PS injection moldingis widely used in consumer goods, electronics housings, medical disposables, and packaging products. Thanks to its low material cost, good dimensional stability, and easy processing, PS for injection molding remains a preferred choice for manufacturers seeking efficiency and consistency.

Among polystyrene materials, GPPS injection molding and HIPS injection molding are the two most common options. Even though they start with the same basic stuff, these materials act differently, look different, and are used in different situations. Knowing how they differ is super important for picking the right one and figuring out the best way to work with them.

GPPSis a clear, hard type of polystyrene that's known for being shiny and keeping its shape well. People usually use it when how things look and how clear they are really matter.

HIPSis a type of polystyrene modified with rubber to make it stronger against impacts. While it's not as see-through, it's much tougher and lasts longer, which makes it a good choice for things like housings and everyday consumer goods.

When it comes to making things with polystyrene, the injection molding process is easier than with some of the more complicated engineering plastics. PS melts easily and doesn't absorb much moisture, so you usually don't have to dry it beforehand. Both regular polystyrene (GPPS) and HIPS are easy to work with because they melt and shrink consistently. This makes PS a solid option for making lots of products quickly.

Correct parameter control is essential for surface quality, dimensional accuracy, and cycle efficiency. Below are the 2026 mainstream recommended settings used in industrial production.

These optimized settings ensure stable GPPS injection molding temperature and HIPS injection molding temperature control across different mold designs and production scales.

For PS injection molding, the required clamping force is generally calculated using the projected area multiplied by an empirical constant (≈30–40 kN/cm² for PS), with an additional 10–20% safety margin. Because PS has good flowability, medium-pressure machines are usually sufficient. Make sure the mold fits, considering the size of the platen, the space between tie bars, and how far it opens. This is especially important for parts with deep cavities or that need to look good. Also, make sure there's enough room for cooling and vents to keep the surface smooth and production consistent.

When designing the mold, keep in mind the material. For GPPS, the mold needs to be polished like a mirror to get that glossy, clear look. HIPS molds can have a regular polish or a slightly matte finish. Proper venting is critical for GPPS to avoid burn marks or haze, whereas HIPS benefits from balanced air release for high-speed filling. Both types need to prevent flashing and have a uniform ejection. GPPS parts need tighter control where the mold comes together and careful ejector design to avoid stress marks.

PS injection molding is still a good, cheap way to make lots of plastic stuff. Whether you pick GPPS for clear parts or HIPS for strong parts, polystyrene is easy to work with, does what you expect, and can be used for many things.

If you pick the right plastic, set the temp just right, and use the right machines, you can make lots of high-quality parts. If you need aPS molding solution, get in touch today. We can offer guidance and a fair price.