Building a 3-axis plasma table with mesa 7i96s, THCad-2 and nema23 steppers

I've decided to immediately apply a 1:3 reduction ratio, which translates to 25mm (15T) or 20mm (12T) of displacement per revolution.

I want to listen to the advice of  rodw and  tommylight

This will change the design somewhat. I think I'll place the linear guide directly on the underside of the tubes to reduce contamination.

Slowly, all the parts are arriving, and I've started welding the table. Unfortunately, I have limited time

For now, I think I'll test it this way.
Later, I can make a support from cut aluminum plates.

I've also ordered the plasma source.
Any other tips and tricks? 

 

 

@tommylight
Sorry for the questions, but I'd like to get it right the first time. I'm not yet that good with various electrical components at a detailed level.
I've read through your other threads and I think I found the right info, thank you very much!!
Are the following components suitable for making a voltage divider? My plasma has a 1:1 arc output.
I'm using a TH-CAD2 in combination with two resistors in series and a 0.1uF capacitor to absorb the voltage spikes. Am I doing this correctly?
What happens if a voltage spike does occur? Will the capacitor fail?
 

I have another question.
Can I connect the start arc and arc OK signals directly to the Mesa board, or is it better to use a relay to protect the mesa board?
Can I route these signals to the plasma cutter through the same cable as the THC?
 

Daan96 wrote:

Are the following components suitable for making a voltage divider? My plasma has a 1:1 arc output.
 

Yes.

Daan96 wrote:

I'm using a TH-CAD2 in combination with two resistors in series and a 0.1uF capacitor to absorb the voltage spikes. Am I doing this correctly?
 

Yes, but wire one resistor to each side of the arc voltage, not both on the same wire. That makes it much safer in case the cable is kicked somewhere on the way to electronics and lowers the interference caused by plasma source.
And you can skip the capacitor as it does work without it, but i like to have it as it smooths the voltage readout and subsequently the torch motion up/down while cutting, but it will limit a bit the reaction speed.

Daan96 wrote:

What happens if a voltage spike does occur? Will the capacitor fail?
 

Usually nothing, if the polarity is correct.

Daan96 wrote:

Can I connect the start arc and arc OK signals directly to the Mesa board, or is it better to use a relay to protect the mesa board?
 

Yes you can, 7i96S has two fully isolated outputs ( 4 and 5 i think, double check that), so no need for relay.

Daan96 wrote:

Can I route these signals to the plasma cutter through the same cable as the THC?
 

Yes, if the resistors are mounted inside or outside the plasma source, but close to the plasma source.