How to produce plastic injection molded parts with high tolerance?

How to produce plastic injection molded parts with high tolerance?

Plastic has extremely high fluidity, making it difficult to strictly produce the dimensions of plastic injection molded parts according to the requirements of the drawings. Especially for some precision plastic injection molding parts with high dimensional accuracy requirements, the dimensional accuracy of plastic injection molded parts refers to the degree of conformity between the obtained dimensions of the plastic parts and the dimensions in the product drawings, that is, the accuracy of the obtained dimensions of the plastic parts. How can we produce products with high tolerance of plastic injection molded parts?

There are many factors that affect the dimensional accuracy of precision plastic injection molding parts, first of all the precision of mold manufacturing and the degree of mold wear, followed by fluctuations in plastic shrinkage rate and changes in process conditions during molding.

The aging changes after the precision plastic injection molding parts and the structural shape of the mold, therefore, in order to reduce the processing difficulty and manufacturing cost of the mold, while meeting the requirements for the use of injection molded parts, the dimensional accuracy of the plastic parts should be designed as low as possible.

What are levels of injection molded parts dimension tolerance?

The dimensional tolerance of plastic injection molded parts can be designed and processed according to SJ1372-78, the plastic part tolerance numerical standard. According to this standard, the precision plastic injection molding part accuracy is divided into 8 accuracy levels, of which levels 1 and 2 belong to the precision injection molding technology level and are only used under special requirements. This standard only specifies the standard tolerance value, and the basic dimensional upper and lower deviations can be allocated according to the fitting properties of the plastic parts.

For dimensions that are greatly affected by the movement of the mold, such as the height dimension of compressed parts, due to the influence of the thickness of the horizontal surface overflow, the tolerance value is taken as the sum of the tolerance value and the additional value in the table. The additional value for Level 2 accuracy is 0.05mm, Level 3-5 accuracy is 0.10mm, and Level 6-8 accuracy is 0.20mm.

In addition, for dimensions without tolerance indications, it is recommended to use level 8 accuracy in the standard. Only by strictly following the tolerance numerical standards for precision plastic injection molding parts can the dimensional accuracy and quality of the plastic parts be guaranteed.

In order to meet the human pursuit of injection molding materials, the performance of products in various industries is constantly improving. Products are composed of accessories, which requires product accessories to become more and more precise, maximizing the size of product accessories to the original design. The injection molding industry is the same, and precision injection molding has become a competitive field for major excellent injection molding enterprises.

Many products nowadays cannot reach their original design lifespan due to various reasons. One of the reasons is that product accessories cannot reach the original design size. A complete product is composed of several or even tens of thousands of accessories, and the size does not meet the design requirements, leading to problems during use, and even if the time is long, the accessories need to be replaced.

For example, every accessory on a spacecraft is manufactured through thousands of choices, and perhaps a small size issue can lead to a major accident. Therefore, in recent years, various industries have increased investment in precision manufacturing. Whoever can master precision plastic injection molding manufacturing technology can occupy a dominant position in the future competition.

In recent years, the precision injection molding industry in the injection molding industry has also developed rapidly.

What aspects are generally required to meet the conditions of precision injection molding processing?

• Advanced injection molding machine equipment. As the foundation of injection molding, if the foundation is not good, it will definitely not produce good products.

• The manufacturing of molds is inseparable from the precision plastic injection molding industry, and high-performance molds can add a lot of points to precision injection molding.

• Injection molding operators, without an excellent injection molding engineer, even the best equipment is futile.

• The procurement of raw materials. The different processes of the same type of plastic result in different properties of the plastic, such as injection molding.