Changing a Welding Shoe on a Leister Extrusion Welder

Disassembly

• The welding shoe must only be changed when the tool has attained its operating temperature. Wear temperature resistant gloves.
  
• Remove the welding shoe holder (17) by unfastening the clamp screws (18) from the extruder nozzle (19)
• Every time the welding shoe is changed, clean the extruder nozzle (19) of welding residue. The extruder nozzle has a left-handed thread. Make sure that the nozzle is screwed in tight by turning it counter-clockwise using a 13 mm wrench.
• Remove the welding shoe (5) from the welding shoe holder (17) by either
  1. Unfastening the fastening screws (20), or
  2. In the case of an older shoe, unfastening the four screws at the rear of the welding shoe holder

Assembly

• Use a welding shoe (5) appropriate to the welding seam
• So that extrudate will not leak from behind the shoe, check that either
  1. The two mount holes in the side of the shoe are round and not worn oval, or that
  2. The four screws from the rear are not stripped so that they cannot be tightened properly.
• Fasten the welding shoe (5) onto the welding shoe holder (17) with fastening screws (20) or the four screws at the rear
• Place the welding shoe holder (17) over the extruder nozzle (19). Make sure that the welding shoe is far enough back so that it overlaps all the way around or air will leak behind the welding shoe holder.
• If at any time air is coming out behind the shoe, loosen the clamp screws (18) and turn the welding shoe holder one way and then the other while pushing the welding shoe holder further back. Tighten the clamp screws (18). If air continues to leak, replace the shoe.

Welding direction

• The welding shoe (5) can be turned to any desired welding direction by loosening the clamp screws (18)
• The clamp screws (18) must be tightened well again afterwards