Plastic Injection Molding

50 to 100,000+ Parts

Molds and Moldings

Start With A Free Project Review

Plastic Injection Molding Service

At Star Rapid, we specialize in high-quality custom plastic injection molding and mold tool making. Plastic injection molding is by far the industry’s most common way to manufacture plastic parts, especially when making larger quantities. We provide custom molding for 50 to 100,000+ injection molded parts as well as a wide range of other manufacturing and finishing services to complete your project. Contact our international injection molding team for a free quote and to talk about your next injection molding project.

What Is Plastic Injection Molding?

Plastic injection molding involves melting granular plastic pellets into a liquid form and then compressing this liquid into the empty cavity of a mold tool. The plastic will retain the shape of the mold as well as the surface texture of the walls of the cavity. After an optimized injection and cooling phase, the now solidified plastic part is ejected and the molding cycle is repeated. This molding cycle can take from as little as a few seconds to several minutes depending upon part size, molding resin and part design.

Plastic Injection Molded Watch

Plastic Injection Molded Watch

Advantages Of Plastic Injection Molding

  • We have thousands of different types of plastic available for you to choose from, for a wide range of mechanical and cosmetic properties.
  • Plastic injection molding is great for larger volumes. For smaller volumes we might recommend other services like CNC machining, vacuum casting or 3D printing depending on the needs of your project.
  • Hundreds of thousands of parts can be produced from a single mold tool.
  • Your part can have excellent surface quality finishes in a wide range of polishes and textures.
  • Injection molding allows you to do overmolding to combine different types of plastic in one piece. It is ideal for lightweight parts that are immune to corrosion.
Plastic Injection Molded Camera

Plastic Injection Molded Camera

Plastic Injection Molding Case Study

See how we made the plastic components for this tactical pen. This build was a great example of how the close cooperation between a product developer and manufacturing engineers can help to overcome design challenges to ultimately create a beautiful product.


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Mold Tool Production

At Star Rapid, we make great tools for low-volume manufacturing. When making your mold tool we use aluminum 7075, pre-hardened tool steels such as P20 and NAK-80, and fully-hardened H13 tool steel. The material used will depend on your specifications, the type of resin and the number of parts you want to produce.

Aluminum Tooling

Aluminum tools are quickest to produce and most cost effective. Aluminum is softer and therefore suited to smaller volumes. For larger volume production, and for aggressive resins or part geometries requiring thin blades or ribs, it’s best to use harder materials that are more durable.

Steel Tooling

Steel tools are tougher and more durable but can take longer to produce. These are suited for larger volumes or when injecting abrasive or corrosive plastics that would damage aluminum molds.

  • Pre-hardened tool steel is used for quantities of 100,000 and more, depending on plastic material and part geometry. We use P20 and NAK80 stress-relieved steel.
  • Fully-hardened tool steel is the most durable and can be used for millions of injected parts. H13 hardened steel is ideal for full production volumes or when injecting abrasive engineering-grade plastics.

OMOM® (One Man One Mold) Service

In a hurry for quick-turnaround plastic injection mold tools? Our OMOM® service was created to provide injection tooling in as little as half the time of conventional tools. We do this by streamlining the entire tooling project, from conception to completion, using a single master machinist who takes ownership of the project from start to finish. 

Tooling for Injection Molding

Tooling for Injection Molding

Plastic Injection Molding Machines At Our Star Rapid Facilities

Plastic Injection Molding Machines At Our Star Rapid Facilities

Part Production

When producing plastic parts, a variety of polymers are available including thermoforming plastics, thermosets and some elastomers. Mold tools and the plastic injection molding process are both carefully engineered to match the unique requirements of each material in order to produce the highest quality finished parts. Thermoforming plastics are relatively softer, more flexible, less durable and easily recycled whereas thermosetting plastics are more rigid, durable and expensive and cannot be repaired or recycled once formed. Find out more about materials you can choose from by checking out our materials sheet and tolerance guide.

Injection Molding Production Parts

Injection Molding Production Parts

Tolerance Guide Sheet

Unless otherwise specified, we comply with the DIN 16742 standard tolerances for plastic injection moldings. We need to know your requirements in advance so that we can manage key features in the tooling and molding process. As a general rule, high-precision features can only be achieved on select areas of the tool depending on the application. Download our Plastic Injection Molding Tolerance Guide.


Design For Manufacturing

When developing a new product it is important to make sure you design for manufacturing. If you don’t you could run into costs and delays when it comes time to produce your parts. To help, our veteran plastic injection molding engineer, Ken Adams, put together a white paper addressing the cause and avoidance of sink marks. Learn more about what it means to design for manufacturing when creating parts using plastic injection molding.


At Star Rapid, we can use virtually any plastic resin that you require for plastic injection molding project. Please check out the list of standard materials that we use. If you would like to use customized plastic simply let our engineers know when you request a quote.

Color Consistency

We pride ourselves on achieving great color through our color matching service when making plastic injection molded parts. There are , however, some challenges that can arise when trying to achieve color consistency. We wrote this white paper to help you learn all you need to know about color consistency.

Are You Ready To Start Your Next Project?

Once you send us a 3D CAD file for your project, our engineers will review draft angles, wall thickness, corner angles and material type, etc. to ensure it is optimized for manufacturing. We will also make sure the right materials are combined with the correct design considerations to ensure your project meets and exceeds your expectations. We also have a Visual Quality Standard for our plastic injection molding services ensuring we have a consistent method for inspecting injection molded parts. Contact us to get your free quote today.