I have made few projets using Arduino Duemilanove - waste oil burner and heating control unit.
Now I am making TIG AC/DC welder but have no idea
I'd like to use same Arduino (Duemilanove/Uno)
I think that I have to change PWM frequencies
PWM - 1-300hz made from internal EEPROM parameter (frequncy for square AC (constant during usage)
PWM - aprox 10khz which percentatge continiously determined from analog input (curent sense using hall effect sensor)
PWM - aprox 0.5hz - made from internal EEPROM parameter (for point/thin metal welding(constant during usage)
LCD display conected thru i2c (analog 4,5), rotary encoder for parameter change
in final stage I already purchased 300A 1200V IGBT transistors Totaly I have to reach 1 signal controling IGBT's
invest in some good gate drivers and use an isolated supply to provide a positive and negative supply (+15, -5 or 15) to drive the gate. also, gate resistors are pretty important, don't forget them.
There are a lot of good ideas here, particularly regarding duty cycle and polarity tuning requirements, frequencies, and HV arc starters and how to put together the high current circuits. Definitely worth a read.
That sounds about as "far out there" as something I happened upon while reading an old issue of PopSci on Google books today (April or May 1950, I think). Basically, they had a very small picture blurb about a "cold flame" torch that used a magnetron to energize nitrogen gas, and when it hit a material (they talked about cutting tungsten, IIRC), the energy imparted to the nitrogen by the magnetron was released, heating it up to cutting temperature. I haven't researched this further, but it sounds kinda like some form of plasma cutter. Given that nitrogen is easy to purchase at a welding gas store, and magnetrons can be had cheaply from a microwave oven, it started to make me wonder if a highly precise, thin sheet-metal CNC X/Y plasma cutting table could be constructed (controlled by one or more Arduinos, of course)...
I have already made gate drivers with power supply and invertor now I need only 2 signals from arduino 1-cobined AC signal + pointwelding (can be seperated) 2-5-10khz for current regulation
Final stage is finished(finish test 10min ago) - at this moment I'm testing using NE555, LM324(inverting) IXDD414PI(driver) and 2MBI300P-140 IGBT's I got totally closed time for 40 microseconds @50hz and @250hz not depending on duty cycle. Tomorw I'll try conect them to VD306 - one of the best Soviet Union DC MMA welding station (Full power 500amps)
Yea for aluminium square wave poarity change necessary whith changeagble duty cycle and frequency
full H-bridge necessary each MBI contains 2 IGBT's each 300A 1400V.
VD306 is 3phase(32A) simple welding transformer with changeable air gap for current change It has 6 diodes - don't remember type.m
At this moment I'm thinking about arc starter made from pasma ball or from luminiscent lamp electronic starter - both of tfem have HV HF
Mr_Manny:
Any little mistake in this can be fatal. A commercially made TIG welded can be had for $1000.
Just throwing out a couple bits of information.
yesss - its so but if I want to show my knoledge whithin budget of 200eur.... - AC TIG with such a big current costs from 3000Eur in latvia
Yesterday I finiished arc starter from vintage TV HV transormer it has frequency somewhere around 100khz
Mr_Manny:
A commercially made TIG welder can be had for $1000.
A commercial 300 to 500 AMP TIG welder with a HF arc starter and fully programmable duty cycle, frequency and polarity as well as start and end current envelopes is still a fairly expensive proposition. What I can find is more in the $5-$10 grand area. I agree that this is dangerous stuff, but rabits seems to know what he/she is doing, so I would say that angle is under control.
I do think that the best bet for all the ancillary parts -- TIG torch, gas fittings and gas valving, controls, housing -- rabit's best bet is to find a basic TIG welder and then retrofit all his circuitry into that.
talking about dangerous things - I have made system with explosive risk - solvent cleaner where 60 litres of solvent is heated up to 180 degrees Celsium an pressure up to 0,2bar - it works fine from year 2001 - 10 years - now I want to rebuild it to arduino because it was made using discret components - most of them is soviet union made
P.S.
gardner:
I do think that the best bet for all the ancillary parts -- TIG torch, gas fittings and gas valving, controls, housing -- rabit's best bet is to find a basic TIG welder and then retrofit all his circuitry into that.
If I buy basic tig welder I'll get only some parts of it - maybe some is unusable - Tig torch can be purchased for 40Eur in ebay gas fitings and valves can purchase near my house - aprox 30eur all necessary parts At work I have old MIG welder, metal lathe and good MIG welding stand Most of all this projet is hobby....
yesterday I made first test for my project - still without arduino it works near perfect but only HV starter necessary
P.S. IXDD414PI I changed to IXDD614PI - next generation - peak for IGBT's switching is 1us 6amps pictures I add monday
Yes, I have read many of them but I want to make it digital with LCD display but I need to change PWM frequency
You probably need to read up about the ATmega328 counter/timers - you only need 3 frequencies, its not clear to me if you need them all at the same time. There are 3 timer units though so should all be doable. Very low frequencies may be easy to code directly rather than devote a timer to.
There are a lot of good ideas here, particularly regarding duty cycle and polarity tuning requirements, frequencies, and HV arc starters and how to put together the high current circuits. Definitely worth a read.
Yes.! Duty cycle is the most important factor of any the best tig welder..
