Polystyrene Injection Molding

Polystyrene (PS) injection molding is a reliable process for producing lightweight and durable plastic parts.

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We Provide Polystyrene Injection Molding Service to Match Your Needs!

Polystyrene (PS) injection molding is a common process we use when we need to make lightweight and rigid plastic parts at a lower cost. PS is easy to mold and holds its shape well, which makes it a good fit for parts that need fine details and smooth surfaces. We use this process a lot for things like consumer goods, packaging parts, and some basic industrial components—anywhere a clean, precise result is needed.

Custom PS injection molding for various applications
Able to run small batches or large volume production
Capable of both general-purpose or high-impact PS based on your needs
Can take care of extra steps like assembly or surface finishing
We check every batch to make sure quality stays consistent

Polystyrene Injection Molding Design Guide

To get better results with PS molding, there are a few basic things we usually keep in mind:

Item	Description
Wall Thickness	Keep the wall thickness between 1.5–3.0 mm and try to keep it uniform. That helps prevent warping and stress spots. If you're working with thin-walled parts, PS can still mold down to about 0.8 mm.
Draft Angles for Ejection	Add draft angles to make demolding easier. For polished surfaces, go with at least 1.5°. If the surface has texture, 2–3° works better to avoid drag marks.
Ribs & Reinforcements	Ribs should be about 50–60% of the wall thickness. That gives strength without causing sink marks. We also add a fillet radius at the rib base, around 0.25 times the wall thickness, to cut down on stress buildup.
Shrinkage & Dimensional Stability	PS has pretty low shrinkage, around 0.3–0.6%, which makes it dimensionally stable. If you're using reinforced grades, expect even better performance and slightly lower shrinkage.
Snap-Fits & Living Hinges	When we design snap-fits in PS, we use fillets to avoid stress cracks. PS is on the brittle side, so it's not really suited for living hinges.

Advantages of Polystyrene Molding

Good Dimensional Stability

PS doesn’t shrink much (about 0.3–0.6%), so parts come out with consistent sizes. That’s useful when tight tolerances matter.

Budget-Friendly for Large Runs

PS is one of the cheaper plastics out there. It molds fast and keeps unit costs low, which helps when making a lot of parts.

Lightweight but Still Rigid

It’s got a low density (around 1.04–1.07 g/cm³), so parts stay light without feeling flimsy. Works well for things like packaging or appliance covers.

Clear or Opaque Options

You can get PS in clear or solid colors. That makes it a good pick for stuff like see-through food containers or medical trays.

Start Polystyrene Injection Molding Project

Get high-quality PS injection molded parts! Contact with Erye to request a quote!

Polystyrene Injection Molding Application

Packaging

Rigid food containers
Disposable cups and cutlery
CD and DVD cases
Cosmetic packaging

Consumer Goods

Household appliance casings
Stationery items (rulers, pen bodies)
Toys and figurines

Electronics

Battery housings
Electrical insulation components
TV and computer casings

Industrial & Construction

Light diffusers and panels
Insulating foam inserts
Disposable lab equipment

Additonal Options for Polystyrene Parts