The Kemppi FastMig M420 is a modular inverter MIG/MAG system for a 3 x 400 V supply. The source gives 420 A at a 60% duty cycle and 380 A under a continuous load of 100%. The set stands on a trolley together with the MXF 67 feeder and the FastCool 10 cooler of 1 kW, and it weighs about 200 kg.
What this machine is for
This is a power source for heavy production in carbon steel. A current of 420 A at a 60% duty cycle and 380 A in continuous work lets you lay thick fillet welds and multi run joints through the whole shift, with no breaks for cooling. The machine melts solid and flux cored wires up to 1.6 mm in diameter, and it keeps the pool fluid in thick joints. The maker lists here the series production of large structures in carbon steel for building, the welding of thick walled shells and ship hulls on the open yards of shipbuilders, the prefabrication of heavy crane components and farm machines, the hand building of transfer pipelines with cored wires, the rebuilding of transport trailers, and repairs with an electrode in hard conditions outdoors, for example on the grounds of a refinery.
The build is modular. The source, the wire feeder and the liquid cooler are separate units, so in the hall you lay them out around a large part and not the other way round. The MXF 67 feeder has a housing of reinforced plastic and a four roll DuraTorque drive: four toothed rolls push the filler without crushing soft aluminium and cored wires, also with the long liners of liquid cooled torches. The feeder takes spools of up to 20 kg, which in series production cuts the number of changeovers.
The control is manual. The MR300 panel has no synergic curves: you set the welding voltage and the speed of the wire feed with potentiometers, looking at the pool. For a practised welder and for a process engineer working to a WPS instruction that is an advantage, because the settings are corrected on the spot, without a fight with the automation. A person without practice will have it harder, because you have to know how to match the voltage to the thickness of the wall. Besides MIG/MAG the machine welds with a covered electrode, so you move the same cables over to an electrode holder and make repairs in the field. The coating protects the zone where the alloy crystallises, so you work in wind and at height, on the frames of wind turbines or on a pipeline, where the gas shield would be blown off the pool.
Features and equipment
- Modular inverter source for 420 A at a 60% duty cycle and 380 A in continuous work at 100%: the circuits answer fast to a change of resistance in the arc and make up for swings of voltage from the mains, so the arc burns evenly on thick materials.
- External Kemppi MXF 67 feeder with a four roll DuraTorque drive: four toothed rolls press and push the wire without slip, and the four point contact crushes neither soft aluminium filler nor cored wire.
- Spools of up to 20 kg in the feeder: fewer breaks to change the wire in series production.
- Kemppi FastCool 10 liquid cooler of 1 kW mounted on the trolley: the pump forces the fluid round to the chamber in the torch, so at work above 300 A the contact tip does not char and the wire does not fuse into it.
- Liquid cooled torch with a load capacity of 500 A: cooling with fluid lets you cut the cross section of the current cables, so the grip is lighter at the same current.
- Analogue Kemppi MR300 panel: you set the welding voltage and the pace of the wire feed with potentiometers, with no synergic curves and no software forcing the settings on you.
- 2T and 4T modes: in two step the current and the gas flow only while the trigger is pressed, in four step you start with one click and finish with a second, which spares the hand on long runs.
- Control of the dynamics of the arc, that is an electronic counterpart of a choke: a hard characteristic gives a narrow and deep penetration of the root, a soft one a wide, even face and less spatter that sticks.
- MMA mode: after you disconnect the roll unit you plug cables with an electrode holder into the inverter and weld with a rutile or basic electrode at a current up to 420 A.
- Interconnection cable of 1.8 m with channels for fluid and control, and a trolley on four wheels: you move the whole set round the hall in one piece.
Technical data
| Brand | Kemppi |
|---|---|
| Model | FastMig M420 |
| Type | modular MIG/MAG welder with an MMA mode, digital inverter |
| Supply voltage | 3 x 400 V |
| Maximum welding current | 420 A at a 60% duty cycle |
| Continuous current | 380 A at a 100% duty cycle |
| Welding current given on the record | up to 500 A |
| Wire feeder | external Kemppi MXF 67, four roll DuraTorque |
| Wire spools | up to 20 kg |
| Control panel | analogue Kemppi MR300, manual, with no synergy |
| Interconnection cable | 1.8 m, channels for fluid and control |
| Cooler | Kemppi FastCool 10, cooling power 1 kW |
| Welding torch | liquid cooled, load capacity 500 A |
| Wire diameter | up to 1.6 mm, solid and flux cored wires |
| Trolley | original, on four wheels |
| Weight of the set | about 200 kg, source with feeder and trolley |
| Cooling | gas per the product record, in the source description liquid with the FastCool 10 cooler |
| Processes | MIG/MAG, MMA, 2T and 4T modes, control of the dynamics of the arc |
What you get
- Kemppi FastMig M420 inverter power source
- Kemppi MXF 67 wire feeder with a four roll drive
- Kemppi FastCool 10 liquid cooler of 1 kW
- Kemppi MR300 control panel
- liquid cooled torch for 500 A
- interconnection cable 1.8 m
- trolley on four wheels
What to watch out for
The product record gives gas cooling and the source description liquid cooling with the FastCool 10 cooler and a torch for 500 A, so confirm with us the version of cooling and what the set of this unit holds before you buy. With a fluid circuit watch the cleanliness of the filter and the strength of the fluid, because a block in the channels of the torch ends with the grip overheating. Before the first arc check the level of the fluid, the flow and the seals at the quick couplings. The interconnection cable is only 1.8 m, so the feeder stands right by the trolley with the source, and for work at height or inside a tank you have to haul the whole set up or add a longer pack.
The supply is a 3 x 400 V mains, and the three phase circuit you pick for work at 420 A and settle with an electrician. The set weighs about 200 kg, so plan the transport, the unloading and the way onto the station in advance. The MR300 panel has no synergy, so the operator picks the voltage and the feed, and with no pulse the machine does not suit welding aluminium and acid resistant steel without spatter. This is a source for carbon steel. In the four step mode putting the arc out needs a second click, which on a thin, heated edge is at times a fraction of a second too slow. A hard setting of the dynamics gives deep penetration but also more spatter, a soft one the other way round. The electronics of the inverter take grinding dust badly, so the cooling channels have to be blown through from time to time. Work with an electrode in the MMA mode goes slower than with wire, because changing electrodes and chipping slag come on top.
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.