Mold Type

Transparent Plastic Injection Molding

We run special injection molding machines built for high-quality transparent and clear plastic injection molding. If you're looking for a clear plastic injection molding partner in China, we'll offer you the best solution — including custom acrylic box manufacturing.

What Is It

Clear plastic, precisely molded.

Transparent plastic injection molding, or clear plastic injection molding, is a manufacturing process where clear plastic material is heated and injected into a mold in liquid form. The mold then cools, solidifying the plastic into the shape of the cavity — producing a finished, transparent plastic part.

The process is commonly used to make clear products such as plastic containers, lenses, and other transparent components. Because these parts rely on high light transmittance, product quality standards are strict — holes, marking or whitening are never acceptable.

Raw material preparation, equipment and tooling, the molding process, and material handling all have to be carried out strictly to hit that standard.

Process Control

What It Takes To Get It Right

01

Raw Plastic Material

Any impurity in the plastic affects the finished transparent part, so material must stay sealed and clean through storage, transport and feeding. Material containing moisture will deteriorate under heat, so it must be dried — using drying equipment with filtered air to avoid contaminating the raw material.

Material	Drying Temp (℃)	Drying Time (h)	Material Thickness (mm)	Remarks
PMMA	70–80	2–4	30–40	—
PC	120–130	>6	<30	Dried by hot wind
PET	140–180	3–4	—	Dry feeding equipment is optimal

02

Cleaning of Barrel, Screw & Spare Parts

Before and after each run, every part is cleaned with PE, PS and other washing agents to keep it clear. During a temporary shutdown, we lower barrel temperature to prevent material sitting at high heat for too long and dripping — for PC, PMMA and PS, barrel temperature is reduced to below 160℃.

03

Mold Design Considerations

Uneven cooling causes bad molding, surface defects and deterioration, so mold design has to account for:

Uniform wall thickness with a large enough stripping gradient
Wide, chunky gates and runners, positioned for the contraction process — with a cold slug well if needed
Smooth, gradual transitions with no sharp corners (PC parts must not have gaps)
A smooth mold surface, with roughness ideally below 0.8
Sufficient air vents to fully discharge gas from the melt
Wall thickness generally no less than 1mm (except for PET)

04

Cleaning of Injection Molding Process , Screw & Spare Parts

To reduce internal stress and surface defects, we control these process variables closely:

Special screws and separate temperature-controlled nozzles
High injection humidity control
High injection pressure to overcome melt viscosity — balanced carefully, since too much causes internal stress and stripping issues
Low injection speed, with multi-stage fast-then-slow injection for best results
Short holding and molding time once the mold is fully filled, to minimize melt residence time
Low screw speed and back pressure wherever quality allows
Precisely controlled mold temperature — generally higher is better

05

Other Considerations

We never use release agents, since any trace will show on the finished transparent surface. Aside from PET, parts typically need post-processing to relieve internal stress — PMMA gets a 70–80℃, 4-hour hot air cycle; PC is heated with clean air, glycerin or liquid paraffin to 110–135℃, sometimes for more than 10 hours depending on the part. PET needs a two-way stretch process for good mechanical properties.

See Our Work

Transparent Molding & Clear Acrylic Boxes We've Made

These are the standards behind every transparent plastic injection molding and clear acrylic box project we take on. If you have a clear plastic injection molding project in mind, we'd welcome the chance to work on it with you.

Start Your Project

Have a part to manufacture? Let's make it production-ready.

Send your drawings, 3D files or project requirements and our team can review the next step.