My Newb Plasma Table Attempted Build

Now that I'm outside of pncconf and working on learning and dialing things in, I got everything to home. Then I went to jog X from home to it's limit on the other end and it only went half way. Travel was perfect in pncconf. I'm a newb, but I think this is what PCW was referring to.

It looked to be about half way across, so I doubled the scale. I have the travel limit set to 49.75in. It traveled 48.375in. I'm only guessing here, but maybe the wheels are acting as a minor reduction?

dvn4life1972 wrote: It looked to be about half way across, so I doubled the scale. I have the travel limit set to 49.75in. It traveled 48.375in. I'm only guessing here, but maybe the wheels are acting as a minor reduction?

Wheels can not reduce anything in that case.
Measure, change the scale a bit, measure again, change the scale.....till you get the exact distance.
You can do that from the calibration in the machine menu in Linuxcnc, so no need to restart Linuxcnc each time you change something. Just be sure to save to file when done.

Tommy if you look at his screen shot should the pitch be set to 3 mm rather than 6 mm ? basically he has a 20 to 1 gear ratio if i'm not mistaken. your the expert with belts as drives

He has no gearing, the pulley is mounter on the motor shaft.
So the settings should be
motor:pulley = 1:1
pitch should be 60mm or 2.3622 inch.
microstepping should be what is set on the drives.

that's pretty coarse as a pitch. maybe show him how to add some more gears to the drive so he can get close to where he needs to be. or post a link to your builds. i think you have some good pictures posted that might help him get to where he needs to be. i don't think it can be done with just one pulley. you would never get one that small to slow it down enough.

Pictures of building a reduction system using pulleys and belts, as requested.
forum.linuxcnc.org/show-your-stuff/38547...lasma-build?start=20

tommylight wrote: Pictures of building a reduction system using pulleys and belts, as requested.
forum.linuxcnc.org/show-your-stuff/38547...lasma-build?start=20

Holy cow! That thing is awesome man!

Machindude ... I have no point of reference for a coarse machine vs anything else (total newb, 1st ever attempt), but Tommy also stated the same before. I'm making mental notes on that input though, as I can see changes will need to be made in the future. In the meantime, I'm going to continue with what I have in front of me. I think it should be enough to get me started. I like using a belt as a rack gear in the vslot, so I'll probably adapt my table with reduction to do that in the future. It's just a 1500x1500 (smaller working envelope, though), and it's really those dimensions for 2 reasons: limited space to work in (at home); I'm building my table primarily for the purpose of making some products and parts I need for products. Of course, I'm going to attempt to get more cut business in the future, but I'm not expecting any for a little while. Time will tell, but I need to get the machine running so I can see how consistantly and precisely (or not) it will cut with what I have for the time being.

All that said, I now have the X and Y homes/limits/scaling all set. For some unknown reason the X and Y required very slightly different scaling, although the limits for each are the same (48.50in). Maybe it's because of the dual motors on the Y axis, I don't know. But it's working and repeating at slow speeds now. I'm now working on dialing in the Z axis (it's a mess at the moment). Once that's completed, I'm going to bump the speed up and see what my threshold is for accuracy/repeatability. I think this is a reasonable plan.

I still have to make a mount on the table leg to secure the electronics enclosure to, wiring in the voltage divider/arc ok/torch start from the plasma to the enclosure, then I can test with all of that connected and get into plasmac. I guess a fortunate coincidence of this whole crazy covid-19 thing is that I have time on my hands to really get after it. I can already say that I would be MUCH farther behind where I am now without help from this forum and it's members, I'm very grateful.

Pat

dvn4life1972 wrote:

tommylight wrote: Pictures of building a reduction system using pulleys and belts, as requested.
forum.linuxcnc.org/show-your-stuff/38547...lasma-build?start=20

Holy cow! That thing is awesome man!

LOL, yes they are, made 4 of those in 2 days, 2 are 15cm wide and 2 are 20cm wide, the narrow ones have 1.8A steppers while the wide ones have 2.4A motors. Just working on installing the wide ones on the bigger machine.
BTW, check by the end of that topic to see what those reductions are doing!

Haha I'm actually using that build thread to occupy me in between failed Z axis dialing attempts! The plastic work is awesome too, very fine craftsmanship.

Pat