Kemppi Pro 4000 with the ML panel is an inverter MIG/MAG power source with pulse and an MMA mode. The current reaches 400 A, at an 80% duty cycle the machine gives the full 400 A, and 310 A it pulls without a break. The documentation points to work with steel, aluminium and CrNi stainless steel.
What this machine is for
This is a power source for plants where mild steel is welded one day and aluminium or stainless steel the next. The ML panel, that is Multi-Logic, is analogue to operate: you set the voltage and the wire feed speed with knobs, without going into submenus. You correct a setting during work while looking at the pool and not at messages, and you do it in thick welding gloves as well, because the knobs give clear resistance when turned.
Pulse changes the way metal is carried across: the droplet is detached by a current impulse, so there is less spatter and the heat input to the material drops. On aluminium this helps to break the oxide layer and to hold a pool that does not collapse into the gap. On stainless steel a smaller heat affected zone limits the precipitation of chromium carbides at the grain boundaries, and that protects the joint against intergranular corrosion. Because you reach penetration at a lower average current, you also weld parts of different thickness without distorting the whole structure.
You set the arc dynamics separately. On carbon steel you harden the arc and go deeper into a thick part, on stainless and acid resistant steel you soften it, so that the pool spreads gently and passes smoothly into the parent material. The system compensates changes in wire stickout, so the process stays stable even with a less sure torch movement. A station like this went to workshops and to medium and heavy industry, among others to thin walled aluminium structures and stainless steel pipelines.
Features and equipment
- ML Multi-Logic panel with physical knobs for voltage and wire feed speed, operated in gloves.
- No multi level menu, which cuts the time needed to prepare the machine and limits mistakes in the settings.
- MIG/MAG welding in manual mode.
- Pulse for aluminium and stainless steel: less spatter, lower heat input, a cleaner face.
- Arc dynamics adjustment from hard for thick plate to soft for stainless steel.
- Compensation of wire stickout change, which steadies the process when working in fixed positions.
- MMA mode for the covered electrode.
- Hot Start in MMA mode, which makes striking on a cold part easier.
- Anti-Stick, which cuts the current on a short circuit and protects the electrode coating.
- Encoders with a felt step, so you correct by ear and by touch, without looking at the panel.
- Fast change of settings when the weld gap varies, without going into submenus.
- Modular build: you add a liquid cooling unit or another panel from the Pro series to the power source.
- A build prepared for service repairs, with access to the components.
Technical data
| Brand | Kemppi |
|---|---|
| Control panel | Kemppi ML, that is Multi-Logic |
| Maximum welding current | 400 A |
| Duty cycle at 40 degrees | 400 A at 80%, 310 A at 100% |
| Processes | MIG/MAG, pulse, MMA |
| Materials | steel, aluminium, CrNi stainless steel |
| Supply voltage | 400 V |
| Cooling | liquid, cooling unit as a separate module |
What to watch out for
Supply 400 V, so you need a power connection. The product record gives liquid cooling, and in this build the cooling unit is a separate module, the same as the wire feeder and the panel. So you put the set together for your own station and at purchase settle which modules you have on site and which have to be added. You get 400 A at an 80% duty cycle, in work without breaks stay at 310 A, and it is that second number that sets the pace of production.
The ML panel has no synergic programs: the welder sets the parameters, so this is a set for a settled procedure and experienced operators, not for frequent changes without preparation. On the plus side you have a fast correction during the bead and a shorter time to prepare the machine, so more of the shift goes to arc time. On the minus side there remains the need to note the settings for each job, so that a second person repeats the same parameter. For aluminium prepare rollers for soft wire and the right liner, for flux cored wire knurled rollers.
Compensation of wire stickout change limits the usual faults from uneven torch movement, that is sticking and lack of fusion, but it does not replace edge preparation and a clean surface. With pulse check that you have the gas right for the material, because the stability of droplet transfer depends on it.
This unit is sold
This machine has already gone to a customer. Similar units are listed below, and if you want the same model, leave your contact details in the form and we will let you know when the next one arrives.