Got another new toy on the way that I am buying from work. A 4 axis CNC laser welder!
The laser itself is a Nd:YAG made by JK Laser in England. It is rated at 55J per pulse, .5ms to 20ms pulse length, up to 100Hz pulse rep, 400W average power. The manual says it can be used for laser welding, drilling and cutting up to 5mm metal. Fun! Great for welding odd-ball metals.
Bad thing is it sucks power, at 240 3 phase it wants 66 amps peak. Ouch! The power supply is Two 19" rack cabinets bolted side by side about 4-1/2 feet tall and weighs in at about 880lbs (400kg). It also wants about 5 gal/min water cooling.
It was originally bought by Tektronix in 1985 for the display division. A friend who used to work down there said when he was there they used a ruby laser to zap tabs inside evacuated CRTs. The machine has sat for about 10-12 years now. About that time the original Anorad control died and they decided to upgrade the control to something more modern. They used MDSI OpenCNC with Yaskawa Sigma II brushless servos. After spending a LOT of money on the software, drives, and I/O the management decided this was costing too much and wanted to get out of the laser welding side of things so the project was dropped. The machine has sat ever since.
This is the software, yeah, $11,000 for the 4 axis version: http://www.mdsi2.com/Solutions/CNC_Cont ... fault.aspx
The machine has an amazing amount of documentation including copies of the original correspondence between Tek and the machine integrator, Lumonics. There are two filing cabinet drawers of complete schematics and blueprints for the laser and the machine it was integrated into. Every custom part used to put it together seems to have a print.
I am hoping I can modify it to run off of single phase. According to the schematics the power comes in and is routed to three places, a single phase transformer which supplies the DC for the control electronics, a three phase pump for the head cooling loop and two main three phase transformers in parallel. The first two are easy to deal with, a small VFD on the pump. What I am hoping is since the transformer is tapped for voltage selection I can rewire the windings for single phase operation. The output does not matter so much, it is just rectified for a 425v DC buss to charge the capacitor banks. If this does not work I have a 15HP rotary phase converter I built for my lathe that might run it.
For the cooling I will just use a garden hose for now, it wants 2 to 6 bar at 20l/min of water. If this thing does work I will probably get a plastic 55 gal drum and use a pump to circulate from that into the power supply's heat exchanger. A thermostat would add tap water to the tank as it heated to keep the temp stable. Maybe an evaporative cooler too.
It comes with an extra set of new lamps. Bad news is it sounds like it may need to have the YAG rod repolished. I cant imagine how much this is going to cost. It is a pretty good sized rod too, 3/8" diameter and 6.25" long.
Lumonics laser welder by macona, on Flickr
Lumonics laser welder by macona, on Flickr