6 Types of Plastic Molding

When designing plastic products and components, one of the most challenging decisions is determining the right method of manufacturing them. Your goal is to have a durable, high-quality finished product while minimizing costs and speeding up efficiency and the right manufacturing method is key to meeting these goals. There are six main types of plastic manufacturing, and our thermoforming company in North Carolina is looking at each type and the associated benefits they offer.


Thermoforming involves heating a large sheet of plastic until it is soft and flexible, then stretching it over a single-sided, custom mold. Vacuum pressure or compressed air presses the thermoplastic tightly against the mold, creating the desired shape.

Benefits of Thermoforming

  • Low tooling cost
  • Quick lead time
  • Ideal for large pieces, such as bathtubs or car dashboards
  • Fast prototyping
  • Highly customizable

Injection Molding

Injection molding is a plastic manufacturing method in which a thermoplastic is melted to a liquid, then injected into a double-sided mold using a highly pressurized injector. The plastic coats and fills the mold to create the needed shape, and is then cooled and ejected for finishing.

Benefits of Injection Molding

  • Versatile
  • Efficient and cost-effective for high production runs or repeat product runs
  • Achieves variable thickness and complex detailing
  • Incredibly high accuracy to design and consistency between parts

Extrusion Molding

Extrusion molding is primarily used to manufacture long, straight pieces, such as tubing, hoses, or pipes. This method involves forcing liquid plastic into a die to form a shape.  While round pieces are common, t-shapes, l-shapes, and squares are also achieved, depending on the shape of the die.  Many thermoplastics can be used during extrusion molding.

Benefits of Extrusion Molding

  • Simple tooling and machinery reduce operating costs
  • Minimal post-production finishing aside from cutting pieces to a desired length
  • Can achieve complex and consistent cross-sections

Compression Molding

Compression molding is most often used with thermoset plastics whose chemical structure changes when melted and cooled to create a hard, rigid final product. Plastic resin is heated to a soft, almost "putty" state where it's not quite liquid, then it's placed into a heated mold. The putty is then pressed into shape by the mold and allowed to cool.

Benefits of Compression Molding

  • Used to manufacture plastics that replace metal.
  • Works well for rigid, lightweight thermosets
  • Often used in fiberglass-reinforced or rubberized plastics.

Blow Molding

Blow molding is similar to injection molding as the plastic is heated to a liquid state and injected into a mold. However, once the plastic is placed in the mold, air is injected into the plastic, inflating it so that it presses against the walls of the mold and achieves the desired shape.

Benefits of Blow Molding

  • Ideal for producing thin, hollow-walled pieces such as water bottles or 2-liter soda bottles.
  • Fast production
  • Low-cost production at high volumes

Rotational Molding

Rotational molding, or "roto-molding," involves pouring melted plastic into a mold, which is then rotated at a high speed. This coats the plastic evenly along the walls of the heated metal mold, leaving the interior hollow. This method is primarily used for large, hollow-walled containers, storage bins, and even kayaks.

Benefits of Rotational Molding

  • Minimal setup costs
  • Uniform wall thickness
  • Cost-effective for very short or low volume production runs

Get a Free Quote for Thermoforming and Injection Molding

At Advanced Plastiform, Inc., we specialize in heavy-gauge thermoforming and injection molding. Our experienced team includes engineers and designers as well as manufacturers, all of whom are dedicated to helping you meet your goals. Our company works with industries across the Mid-Atlantic and Southeast, including  North CarolinaSouth CarolinaPennsylvaniaMaryland,  TennesseeGeorgia, and Virginia. To learn more, call us at  919-404-2080 or fill out the contact form to get started.

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