touch probe ideas?

Mostly Printed CNC - MPCNC Advice
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Anybody make there own touch probe? I’m looking for ideas. Love to see other peoples designs.

 

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Mine is pretty simple. I scraped the paint from a thin piece of conductive material (e.g. hacksaw blade) and place that on top of my material at the origin. In repetier, I do a home operation, followed by a custom script that sets x0,y0,z-t where t is the thickness of my hacksaw blade. In theory, this sets the origin to the surface and lower left corner of my material.

 

 

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Hmm hacksaw blade. Creative!

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@Dalton Porter

Do you mind to share your script?

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Printer Settings ->Scripts

“Script 1”

G92 X0 Y0 Z.6

This drops the origin by .6 mm

This will be stored in the manual tab under the “1” button.

I connect my zprobe wires (one to the bit and the other to the hacksaw blade) using alligator clips. I do a home, then I press the “1” script.

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Can you use the G38.2 probe command in marlin? I know in GRBL you can. By using this command makes the cutter come down to the touch plate and when it gets contact it stops. Then you can use the G92 command the set your new z height.

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I’ve not tried G38.2, at least not directly. It may be what the home button is doing. When I use home, the cutter does a slow dropdown, touch, then doest a retract, then does a slower drop down to get a more refined location for the touchplate. It stops the 2nd time it hits the touchplate.

I’m using Marlin.

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I have not set up a probe yet. but from what I’ve ready for GRBL by running this does something similar to what your doing in marlin.

G38.2 Z-20 F1; G92 Z 16.82; G0 Z20;

g38.2 starts the probing going down 20mm at feedrate of 1mm

after it touches it sets G92 to the Z thickness of your touch plate(which is whatever yours is)

then it has the Z move up 20mm and your ready to go.

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I’m pretty sure we don’t have that command for marlin. I could be wrong, I’ll have to try it in a few minutes.

 

Yea, that’s what I thought, we don’t have that command.

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I don’t think we need that command in marlin, since the Z homing function basically does that. You use G28 Z to home just the Z, Attach probe to the Z endstop pins.

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I was really just looking for touch probe ideas. Looking to make one.

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Here’s a touch plate I added on to Ryan’s pen holder. It may give you some ideas.

Foil tape (for AC ductwork) and alligator clips are cheap & stupid.

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Here’s mine. I don’t even take the thickness into account. For 99% of the stuff I do with it, it doesn’t matter.

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Okay, just responding to your question if we can use G38.2 in Marlin.

 

I just took a piece of bar aluminum, screwed a wire on to it. My particular piece is 5.5mm thick. That wire goes to one pin on the Z endstop pin, and the other pin goes to an alligator clip on the bit.

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I just use a piece of aluminum tape .1mm and alligator clips 1 to tape and 1 ground to bit. I’m using gerbl and UGS and it works great as long as you remember to remove the clips BEFORE you start the router :frowning:

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That was exciting!

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Did you get a video of that? :slight_smile:

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Nooo video but Even if I did nobody would ever see it :slight_smile: There was a high pitch whistle and everything within 3 inches whisked off the table and I was left with a shorter wire than I started with while I scratched my head for a second thing what the H___ just happened. Fortunately I had improvised and used a wire with alligator clips on both ends connected to a wire connected to my Rambo mini otherwise I see my mini flying around the room but i never have found the second clip yet

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And there it is a new use for the CNC, you made the worlds first CNC Weed Whacker!

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LOL.