What temperature does the plastic need to reach for injection molding?
From auto parts to home appliances, from precision instruments to daily necessities, injection molding is everywhere. But are you curious about how many degrees the plastic needs to reach in order to be perfectly formed during the injection molding process? Today, let's uncover this mystery together.
First of all, we must make it clear that different plastic materials require different processing temperatures. This is because the melting point, fluidity, thermal stability and other characteristics of various plastics are different. Therefore, when performing injection molding, the appropriate processing temperature must be set according to the selected plastic material.
Generally speaking, the processing temperature of common plastic materials such as polyethylene (PE) and polypropylene (PP) is usually between 150℃ and 250℃. For some high-temperature plastics, such as polycarbonate (PC) and polyamide (PA), the processing temperature may be as high as 300℃ or more. Of course, this is only a rough range, and the specific processing temperature needs to be adjusted according to factors such as the plastic grade, thickness, and mold structure.
So, why does injection molding require strict control of plastic temperature? This is because plastic has fluidity in the molten state. Only at the appropriate temperature can the plastic flow fully and fill the mold cavity, thus obtaining an injection molded part with a complete shape and precise size. If the temperature is too low, the plastic has poor fluidity, which may lead to defects such as lack of material and rough surface of the injection molded part; if the temperature is too high, the plastic may decompose, burn, or even damage the mold.
In addition to temperature control, injection molding also needs to pay attention to the setting of other process parameters, such as injection pressure, injection speed, holding time, etc. The setting of these parameters will also have an important impact on the quality of the injection molded part. Therefore, when performing injection molding, various factors must be considered comprehensively to formulate a reasonable process plan.
