My Newb Plasma Table Attempted Build

Fabricator...I'm taking more than just a couple of days away from it. It's a great suggestion. Hope you get to feeling better soon. I've heard (read) some stories about CandCNC, no personal experience with them though

Rod...thanks for all the help anyway. I did state before I was gonna just get the rack and pinion and I now have parts ordered for that. I have a small business where I do network infrastructure in the field, and a small project for a couple of weeks that will keep me busy while the bits and pieces trickle in for the upgrades. The changeover won't be that bad I *think*. I can use the vslot I have for rails for mounting hiwin style rails, etc etc.

Tommy...it's your prerogative whether or not you want to respond to something or someone. I will say I missed the request(s) for video. Not gonna justify what else you said by responding to it, take care and good luck though. You are very helpful when you choose to engage and I appreciate the times you chose to do so.

Not going anywhere, yet.
I love challenges, but this was getting to painful to watch you go through it.
Whenever you are ready, we will have another go at it.

phillc54 wrote: Well I am sorry to see you go and also sorry I couldn't be of more help.

I can see that it has been very frustrating for you and good luck to you as well, I do hope you get your table working.

I'm outside getting things ready to tear down (for the rack & pinion upgrades), and I notice that I've left the control box powered on all night. I went to feel on the motors just to see how warm they might be from being held on (they were warm but not hot to the touch).

Anyway I figure to myself...give the gantry another shove. I noticed some play. So then I go back and forth, and to my eye it seems to be about 1/16" or so. This happens to be the ballpark of the error. So, I fired up the PC and linuxcnc and used MDI to take measurements going positive and negative 2". On the negative I lose about 1/16" on the Y. I'm sure I made a mistake or several mistakes measuring for the backlash. Phil I think you had it right all along.

I'm still going to upgrade to rack and pinion, especially since I've ordered 75% of the necessary stuff to do it...but it would be very nice to be able to use the machine in it's current state (corrected for the backlash) to cut the custom plates I'll need for the new drive system.

What do I do now?

dvn4life1972 wrote: What do I do now?

Find some scrap material to cut for testing, a bucket of coffee and send me the drawing of what you intend to cut.
Besides that, get the original and PlasmaC configs ready, a camera and a grid of some kind to have as reference behind the machine while camera is recording.
While doing test cuts, move the part on the table so they are not cut in the same place and consequently show the same error.
Might be there is a part of the table that is perfectly usable, but some part of it might not be.

Uploading videos are pretty much out of the question. Our internet is very sketchy, and when it is stable there isn't much bandwidth to be had (we are far away from any decent coverage areas). "Normally" I could just take the shots and next time I'm in a populated area just go somewhere with good wifi, but with Covid that isn't an option.

Edit: I may just skip trying to get the present setup to work at all. Everything you're suggesting there seems to be a royal pain. I can definitively tell you the structure of the table is square and built very well. What I lack in CNC experience I more than make up for in fabrication experience and capability. 1500x1500 frame is square on all planes to within 1/32" or less. In fact I'll go so far as to say I can definitely school you on steel fabrication lol.

That is OK, but you will have to do the slow motion checking of the video to look for deviation.
Yeah, that CCP thingy is back with a vengeance here, the hospitals are full, they were empty during the first round.

It's getting worse here than it has been, they have been reopening some businesses and too soon at that. I have a feeling it's all gonna get locked back down, probably even tighter than before.

I don't see a benefit in all of those steps considering the whole drive system is gonna be changed anyway to rack and pinion. I was just wondering if there's a bandaid fix that would be good enough to use it to cut brackets for the new setup. I don't have any pending paying work hanging over my head anymore, so I don't feel.pressure to hurry.

I do recall making test cuts all over the machine cutting area and the same error occurred every time, without variation. I'm thinking now that the 3GT belts didn't have as much backlash in them that these 2GT belts do...it's one of the few changes that were made to the machine between the time it was cutting ok and not.

- That could be backlash on one axis, but that does not count for the weave at the end of the cut.
- GT2 belts are quite strong and can be tightened quite hard leaving no backlash, for a time period i had a 45KG gantry moving by two miserable 6mm wide GT2 belts at 2.2 meter long each, directly driven by 2 motors at 2NM each, and it was very usable till i pushed it to fast. It was set to low acceleration as i was cutting some 20mm thick parts, worked like a charm.
- The only thing bothering me is why it does not show when doing a plain hand coded square, or maybe it does but i did not see it, i am wearing glasses after all.

I think that seeing you have made the decision to swap out the belts for rack and pinion there is not much point in chasing up what may be wrong with the belt drive system, you may as well use that time preparing for the changeover.

phillc54 wrote: I think that seeing you have made the decision to swap out the belts for rack and pinion there is not much point in chasing up what may be wrong with the belt drive system, you may as well use that time preparing for the changeover.

That's the plan. I'm still using the machine to cut some plates I need for my Jeep project. I just use the line cut feature on plasmac. Then I drill on a drill press and it's all gravy. I bet I can use it to make suitable plates for the rack and pinion setup too.