Plastic Injection Molding Service
At Star Rapid we specialize in producing high-quality plastic injection molded parts and mold tools. We offer machining and finishing services to make tools from a variety of materials, and can produce 50 to 100,000+ finished parts in a wide variety of plastics.
With advanced material verification and quality processes we can ensure your tools and parts exceed your expectations. If you’re ready to start your next project, upload your product design information for a competitive injection molding quote today.
How Plastic Injection Molding Works
Plastic injection molding is by far the most common way to produce large volumes of finished plastic parts for every kind of commercial and industrial use. Molten resin is injected under high pressure into the cavity of a metal die and then rapidly cooled, forming a solid shape. A single cycle to make a finished part may take anywhere from a few seconds to minutes depending on part complexity and size.
The Plastic Injection Molding Process
Once your plastic injection mold tools are ready, the molding process consists of the following basic steps:
Step 1. The plastic resin comes in raw pellets. These are dried to the right moisture content, and then if necessary they can be blended with pigments or master batch colorants.
Step 2. The dried pellets are poured into the hopper of the molding machine. A reciprocating screw inside the barrel of the machine will transport these pellets towards the mold.
Step 3. Within the barrel, the pellets are mixed and heated until fully molten, forming the liquid resin.
Step 4. The heated mold closes automatically and resin, under great pressure, is injected through a gate and into the mold cavity.
Step 5. The mold is cooled to solidify the part inside.
Step 6. The mold opens and the part is ejected to begin a new cycle.
Want to learn more about plastic injection molding?
Advantages Of Plastic Injection Molding
There are many advantages to plastic injection molding. These include the ability to make large volumes of parts quickly, high surface quality, many resins to choose from, and durable tooling that can last for years.
Thousands of plastic materials
Make large volumes fast
Stable and reliable process
Excellent surface quality
Overmolding for more designs
Plastic Injection Molding Resources
Design For Manufacturing
It’s important that your product idea is design suitably for manufacturing. Learn more about designing for manufacturing.
We offer a range of materials for your mold tools and injected parts. Learn more.
Visual Quality Standards
Learn more about the visual quality standards we apply to plastic injected molded parts to ensure high quality.
Avoidance Of Sink Marks
Learn about what causes sink marks in plastic injection molding and how to avoid them in this white paper.
All plastic material will expand and contract under the influence of heat and moisture. Our tolerance guide will give more general information on the characteristics of most common resin types for typical part features.
We will work closely with you to optimize your designs for manufacturing. We will indicate any areas where poor design may produce thermal stress, shrinkage, warping, etc. Consult our design guide for more information on common defects and how to avoid them.
Unless otherwise specified, we comply with the DIN 16742 standard tolerances for plastic injection moldings. Read about the visual quality standards that we apply to injection molded parts.
Plastic Injection Molding Quickfacts
What plastic is used in injection molding?
Virtually any type of plastic can be used in the injection molding process. There are thousands of thermoforming and thermosetting plastics to choose from for your project. Check out our list of frequently used materials.
What is the plastic molding process?
Resin in the form of plastic pellets is mixed and heated until it’s melted. Under high pressure this liquid plastic is injected into the hollow cavity of a mold tool and allowed to cool, forming a solid part that is then ejected from the cavity to begin the next cycle.
What are the advantages of plastic injection molding?
Once a tool is made, plastic injection molding is the fastest and most cost-effective way to make up to hundreds of thousands of finished parts.
How long does it take to make an injection mold tool?
Depending on the complexity of the design and possible heat treatment, a plastic injection mold tool can be made in five days to two weeks.
See Our Past Projects
Powelectrics Sensing and Telemetry Solutions designed its flagship IoT hardware device, the Metron4, to make remote monitoring simple. Portable and durable, the Metron4 is outfitted with a wide range of sensors capable of monitoring temperature, pressure, humidity, vibration, energy consumption and more. The Metron4 also includes a number of analog inputs, digital card inputs, a solar battery and hardware for data transmission. Our plastic injection molding service providers created the plastic housing for this device, which consisted of a lid, base and two internal dividers. Read this case study to learn how we developed the Metron4 housing while optimizing for durability and functionality. Read more…
Harnessing the power of the portable Raspberry Pi portable controller, the OTTO digital camera allows users to capture photos in fully-customizable modes and upload them to their smartphones in seconds. OTTO partnered with Star Rapid to develop a prototype that was portable, aesthetically pleasing and easy to use. To start, we built a two-cavity mold from P20 tool steel machined with EDM, which allowed us to produce the distinctive grain of the camera body. Using this mold, our plastic injection molding service team successfully manufactured several OTTO prototypes. Learn more about our process for OTTO in this case study. Read more…
While developing the SP9 Coffee Maker, Marco Beverage opted to use a transparent reservoir to supply hot water to their system. Both a crucial aesthetic and functional component of the pour-over coffee-making process, hot water reservoirs must be resilient while revealing their contents to outside viewers. Working with Marco Beverage, our plastic injection molding service team designed and manufactured a reservoir out of Eastman Tritex 2001 polyester. Read our step-by-step process for developing this product in our short guide, and learn how we finished with a food-grade, high-gloss, ultra-durable product that met Marco Beverage’s expectations in every respect. Read more…
Plastic Injection Molding: Further Reading
When developing a new product, you should choose the type of plastic resin that offers the best performance for your application. Factors to consider include food safety, impact resistance, flexibility, strength, fire resistance and biocompatibility. In this guide, our plastic injection molding services team offers useful tips to help you find the plastic that’s best suited for your needs. Read more…
As a premier provider of plastic injection molding services, Star Rapid has manufactured countless products to support a variety of industries. We want to offer you our expertise to help you optimize your designs for this process. Please check out this guide for useful tips on improving these four important areas. Read more…
In plastic injection molding, the type of resin is not the only material choice you need to make. The type of metal used to make the mold tool also plays a large role in the success of production.. With several different injection mold tool materials on the market today, it can be difficult to choose the right one for your product. In this guide, our plastic injection molding services team gives you the information you need to make an educated decision before production. We discuss today’s most popular types of injection mold tool materials, including aluminum Read more…
Getting the best results from plastic injection molding requires that the manufacturer has a keen understanding of how several forms of pressure interact during the molding process. Product developers should also know about these fundamentals and how they can affect cycle times, product quality and cost. In this guide, our plastic injection molding services team explains the role of injection, holding and back pressure. And you can also read more about the importance of clamping pressure, here. Read more…