Exported the various relevant features as DXF files and CAM'd them using VisualCAM. I learned to use and drew it up in DesignSpark Mechanical - literally the first 3D CAD program I've ever used. My machine only has a few inches of travel so I needed something with a super low profile, and since apparently I'm the only person on the planet who needs a low-profile touch probe I had to design and fabricate one myself from scratch. Originally I planned to just buy one off Ebay/Amazon, but all of them were way too long. I've been having no problems whatsoever with my custom-made 'always-on' probe: My purposes are a bit more involved than that though.
Yes, if your one and only goal is to figure out just where the tool is relative to the top surface of the workpiece then a simple little contact piece sitting on there with a known thickness is just fine. My goal is to map the top surface of a workpiece for a V-carving, which is very sensitive to an irregular surface because it can totally ruin the end result if not planed out or compensated for, and because I work with various pieces of degraded wood (for aesthetic) the goal is to not plane the top surface perfectly flat. it does not matter what it is so long as the thickness is known. alternativly i small piece of metall sheet with one corner bent up, and a hole drilled thought it would allow attachment of a wire with a nut and bolt. that then becomes a flat conductive surface to lay ontop of the work while probing. Just buy a small piece of copper clad blank printed circuit board, and solder a wire to one corner.
The new 0-point will be stored into the arduino to keep it if you need more parts with similar thickness. Then z will be lifted up 0,5 mm again and stop. Then I run the probe-sequence with fast z-movement.Īfter switch has been activated, the z-axis will lift up 10mm and move then down again, but now with really low speed, to stop directly after the switch is 2nd activated. Now I have to add this switch on top of the material (if material thickness is increased, the switch is on a higher position). It´s a normally open one with a long pcs of metal (to have a long "spring"-way after 1st contact). Why you need to invert the pin, because of an nc-used switch? I can´t answer your question about the capacitor, because I don´t use any.īut I think you need to insert it in paralell to the switch. Just run gcode ripper on one of your gcode files and look at its output, you will see the sequence of operations. Grbl doesn't do variables (yet/never?) so you would need to write some sort of preprocessor to handle the operation based on the gcode that GcodeRipper outputs. If using Mach3 or LinuxCNC, then this would work directly. (this is what comes back from Grbl when the probe switches to ground) Grbl will report the machine position of the probe touch.
The G38 will move to X and Y, then Z axis will lower to -100 until the probe makes contact with your object, at which time movement stops. A typical porbe command might be G38.2 X20 Y15 Z-100 (in mm mode). The probe position is relative to machine 0. So the probe is anything that will take pin A5 to ground when it touches your object. Some sort of spring arrangement would do. Whatever probe you design should be able to handle some over travel, the Z movement likely won't stop immediately. Grbl will report the probe position back to the user when the probing cycle detects a pin state change. A simple probe switch must be connected to the Uno analog pin 5 (normally-open to ground). The G38.2 straight probe and G43.1/49 tool offset g-code commands are now supported.
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