The problems with injection molds may be caused by various factors such as processing, mold design, materials, and machines. The following is a specific analysis of the reasons:

In terms of processing:

Pressure and speed: Excessive processing pressure, fast speed, excessive filling, and long injection and holding time can all cause excessive internal stress, leading to product cracking.

Mold temperature and material temperature: If the mold temperature is too low or the material temperature is too high or too low, it will affect the quality of the product. Low mold temperature may cause difficulty in demolding, high material temperature may cause plastic degradation, and low material temperature may cause poor fluidity.

Use of release agent: Improper use of release agent or failure to remove aerosols and other substances attached to the mold surface in a timely manner may lead to difficulties in demolding and product defects.

In terms of molds:

Top out system: Unbalanced top out, such as insufficient number or cross-sectional area of top rods, insufficient demolding slope, and uneven cavity surface, may lead to residual stress concentration and cracking of the product during top out.

Product structure: The product structure is too thin, the transition part does not use circular arc transition, or there are sharp corners and chamfers, which may lead to stress concentration.

Gate design: Poor smoothness of the gate taper hole, knife marks on the inner hole, or improper processing of the taper hole of the gate sleeve may cause difficulty in material removal from the gate.

Cooling system: Unreasonable design of the cooling system can result in uneven temperature in various parts of the mold cavity, which may cause product warping or shrinkage and depression.

Exhaust system: The mold exhaust is not smooth, resulting in incomplete gas discharge, which may form air pockets or bubbles.

In terms of materials:

Recycled material content: Excessive recycled material content may lead to a decrease in product strength.

Material humidity: Excessive material humidity may cause chemical reactions between plastic and water vapor, reducing strength.

Material quality: The material itself is not suitable for the processing environment or has poor quality. If it is contaminated, it may cause the product to crack.

In terms of equipment:

Plasticization capacity: If the plasticization capacity of the injection molding machine is too small, it may lead to insufficient plasticization; Excessive size may lead to material degradation.

Nozzle hole size: If the nozzle hole is too large or too small, it may cause material reflux or insufficient amount, leading to shrinkage.

Mold assembly and maintenance:

Assembly accuracy: During mold assembly, if the assembly benchmarks of the moving fixed mold and the inserts do not meet the requirements, it may affect the quality of the product

Improper maintenance: If the mold is not properly maintained after long-term use and the moving parts are not cleaned and lubricated in a timely manner, it may lead to mold wear or damage.