What are the Reasons for the Damage of the Syringe Mold


The design of the Syringe Mould cooling system is often […]

The design of the Syringe Mould cooling system is often regarded as a secondary issue. Not enough attention has been paid to the size and structural design of the cooling system. The design of the cooling system is not in line with the principle of the syringe mold. It will cause internal stress for small plastic parts, and deformation and even stress cracking for large plastic parts with thin walls.

Moreover, insufficient cooling will lead to prolonged molding cycle, thereby reducing production efficiency. Determining the size of the cooling system is undoubtedly not a simple task. Generally speaking, mold designers are still unfamiliar with certain aspects, and this kind of work is very complicated.

Part of the heat conduction equations are well known, and now computers and pocket programmable calculators can be used to solve these equations. Nevertheless, situations encountered in actual problems often bring difficulties to the solution of the problem. For example, the cavity wall is periodically heated by injected high-temperature plastic melt. As a result, the temperature difference between the mold and the cooling water increases, and the cooling effect becomes stronger. After the mold is opened and the plastic part is ejected, the cavity is cooled by the surrounding air. Therefore, the temperature of the cavity surface changes periodically. The solution of the problem becomes more difficult, because the injected high-temperature plastic melt is only in contact with a part of the mold-the cavity, while the entire mold is cooled by the cooling water in the cooling channel. In addition, the cooling water is heated while passing through the cooling channels of the mold, thereby changing the temperature difference between the mold and the cooling water.

What are the reasons for the damage of the injection mold?

  1. In plastic injection products, if there are metal inserts, when the metal inserts are placed in the mold, they are not firmly or skewed. After the mold is closed, local damage, indentations or pits in the molding cavity will occur.
  2. Due to the high pressure of the injected molten material, the fast flow rate, overturning or changing the position of the metal insert, the mold is damaged.
  3. The parting joint surface of the mold is closed for a long time, and occasionally impurities are trapped in the middle or the sliding part of the template is worn for a long time, which causes the template to run non-parallel, which makes the tightness of the mold joint surface worse after closing, and it is easy to form. Product flash and other issues seriously affect the quality of the product. At this time, the Needleless Injection Site should be inspected and repaired.