What injection molding machine manufacturers must know about plastics

Plastics are polymers that, under moderate pressure, are capable of deforming or injection molding. This is different from rubber, which has higher rigidity and cannot be plastically restored. It can be mainly divided into thermoplastic and thermosetting plastic two types.

There are two primary types of amorphous and crystalline thermoplastics: amorphous and crystalline. Amorphous thermoplastics are generally stable, bright rigid, and are of low shortening and low impact force. Crystalline plastics also contain non-crystalline materials, known as semi-crystalline thermoplastic plastics. Such plastics are generally softer and more resistant, but have higher thermal deformation than non-crystalline thermoplastics, are translucent or opaque, and have a greater shortening rate and high specific heat.

Inspection of plastic activity because most plastic injection methods are fusion processing, such as injection molding and extrusion, therefore, inspection of plastic activity is extremely important. Although many tests have been set up to examine these functions, they can be generalized into low shear rate tests and high shear rate tests.

The rate of activity (FR) is usually indicated by MFR and MET, which separately represent mehflow rateT9 melt flow index, which have the same meaning. Because the test is easy to do and easy to understand, it is widely used. When a thermoplastic material (such as PE) is injected into a specified hole (mold) at a specified temperature and pressure, the amount of pressing out is called MFR. For example, MFR (190,2.16) =2.3, indicating that the temperature is 1900C and a pressure of 2.16kg is applied. Under this heavy condition, 2.3g of plastic is pressed out of the mold.

Length to thickness ratio This is another way to check the simplicity of the molding process. The test is carried out on an injection molding machine under specified conditions using typical injection molding parts. Its function is indicated in proportion. If the ratio is 150:1, then the wall thickness of the injection parts is about 1mm red, and the maximum length of the active length is about 150mm. Injection molding machine supplier