Post by ibohan on Mar 12, 2019 5:09:50 GMT
I've been reading around the interwebs about better ways to zero the machine aside from eye balling it against an edge. I came across the touchplate idea, and was a little disappointed with the options and the prices, so I decided it was worth it to go ahead and make my own.
Coincidentally, as I was reading about it I came across a couple recent posts about how to setup and use the touchplate, so I decided to show a how I did it, step by step. Thanks to Bruce for asking me to post what I learned.
First off, I like to set the zero as a corner on the fixed jaw of my vise.
This helps, because most jaws are metal and an extra touchplate isn't actually needed if you have a metal vise. If you don't have a metal vise, or if you want to set the zero off your stock, I quickly modeled up a touchplate in Fusion 360.
Here is the link to the touchplate model: a360.co/2EUpcCu I'll go into more details on how to use this particular touchplate at the end.
What I needed to set up my touchplate system:
2 wires about 2' long. I used 22 gage wire
2 .1" pin connectors (or one 4x1 .1" connector)
1 alligator clip
1 spade connector
I created two wire assemblies, one with an alligator clip, and one with a spade connector. Each wire had a .1" pin connector on the opposite side. (Sorry I didn't take any pictures.)
On the motor board, I connected the spade connector wire to the SCL pin, and the alligator clip wire to the GND pin.
(This is a picture of mrbigj's board)
On the vise, I attached the spade connector to my fixed jaw. I did this by flatting the spade connector and sandwiching it behind the jaw. I'm eventually going to find a more permanent solution, but for now it works well.
Now, I use UGS platform, which allows for custom macros. I created a macro to automatically zero, one for each direction
Here's the G code:
Probe X:
Probe Y:
Probe Z:
The thing I noticed about this command is the tool will move towards the already set 0 location. I'm not sure if this is specific to UGS, or its how the G38.2 command works. So I need to make sure the zero point is set past the vise in the direction I want the tool to move.
To test the macros, I ran each one and touched the alligator clip to the vise. When I touched the alligator clip to the vise, UGS set the position to 0 and the tool moved back 6mm.
Now, to use the whole setup, I clipped the alligator clip to the tool, moved the tool 12mm from the vise surface, and ran the macro
(GIF link)
(I noticed some end mills didn't trigger the sensor, likely because of a coating. Pushing the end mill lightly while its moving helps)
Now, after doing this for each direction, this sets the tool edge to the corner of the vise, not the center of the tool. So I just manually adjusted the tool by the radius of the end mill to set the center. I also created macros to do this for my most common end mills.
--If you want to use the separate touchplate--
First: download that model I made.
I modeled it from .5" aluminum stock. It's 2" x 2" and has a 4mm hole for a 4mm banana jack.
Second: make it on your machine.
Third: place the touchplate against the corner you want to set as zero and do as I did above, except replace the spade connector with a 4mm banana jack and plug the banana jack into the 4mm hole in the touchplate.
Fourth: use the macro as I did, except now you will need to offset an additional .25" in the Z direction, and .5" in the X and Y (plus the radius of your end mill). This is because the edge of the touchplate is offset from the edge you want to set to zero.
To be more accurate, you can measure the offset of the touchplate with calipers or micrometers and offset that value instead. It could be a little large or a little small depending on your tolerances. If you want the surfaces of the touchplate to be flatter and smoother, you can sand and polish the surfaces on a known flat surface, like a jointer table or a granite plate.
Coincidentally, as I was reading about it I came across a couple recent posts about how to setup and use the touchplate, so I decided to show a how I did it, step by step. Thanks to Bruce for asking me to post what I learned.
First off, I like to set the zero as a corner on the fixed jaw of my vise.
This helps, because most jaws are metal and an extra touchplate isn't actually needed if you have a metal vise. If you don't have a metal vise, or if you want to set the zero off your stock, I quickly modeled up a touchplate in Fusion 360.
Here is the link to the touchplate model: a360.co/2EUpcCu I'll go into more details on how to use this particular touchplate at the end.
What I needed to set up my touchplate system:
2 wires about 2' long. I used 22 gage wire
2 .1" pin connectors (or one 4x1 .1" connector)
1 alligator clip
1 spade connector
I created two wire assemblies, one with an alligator clip, and one with a spade connector. Each wire had a .1" pin connector on the opposite side. (Sorry I didn't take any pictures.)
On the motor board, I connected the spade connector wire to the SCL pin, and the alligator clip wire to the GND pin.
(This is a picture of mrbigj's board)
On the vise, I attached the spade connector to my fixed jaw. I did this by flatting the spade connector and sandwiching it behind the jaw. I'm eventually going to find a more permanent solution, but for now it works well.
Now, I use UGS platform, which allows for custom macros. I created a macro to automatically zero, one for each direction
Here's the G code:
Probe X:
G38.2 X -12 F25; G92 X 0; G0 X 6 (Move the tool in the X direction -12mm, 25mm/min. When the sensor is triggered, set X=0, rapid move the tool 6mm)Probe Y:
G38.2 Y -12 F25; G92 Y 0; G0 Y 6Probe Z:
G38.2 Z -12 F25; G92 Z 0; G0 Z 6The thing I noticed about this command is the tool will move towards the already set 0 location. I'm not sure if this is specific to UGS, or its how the G38.2 command works. So I need to make sure the zero point is set past the vise in the direction I want the tool to move.
To test the macros, I ran each one and touched the alligator clip to the vise. When I touched the alligator clip to the vise, UGS set the position to 0 and the tool moved back 6mm.
Now, to use the whole setup, I clipped the alligator clip to the tool, moved the tool 12mm from the vise surface, and ran the macro
(GIF link)
(I noticed some end mills didn't trigger the sensor, likely because of a coating. Pushing the end mill lightly while its moving helps)
Now, after doing this for each direction, this sets the tool edge to the corner of the vise, not the center of the tool. So I just manually adjusted the tool by the radius of the end mill to set the center. I also created macros to do this for my most common end mills.
--If you want to use the separate touchplate--
First: download that model I made.
I modeled it from .5" aluminum stock. It's 2" x 2" and has a 4mm hole for a 4mm banana jack.
Second: make it on your machine.
Third: place the touchplate against the corner you want to set as zero and do as I did above, except replace the spade connector with a 4mm banana jack and plug the banana jack into the 4mm hole in the touchplate.
Fourth: use the macro as I did, except now you will need to offset an additional .25" in the Z direction, and .5" in the X and Y (plus the radius of your end mill). This is because the edge of the touchplate is offset from the edge you want to set to zero.
To be more accurate, you can measure the offset of the touchplate with calipers or micrometers and offset that value instead. It could be a little large or a little small depending on your tolerances. If you want the surfaces of the touchplate to be flatter and smoother, you can sand and polish the surfaces on a known flat surface, like a jointer table or a granite plate.
