I started with an old Rack case I had from another project.
I than worked on mounting the TinyG ( I do wish it came with its own standoffs! )
As well as the power supply and a Volt/Current gauge onto the case.
At first it looked like I had a ton of room, but that starts to fill up quickly.
Here I got the motor wires in to start testing.
This is where to fun began.. Setting up the TinyG to work with the old Shopbot motors. I was able to find an old data sheet that helped get things setup but nothing listed the distance per rev.
I came to find out the motors have a build in gear reduction of 6:1
So first thing first I strapped a router to the unit and did some test cuts.
Egad! That’s not good. I am getting drift and mist steps that and the noise oh the noise!
So after allot of troubleshooting I got this,
So what did I figure out?
Well I may have missed it in the wiki, but every time I made a system variable change, I noticed nothing would change in operation, if I changed step rate or in/rev nothing would change, so i would get frustrated shut it down and start again another day, only to find it not working or in bad shape, so I would make some changes, nothing would happen and the cycle would repeat.. I was about ready to pitch the TinyG thinking how unreliable it is… then it hit me!
After you make changes, it will reflect them, but you have to reset the TinyG for it to implement them! BAH! So once I figured that out, I was finally able to work at fine tuning the system.
In the process of all of this my plasma torch came in!
It is an 80Amp CNC torch I scored of ebay cheap! And came with a 13′ hose!
I ordered one with Pilot arc, so it can strike the torch without contact with the metal.
So I set out to build my own Plasma cutter power supply. I was stepping down 240V to 120V at about 60 amps. I than ran it through a massive Bridge rectifier, and large cap bank to give me just shy of 180VDC.
I used a 19Kv DC power supply for my pilot arc. and (2) massive 2Kw isolation transformers in parallel to keep me safe. last a set of stacked variacs for voltage control.
I got everything setup, and it worked!!!
… for about 20 seconds, the very next time I struck and arc, the insulation in my isolation transformer broke down, sending the 19Kv back through my panel, the massive current spike from the caps, blew my main breaker in the panel, but because of the high voltage DC, only one leg opened, the other was left floating at 8 Volts! Eeek… This was not good. Fortuitously I have a 100Amp DC contractor that was able to break the loop upon the drop out of the 220.
This lead me to the idea It is not always best to build you own, so I went and bought one.
So I picked up this guy Lotos 60Amp Pilot arc plasma cutter power supply.
Next lets see how it works with the system!