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.

[JCFab]

The Baker's Gas video convinced me that the MM255 Pulsed Auto-Set software is jacked up. I have been fighting with a 255 (and Miller) since January 2021. I've had the machine to two service centers and welded with it in front of them. They agree that pulse is an open arc transfer method and we shouldn't be hearing harsh crackle or seeing showers of sparks like in the video. I have to set the Arc Length to 90 or better and I still get some spatter! They are supposed to be sending me a new machine and I'll let you know if this one behaves better. I am pretty sure the software sets the max voltage about 1 to 1.5 volts lower than is actually necessary. I've tried various grounding methods to reduce voltage drop with no success. You can find a "Kane Kid" youtube video of him using a Multimatic 255 and he has showers of sparks also. I think there should be a software update to make this a really good welder.

Jeff

[JCFab]

A VICTORY!!! The MM255 works pretty well after all!

So after fighting with this and another MM255 for seven months, Miller did get back with me and suggested turning up the "Arc Control" setting a few points. Factory setting is 30 so I went up to 35. There was minimal improvement but I was able to reduce the Arc Length to about 70. Ran an additional 2 spools of .035 VIKING ER70 S-6. I was having constant burn backs, spatter balls on the tip and BB's all over my parts. I changed every consumable including the entire gun with no noticeable improvement. I was furious and very disappointed having to change tips every five welds or so and knocking BB's and smoke off of every part.

At my wit's end I bought a roll of Lincoln L-56 and put it in and pulled the trigger. Well paint me yellow and call me a Cab! Every single problem I was having disappeared! Changed all the Arc Lengths back to 50 and finished an entire rig with the same tip. No BB's, minimal smoke, no crackle, no feed issues and no visible arc length changes. It seems the MM255 just LOVES this wire! I know it's expensive but the time saved in changing consumables and part cleanup may well be worth it. I'm willing to test other wires but at this point I am happy!

[G-ManBart]

A VICTORY!!! The MM255 works pretty well after all!

So after fighting with this and another MM255 for seven months, Miller did get back with me and suggested turning up the "Arc Control" setting a few points. Factory setting is 30 so I went up to 35. There was minimal improvement but I was able to reduce the Arc Length to about 70. Ran an additional 2 spools of .035 VIKING ER70 S-6. I was having constant burn backs, spatter balls on the tip and BB's all over my parts. I changed every consumable including the entire gun with no noticeable improvement. I was furious and very disappointed having to change tips every five welds or so and knocking BB's and smoke off of every part.

At my wit's end I bought a roll of Lincoln L-56 and put it in and pulled the trigger. Well paint me yellow and call me a Cab! Every single problem I was having disappeared! Changed all the Arc Lengths back to 50 and finished an entire rig with the same tip. No BB's, minimal smoke, no crackle, no feed issues and no visible arc length changes. It seems the MM255 just LOVES this wire! I know it's expensive but the time saved in changing consumables and part cleanup may well be worth it. I'm willing to test other wires but at this point I am happy!

What wire were you using previously? There are a couple less expensive wires I've read about that suddenly folks are reporting as being problematic for normal short-circuit MIG. I definitely recall folks complaining about the newer wire from Harbor Freight (the old stuff made in Italy was good).

Edit to add: thanks for following up! So often people find a solution and don't circle back to let us know.

[BukitCase]

When I got my first mig (Transformer version of the MM211) the ONLY wire I tried that NEVER screwed with my was Lincoln L56 - so the second one (MM252) and third one (inverter MM211) have never seen anything ELSE - Still have the 252 and newer 211, so I simplify life a little, just stock these

https://www.zoro.com/lincoln-electri...specifications

The .035 wire is actually cheaper per pound in those 12.5 pound spools ($3.44 vs. $4.39/pound in the 33 lb. spool - might not be true somewhere other than Zoro, they get a bit strange every now and then - In my case, it'd be a little tough to fit a 33 pounder in the 211, this way I just keep a couple of the 12.5 pounders in stock. Simplifies stocking and NEVER screws with my welds (I can do that WITHOUT help :=)... Steve

[tackit]

I bought a roll of this wire to try it out, I liked it so much I ordered two more rolls of it. I run it on 75/25 through my mighty 2003 MM251, man I love that welder.. The trailer project was built using it.. I like .030 wire best, I believe it gives a larger arc sweet spot.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[Aeronca41]

A couple of years ago I had a very frustrating time with a roll of Radnor wire from Airgas. Took quite a while to figure out it was the wire--I was blaming me and the machine. Then I learned that if I'd run out a good long piece and throw it away, welding was fine again. I chucked the whole roll, and have since used the standard Hobart ER70S-6 from TSC and the equivalent Lincoln L-56--no problems since. I have been running it in the MM200 and MM211 (the old one). Learned my lesson about cheap wire.

[tackit]

A couple of years ago I had a very frustrating time with a roll of Radnor wire from Airgas. Took quite a while to figure out it was the wire--I was blaming me and the machine. Then I learned that if I'd run out a good long piece and throw it away, welding was fine again. I chucked the whole roll, and have since used the standard Hobart ER70S-6 from TSC and the equivalent Lincoln L-56--no problems since. I have been running it in the MM200 and MM211 (the old one). Learned my lesson about cheap wire.

I once had rust on the wire problem that I couldn't see, finally, I wiped the wire with a clean paper rag and the rust showed up, I threw away a good part of the wire, from then on I've never allowed my wire to over winter in the machines.