[Welder]

Hi. I am welding metal parts and components using Kemppi FastMig power source and X37 Wire Feeder.
The machine has the so called 'state of the art' WiseFusion and WisePenetration welding 'modes' in which the welding current and inductance values are modulated so that you get 'perfect penetration' and 'perfect fusion'.
After some research online it turns out this technology was developed decades ago by other companies such as Lorch - SAPROM, EWM, Lincoln Electric, and others, while smaller (at the time) companies like Fronius, Kemppi and others took on this and developed and perfected further these technologies by branding them with their own names.

But anyway, I am not going to talk about this since this is not the topic of this thread.

The topic of this thread is related to the above mentioned Kemppi equipment, that I use in Pulsed mode to weld mild steel.

Why am I disappointed and what I don't like about this machine I explain bellow:
Using 10% Co2 and 90 Argon. Gas flow rate: 10-11 liters per minute.
Using 1 mm diameter ER 70 S-6 electrode wire.
Welding mild steel thickness 3-6 mm and sometimes up to 12.
WElding machine setting: Pulsed mode, WiseFusion OFF, WisePenetration OFF, Program for MildSteel is being used.
In most of the cases the joints I weld are of different thickness, meaning one of the parts is thicker/has more mass and heats up slower. This is very important (as all of you experienced in GMAW/FCAW and SAW welding know).
But for the sake of finding out what is wrong with this machine, I have welded and conducted numerous tests on joints of which both parts are with same thickness and mass size.

Example: 3 mm thickness mild steel plate welded to the same part, joint type: Lap Joint. Single Fillet.
Welding position: horizontal.
Wire Feed Speed, Voltage and Dynamic Inductance Settings Used:
Example 1: WFS = 3.3, Voltage/VTrim(Deviation from factory set synergic curve) = 0, Inductance settings - full range tested ( from -9 to +9 ).
Example 2: WFS = 3.6, same as above
Example 3: WFS = 4, same as above
Example 4: WFS = 4.6, same as above
...and so on up to WFS of 6.7~6.8.

Results: Good looking weld, fuses good with base metal(but only on the wider area the arc cone covers), good weld bead profile, size of weld and reinforcement as expected and can be varied by changing travel speed and torch angles and torch leading techniques as expected. NO undercuts (except when using excessive travel speed that causes arc to stray away from puddle and vice versa, see bellow)

Bad fusion at the rood of the weld. Arc is too wide. Bad pool 'wettening' at the arc cone's center. Arc is too wide, not stable and wanders and melts and gouges the base metal at the toes of the weld (at the edges of the pool), Puddle is hard to control and it is impossible to weld with faster travel speed since the pool is melting but not 'wettening' the base metal where its melted and material does not go where it is supposed to. Arc length seems a bit longer than on other pulsed welding machines I used, but not significantly.
Changes ATTEMPTED:
1)Decrease voltage(VoltTrim) to narrow the arc cone. Results - minimal arc cone narrowing, when you go bellow VTrim < -1.5~2, the arc becomes unstable, interrupts, wire feeding stops being stable, metal transfer becomes unstable, excessive spatter is generated. Above this voltage level no spatter or minimum spatter is created at all inductance settings (-9 to +9).
2)Tested welding using the full Inductance range, same results. Higher choke settings does seem to narrow the arc a but (although not visually but you can feel it while welding, the puddle wettens the root better and gouges the toes less.

Absolutely the same test was done multiple times using higher WFS settings and various voltages going from VTrim of -4 to +4. All tests were done using full inductance range. No significant change in puddle behavior and heat distribution in and around the pool. I did notice though that using Inductance setting at -5 OR +5 gives most stable arc with zero spatter.

Wire speeds of up to 6.8 were testing using same procedure mentioned as above (with faster travel speed of course).
Pushing and pooling gun manipulation techniques were tried too. Circular motions, back and forth motions and so on. Using back and forth motions similar to when welding with 6010 high penetration rods in SMAW did yield better results but still far from perfect.

I do not believe this to be hardware or other electrical or technical problem with the machine, since the machine is welding PERFECTLY when using low-tech and 'ordinary' MIG processes in Spray and Globular transfer modes.

I do think that the problem might be solved or at least weld quality and puddle control improved if the pulse frequency is increased: this should narrow the arc somewhat and fix the above mentioned problems with lack of fusion/penetration at the root and excessive overheating/gouging at the toes of the pool. But the machine does not allow for increase of pulse frequency so I am awaiting for your ideas suggestions.

I can weld like that but controlling the weld and laying it properly and where I want it is extremely difficult compared to the normal MIG processes on the same machine using same gas, gas flow rate and WFS settings.

Thanx to all who have welded using this machine and are willing to help me solve this issue and start laying decent beads in Pulsed-Spray mode the way it should be.

[weldin mike 27]

You need to experiment with different gas mixes. It absolutely makes a massive difference to outcomes.

[Welder]

Hi Mike I know, what you mean but the mix that is mentioned in the 1st post is de-facto the standard and most used mix for Pulsed MIG welding for the past decade? Today I was welding the same stuff and I switched off Pulsed mode on the machine because I have tried every possible setting, including using different programs for different metals like for example stainless etc. but I just could not get satisfied enough with the consistency of the weld and the above mentioned problems were still not cleared.
Switched back to non-pulsed spray MIG and at the expense of more spatter I get stable arc, I get the puddle to flow and form where I want it and how I want it, much better consistency and better weld profle without having to do weirdo-stunts with the gun. Just plain old MIG-ing and expected results.
May be I am expecting too much from this machine? Or may be I fall victim to marketing and advertising?
I wish the manufacturer (Kemppi) would post videos on their website and YouTube on actually using and welding with this machine, setting it up and so on.
They have this video, but no welding is seen and no end result?

https://www.youtube.com/watch?v=dLqfTtGGffY

[Coldman]

I think that 1mm wire is large for 3mm bar stock welding and would result in lack of fusion at the root because of the resultant travel speed.
I use 0.9mm wire mostly and have noticed the same thing can happen as well. I switched to 0.8mm wire, travel speed slowed down on thin bar stock allowing heat and fusion to get into the root. Much better results.

Your Kempi machine is a very fine power source and you are lucky to have it. Try 0.8mm wire on thinner metal jobs and I think you will be much happier with the results.

[weldin mike 27]

I would see what kemppi themselves have to say about it. I know what you mean about a fancy machine acting up,they really need a skilled hand to set the initial perimeters. Once the tech is locked in, you'll have a fantastic machine.

[Fusionpuddle]

Won’t let me put a message up yet
but could someone tell me how to set up the Fronius tps 400i
100 percent CO2 .045 wire around 11-12 gage welding
to 17 -18 gage for now want to set it to just spot weld
It a company welder, I just haven’t had time to mess with the settings yet thanks