Automatic Wire Feed To Gun; Adjustment Of Pressure; Adjustment Of Tightness Of Spool Brake; Burn Back Time - Kemppi MF 33 Operating Manual

3.4

Automatic wire feed to gun

Automatic wire feed makes change of wire spool more rapid. In spool change the pressure of
feed rolls need not to be released and filler wire goes automatically to correct wire line.
• Make sure that groove of feed roll matches the diameter of welding wire used.
• Release the wire end from spool and cut off the bent length. Be careful that the wire
does not spill from the spool to sides!
• Straighten about 20 cm of the wire and see that the end of it has no sharp edges (file
off if necessary). A sharp edge may damage the wire guide tube and contact tip of the
welding gun.
FastMig MF wire feed units:
• Draw a bit of loose wire from wire spool. Feed wire through back liner to feed rolls. Do
not release pressure of feed rolls!
• Press the gun switch and feed a bit wire until wire goes through feed rolls to gun. See
that wire is in grooves of both feed roll pairs!
• Press still the gun switch until wire has come through contact tip.
Automatic feed may sometimes fail with thin wires (Fe, Fc, Ss: 0,6 – 0,8 mm, Al: 0,8 – 1,0 mm).
In that case you might have to open feed rolls and feed wire manually through feed rolls.
EN 3.5

Adjustment of pressure

Adjust the pressure of feed rolls with the control screw (20) so that the wire is fed into the wire
guide tube evenly and allows a little braking when coming out from the contact tip without
slipping at the feed rolls.
Excessive pressure causes flattening of the filler wire and damage to the coating. It also
NOTE!
causes undue wear of the feed rolls as well as friction.
3.6

Adjustment of tightness of spool brake

Brake force is adjusted through hole in locking device of spool hub by screwing the control
screw (A) with screwdriver.
Adjust brake force as so big that the wire is not allowed to become too loose on the spool so
that it would spill from the spool when the rotation of the spool stops. Need for brake force is
increased with increase of wire feed speed.
Since the brake loads for its part the motor, you shouldn't keep it unnecessarily tight.
3.7

Burn back time

Electronics of feed unit controls stopping of welding automatically so that the wire end
doesn't melt fastened to the contact tip or the work piece. Automatics work regardless of the
wire feed speed. Can be adjusted also from power source SETUP-menu ('PoC').
3.8

Ground cable

Connecting of earth cable should be preferably connected directly to the welding material.
Contact surface of press always should be as large as possible.
Clean the fastening surface from paint and rust!
Use in your MIG equipment at least 70 mm². Thinner cross-sectional areas might cause
overheating of connectors and insulations.
Make sure that the welding gun in your use is designed for max. welding current needed by
you!
Never use a damaged welding gun!
NOTE!
8
FastMig MF 33
A