Other Touch Probes

Hi,

well technically still a DIY solution but a really simple and affordable "poor man's touch plate":

http://www.youtube.com/watch?v=aT_9LtDPnKw

I'm not sure about UCCNC but as it is basically just a really large switch it should be possible to do something like this with most controllers.

Christian

Hi SFDeeJay,

Surely what you are after is a simple tool length sensor similar to this one? Standard Stepcraft accessory if you don't want to make one yourself.

Use a double speed probe macro (M31) to get the best accuracy. Mine has a repeatability of the order of 10 microns or so. I can post my M31 macro if you are interested - no fancy frills, the offset is set in the macro itself.

Peter

Peter - I feel like such a floundering newbie, thanks for your patience. I (wrongly?) assumed that the tool length sensor only shows depth, NOT where the tool is on the X and Y planes. If it can, indeed point to the exact position of the tool, then that is quite a bargain for someone who lacks confidence in building even a simple one from scratch. My only hope is that by not being afraid to ask basic questions, someone else may benefit from experience such as yours.

Hi SFDeeJay,

No need to be embarrased about asking for help - we have all been in your position during the learning process. Only too glad to pass on what little experience I have if it can help enjoyment of the hobby.

Just to clear up some points of terminology as far as I understand them. A tool length sensor only detects changes in the Z-axis direction, whilst a touch probe will detect motion in all three axes (X and Y as well as Z) and is necessarily a much more complex device. Of course it needs much more sophisticated software to utilise the extra spacial information it can provide.

I think the Stepcraft tool length sensor is a simple microswitch in a fancy case, the normally closed contacts always (in theory at least) open at the same physical position of the little moving platform as the tool is lowered slowly by the M31 macro. The distance above the base at which this occurs is set in the macro, hence the Z-axis DRO can be set so that the tool just touches the baseplate when the DRO reads"0"

Peter

Thanks again, Peter. You confirmed what I thought, but was unsure. Here is a link to what I think might be a good solution, not too costly ( https://triquetra-cnc.com) unknown is whether it will work with the UC-100. It does work with Mach3 and an Arduino. I'm tempted to go for it.

I think the one you mention is primarily an accurately machined corner piece with known dimensions. When electrical contact is made, it seems as though the software generates appropriate Gcode that you would have to add into your application Gcode manually.

You could achieve similar results using some self adhesive aluminium or copper foil a battery and a lamp!! Oh - and some wire!!!!!

Seriously though, a Stepcraft sensor is less expensive, does the Z-axis job without you having to edit Gcode files. One less thing to worry about at the early learning stage - later on as you gain experience, by all means go more sophisticated.

A proper touch probe is, IMHO, a much better physical solution whilst still requiring code manipulation or manual setting of the DRO. The may well be macros already available for UCCNC and/or Mach3 or 4.

I made my own tool length sensor a few months back - it works very well and is extremely accurate (+- 0.0005")

Peter