Easyscriber engrave attachment for Hypertherm torch's
 

Proma Retrofit on Burntables Mach3, G31 problem

Mach 3 CNC from Artsoft questions or tips can be posted to this forum.
Post Reply
WhitesPerformanceMachine
Posts: 19
Joined: Wed Oct 12, 2016 6:34 pm

Proma Retrofit on Burntables Mach3, G31 problem

Post by WhitesPerformanceMachine » Wed Nov 09, 2016 10:27 am

Hi all,
I'm new here, been doing A LOT of reading and learning on how the whole Mach3/Probotix drive system that Burntables uses actually works. I had relatively good luck with my table for about a year once I got through the learning and growing pain of being new to CNC Plasma cutting.
As basically everyone will agree the THC on Burntables seems to be the biggest issue people have. I will not go through the whoel story, but I wasn't able to get the help I needed from Burntables to get my machine working again. I wrote to Eagle Plasma about trying to use a Proma THC.
As of now I have it wired in, it moves properly in test mode etc.
My next step is to get the Probe function for G31 to work properly as it is quite a bit different than what Burntables was using? (g28.1 IIRC)
What my machine is doing is feeding down till it hits the switch, then instead of promptly stopping z-movement and retracting it "coasts" to a stop thankfully there is some "flex" in the mount for the switch to prevent damage. What variable/setup option should I be looking for to correct this problem?
I'm looking forward to correcting the dreaded Burntables THC and getting back to cutting. I understand there are other shortfalls with the table, but it is bought and paid for and I was doing decent work with it on a hobby level until the THC died on me one day.
Thanks in advance.
Burntable 4x8 with PM65
13x36 lathe
Miller MIG

User avatar
acourtjester
Elite Contributing Member
Elite Contributing Member
Posts: 3264
Joined: Sat Jun 02, 2012 6:04 pm
Location: Pensacola, Fla

Re: Proma Retrofit on Burntables Mach3, G31 problem

Post by acourtjester » Wed Nov 09, 2016 12:24 pm

There are 2 thing you will need to do first use a post processor that has the G31 command in it. Shown below is the change in the post processor I made in one of the standard Mach 3 posts. And wire the signal to the to the pin shown in Mach for the probe

function OnPenDown()
if(dist >= (refdistance/scale)) then
dist = 0
post.ModalText(" G31 Z -100")
post.ModalNumber (" F", 500 * scale, "0.0###")
post.Eol()
post.ModalText(" G92")
post.NonModalNumber(" Z", switchoffset, "0.0000")
post.Eol()
post.CancelModalNumbers()
end
probe.jpg

You do not have access to download this dxf file.
Become a Contributing Member to gain access to the thousands of files shared by our members. Click Here

DIY 4X4 Plasma/Router Table
CandCNC DTHC-IV & Feather Touch
Hypertherm PM65 Machine Torch
Drag Knife and Scribe
Miller Mig welder
13" metal lathe
Small Mill
Everlast PM 256 tig

WhitesPerformanceMachine
Posts: 19
Joined: Wed Oct 12, 2016 6:34 pm

Re: Proma Retrofit on Burntables Mach3, G31 problem

Post by WhitesPerformanceMachine » Wed Nov 09, 2016 1:42 pm

Thanks for the quick reply. I've got a post from Eagle Plasma for G31 floating head. The issue I'm trying to work through is how the Z acts when the Probe switch is triggered. It doesn't immediately stop. It "coasts" or decelerates slowly to a stop. It seems to me that it should stop quickly, Just like if you take your finger off the job button. I will be able to provide any information tonight when I get to the shop. So please ask for any info you would need to help.
Thanks again!
Burntable 4x8 with PM65
13x36 lathe
Miller MIG

User avatar
acourtjester
Elite Contributing Member
Elite Contributing Member
Posts: 3264
Joined: Sat Jun 02, 2012 6:04 pm
Location: Pensacola, Fla

Re: Proma Retrofit on Burntables Mach3, G31 problem

Post by acourtjester » Wed Nov 09, 2016 4:18 pm

There should be no coast when triggered, maybe you had the Z speed to high or the last time Mach changed speed it was a high speed movement.
Until mach is told to change speed it uses the last speed command. If you do a rapid movement and then tell mach to do a probe action it will move the Z at the rapid speed. Here is a probe command with a speed command of F10 :)
probe A.jpg

