How to choose between thermoforming and injection molding?

Thermoforming and injection molding are two of the most popular manufacturing processes for plastic parts, each offering unique advantages depending on the specific application. Below is a brief description of some aspects of these two processes.

**Molding:** In the thermoforming molding stage, a single 3D form is created using aluminum, wood, polyurethane, or a 3D printer.

In injection molding, double-sided 3D molds are made of aluminum, steel, or beryllium copper alloys. Thermoforming offers advantages in time and price because prototype samples can be made from CNC-cut wooden molds.

**Materials:** Thermoforming can use a wide variety of materials to create flat sheets, which are then shaped. Different finishes, colors, and product thicknesses can be selected.

Injection molding uses thermoplastic granules, available in a wide range of materials and colors.

**Production:** In thermoforming, a sheet of plastic is heated to a pliable temperature and then shaped into a tool using vacuum suction or a combination of suction and pressure.

In injection molding, plastic spheres are heated to a liquid state and injected into a mold.

**Time:** Through the combination of tooling and production, the time required to manufacture a product can be accurately measured. In thermoforming, the average processing time is 0-8 weeks. After processing, production typically begins within 1-2 weeks of mold approval.

For injection molding, molds require 12-16 weeks, with a maximum of 4-5 weeks after production begins.

Cost: Mold costs for thermoforming are significantly lower than for injection molding. However, the per-part production cost of injection molding can be lower than that of thermoforming. Generally, plastic injection molding is used for large, high-volume production runs, while thermoforming is used for smaller production quantities and larger production runs.

As manufacturing technologies continue to advance, the demand for products and the areas where the capabilities of plastic thermoforming and injection molding overlap are increasing. Choosing the right approach in these situations requires a more in-depth evaluation of the characteristics, benefits, and costs associated with each process.