Advice on voltage /wire speed.....

[medroberts]

Hi Everybody,
I have a kemppi KM 400 mig, which I need some help on setting voltage/wires speeds. I have downloaded the manual from the kemppi web site. Iam using 1mm wire and argoshield @12LPM. I have been on the Miller website and tried using there free calculator. I set the mig to 30 volts(spray transfer)/9.8metres/min(386ipm) on 12mm plate. I had problems when striking the arc, the wire would burn back to the tip and then jam the feed ? When the arc could be maintained the display only shows just over 200 amps ! The weld appearance does not seem to have penertrated as I would expect (hasnt washed into the steel) Is there anybody with experience of my machine or point out were Iam going wrong? Settings etc

 

[dannyp]

i would be useing quite a lot more wirespeed.

machenes i use are diffrent makes but simalar power.

my wire feeds normaly set at between 13.5 mtrs/min and 18mtrs min when spraying

 

[Drains]

Aye, wire speed far too low. More like 24v or less for that speed. 30v is high for 1mm wire anyway At whatever voltage though, adjust the feed speed right up, then back it off until the arc stops sputtering and goes into spray. If you go globular, speed it up again.
You need a piece of scrap to set up on, gun in one hand, feed knob in the other.
You can do it the other way and set the wire speed and adjust the voltage to suit.

Also, your machine make isn't important. Voltage and wire speed settings are generic, more or less.

 

[Delgado]

Are you sure you conveted the wire size correctly when you input it into the miller calculator? Those settings are pretty much what I would expect to see when running 1.2mm wire in spray transfer.

 

[medroberts]

Drains,Danny p
Thanks for the help. Is there a chart/info regards setting wire speed/voltage using 1mm wire ?

 

[medroberts]

Delgado,
The miller calculator only quotes imperial wire gauge. This is maybe were Iam going wrong. Were can I get this info using 1mm wire ?

 

[Drains]

Drains,Danny p
Thanks for the help. Is there a chart/info regards setting wire speed/voltage using 1mm wire ?

Not that I know of. Bear in mind, even if you match the wire size, if the gas type is different then the settings will change. You have to work it out yourself and it's not so hard. Set to 27v, and do what I suggested above- adjust your wire speed until you get a smooth quiet spray. And hold the tip off about 15-20mm

 

[pedrobedro]

Torch distance can affect your readings as well, there are many variables to take into consideration.

 

[medroberts]

Guys,
Still get trouble on arc being struck. The wire seems to contact steel ,melt back and end as a blob on the tip all in a milli second. Result jammed wire feed, very frustrating. If I can get the weld going , starting to get better looking welds.Increased wire speed as all suggested, but why would I still only just getting over 200 amps, with the voltage set to 28volts, 1mm wire etc ? Should it not be higher ? Could there be a fault on the set ?

 

[dannyp]

try a new contact tip, my welder at work likes to exactly as you describe when the tip is about knackerd.

there are no magic settings tho each person welds slightly diffrently each machene is slightly diffrent, of the 3 big migs is use daily at work if doing the sme job with each id set them all slightly diffrently. as you get used to the maches you find yourself setting them without thinking about it

as said just play with the wire feed it'll tell you when it's happy

 

[Drains]

Turn the volts to 20 and see if you can sort it, then just turn up gradually. Have you tried welding in dip or are you going straight to spray? I assume you have welded with this machine before?
Tbh, it just sounds like your feed is far too low, although I'm more inclined to say your voltage is too high... 28v is high end for 1mm wire. You don't have to have it for welding 12mm plate and if you're not experienced then it's a bad idea anyway. Just use a lower voltage and more runs.

 

[Deepwinter]

I have used a different Kempi, a 323R,
I typically set it to 30.2Volts and 10.1 mpm
That works well with 1.0mm on a root pass on a T fillet type weld.

I've gone as high as 30.4 and 10.4
Anything in that range works and gives excellent root penetration.

I drop down to 19.5 to 20v and 6.2 to 7mpm ish short circuit to cover the root if necessary.