How to Setup Pulse on MM255

[robert-r]

Using the "stock" settings for pulse on my 255 gets me a fair amount of spatter (BBs). Am wondering how to adjust the setting to eliminate that and still get good penetration. Am using .035 ER70S-6 Hobart wire, C10. Material is 1/4" mild steel. Tutorials anywhere?

Recently upgraded from a 11 year old MM212. & things seem different, to say the least.

TIA.

[robert-r]

No one has experience with the pulse settings on this machine that they are willing to share?

[jjohn76]

Robert, I don't have any experiences with that machine. However, I have run pulsed aluminum mig on other machines. As soon as I use up my cored .045, I might try it with steel. All that said, how does it run in pure spray transfer? I found I needed to use a longer stickout and clean the metal quite a bit more when switching from short arc to spray transfer mig.

I watched the Baker gas YouTube video on the MM255 pulsed mig steel and was surprised how much spatter it had. When you watch the arc and puddle, does it look like the wire is close to touching the puddle (goes into a very short arc)? If so, and your stickout is 3/4-1", you might benefit from higher trim voltage.

[MasterKwan]

I don't know that machine either but my Lincoln with pulse had a "Trim" setting which controlled where in the air the wire melted (how close to the puddle). You need to use twice the tip to joint distance over short-arc. I'd get spatter if I was too close to the weld pool.

Short arc spatters because you're jamming wire into a molten pool of metal. Pulse doesn't spatter because the wire is supposed to melt in the air and only droplets of molten metal feed into the weld pool.

[G-ManBart]

This machine has both automatic settings and a way to manually adjust the parameters. I looked at the manual and it seems to cover it pretty well...seemed similar to the pulse settings on my 350P (that I haven't even messed with yet).

[robert-r]

Thanks for the comments and suggestions, everyone. Because of the holidays and house guests, I haven't been able to spend any time with the 255.
Hopefully, after the holidays I can try different settings and see what they do.

fwiw - I've been running about 1/2" stickout and about 1/4" from the tip of the wire to the weld pool. After what has been mentioned, I suspect that this is at least part of the problem. 3/4" stickout and 1/2" tip of the wire to the puddle would be better? Am not sure there is a trim setting on the machine. The manual does not mention it. There is an arc length setting (varies the length of the welding arc cone) which might be the same thing? I can find no mention in the manual about the machine running in pure spray transfer - does it do that?

[jjohn76]

Robert, the C10 1/4" and above thickness weld settings in the manual look like they're for spray transfer - that's why the voltages jump up by about 6V from 3/16" to 1/4" settings. I only mentioned spray transfer because it's easier to rule out some of the non-power supply issues. That's more from experience with older pulsers, I still haven't had too much time to work with my current setup. If you can get spray transfer dialed in on flat and horizontal welds for 1/4", you should be able to switch over to pulsed mig with a good baseline to tweak the pulsed parameters if needed for in and out of position welds. There is more information available on spray mig too, to get you set up faster.

[G-ManBart]

fwiw - I've been running about 1/2" stickout and about 1/4" from the tip of the wire to the weld pool. After what has been mentioned, I suspect that this is at least part of the problem. 3/4" stickout and 1/2" tip of the wire to the puddle would be better? Am not sure there is a trim setting on the machine. The manual does not mention it. There is an arc length setting (varies the length of the welding arc cone) which might be the same thing? I can find no mention in the manual about the machine running in pure spray transfer - does it do that?

Section 6-9 of the most recent manual starts with: "Pulsed MIG is a spray transfer that produces less heat input than conventional spray transfer, resulting in less warping, distortion, and spatter. Pulsed MIG is often used for MIG welding aluminum."

Section 6-10 covers manually adjusting the arc length and control (width) settings.

Since you're running 90/10 you would also want to ensure that setting was done correctly since the Auto-Set features factor that in along with wire type/diameter if my memory is correct.