My Experience with the Millermatic 255
On a recent pulsed MIG demo with the new Millermatic 255, I noticed a strange arc length quirk. This machine, like all Miller pulsing machines, has an arc length range of 0 to 100, 50 being nominal and the logical place to start for tuning in a procedure. For 035 ER70S-6 carbon steel MIG wire, I had to turn the arc length all the way up to 70. For 035 4043 aluminum, I had to turn it down to 30.
Our Miller local rep confirmed that their engineers programmed the new Millermatic & Multimatic 255 to have a less sensitive arc length setting and a larger sweet spot. He also confirmed that the machines were performing as designed. I found that with these changes, arc quality is still excellent. However, it’s unlikely that arc length for whatever alloy or wire diameter you’re welding with will be anywhere around 50 as was common with older Miller pulsing machines.
Author: Bob Page