The same plastic material, why can some be called engineering plastics?

Feb 16, 2023

Leave a message

Let’s take a look at the definition of Baidu: “Engineering plastics can be used as engineering materials and substitute for metals to make machine parts and other plastics. Engineering plastics have excellent comprehensive properties, high rigidity, small creep, high mechanical strength, good heat resistance, and good electrical insulation.

They can be used in harsh chemical and physical environments for a long time, and can be used as engineering structural materials instead of metals, but the price is expensive and the output is small”. Let’s take a look at the definition of Japanese industry: “It can be used as high-performance plastics for construction and mechanical parts, with heat resistance of more than 100 ℃, and mainly used in industry”. After careful deliberation, it is not difficult to find that in fact, the written definitions are very broad, only from the application environment of materials and products.

In fact, many materials classified as “general plastics” can also be used to replace steel with plastics, and can also withstand high temperature. However, from the perspective of application development process, it does not conform to the engineering emphasis that “more manpower and material resources are needed to carry out large and complex work, which needs to be completed in a long period of time”. The development cycle of engineering plastic material application is longer than that of general plastics, with more steps, more complex analysis software and equipment to be used, and greater risk of trial and error. Under normal circumstances, the process of selecting materials for product development can be divided into the following steps:

1、 Define the key requirements of the product, namely CTQ, such as: V0 flame retardant, long-term use temperature higher than 80 ℃, tensile modulus greater than 10Gpa… The requirements should be specific, and it is better to have detailed data definition.

2、 According to CTQ, the material types are preliminarily selected, such as nylon 66, glass fiber reinforced PC, POM, etc. At this time, not only the product manual issued by the material manufacturer, but also the application cases of the material should be checked. Referring to the requirements and reasons for selecting materials for similar products from other manufacturers can reduce the trial and error costs of the project in this step and shorten the project development cycle.

3、 Select the specific material specification according to the material type determined in the previous step. When selecting the specification, you should not only refer to the material application case, but also refer to the reference price in the material property table to understand the cost and procurement channel of raw materials in advance.

4、 After selecting the specific material specification, the feasibility analysis needs to be carried out before opening the mold. Perform mold flow analysis and optimize mold design for more complex structural parts, and even some products need to be verified by 3D printing models.

5、 After various verifications are passed, the mold can be opened. After the mold is completed, the mold can be tested to verify whether the mold can work normally, and the performance of the product sample can be tested. This process is also a stage of high incidence of errors, and most of them need to be optimized and re-optimized repeatedly. In this process, it is recommended to ask questions about materials, molds and molding process with senior engineers.