Common problems and solutions in injection molding

Injection molding is a common manufacturing process, mainly suitable for the production of well-formed, accurate size, beautiful appearance of small parts, widely used in automotive, electronics, medical equipment and other fields. However, there are often various problems in injection molding, such as warping, shrinkage, bubbles, hot cracks, etc., which affect product quality and production efficiency. Therefore, this paper will discuss the common problems and solutions in injection molding.

First, warping

Warping is one of the common defects in injection molding, usually appearing on long and thin parts. The cause of warping is mainly due to the uneven internal stress of the material, and may also be caused by the uneven heat of the mold.

The solution:

1. Optimize the injection process parameters, such as adjusting the injection speed, pressure, temperature, etc., so that the material flows and solidifies evenly in the mold cavity.

2. Optimize the mold structure and temperature control system, can use hot runner mold, temperature controller and other equipment to ensure the uniformity of mold temperature, reduce the generation of internal stress.

2. Shrinkage hole

A shrinkage hole is a hole on the surface or inside of an injection molded product, usually caused by the accumulation of air or volatile components inside the product. In addition, in the solidification process of the product, there may also be premature heat shrinkage, resulting in the material can not fill the entire mold, resulting in the formation of shrinkage holes.

The solution:

1. Optimize the matching degree of injection material and mold to ensure the excellent performance of the material.

2. Adjust the injection molding process parameters, such as increasing the mold temperature, adjusting the injection speed, reducing the injection pressure, etc., so that the material can be better filled in the flow process.

3. To increase the filling degree of the material, you can try to increase the injection time or increase the injection amount to ensure that the material is filled to the whole mold.

3. Bubbles

The bubble refers to the gas aggregate appearing on the surface or inside the injection molding product, usually due to the extrusion of gas or air during the injection molding process is wrapped in the plastic. At the same time, the water content of the material also affects the formation of bubbles.

The solution:

1. By reducing the injection speed and increasing the injection time, the material can be successfully filled in the mold, thus reducing the possibility of air being enclosed inside.

2. Through mold design and temperature control, the flow speed of the material is prevented from being too slow and the temperature of the material is uneven, so that the material can flow and solidify better.

3. Ensure that the material is dry and avoid moisture in the material.

4, hot crack Hot cracks are cracks on the surface of injection molded products, usually caused by uneven cooling or excessive internal stress. In addition, the mold temperature may also affect the thermal crack of the product.

The solution:

1. By adjusting the injection molding process parameters, such as injection molding time, injection molding temperature, mold temperature, etc., to ensure that the cooling rate of the material is uniform, so as to avoid the generation of thermal stress.

2. Through reasonable mold design, increase or reduce the number and shape of the mold cavity, adjust the distance between the mold cavity, etc., to reduce the generation of internal stress.

3. Use hot runner mold or temperature controller and other equipment to control the uniformity of mold temperature to avoid material deformation or hot crack caused by too high or too low mold temperature.

In general, the common problems in injection molding need to take different solutions according to the specific situation, and it is necessary to pay attention to process optimization and mold improvement in order to improve product quality and production efficiency.