

Are you running the vacuum while you zero. is there anything under the plate and is your plate flat

[lutchman]

yes...i always turn on the vacuum when zeroing and i blow out any debris around the area i am zeroing at! the plate is flat and smooth except for a few minor scratches but i always use the same area of the plate to zero.

[billp]

Have you actually measured the thickness of your Z Zero plate to be absolutely SURE it is the SAME thickness that your zeroing program THINKS it is?

[lutchman]

bill...no i have not, but even if i did where can i find the zeroing file, in the event that i may need to change the values? Also, if there is an issue with the zeroing program, wouldn't the error be consistent each time i zero? thanks for your comments and suggestions, really do appreciate it.

[blackhawk]

Lutchman, when you use the zero plate, do not touch any part of the machine frame. I have gotten errors on my Z zero, when I am holding the zero plate with one hand and then have my other hand touching a rail, for example. Your body can act as a grounding path, giving a false signal.

[jerry_stanek]

Once you get the exact thickness go to tools setup and on the third screen is where you pit the thickness in

[lutchman]

jerry- thanks! will measure and double check with the file
brad- that bit of info i didnt know, cause i am usually holding onto the rails myself...it could be possible that that is my problem.

while we are on this topic, is it ok to permanently ground one of the z-zero lines to the machine thereby eliminating the use of the clip, so when zeroing just place the z plate under the bit and hit enter?

[shilala]

jerry- thanks! will measure and double check with the file
brad- that bit of info i didnt know, cause i am usually holding onto the rails myself...it could be possible that that is my problem.

while we are on this topic, is it ok to permanently ground one of the z-zero lines to the machine thereby eliminating the use of the clip, so when zeroing just place the z plate under the bit and hit enter?
If the zero plate is grounded when using a digitizing probe, it'll destroy the probe. I read that somewhere in shopbot material, someone please correct me if I'm wrong.
Being as the plate isn't grounded, there's got to be good reason. It may just be because of the digitizing probe issue, I don't know. Regardless, I wouldn't modify it.
I've even taught myself to clip the ground clamp to a zip tie that's on my machine so I'm certain it's never grounded, just in the odd circumstance that it could possibly cause a problem.

[steve_g]

The voltage signal would have to go through the brushes of the router... I don't think that you can depend on every thing stopping at the right point 100% of the time.

SG

[waterwheelman]

I have my z-zeroing plate wired direct to the input on the controller. The cord is a spiral telephone cord that stretches to the table top or material for zeroing. I have a plastic sleeve on the Y carriage that I slip the plate into when I'm done using it. The plastic sleeve keeps it from touching any part of the frame and sending a false signal during machine operation and cutting. This setup has worked fine for about ten years.

[curtiss]

If you ....watch your screen.... during the z zero,

when the bit makes electrical contact, the z number should change to the exact thickness of your z plate.