SERVICES
Polystyrene Injection Molding
Polystyrene (PS) is a low-cost, easy-flowing rigid plastic ideal for disposable, decorative and lightweight parts. We run GPPS for clarity and HIPS for impact-resistant housings, caps and consumer goods where budget drives the spec.
WHAT WE OFFER
What We Offer
HOW IT WORKS
From Inquiry to Delivery
CHALLENGES
Challenges This Service Solves
Crazing & stress cracking
Molded-in stress + brittleness = micro-cracks around gates, inserts and snap-fits.
Sink marks
A stiff, low-shrink resin shows every thick boss and rib as a surface sink.
Weld lines
Knit lines are visible and weak in PS — cosmetic and structural risk in one.
Flash
Easy-flow PS bleeds through worn parting lines the moment pressure over-reaches.
FAQ
Polystyrene Injection Molding — FAQ
Can you help with product development?
Yes. From design review and material selection to prototyping, tooling and mass production — our engineers support you through the entire product lifecycle.
Do you ship internationally?
Yes. We ship worldwide via air and sea freight, with export packing, documentation and delivery tracking handled by our team.
What quality inspections do you perform?
First article inspection, dimensional measurement, material verification and surface checks — with inspection reports provided per batch. Full details are agreed before production.
What is the difference between rapid and production tooling?
Rapid tooling uses softer materials and simplified construction for fast, low-cost validation runs (hundreds to low thousands of parts). Production tooling uses hardened steel for high-volume, long-life programs.
How long does injection mold making take?
Rapid tooling prototypes can be ready in days; production tooling typically takes several weeks depending on complexity, cavity count and steel grade. We confirm a detailed schedule with your quotation.
Do you provide DFM feedback?
Yes. Every quotation includes a design-for-manufacturing review: draft angles, wall thickness, gate and weld-line locations, tolerance recommendations and cost-saving suggestions — before any tooling is cut.
What file formats do you accept?
We accept STEP, IGES, STL, X_T and 2D drawings (PDF or DWG). A 3D model lets us quote most accurately; 2D drawings are used to confirm critical tolerances and specifications.
How do I get a quote?
Upload your 3D file (STEP, IGES, STL or X_T) through the quote page, or email it directly. Our engineers review the design, run a DFM check and send you a detailed quotation — usually within one business day.
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What Buyers Search
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Polystyrene: Low Cost, Easy Flow, High Stiffness
Polystyrene is one of the most moldable thermoplastics there is — it flows easily, cycles fast and delivers glass-like stiffness at commodity prices. FirstMold molds it for automotive lights, precision medical components and high-volume consumer parts, up to 1500×1000 mm (https://firstmold.com/ps-injection-molding/). MOLDITQUICK runs the same grades under ISO9001 control.
High stiffness at low cost — one of the cheapest resins to mold, with rigidity that suits housings and trays.
Easy flow and fast cycles — a wide melt window (180–280 °C) fills thin walls and long flows without fuss.
Excellent transparency — clear GPPS is the budget answer to acrylic for see-through parts.
Superior electrical insulation — a standard dielectric for high-frequency and switchgear applications.
Predictable amorphous shrinkage (0.4–0.7 %) — holds tight tolerances without crystalline surprises.
Wide modification range — HIPS, antistatic, high-temperature, glass-filled and talc-filled grades cover the application map.
Proven in precision work — high-end automotive lighting and precision medical parts molded with mold-flow-backed design (https://firstmold.com/ps-injection-molding/).
Polystyrene Processing Parameters We Control
Barrel and mold windows per published PS molding data (https://firstmold.com/ps-injection-molding/), verified in-house on Sodick presses under ISO9001 control — the widest, most forgiving window of any resin we mold.
| Parameter | Recommended Range | Why It Matters |
|---|---|---|
| Barrel temperature | 180–280 °C | Wide window — PS flows freely across it; upper end suits thin-wall and high-flow parts. |
| Mold temperature | 20–70 °C | Cool molds cycle fast; hotter molds improve gloss and weld-line strength. |
| Mold shrinkage | 0.4–0.7 % | Amorphous and predictable — cavity compensation holds mating dimensions. |
| Drying | Not required (< 0.1 % absorption) | PS is not hygroscopic — hopper to screw without pre-drying. |
| Wall thickness | 1.0–4 mm typical | Uniform walls prevent sink marks in this stiff resin. |
| Injection pressure | 70–140 MPa typical | Plenty for thin walls — monitor flash, as PS flows very easily. |
GPPS vs. HIPS: Picking the Right Polystyrene
The two PS families behave very differently in service — clarity vs. toughness is the classic trade (https://firstmold.com/ps-injection-molding/).
GPPS (crystal)
Water-clear, stiff and cheap — for transparent packaging, display parts and cosmetic housings.
- ~90% clarity
- Highest stiffness
- Lowest cost
HIPS (high impact)
Rubber-modified PS that takes drops and knocks — the standard for TV housings, refrigerator liners and toys.
- 5–10× more impact
- Opaque white
- Paintable surface
Specialty modified
Antistatic, high-temperature, glass- and talc-filled grades for static control, heat and stiffness demands.
- Antistatic 10⁹–10¹² Ω
- GF stiffened
- Talc filled
PS vs. other budget resins
Choose PS for stiffness, clarity and cost; PP for chemical resistance and living hinges; acrylic for optics and UV — we shortlist at DFM against your real requirements.
- Stiff & cheap
- Clear (GPPS)
- Not for heat or solvents
Where Polystyrene Injection Molding Pays
Packaging & disposables
Clear boxes, trays, cups and blister packs in low-cost GPPS at high volume.
Automotive
Lamp covers, glove-box parts, center-console elements, mirror housings and tail-light lenses (https://firstmold.com/ps-injection-molding/).
Consumer electronics
TV and speaker housings, printer parts, battery-pack housings and switch plates in HIPS.
Daily goods
Storage cases, combs, pen barrels, cosmetic cases and transparent buttons.
Medical & lab
Petri dishes, diagnostic housings, blister packs and IV-set components in disposable grades.
Electrical
High-frequency capacitors, insulating components and light-switch plates using PS's dielectric properties.