Acorn cnc plasma z axis home

[mjf53123]

Hello all, I am having some trouble with my new Acorn install. I got it all installed and everything works well besides when I try to home all axes', I have it set up Z, Y, and X as I want it but when it plunges the Z, throws a code for torch break away. I have a breakaway, float switch, and ohmic touch-off. it is all wired correctly and the inputs are set up correctly.

Firstly, it doesn't use the ohmic touch-off on home, it pushes past it until the float switch is triggered (~1/8") but when the float switch is triggered, CNC12 says touch collision torch breakaway. I have confirmed that they are not crossed, inputs are correct, pulled the wires out and just jumped them to the ground, and same result.

My only thought is that I could wire the float switch in with all of the other home switches into the same input but I don't want to do that as the wiring diagram says to wire it to the THC TX board. So, I assume that I must be missing something.

The torch touch-off does work when I click the torch touch-off button, just not when I try to "home all" by using the cycle start button. It does recognize it, just doesn't do anything with the information.

Sorry if this doesn't make sense, I tried my best haha.

Long story short, when I "home all" I want the machine to plunge the Z and use the ohmic torch touch-off (or the float switch if the ohmic isn't read (rusty material, ground not hooked up, etc.)) and use that as Z0, offset up 1" and then do the other 2 axes.

Any input is appreciated.

[mjf53123]

Here are a bunch of pictures of my installation and the wiring diagram that I followed. Hopefully this helps!

[ShawnM]

When you first HOME the machine at startup the Z axis should home UP to the TOP of the Z axis travel not down. If it's moving down when you HOME you need to reverse the homing direction in the wizard. You should have a home switch at the top of travel on the Z axis.

When you TOUCH OFF to the top of the material it will of course move down. HOME is at the top of the Z axis travel.

Please post a current report from your machine so we can see your settings. A report is required when asking for support. Thank you for the pics.

[cnckeith]

i moved this thread into the plasma forum

[Joey]

Hey MJF

Can you post a fresh report from the F7 Utility menu. This will help us see the systems settings.

The Machine Home is at the Top of the Z axis since the Z axis Home will be at the same location each time.

Homing the Z on material is very unusual. What is the reasons for this?


Great Pics, Good looking cabinet. Divided voltage look a little sketchy as the run by the Acorn. Hopefully there shielded.

A Fresh report will help a lot.

[mjf53123]

all - please see attached report

Z home in the positive direction is a little strange to me. Do you all have x and y home at the positive limits as well. I came from Mach 3 and had home for all at xyz0 but z was offset 1" up. It may not be common practice, but is it possible? The only reason that I like this is the torch is "always" that 1" of whatever off of the material. I can see it your way as well.

I do not believe that I have a limit switch at the top (ill have to check tonight), what are my other options? Just manually choose a Z home and have x and y use the limit switches?

Joey - the divider voltage is a little closer that I planned but it is about 3" away from the acorn board. You cannot see it in the images, but it is set up 3~4" with a 3d printed platform with the divider voltage wires running underneath.

[Joey]

All axis can be set to home on either side.

The Z is most commonly homed at the top so the home is at the same position each time and the torch or material is not interfering during homing.

axis soft limits need a consistent Homing location. Soft limits for each axis ensure Jobs are not bigger than the work envelope and the machine cannot crash at the end of an axis.

Homing is Just for Machine coordinates.

The Work coordinate is then set for each Job. Only X and Y work coordinates need to be set since the Z sets zero automatically when the Job starts.

The Torch retracts to the Safe height after each cut. The Safe height is set in the profile. Most profiles have a safe height of 1 inch.

You can always choose to not home the machine and not have soft limits tho it is not recommended.

[ShawnM]

Homing Z close to the material is a bad idea and a recipe for disaster in my opinion. When your machine needs to rapid around the table for any reason and you have a clamp, a part, a tip up or anything else that might get in the way when the torch is only 1" off the material surface what do you think is going to happen to the torch when it hits this stuff? I wouldn't want to rely on some mechanical breakaway and hope it works good enough with a machine torch that costs $971. That's the replacement cost for my Hypertherm machine torch. My 5x10 plasma rapids at 900 IPM (and I slowed it down from 1200 IPM) and at 900 IPM it will break things. Z has always homes to the top of travel for many safety reasons and this is just one of them....and the most expensive one.