The Top 10 Factors that Affect Injection Mold Quality

The Top 10 Factors that Affect Injection Mold Quality

  • 2021-12-23

Mold Makingis a complex process, from design, cutting, assembly, debugging and other steps to the final actual use. In the entire life cycle, the factors that affect mold quality mainly include the following 10 aspects.


Mould Steel

Steel is the decisive factor of mold quality, and choosing a reasonable steel is the top priority. The criteria for selecting steel are:

①Requirements for injection molding materials

Different plastics should use different steels, such as high polishing requirements, corrosion resistance requirements, etc.;


The steel is as good as it can be used, not the more expensive the better; considering the cost factor of the mold, the mold steel should choose the material corresponding to the mold life to avoid unnecessary waste; the life of the general P20 material is about 300,000 shots; the 2738 material is around 500,000 shots, H13/2344 is usually above 800,000-1,000,000 shots, you can choose according to the situation;

③Surface treatment

The surface treatment of the mold is also very important. Nitriding can enhance the surface hardness of the steel and effectively extend the life of the mold; electroplating can effectively modify the mold steel. For some plastic parts that require high brightness and corrosion resistance, electroplating can be used to enhance and improve the performance of the steel.


Standard Parts

Although standard parts are not directly involved in forming, they control the operation of the entire mold. Good standard parts should be wear-resistant, hard enough, high precision, and not suitable for deformation.


Mold Fitting (Spotting)

Relying on the experience of the mold fitter, the seemingly simple job is the most technical job. The main focus of complex molds is this effort. The flat mold is the simplest, as long as the fractal surface does not have flashing, it is basically ok.

For example, auto parts molds are very troublesome, not only the fractal surface is relatively irregular, but also often includes multiple sliders and top blocks. At the same time, other problems of the mold can be improved and perfected through the collision, so it is a comprehensive work.


Polishing/Leather Grain

The polishing of the mold is the last link in the manufacture of the mold. Polishing is directly reflected on the plastic parts, so this is the most face-to-face job. Polishing can also help and supplement the mold movement, especially for demolding. Often the production of some molds is not smooth because of improper lighting, excessive resistance, difficulty in demolding, and even whitening and cracking.


Mold Assembly

Mold assembly is just like assembling a machine. Every component and every screw must not be wrong, otherwise the consequences will be quite serious, ranging from product defects and affecting production, or completely damaging the mold and causing scrap. Therefore, the assembly work must be very meticulous. Pay special attention to the cleaning of the mold during the assembly process, especially the waterway and screw holes, and the iron filings inside must be blown out.


Hot Runner Mold or Cold runner Mold

In fact, this has the least impact on mold quality, because hot runners are generally designated by customers, especially some large customers. Well-known foreign brands are very good in quality and after-sales service, so there is generally no problem in quality.

It's just that the quality of some domestic hot runners is quite different. In order to save costs and strive for price advantages, individual small companies use unreliable heating and conduction accessories, which are prone to problems. The main problem of the cold runner is how to ensure the balance of injection molding, gate size, injection pressure and so on.


Cooling water circuit

Anyone who has mold experience knows how important cooling is to a mold. Due to the increase in prices and labor wages, when mass production of products, the profit brought by the injection cycle without one second is unimaginable.

However, speeding up the production cycle will also cause the mold temperature to rise. If it is not effectively controlled, the mold will be too hot to form, and even cause the mold to deform and fail. Therefore, good waterway design is particularly important, including the arrangement density, diameter, and mutual links of the waterways.


Mold maintenance

Mold maintenance is mainly maintenance and maintenance during the production process. The mold is like a car. If it is not used for a long time without maintenance, it may cause the mold to be scrapped. Therefore, every time the mold is used, a comprehensive maintenance must be carried out, especially the rust prevention of the forming part and the rust prevention of the main moving parts.

Because the mold needs to receive water during the production process, water may get onto the mold during the installation or disassembly process, so you must ensure that the mold is dry, and then apply a layer of oil to protect it.

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