You do not have access to download this dxf file.
Become a Contributing Member to gain access to the thousands of files shared by our members. Click Here

DIY 4X4 Plasma/Router Table
CandCNC DTHC-IV & Feather Touch
Hypertherm PM65 Machine Torch
Drag Knife and Scribe
Miller Mig welder
13" metal lathe
Small Mill
Everlast PM 256 tig

WhitesPerformanceMachine
Posts: 19
Joined: Wed Oct 12, 2016 6:34 pm

Re: Proma Retrofit on Burntables Mach3, G31 problem

Post by WhitesPerformanceMachine » Wed Nov 09, 2016 4:31 pm

Yes.
I was looking at the Feed speed I think it was 19.xxx it was an odd number I figured was a default.
I appreciate the help. I will be to my shop by 6PM EST and will dig into it and post more info. I've been refusing work and putting off jobs almost all summer, I even had to sub some to another local guy. Thankfully it is more of a hobby than a necessity.
Burntable 4x8 with PM65
13x36 lathe
Miller MIG

User avatar
acourtjester
Elite Contributing Member
Elite Contributing Member
Posts: 3264
Joined: Sat Jun 02, 2012 6:04 pm
Location: Pensacola, Fla

Re: Proma Retrofit on Burntables Mach3, G31 problem

Post by acourtjester » Wed Nov 09, 2016 5:49 pm

Are you looking at the speed command in the G-code or the velocity in the motor tune (19.xxx)?? they not the same thing.
The speed command (F10) is 10 inches per minute.
DIY 4X4 Plasma/Router Table
CandCNC DTHC-IV & Feather Touch
Hypertherm PM65 Machine Torch
Drag Knife and Scribe
Miller Mig welder
13" metal lathe
Small Mill
Everlast PM 256 tig

WhitesPerformanceMachine
Posts: 19
Joined: Wed Oct 12, 2016 6:34 pm

Re: Proma Retrofit on Burntables Mach3, G31 problem

Post by WhitesPerformanceMachine » Fri Nov 11, 2016 12:46 pm

This is what I just tried using. It still ramps up and ramps down on the feed on the Z while probing. I will attach a video next.
Burntable 4x8 with PM65
13x36 lathe
Miller MIG

WhitesPerformanceMachine
Posts: 19
Joined: Wed Oct 12, 2016 6:34 pm

Re: Proma Retrofit on Burntables Mach3, G31 problem

Post by WhitesPerformanceMachine » Sat Nov 12, 2016 12:11 pm

What is the easiest way to post pictures/video from an android cell phone? It didn't seem to want to work when I was at the shop.
The progress I made was playing with the numbers in the post and slowing the feed down, that kept it from smashing into the switch. unfortunately I had to slow the Z feed down so much that it would take forever to do it's job.
I dug into the way Burntables had it setup before and they were using G28.1 vice G31. Does the machine react differently to the G28.1 when it hits the switch vs G31? Because I could just as easy use G28.1. My other idea was to figure out (not sure how to do it yet or if its possible) how to keep the 1" safe travel height, move in X/Y, have the machine feed down to .375 above the plate and then slow down for the probe. I'm just not sure how to do it properly. for simple programs it would be pretty easy to manually edit the g-code. However it wouldn't be very fun on a large job with a lot of starts.
Burntable 4x8 with PM65
13x36 lathe
Miller MIG

User avatar
acourtjester
Elite Contributing Member
Elite Contributing Member
Posts: 3264
Joined: Sat Jun 02, 2012 6:04 pm
Location: Pensacola, Fla

Re: Proma Retrofit on Burntables Mach3, G31 problem

Post by acourtjester » Sat Nov 12, 2016 1:56 pm

If you are using SheetCam to create your G-code you can use the "Plunge safety clearance" it is located under the options tab, options down at the bottom of the page. The probe G31 is hooked up NO to the probe input pin, and G28 is NC hooked to the Z home input.
Load your video to a PC make it a movie file and then ZIP it using winrar (free) and then attach that ZIP file here using the attachments option. we can then download it and watch it.

