A General Guide for Custom Injection Molding Costs

Custom molding injection is not exactly the simplest or most straightforward process. Most people are unaware as to what custom molding injection means and why it is so important. Furthermore, there are nuanced costs associated with this process that stem from different areas. Each portion of custom injection molding costs a unique amount of money for complex reasons. Quotes vary quite widely based on each project’s unique factors. Let’s examine custom injection molding costs to help our audience better understand the financial aspect of this process.

A Diverse Industry with Varying Costs

Plastic manufacturing projects are unique in nature. Customers have an array of options for products as well as the processes necessary to create those items. Each unique technique has its own distinct cost. These costs are not uniform across the board. They hinge on the nuances of the project and whether multiple techniques are required to create the final product. In general, the mold itself accounts for the brunt of the initial production cost. Let’s take a look at the different approaches and other variables that impact custom injection molding costs.

Plastic Injection Molding

This approach is one of the most popular ways to create plastic parts as well as plastic components. This method injects plastic into a mold to generate an inverse form. All sorts of useful products are created with custom plastic injection molding. For the most part, plastic injection molding is quite complex compared to other approaches. It requires a highly nuanced mold so it tends to cost more than other methods.

Blow Molding

Blow molding is a form of manufacturing similar to other methods yet unique in the fact that it has an extra step that permits the plastic portion to have a hollowed out middle portion. Plastic injection molding or thermoforming are used to move a hot component to a separate tool that transmits gas to the center portion. This gas stretches it out into a brand new mold. Blow molding is regularly used for bottles and all sorts of other plastic products.

In terms of cost, blow molding is comparably cheap. However, blow molding is a component of a larger, overarching process so the total expenses of the project might end up being higher than originally anticipated.


Plastic items can also be manufactured with extrusion and thermoforming. This process necessitates a couple additional steps compared to plastic injection. Extrusion requires the processing of plastic pellets or powder. This allows for the precise manufacturing of plastic sheets. Thermoforming heats the finished plastic sheets in ovens to make them malleable. The sheets are then pressed to a mold with a vacuum or air pressure to form the desired shape of the final components. Thermoforming for plastic manufacturing is comparably simple and direct so it typically costs less than other methods.

Quotes for Custom Plastic Injection Molding

Obtaining and analyzing quotes from different mold makers for custom injection molding costs is inherently complex. The quote hinges on input such as sample parts, prototypes, drawings and so on. Designers must examine each of these inputs to identify the optimal molding solution. Note that it is possible for the part to be redesigned to enhance efficiency during the manufacturing process and boost the number of parts generated during the molding process.

Costs tend to rise when molds are created with more cavities, especially tight tolerances and an extensive production life. However, the additional upfront cost is almost always worth the money. Such elite molds stand the test of time and require minimal maintenance.

Additional Variables That Impact Custom Injection Molding Costs

The mold base is one of many additional factors that influences custom injection molding costs. The mold base is a case that stores the mold cavities and combines the components with one another. The cost of this base is estimated according to the mold size and the type of steel that makes the base. Even the level of customization desired by the customer plays a part in determining cost. The core metal impacts costs in that long-lasting molds require a metal that stands the test of time. Such core metal is more expensive. Alternatively, short production runs can make use of a metal that does not last as long and costs less.

Part complexity influences custom injection molding costs as well. Whether the final part requires an elaborate surface finish, a tight tolerance or a certain number of undercuts, such specifications ultimately play a part in shaping the total cost. Core/cavity machining matters as well. Every mold must be customized. Customization requires the placement of cavities, cooling lines, ejectors etc. Even the steel used in the part alters the cost. Hardened steel molds that are especially durable are more costly to manufacture. Yet, once these uber-strong steel molds are finished, they have quite the lengthy production life.