Plasma drill

Request and discuss new features
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Les Newell
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Re: Plasma drill

Post by Les Newell » Fri Feb 23, 2018 12:44 pm

What does Tom have against pre-pierce? It makes a lot of sense to me.

motoguy
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Re: Plasma drill

Post by motoguy » Fri Feb 23, 2018 3:19 pm

Here is what he has to say about it:

"I pointed out that the idea of pre-piercing is not a valid method of doing plasma cutting. The whole pierce process on thick metal is to prevent blowback that kills consumables. For pecking drill spots we have the Peck pierce option that can be used to change the pierce characteristics and just make divots. I have used all the way down to 16 ga without piercing completely through. On thicker material the BEST solution is to have the RS485 serial port on a Hypertherm and use the "Soft Pierce" option in SheetCAM (using our POST) and set a % of the full cut current to start the pierce . It automatically lowers the Z plunge rate too . The concept is to get a more controlled pierce and prevent the consumable killing back splash. Users report they double their consumables life on cutting 1/4" and thicker material."

and

"Once again this is forcing the plasma to do things that make little sense. Pre-piercing holes does nothing to increase consumable life or improve the cuts. What destroys consumables is piercing no matter when its done. If you did the pierces at one current setting and plunge rate versus the other it MIGHT help, but then again so does having control of the cut current dynamically and altering the pierce process in real time. I am sorry but I cannot release a POST that I then have to support and maintain that is contrary to doing proper plasma cutting. If you want to modify and distribute a Post to do that then please be prepared to support it. My tech team is drilled on the proper methods of cutting and how to get the best results."

https://www.candcnc.com/supportforum/vi ... 0&start=20

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Les Newell
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Re: Plasma drill

Post by Les Newell » Fri Feb 23, 2018 3:45 pm

I can see where Tom is coming from. It looks like his system has a way of piercing that reduces the blowback problem, making pre-pierce largely unnecessary.
Once again this is forcing the plasma to do things that make little sense. Pre-piercing holes does nothing to increase consumable life or improve the cuts.
However if you use worn out consumables for piercing it can save your good consumables.

motoguy
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Re: Plasma drill

Post by motoguy » Wed Feb 28, 2018 3:44 pm

Les Newell wrote:
Fri Feb 23, 2018 3:45 pm
I can see where Tom is coming from. It looks like his system has a way of piercing that reduces the blowback problem, making pre-pierce largely unnecessary.
Once again this is forcing the plasma to do things that make little sense. Pre-piercing holes does nothing to increase consumable life or improve the cuts.
However if you use worn out consumables for piercing it can save your good consumables.
Those are benefits. For me, the largest benefit was the ability to pierce the holes, then remove the slag-pile from the area before proceeding to the cut. Prior to the pierce-only post, the torch often proceeded through the slag pile as it moved along the lead-in. This resulted in a snagged torch tip, and pulling the torch off the mag mount.

It also allows you to pierce beyond recommended thickness, because you're using already-trashed consumables.

djreiswig
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Re: Plasma drill

Post by djreiswig » Wed Feb 28, 2018 7:25 pm

A ramp pierce moves the torch away from the slag pile as well as allowing piercing thicker than rated material. And you don't have to change consumables.

motoguy
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Re: Plasma drill

Post by motoguy » Thu Mar 01, 2018 3:51 am

djreiswig wrote:
Wed Feb 28, 2018 7:25 pm
A ramp pierce moves the torch away from the slag pile as well as allowing piercing thicker than rated material. And you don't have to change consumables.
Tom states several times that using the ramp pierce in sheetcam messes with the DTHC activation/timing in CandCNC systems.

djreiswig
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Re: Plasma drill

Post by djreiswig » Thu Mar 01, 2018 4:18 am

Well, for some reason it works fine for me. Just cut some more 1/2" tonight using nothing but the ramp pierce. Maybe my post processor is set up differently, I don't know. But it cuts wonderfully and never hits the slag pile. DTHC turns on and follows the cut height without missing a beat.

motoguy
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Re: Plasma drill

Post by motoguy » Wed Mar 07, 2018 3:56 pm

Les Newell wrote:
Thu Feb 22, 2018 8:50 am
I'll see if I have a CommandCNC post and tweak it to just pierce.
Les,

I know (based on your PlasmaSpider post) that working on CandCNC posts isn't your favorite thing. LOL That being said, any chance you've been able to look at this, and see what needs to happen to make it work? Moses has been quiet on the CandCNC site since Tom chimed in with his opinion on the "correct" way to use the posts.

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Les Newell
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Re: Plasma drill

Post by Les Newell » Wed Mar 07, 2018 5:07 pm

Sorry I thought that one you posted on this thread worked. What is wrong with it?

WyoGreen
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Re: Plasma drill

Post by WyoGreen » Wed Mar 07, 2018 7:07 pm

I have attached a post that should do the piercing. You will have to use a different post for cutting. If you go to Options->plugin options->moreposts you can add extra post processor buttons so you don't need to go through Options->machine->post processor each time.
Les, the moreposts plugin does not seem to be in the Linux version of Sheetcam.

Steve

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Les Newell
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Re: Plasma drill

Post by Les Newell » Thu Mar 08, 2018 11:20 am

Les, the moreposts plugin does not seem to be in the Linux version of Sheetcam.
It is there. In plugin options you may need to click on the right arrow to scroll through all of the tabs.

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Re: Plasma drill

Post by WyoGreen » Fri Mar 09, 2018 12:09 am

Hey Les, I found the plugin, but not by using the right and left arrows on the screen to access it. I had to use the keyboard right and left arrows to access it. The screen arrows display only the far left 8 plugins, or the the far right 6 plugins out of a total of 16. The 2 in the middle are not displayed.
The screen arrows don't scroll, they jump.

Steve

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Les Newell
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Re: Plasma drill

Post by Les Newell » Fri Mar 09, 2018 11:42 am

That's odd. I checked again here and it worked fine. Controls like this are handled by GTK+ 2. All I can think of is that you have either a different version of GTK or it is set up differently.

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Re: Plasma drill

Post by WyoGreen » Fri Mar 09, 2018 5:52 pm

Thanks Les,
It is probably the desktop environment I am running or some such thing. Linux does seem to be a bit picky depending on what version you are running.

I'll play with it a little more and see what I come up with. It's really no big deal now that I have found it. The only odd thing left is after using the more posts option to add another post is it doesn't put an icon on the tool-bar like windows sheetcam, but it does put a menu selection at the bottom of the File menu drop-down.

Steve

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Les Newell
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Re: Plasma drill

Post by Les Newell » Mon Mar 12, 2018 4:59 pm

Yup, I can see the icon problem. I'm not sure what is going on there. I'll run some tests.

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