MPCNC Plasma

I love this machine :slight_smile:

https://youtu.be/zxdziLFo3-w

Just need to dial in settings now

Oh man I need to get a plasma!

My brain is going wild with ideas of what to make now :).

I’m totally new to plasma cutting, and would love if someone could give me a bit of advice on feed rates and amps for different materials and thicknesses.

I noticed that the two small circles were a bit oblong. I’m wondering if I was going too fast. I was using 15mm/s feed at 40 amps on 3mm steel. I was getting a cut width of about 1mm, so in the tools of estlcam I made a 1mm bit profile. Is this the correct thing to do?

 

I had this in the start cut section of estlcam:

G01 z0 f200
M106
g4 s0.7

But it doesn’t seem to have paused after starting torch. Is that not what g4 s0.7 does?

Cheers.

I haven’t had any experience with a plasma on a cnc, only free hand. I would set the tool path to the thickness of your kerf.

g4, yup that is 0.7 seconds. Did you place it in the plasma section?

About the oval. First thing I would say is check your pulleys, and make sure you start your machine square by measuring from the rollers to the corners and matching the pairs.

lol, I had to lookup the meaning of kerf :slight_smile:

Yeah I put the g4 in the plasma section. Might extend it a bit.

I think you might be rite. I don’t think I started the machine square for that cut. There is a good bit of flex with it. Might try the dual endstops.

Is there a way of zeroing the origin point through the lcd, or can it only be done through computer?

Thanks.

There are a couple of options. The simplest is to just reset the controller (or cycle power to it). A more complex route is to change the menu in the firmware to replace one of the custom menu items with the “G92 Z0 X0 Y0” command - search for CUSTOM_USER_MENUS in Configuration_adv.h.

Thanks I’ll have a look at the firmware option. I don’t like resetting the controller because there can be a bit of movement when the axis relax on a reset.

 

Thats awesome!

would you mind sharing the stl for your toolmount for the torch? I have the exact same, so it would be awesome not having to scetch it out my self

The forum wont allow me to upload .stl’s

Zip it first, but it is better to add it to thingiverse instead.

Here you go. The one with T is upper most piece.

[attachment file=“Plasma torch mount.rar”]

Think I got it :slight_smile:

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Great! Thanks a lot!

Does anyone know how to change direction of tool paths in estlcam?

When using lead in, a hole path is clockwise, and a part path is anti-clockwise. It needs to be the opposite way around for better plasma cutting. I read somewhere that this can cause oblong holes.

 

Cheers.

Not sure why it would matter with a plasma but to switch directions switch between climb/conventional milling in the settings.

This is my end goal with my new MPCNC I am currently building. Good Job.

Not sure about the CAM you are using but in Omax and FlowCAM softwares the direction is based on the side of the cut when you select the feature, I cant remember if PlasmaCAM did the same or not. (This shows up in Solidworks/HSMWorks CAM also when doing 2D Profiles)

Although it shouldnt effect the quality of a cut which direction it travels you want to make sure that it is cutting the correct side. When cutting a circle out on the inside of a part, the cut should be offset in ward. This compensates for the cut curf (spelling?) the width of your cut so the circle will be the correct size. If it is cutting on the outside of that same circle it will be too big by half your curf (from the offset) plus the width of the cut.

Apparently it has to do with the way the plasma spins. It makes the right side of the cut better.

 

I’m making a floating z mount at the min, and modding my plasma cutter to work with pilot arc.

I’ll keep you updated.