[willower]

I have recently installed the Big-Tex Probing screen v3.2 which seems to work absolutely fine.

However, after much testing now, I am getting a consistent error in that, once I take the touch plate away and 'GotoZero' I am always left with a clearance of 0.015" above the workpiece?

I have checked and re-checked everything I can think of which would affect the accuracy of the machine as follows.

1. Z axis movement 100% accurate when measured using a DTI (within 0.0005 over a 1" travel).
2. Plate thickness set at 0.07874" (2mm Brass Plate).
3. Z axis movement is smoothly operating with no binding.
4. All offsets set to zero prior to using the probe function.
5. Have tried various 'Debounce' settings between 0 - 2000 with no improvement or difference.

The Z axis has a 3" total movement (Marchant Dice manufactured) and has proved itself over time to be very reliable and accurate.

I really am stumped as to where this inaccuracy is coming from as most people seem to get very good results using this screenset - it's just that I can't seem to get the accuracy that I'm looking for.

Has anyone any idea why this is happening - or am I being too hopeful in looking for this degree of accuracy.

[ger21]

Debounce has no effect on probing.

Did you measure the actual plate thickness?

Are you using the parallel port, or a motion controller?

[willower]

Hi Ger21,

Yes I did measure the plate - once by vernier and twice by micrometer - both results tallying...

And yes, I am using a parallel port.

[ger21]

Is the tool actually touching the plate each time? Sometimes noise can trigger the input slightly early.

[willower]

Definitely touching - twice in fact, once at 10.0 IPM and the second time at 5.0 IPM...

[willower]

OK everyone, have sorted the issue now and would like to say it has all been my fault completely:withstupi

As I said, I did all the measurements correctly - before actually finishing off the actual touch-off plate, which I backed with a piece of clear plastic to avoid marring the polished Brass/aluminium/stainless steel plates I use for engraving. Guess who forgot to add the thickness of the plastic? Doh!

Anyway, many thanks Ger21 for making me think harder - I knew it must be something stupid,it was ME!!!

If we didn't make any mistakes, we would learn nothing of any real value....