Injection mold header

Injection mold

High-quality tools for consistent quality

What is an injection mold?

An injection mold is used to shape plastic(s) into an end product.

Molds have a hollow, a cavity. This is the counter-form, or negative, of the end product. The plastic is injected as a liquid into the injection mold and then cooled to a product that retains its shape. The product is ejected of the mold and cools down further. The product shrinks during this process until it reaches its final product shape with the correct dimensions. The result is a high-quality product made from plastic that meets the set requirements. A mold can be single or multiple. With a single-cavity injection mold, one product is produced per (injection) cycle. A multiple-cavity mold can be used to produce 2, 4, 8 or even 16 products at the same time. This increases the production output significantly.

Injection mold close-up

Long-lasting injection molds

Depending on the cycle time, a mold can process up to more than 8,000 injections per 24 hours. Even three years later, the products that come out of it must still have exactly the same dimensions. A high-quality mold is therefore essential for a stable process. Every mold is unique and manufactured fully in accordance with pre-determined specifications. The design and the choice of material depend on factors including the kind of plastic that will be injected (or, with 2K injection molding, the different plastic granules), the product shape, the wall thickness, the temperature at which injection takes place and the number of cavities in the mold. The engineers at Alligator Plastics cooperate intensively with carefully selected mold builders and configure the best suitable mold for your product.

Injection molding process and cycle times

The injection molding process goes through a number of phases.

  • The plastic, the granules, are fed via an opening into the auger.
  • The granules are heated, after which an auger injects them at high pressure via a nozzle into the mold.
  • The melted plastic fills the mold hollows in the injection molding machine.
  • Cooling pipes cool the mold at constant or progressive pressure, until the mold is completely filled and the plastic has solidified.
  • The machine pulls the two mold parts apart, after which the product or products are removed by a robot or unloaded on a conveyor belt.
  • The mold is closed again and is ready for the next injection.

Together, these steps form one injection cycle. Depending on the wall thickness and size of the product, a cycle generally lasts between 10 and 90 seconds. A multiple-cavity mold increases production output considerably.

Our engineers are happy to advise you on the most suitable solution for your product.