Plastics are synthetically produced non-metallic compounds. It can be molded into various shapes and hardened for commercial use. Plastic molding products can be seen everywhere. Some examples are jars, protective caps, plastic tubes, pot holders, toys, bottles, cases, accessories, kitchen utensils and much more.

Even the keyboard and mouse you use are made through plastic molding. Even the plastic parts of the chair you’re sitting on are created this way.

The basic idea in plastic molding is to insert molten liquid plastic into an already formed mould, for example a bottle mould. It will then be allowed to cool, then the mold will be removed to reveal the plastic bottle.

Plastic molding can also custom mold a wide variety of plastic products, including: garden planters, cabinets, office trays and boxes, barriers, barricades and traffic signage and displays for product promotions and marketing.

If you are planning to get into the plastic molding business, you need to know about the different processes first. Choose from a plastic molding process that fits your budget, experience and resources. Here are basic definitions of various plastic molding methods.

Plastic molding processes:

1. Injection molding

In injection molding, molten plastic is forced into a mold cavity. Once cooled, the mold can be removed. This plastic molding process is commonly used in the mass production or prototyping of a product. Injection molding machines were made in the 1930s. These can be used to mass produce toys, kitchen utensils, bottle caps, and cell phone holders to name a few.

2. Blow molding

Blow molding is like injection molding, except hot liquid plastic comes out of a barrel vertically into a molten tube. The mold closes on it and forces it outward to conform to the interior shape of the mold. When it cools, the hollow part forms. Examples of blow molded products are bottles, tubes and containers.

The equipments required to set up a blow molding business are relatively higher than those for injection molding.

3. Compression molding

In this type of plastic molding, a piece of hard plastic is pressed between two heated mold halves. Compression molding generally uses vertical presses instead of the horizontal presses used for injection blow molding. The formed pieces are then air cooled. The prices of the equipment used for compression molding are moderate.

4. Film insert molding

This plastic molding technique embeds an image below the surface of a molded part. A material such as film or cloth is inserted into a mold. Plastic is then injected.

5. Gas assisted molding

Also called gas injection molding, it is used to create plastic parts with hollow interiors. The partial injection of plastic is then followed by high-pressure gas to fill the mold cavity with plastic.

6. Rotational molding

Hollow molds filled with powdered plastic are attached to pipe-like spokes that extend from a central hub. The molds rotate on separate axes at a time. The center turns the entire mold into a closed furnace room, causing the powder to melt and stick to the inside of the tools. As the molds slowly rotate, the tools are moved into a cooling room. Here, the sprayed water causes the plastic to harden into a hollow piece. In this type of plastic molding, tooling costs are low and part prices are high. The cycle time lasts between 40 and 45 minutes.

7. Structural foam molding

Structural foam molding is a plastic molding process typically used for parts that require thicker walls than standard injection molding. Inserting a small amount of nitrogen or chemical blowing agent into the plastic material makes the walls thicker. Foaming occurs when molten plastic material enters the mold cavity. A thin plastic skin forms and solidifies on the wall of the mold. This type of plastic molding can be used with any thermoplastic that can be injection molded.

8. Thermoforming

In this plastic molding process, pre-extruded rigid plastic sheets are heated horizontally and sucked into hollow one-piece tools. When the hot plastic solidifies, its shape adapts to that of the mold.

Tooling costs are typically low, and part prices vary by machine.

Plastic molding is a highly technical process. You need experts in this type of manufacturing business to be competitive in the market. Therefore, a very scientific and systematic study must first be done before undertaking this endeavor.