plunge safety clearance is used when doing a rapid move to cut height. When SheetCam TNG moves to the top of the cut it stops slightly short and moves the remaining distance at feed rate. This allows for inaccuracies in your setup and any chips that may be in the way. The last thing
you want is to slam the tool into the work at full speed. By default the clearance is 0.5mm which seems to work pretty well in most cases. Older versions of SheetCam TNG have always had this hard coded to 0.5mm. Enter your required distance in the box.
DIY 4X4 Plasma/Router Table
CandCNC DTHC-IV & Feather Touch
Hypertherm PM65 Machine Torch
Drag Knife and Scribe
Miller Mig welder
13" metal lathe
Small Mill
Everlast PM 256 tig

tcaudle
Posts: 1059
Joined: Tue Feb 28, 2012 6:47 pm

Re: Proma Retrofit on Burntables Mach3, G31 problem

Post by tcaudle » Sat Nov 12, 2016 4:52 pm

One of the advantages of using the G31 probe compared to the G28.1 is you can define a separate Feedrate for that move where as the G28.1 does not listen to "F" commands; it simply uses the homing federate set in Homing and limits for that axis The other parameter in the G31 you can use is the "overrun" amount you will allow the probe to go below 0 during a touch off. The Plunge Safety Clearance for defining the slow down zone has to be put in the POST for plasma. The default is indeed .5mm (about .020 inches) not much of a slow down zone especially if your material has warped up more than that and the torch slams down at full rapid . 12mm makes a lot better sense.

WhitesPerformanceMachine
Posts: 19
Joined: Wed Oct 12, 2016 6:34 pm

Re: Proma Retrofit on Burntables Mach3, G31 problem

Post by WhitesPerformanceMachine » Sun Nov 13, 2016 6:14 pm

My current progress is that I modified the floating head probe switch so that instead of the slide moving up and touching the switch, the switch is now setup so that when the slide moves it "comes off" the switch, it has plenty of travel and can now "coast" to a stop without damaging the switch. In the process I messed up the post in sheetcam because it now moves before firing the torch..... I'm working on that now. I'm going to load up some pictures in a few min once I get them off my phone and onto my computer.
Burntable 4x8 with PM65
13x36 lathe
Miller MIG

WhitesPerformanceMachine
Posts: 19
Joined: Wed Oct 12, 2016 6:34 pm

Re: Proma Retrofit on Burntables Mach3, G31 problem

Post by WhitesPerformanceMachine » Sun Nov 13, 2016 7:26 pm

Here is a picture of the Code the post is generating, notice the moving before the torch fires. I'm relatively clueless on how to fix the post.

You do not have access to download this dxf file.
Become a Contributing Member to gain access to the thousands of files shared by our members. Click Here

Burntable 4x8 with PM65
13x36 lathe
Miller MIG

WhitesPerformanceMachine
Posts: 19
Joined: Wed Oct 12, 2016 6:34 pm

Re: Proma Retrofit on Burntables Mach3, G31 problem

Post by WhitesPerformanceMachine » Sun Nov 13, 2016 7:28 pm

Please don't mind the metric. I just came ahead 3 versions of sheetcam since I just put it from my machine computer (not internet connected) onto my laptop and it brought me from somewhere in the V3 era to the V6 realm.
Burntable 4x8 with PM65
13x36 lathe
Miller MIG

WhitesPerformanceMachine
Posts: 19
Joined: Wed Oct 12, 2016 6:34 pm

Re: Proma Retrofit on Burntables Mach3, G31 problem

Post by WhitesPerformanceMachine » Sun Nov 13, 2016 8:03 pm

I'm pretty sure this is where I need to fix it, just not sure where.....

You do not have access to download this dxf file.
Become a Contributing Member to gain access to the thousands of files shared by our members. Click Here

Burntable 4x8 with PM65
13x36 lathe
Miller MIG

WhitesPerformanceMachine
Posts: 19
Joined: Wed Oct 12, 2016 6:34 pm

Re: Proma Retrofit on Burntables Mach3, G31 problem

Post by WhitesPerformanceMachine » Thu Dec 15, 2016 6:36 am

this problem resolved itself by upgrading Sheetcam to the latest version. And I mounted my switch different so it's no longer and issue when touching off.
Burntable 4x8 with PM65
13x36 lathe
Miller MIG

Post Reply