Screw barrel removal / maintenance and maintenance

Update:10-08-2018
Summary:

There are usually five reasons for the damage of the sc […]

There are usually five reasons for the damage of the screw: 1: The temperature at the end of the plasticization of the raw material. 2: The raw material is mixed with metal foreign matter or the raw material contains many impurities. 3: The screw running time is too long. 4: The selection of screw material is unreasonable. 5: Screw manufacturing precision bottom, thread working surface heat treatment bottom.

When the screw barrel of the press machine fails and needs to be replaced or taken for renovation, it needs to be disassembled. The following describes the method of removing the screw barrel and what to do before disassembly. Before disassembling the screw and the barrel, first apply the cleaning material to replace the material in the barrel, then unscrew the nozzle and barrel coupling and then disassemble the screw.

The screw sequence is removed by first separating the screw tail from the drive shaft. Remove the split flange, push the screw forward, then insert the wood chip in front of the drive shaft to push the screw forward. When the screw head is completely exposed to the outside of the barrel, loosen the screw head connecting bolt while hot. Note that the thread is usually left-handed. When a bite occurs, it is not hard to pull it. It should be applied with a symmetrical moment to rotate it, or it can be removed by a special hand-pushing to loosen it.

When the screw head is removed, the residual material should be quickly removed with a copper brush. If the residual material is not cleaned before cooling, the fire barbecue parts should not be used to avoid rupture damage. Instead, the oven should be used to heat the material after softening. Remove and clean up.

After the screw head is removed, the check ring and seal ring should also be removed. Carefully inspect the check ring and seal ring for scratches and re-grind or replace if necessary to ensure a good seal.

When reassembling the screw head components, the threaded joints are coated with heat-resistant grease (red or molybdenum disulfide).

Cleaning and maintenance of the screw: After the screw head is removed, pull out the screw or use a special disassembly screw tool to pull out the screw, as shown in Figure 1. Then use a copper wire brush to remove the attached material, and use a mold release agent or mineral oil to make cleaning faster and more thorough. After wiping off the residual melt, observe the wear of the surface of the spiral. For small scars, fine sand cloth or oil stone can be used to polish and smooth. For large scars, the cause should be identified to prevent recurrence. If necessary, photos can be saved.

After the screw temperature has dropped to normal temperature, the oil trace on the screw is wiped off with a non-flammable solvent. Then use the micrometer to measure the outer diameter and analyze the wear. If the local wear is severe, the surfacing repair can be used.