Plasma Z retract not occuring before XY rapids

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propstuff
Posts: 5
Joined: Sun Jun 13, 2021 1:42 am

Plasma Z retract not occuring before XY rapids

Post by propstuff »

SheetCam 7.0.12, Mach4 Plasma Post
Mach4 4.2.0.4612
ESS build 275

When using the above set up and Mach comes to make a rapid between cuts, the Z is not retracting to it's safe height *prior* to the X/Y travel. instead it is progressively reaching it's Z height in the same way that the X and Y axis do over the full extent of the move. This is causing problems.

When I run a simulation in Sheetcam, the Z moves to it's correct safe height before the X and Y moves start (as expected), but not when I actually run it in Mach4

When I run the machine as a router with the same setup, but using a Mill/ Router post this doesn't happen and the spindle retracts prior to rapids as expected.

this is a little chunk of the code Sheetcam is writing (from one cut to the next)
.......
N0100 Z0.0000 M03
N0110 G02 X98.2146 Y1181.7854 I1.7854 J-1.7854 F5000.0
N0120 M05
N0130 G00 X1301.7854 Z20.0000
N0140 Z0.0000 M03
.......

At line 130, SheetCam simulates this as the Z move completing before the X/Y moves start, but, as noted above, this doesn't happen.

I have limited experience, but I believe SheetCam should be writing something like:
N0100 Z0.0000 M03
N0110 G02 X98.2146 Y1181.7854 I1.7854 J-1.7854 F5000.0
N0120 M05
*N0125 G00 Z20.0000*
N0130 G00 X1301.7854
N0140 Z0.0000 M03

Any ides as to how I can get this to happen?

TIA,
Nicholas
propstuff
Posts: 5
Joined: Sun Jun 13, 2021 1:42 am

Re: Plasma Z retract not occuring before XY rapids

Post by propstuff »

**Bump**
Can someone from SheetCam advise if this is WAD , or a bug, or otherwise comment?
At the moment I'm having to manually edit the SheetCam code for every Rapid move between cuts, which is undesirable in the least.

TIA,
Nicholas
User avatar
djreiswig
Posts: 471
Joined: Sat Feb 20, 2016 4:47 am
Location: SE Nebraska

Re: Plasma Z retract not occuring before XY rapids

Post by djreiswig »

Compare the onrapid sections in your 2 posts. The z movie needs to be on its own line before the xy move. You should be able to see how this happens in your router post.
propstuff
Posts: 5
Joined: Sun Jun 13, 2021 1:42 am

Re: Plasma Z retract not occuring before XY rapids

Post by propstuff »

Thanks for your reply.
My understanding is that the Z move *should* be on a separate line prior to the XY rapid. This is what I manually added as per the second example.

My questions are
Why is SheetCam not writing this?
Why is SheetCam simulating the "correct" Z retraction behaviour even though it is not writing code to execute it?
What do I need to do to get it to output code to achieve the required result?

TIA,
Nicholas
User avatar
djreiswig
Posts: 471
Joined: Sat Feb 20, 2016 4:47 am
Location: SE Nebraska

Re: Plasma Z retract not occuring before XY rapids

Post by djreiswig »

I think the simulation uses different settings than the actual post processor.
You said your router post does the rapids correctly. Edit the router post and find the onrapid section. Copy it to a notepad or something so you can see it at the same time as when you have the plasma post open.
Then edit the plasma post and see how the onrapid is formatted in it.
You should see how the router post is causing the z move to appear on a separate line.
If you're still unsure, post both sections here and I'll try to help.
User avatar
Les Newell
Site Admin
Posts: 3661
Joined: Thu May 11, 2006 8:12 pm

Re: Plasma Z retract not occuring before XY rapids

Post by Les Newell »

I found an issue with the Mach4 plasma post. I have attached an update. To install this post, save the attachment to any convenient folder on your computer then run SheetCam and go to Options->machine->post processor. Click on the 'Import post' button. Using the box that appears, navigate to your post and open it. Go back to Options->machine->post processor and make sure your post is selected.
Attachments
Mach4 plasma.scpost
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