Molding plastic is one of the most widely used manufacturing processes in the world. From the phone case in your pocket to the dashboard in your car, molded plastic parts are everywhere. But how does plastic molding work, and how can you get started producing your own plastic parts?
What Is Plastic Molding?
Plastic molding is a manufacturing process that shapes molten plastic into a desired form using a mold. The plastic is heated until it flows, injected or pressed into a mold cavity, and then cooled to hold its shape. The result is a precise, repeatable plastic part that matches the mold exactly.
There are several plastic molding methods, but injection molding is by far the most common for producing small to medium-sized plastic parts with high precision.
Types of Plastic Molding Processes
1. Injection Molding
Injection molding is the most popular method for molding plastic. Plastic pellets are melted and injected under pressure into a closed mold. Once cooled, the mold opens and ejects a finished part. This process is fast (typically 30–90 seconds per cycle), highly repeatable, and works with a wide range of thermoplastic materials.
The APSX-PIM V3 is a desktop injection molding machine that brings this process to any benchtop workspace — no industrial facility required.
2. Blow Molding
Used primarily for hollow parts like bottles and containers. A tube of molten plastic is inflated inside a mold to create the desired shape. Not suitable for solid or complex parts.
3. Rotational Molding
Used for large hollow parts like tanks and playground equipment. Plastic powder is placed inside a mold that rotates in an oven. Slower and less precise than injection molding.
4. Compression Molding
Plastic material is placed in an open mold and compressed with heat and pressure. Commonly used for thermoset plastics and rubber parts.
5. 3D Printing (Additive Manufacturing)
Not traditional molding, but often used alongside molding for prototyping. 3D printed molds can even be used in desktop injection molding machines for low-volume runs — learn more about injection molding with 3D printed molds.
Common Plastics Used in Injection Molding
Not all plastics are suitable for injection molding. The best materials for molding plastic parts are thermoplastics — materials that melt when heated and solidify when cooled. The most common include:
- ABS (Acrylonitrile Butadiene Styrene) — tough, impact-resistant, widely used for enclosures and consumer products
- Polypropylene (PP) — flexible, chemical-resistant, used for living hinges and containers
- Polycarbonate (PC) — transparent, strong, used for lenses and structural parts
- Nylon (PA) — strong, wear-resistant, used for gears and mechanical parts
- Acetal/Delrin (POM) — low friction, dimensionally stable, used for precision parts
- TPE/TPU — flexible, rubber-like, used for grips and seals
The APSX plastic pellet selection covers ABS, PP, PC, Nylon, Delrin, TPE, PEEK, and many more engineering-grade materials.
How Injection Molding Works: Step by Step
- Material loading — Plastic pellets are loaded into the machine's hopper or barrel
- Melting — The barrel heats the pellets to the material's processing temperature (typically 180–330°C)
- Injection — Molten plastic is injected under pressure into the closed mold cavity
- Cooling — The plastic cools and solidifies inside the mold
- Ejection — The mold opens and the finished part is ejected
- Repeat — The cycle repeats every 30–90 seconds
What Do You Need to Start Molding Plastic?
To start molding plastic parts, you need three things:
- An injection molding machine — The APSX-PIM V3 is a compact desktop machine perfect for getting started
- A mold — Metal molds for long production runs, or 3D printed molds for prototyping
- Plastic material — Engineering-grade plastic pellets compatible with your machine
Desktop Plastic Molding: Getting Started Without Industrial Equipment
Until recently, plastic injection molding required expensive industrial equipment costing tens of thousands of dollars. The APSX-PIM V3 changes that — it's a fully automatic desktop injection molding machine with a compact 4ft × 1ft footprint that fits on any workbench.
With the APSX-PIM, you can start molding plastic parts in under 30 minutes after unboxing. It processes dozens of engineering-grade thermoplastics and produces parts with the same quality and repeatability as industrial systems — just at a smaller scale.
Whether you're a product designer, engineer, educator, or small manufacturer, desktop injection molding is the fastest and most cost-effective way to start molding plastic parts in-house.
Learn more about the APSX-PIM V3 or schedule a demo to see it in action.