Rod's Spaceship Scratch Built Plasma Table

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robertspark
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Re: Rod's Spaceship Scratch Built Plasma Table

Post by robertspark » Thu Jul 11, 2019 7:00 am

Rodw wrote:
Thu Jul 11, 2019 6:16 am
reverse run which is used for error recovery which is probably a not a major impediment. Plasmac will auto sense if reverse run exists and configure itself accordingly.

Unfortunately, the release manager for LinuxCNC did not want to release the reverse run feature until there had been further testing so it will be in V 2.9.
hmm, now that is an interesting feature to add.

How does it work?

In UCCNC it works by
A) providing THC is enabled
B) providing M3 is active
C) tracking the arc OK signal

if the ArcOK drops out with both A+B are active, then the torch will decelerate to a stop, and backup to the ARC OK lost position and await a restart.
UCCNC,
Sheetcam
Hypertherm Powermax 45 (nonXP)
Neuron Lite THC
Hobby user (4x4 home table)

Rodw
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Re: Rod's Spaceship Scratch Built Plasma Table

Post by Rodw » Thu Jul 11, 2019 7:17 am

To tell you the truth I don't know as I've never needed it to recover from a fault yet. I think it allows you to move back and forth as far as the last M3 while the machine is paused (which loss of ArcOK triggers). There are some controls on the GUI to control this.

There is a video on Youtube of a guy using a MPG wheel to move back and forth thru the gcode with reverse run active which is cool. Search for user Samco from memory. Because I have 3 spare axes on my pendant, I was going to try that one rainy day...

robertspark
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Re: Rod's Spaceship Scratch Built Plasma Table

Post by robertspark » Thu Jul 11, 2019 7:20 am

UCCNC,
Sheetcam
Hypertherm Powermax 45 (nonXP)
Neuron Lite THC
Hobby user (4x4 home table)

Rodw
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Re: Rod's Spaceship Scratch Built Plasma Table

Post by Rodw » Thu Jul 11, 2019 8:36 am

You found it. I was actually thinking about the UCNC algorithm.

I don't think the travel distance after loss of ArcOk is significant with LinuxCNC. Say I'm cutting 2mm steel at 2100mm/min (35mm/sec). Linuxcnc will sense the loss of ArcOK in 1 millisecond and if my X/Y Maximum Accelleration is 1500 mm/sec/sec (which I think is the rate we will stop at), I've not moved further than about 0.8 mm from the loss of the arc (Just enough to have some material to restart on). I guess thats one of the advantages of running in real time.

beefy
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Re: Rod's Spaceship Scratch Built Plasma Table

Post by beefy » Mon Jul 15, 2019 3:10 am

Hi Rod,

The ultimate would be reverse run to a certain distance BEFORE the flameout point. Then restart the motion but without torch switched on. You'd also need THC off for this of course. Then just a few mm before the flameout point, manually turn the turn on (assuming this would not cause a pause in motion). Once cutting again, manually enable THC again.
8 x 5 water table
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Rodw
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Re: Rod's Spaceship Scratch Built Plasma Table

Post by Rodw » Mon Jul 15, 2019 3:44 am

This does not work for our config (and probably not for LinuxCNC). Our torch is turned on with an M3 and with it all of the probing etc. When a fault ocurs, we pause motion so to restart it is a resume, not a full restart,

beefy
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Re: Rod's Spaceship Scratch Built Plasma Table

Post by beefy » Mon Jul 15, 2019 8:07 am

Rodw wrote:
Mon Jul 15, 2019 3:44 am
This does not work for our config (and probably not for LinuxCNC). Our torch is turned on with an M3 and with it all of the probing etc. When a fault ocurs, we pause motion so to restart it is a resume, not a full restart,
Not sure if I'm understanding that correctly Rod. Are you saying that in Lcnc, an M3 is not simply a torch fire but also initiates a bunch of other things happening. For that matter is there no way to manually fire the torch while doing a dry run of the gcode.

In Mach3 and UCCNC for example there are things like "Run From Here" or "Set Next Line" which can be used to start a program from any point in the gcode file. Of course you may need to manually touch off and set the Z height first, and possibly manually set feedrate before starting these mid file runs, because certain modal commands may not be in place.

Just trying to get a feel for how Lcnc runs compared to what I'm used to.
8 x 5 water table
Powermax 1250 with Duramax torch
UCCNC controller, UC400-ETH & UC300-ETH motion controllers.
Sheetcam
Geomagic Design 3D solid modelling
Coreldraw X5

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