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Topic: AC TIG ALUMINIUM WELDING (Read 12075 times) previous topic - next topic

rabits

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
1. PWM - 1-300hz made from internal EEPROM parameter (frequncy for square AC (constant during usage)
2. PWM - aprox 10khz which percentatge continiously determined from analog input (curent sense using hall effect sensor)
3. 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

Anybody have some good idea?

weirdo557

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.

gardner


Anybody have some good idea?


http://www3.telus.net/public/a5a26316/TIG_Welder.html

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.

keeper63

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)...

:D
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

rabits

Yes, I  have read many of them but I want to make it digital with LCD display but I need to change PWM frequency

rabits

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

rabits

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)


gardner

Are you building a fill H-bridge? or are you just looking for single-polarity welding?

Does your 500-amp stick welder have a good rectifier in it?  Is it full wave?

Are you planning on have an arc starter?

rabits

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

rabits

no more IXDD414pi - one I blow out today (mismatch with tester leg) few minutes before start :(

Mr_Manny

#10
Feb 12, 2011, 06:47 am Last Edit: Feb 12, 2011, 05:19 pm by Mr_Manny Reason: 1
Any little mistake in this can be fatal. A commercially made TIG welder can be had for $1000.
Just throwing out a couple bits of information.

rabits


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

gardner


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.

rabits

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.

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....

electricians and electronics are not nomal people

rabits

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

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