Injection molding machine screw damage cause analysis and repair methods
1, damage to the screw, because raw material plasticizing at low temperature.
Of raw materials mixed with the impurities of metal foreign body or more.
Manufacturing screw material selection is not reasonable.
Screw manufacturing precision is low, thread surface heat treatment hardness is low.
2, screw the disassembly sequence of screw is disassembled should use a special tool, not with a heavy hammer percussion, specific disassembly steps are as follows.
Remove the connecting flange screw back upon.
Note: this thread most commonly for left-handed)
Remove the screw on the non-return ring and seal ring.
Removed the nozzle, non-return ring, sealing ring and screw, should be used immediately strike copper brush, each part of the shovel type tool clear scrap.
Special difficult to clean up the sticky material, should be put in oven heating, temperature is the lowest temperature can make the material softening, and then again to remove residual material.
Screw on top of all the parts assembled together, the threaded connection parts with molybdenum disulfide thermal grease, convenient to remove the next time.
3, screw repair and replacement screw working face if have mild wear or scratch marks, available oil stone or fine grinding emery cloth, light injury.
Heavily damaged if the screw thread, screw and barrel of the fit clearance increases, there was a molten material work when leakage flow increases, injection quantity is unstable, the screw threads of the outside circle should be thermal spraying alloy, and then according to the actual size of barrel inner diameter, in accordance with the requirements for the parts fit clearance (
Sucking 3 -
The screw grinding.
If the barrel wear serious, after repair inner hole diameter increases, the screw grinding after spraying cannot have satisfied fitting clearance of barrel and screw size requirements, the screw should be made again.
Screw thread diameter, should according to the requirements of the two parts fit clearance, referring to the barrel of the actual machining inner hole diameter.