Kemppi MIG no penetration!?

[Deejayry]

First of all this is my first post here so HELLO!

I've just wasted almost a whole day trying to get my friends Kemppi Mig welder to produce a decent weld, but i cannot get any penetration to my welds, Even after trying just about every combination of settings on the wire feed and current control.

I'm trying to weld car body panels, and had the welder working perfectly about a week ago, infact i was getting on so well with the welder i produced my first decent butt weld when repairing the door step on the mini. Since then not of the controls on the welder were touched (not knowingly anyway)
I seem to recall that i had the best results with the wire feed set around the 4 position & the Current set near 6. The welds were consistantly neat, penetration was good, then i try to use it today and cannot get a decent weld.

The welder in question is a Kemppi Super Kempomat, i'm not sure which model, it runs on single phase, its one of the older square syle ones, not of the new design with the angled control panel at the top as shown on the kemppi website. The wire fitted is 0.8mm & the gas is BOC ArgoShield, I'm not sure of the flow rate of the gas as the regulator fitted only tells you the cylinder pressure. I experimented a bit with the flow of the gas but it didn't make much difference to the weld produced.

I would have thought that if i turned the current dial to the maximum, the welder should easily blow holes in the thin 0.5-0.8mm steel used for body panels, but i goud not get more than a raised blob of metal that when given a tap with a cold chisel would just break off the parent metal.

Can any of you give me any advice on what might be the issue here? I am beginning to think that the welder is not working correctly.

 

[Angusdog]

Have you changed the polarity (perhaps when switching between gas & gasless wire?) When I bought my welder it was set up for gasless wire and I got that result.

 

[Deejayry]

Nope, Polarity has not changed. Infact it doesnt look like it can be changed without getting inside the welder.

For clarification the welder is the one shown in the picture linked below but the fixed torch & lead have been removed and replaced with a removable eurotorch kit.
http://image.nettix.fi/extra/machin...uskoneet-kemppi-933313_l_79b1a8d3195824a6.jpg

 

[Engineer]

Have you tried direct earth onto a clean piece of scrap material, and testing on that? Have you carefully checked the earth clamp, and whether the lead is connected to the machine properly? Finally are the any of the wires inside the power lead plug loose at all?

 

[Deejayry]

I didnt even get as far as fitting the earth clamp to the car today, I always start on a piece of scrap metal before i put the torch to the car, The metal was nice and clean on both the earth contact area and both sides of the weld area.

We had all the covers off the welder and there were no signs of bad connections anywhere.

 

[octo0072000]

kempi

are you now using a extension lead and getting a volts drop will give the effect,s of spitting blobbing etc extension lead must be at least 10amps pref 16amps i use a caravan hook up cable for mine 16amps ext must be totally unwound as well

also switch on the welder looks like 3 position for spot weld normal weld and pulse should be in centre looks like is down on pluse mode ???

 

[pedrobedro]

Is it in start and charge mode, it has a battery charger function as well as welding doesn't it?

 

[Deejayry]

are you now using a extension lead and getting a volts drop will give the effect,s of spitting blobbing etc extension lead must be at least 10amps pref 16amps i use a caravan hook up cable for mine 16amps ext must be totally unwound as well

also switch on the welder looks like 3 position for spot weld normal weld and pulse should be in centre looks like is down on pluse mode ???

hrm... well i used he same extension lead as before, but this time i didn't unwind it fully, I'll try it fully unwound tomorrow.

The spot/continuous/stitch switch was set to the middle (continuous) position, the photo linked is not actually the welder i am using, just one of the same model.

Is it in start and charge mode, it has a battery charger function as well as welding doesn't it?

Yes, this was also set to the welding mode.

 

[eddie49]

If you have a voltmeter, try measuring the DC between the torch tip and the earth lead. Slacken the wirefeed pressure roller so that you don't waste wire whilst testing. With no load ( i.e. the torch not arcing ), there should be about 16 to 35 VDC, and it should increase as you click up the power settings.

 

[Deejayry]

My friend tried the welder today with the power cable plugged directly to the 13A ring main socket. unfortunatly this didn't make any difference to the weld.

I'm hoping to get up there tomorrow with my multimeters to test the open circuit voltage.

 

[octo0072000]

kemppi

just under the torch has yours got the ramp up /down voltages if so set them both to zero

 

[SANDMAN]

Kemppi power problem

Hi mate, just saw this on the net while searching for something else so I thought I would join and try and solve your problem.
Like the other guys have said, measure the DC voltage between the contact tip
and the earth clamp. If you adjust the voltage settings, the voltage on the meter should increase or decrease accordingly. DO NOT CHANGE THE VOLTAGE SWITCH POSITION WITH THE TRIGGER PRESSED IN. Clamp one end of the meter terminal in the earth clamp and place the other on the tip (firstly release the pressure off the drive roll) pull the trigger and note the voltage. NOW RELEASE THE TRIGGER, move the voltage selection to another position and repeat the process. The other thing you might want to check is the contactor (the thing that clicks in and out when you pull the trigger). You would need an electrician or similarly qualified person to check the AC Voltage coming out of the contactor is the same as that coming in. She's an old machine and has probably done a lot of tacking in it's day and that is a common fault on all
transformer machines. Last of all, check the diodes on the rectifier (another job for the sparky). This is also a common problem in old migs also.
GOOD LUCK !

 

[SANDMAN]

sorry, just 2 other things I noticed in your photo. The wire speed is on 6 and the voltage is on 3, if that is what you have been using I think with 0.8 wire you might want to turn the wire speed down a bit.
Also, you see where the earth lead plugs into the front of the machine, pull the black rubber cover back and check there is a good connection. There is a grub screw that holds the copper cable into a brass block under that and they come loose or the cable frays under it.
Regards

 

[Wozzaaah]

That photo isn't of his actual machine, just a photo he found of the same model.
Welcome to the forum Sandman, you sound as if you know your stuff, get an intro up.

 

[SANDMAN]

Yeah, I noted that wasn't his machine in an edit but I don't think I posted it properly. I just got lazy and didn't read all of the reply posts BEFORE posting my reply.

I have been selling welding machines, mainly high end Mig and Tig in Australia for 30 years now. I also repair some machines and do a lot of demos. I don't profess to be an expert (always learning) but have learnt a lot over the years.
I am aware of most common brands of machines many of which are common to both Australia and the UK. The main brands that I sell are Kemppi, Fronius and to a lesser extent now ESAB. I probably wont come on here often but when I do I will always be glad to help someone out if I can.
Regards

 

[malcolm]

Have you tried another contact tip? Notice when I lend my welder out it comes back not working properly, and it's usually the tip.