The cable tie manufacturing is one of the plastic injection molding projects, but is more difficult than the normal one, because:
- Cable tie is selling in a very low cost, the cable tie manufactures are under huge cost pressure.
- Cable tie has many different size, each one size request one mold.
- Cable tie is more difficult in the molding than the normal plastic item.
1. Main problem in nylon cable tie manufacturing
1.1 The mold is blowed to open
Injection molding machine has not enough clamping force, so that the mold is blowed to open
Solution: check the clamping force setting
1.2 Short shot
In the photo, the one in the edge is filled full, but the middle one is short shot, check the following:
–mold temperature whether is not even
–mold cavities air release design
If one in the edge is not filled full, but the middle one is done, check the following:
Carefully check the corresponding part of the mold
–Fail to dry the water out from the raw materials,
PA 66 is a relatively complex resin, and absorbs water from air easily. Dry material is the first step to be done. Insufficient dry results in the high temperature water vapour, screw and barrel special for PA will exhaust part of them. But fast injection speed traps air. Poor exhausting design of mold intensifies air trapping.
-design of the screw and barrel
-the molding setting in-correct
1.5 Nylon cable tie gets yellow
Over-heat, the melt plastic resin is degraded due to the over-heat, please consider: the relation between temperature and cycle time in the article: cable tie production
All the machine operator like to set the machine with high temperature, because it is easy for the molding, because:
Error in machine design
Error in raw material formula
Error in mold design
It is one complicated issue, more information, please check this article: cable tie production
The degrade cable tie is brittle, though the yellow color may be hidden by some chemical.
To inspect cable tie quality, tensile strength is the main point, which is need to check by machine. How to check the cable tie quality, please check this link: how to inspect your cable tie