X3 FastMig 420 Synergic Air Cooled Parts FAQs
How to choose and look after the torch, feed rolls, cables, filter and control accessories for an air cooled synergic MIG system.
How do I read a torch current and duty cycle rating?
A torch rating is a current together with a duty cycle: the share of a period that the torch can carry that current without overheating. Duty cycle is normally worked out over a 10 minute block, so read the two figures together rather than looking at the current alone.
The rating can also depend on the shielding gas and the welding mode, so check which gas the rating applies to, and choose a torch with some margin above the current you actually use. The torch or its manual should show the rating.
How do I know when a contact tip needs replacing?
Replace a contact tip when it shows wear, rather than waiting for a set number of hours. The most reliable sign is a bore that is no longer round: wire movement at high temperature stretches the hole into an oval, which upsets feeding and current transfer. Erratic feeding, an unstable arc and more frequent burnback are other signs.
Fit a tip that matches the wire diameter, because undersized wire in an oversized tip causes poor current transfer and early wear. Seat the tip firmly, as a loose tip overheats, and keep to the recess the torch manual gives. Do not file the bore to extend its life.
When should I replace a torch liner, and what mistakes shorten its life?
A liner guides the wire from the feeder to the tip. Replace it if it is kinked, clogged with debris, worn, the wrong size for the wire, or if the wire will not pull through by hand with the roll pressure released. Steel liners suit steel wire, while plastic type liners are normally used for soft wire such as aluminium.
A liner cut too short is a common cause of early failure, so trim it as the torch instructions say, remove burrs at both ends and make sure it seats properly at the power pin and tip. Tight bends in the torch cable and too much feed roll pressure also speed up wear. Never run a torch without a liner.
What does synergic mean, and does it change which parts I choose?
On a synergic machine you select the wire material and diameter once, and the machine sets the matching parameters so you mainly adjust one control, the wire feed speed. The settings are stored in the power source, and they relate to a given material and wire diameter.
The physical parts still have to match the wire you selected. Feed rolls, liner and contact tip must all suit the wire size and type, and the torch must be rated for the current you will use. If you change wire type or diameter, change those parts and the setting on the machine together, and check the manual for the right programme.