RSP: Custom Plastic Injection Molding

We're Your Plastic Molding Company

RSP offers high-quality custom plastic injection molding to bring your vision to life. Whether you need to create a fully functional prototype or large volume production, we can make it happen.

Integrating 50+ years of manufacturing knowledge with current best practices and technology, we offer a variety of injection molding services and value-added processes to meet all of your needs, from single components to full custom turnkey manufacturing.

We take pride in our socially responsible and environmentally friendly facilities in the US and overseas. Our state-of-the-art plastic injection molding and assembly facility in China provides affordable tooling and molding while adhering to the United States’ manufacturing practices and quality standards. RSP is an official Oceanworks® Guaranteed supplier and manufactures products made with recycled ocean plastics.

Our cross-functional experience allows us to assist all customers in meeting their plastic manufacturing objectives. We have experience with the following industries:

  • Telecommunications
  • Consumer
  • Industrial
  • Lighting
  • Housewares
  • Medical
  • Agricultural
  • Automotive
Plastic Molding Manufacturing at China Location
This operator is running one our plastic molding machines at one of our facilities located in China.

Plastic Capabilities Including Sustainable Plastics

We built our facilities to seamlessly integrate a variety of our customers’ custom plastic molding needs. From full engineering to product development support to efficient manufacturing, we offer our customers significant cost savings and additional benefits over our competitors. These include lower costs, decreased setup times, high quality and unmatched precision.

Here are a few capabilities we proudly specialize in:

  • Sonic welding & gluing
  • CNC surface grinding
  • Naturally balanced runners
  • Face-mounted inserts
  • Quick mold change systems
  • Thermoplastic engineering materials

Ocean Plastic

RSP is part of a growing group of manufacturers that have officially joined Oceansworks® and make products from ocean plastic. We supply ocean plastic to several companies that produce consumer products and reusable packaging solutions. These companies are proud to be part of the solution to create a more sustainable environment while meeting an ever-increasing demand for responsibly made products. Contact us today to see if ocean plastic is a good fit for your next product.


RSP is using eco-friendlier plastics to reduce environmental impact in the molding industry. RSP biocomposite plastics include hemp, rice, flax or cotton fibers added to petroleum-based plastic. This reduces the amount of plastic that is used, which in turn reduces pollution.

Hemp is a leading-choice fiber as some of the largest car manufacturers are integrating it into their production. There is good reason beyond the environmental impact for choosing natural fibers: performance. Hemp-infused plastic, for example, can be up to 5 times stiffer and 2.5 times stronger than polypropylene (PP).

Medical Devices & Plastic Molding - ISO 13485

A lot of the clients we work with create products for the medical industry. RSP has a quality management system in place to provide services that meet FDA and other regulatory requirements. The quality system, known as ISO 13485, is recognized internationally and ensures that every step of manufacturing is documented and performed correctly. A full service global contract manufacturer, specializing in plastic molding, we are ISO 13485 certified and take the regulatory requirements very seriously.

RSP: Plastic Injection Process: From Pellets to Product

Injection Process: From Pellets to Product

Turning plastic pellets and even recycled plastic pellets into a perfect molded product is what we do best. It may sound like a fairly simple process, but details are everything when it comes to the plastic injection molding. Here is a quick and simple overview of how we take your design from pellets to product.

The first stage of the process begins by feeding dry plastic pellets, held in a “hopper,” into a heating cylinder by using a hydraulic pump, motor and gears. Within the cylinder there are multiple heating zones that systematically increase the temperature of the material as it moves closer to the gate where it is injected into the tool. Each heating zone is constantly monitored and adjusted. The peak temperature of the plastic depends on the combination of materials being injected, but can reach as high as 725°F. Here at RSP, our average melting temperature for materials is 525°F.

With the help of a stationary and movable platen, the mold is held in place as a nozzle prepares to inject the molten plastic. Next, a clamp mechanism closes the mold halves. The action is performed by a motor rated by the maximum amount of force the machine is capable of creating. Then the molten plastic is injected into the mold as the clamp keeps the mold closed. As the product solidifies and cools down, the finished product is ejected from the mold.

RSP: Plastic Mold Injection Process
Plastic Mold Injection Process

As discussed above, the typical injection molding machine consists of five major components:

  • Hopper
  • Heating Cylinder
  • Hydraulic Pump, Motor and Gears
  • Stationary & Movable Patens
  • Clamp

In-Mold Decoration

For some projects, there may be a need for in-mold decoration (IMD) to include an image or coating on a plastic surface. This process involves printing a high-quality image on a heat-resistant plastic film that will hold up to the stress of in-molding. The printed film is inserted into the open plastic injection mold and held in place via vacuum ports or electrostatic charge while the mold is closed. Once closed, plastic resin is injected into the mold, encapsulating the label to the finished part.

Combining the decoration process with the molding process adds durability; decreases manufacturing costs by eliminating post-molding labeling, handling and storage; and also enables design flexibility. IMD allows for a wide range of colors, effects, textures, and graphic options and can replicate stainless steel, wood grain and carbon fiber. IMD is commonly used on washers and dryers because of its affordability and durability.

RSP: In-Mold Decoration - Image or Coating

A Seamless Process

In order to provide a low-cost product with minimal setup and maximum quality and precision, we practice a seamless process to get the job done right the first time. The first step is to request a quote and discuss the product with an RSP sales rep.

Once both parties agree that RSP is the best partner for the project, an official order can be placed. This launches the design for manufacturing review, where we consider all the best practices of molding and design to optimize the model. After design suggestions are discussed, the engineering team at RSP can create a 3D model of the tooling. This 3D model will need to be approved by the customer before proceeding further, ensuring quality standards are being met every step of the way. During the tooling phase order, we provide weekly updates on tooling status, including photos.

A few other things to note:

RSP offers affordable quick-turn prototypes. We create prototypes using machined blocks of plastic for the highest quality and strength. RSP also has 3D printing available for some sizes and shapes.
If you need to bridge the gap between prototyping and production, we offer several options. Our customers can select from aluminum or softer steel tools, which allow for lower cost tooling and an easier and quicker turnaround. Softer steel and aluminum molds have a limited life of 5,000–50,000 pieces depending on the design.
Our mold transfer program makes it simple for you to seamlessly transfer your tools to us. After an initial assessment, we will be able to determine whether there is a need for additional equipment or safety stock. Everything will be put in writing to protect the interests of all parties.
Because we work with custom projects across many, many industries, we cannot guarantee a standard lead time. When you request a quote, we’ll provide an estimated lead time for your project. Typically, our lead times are 4–6 weeks for standard tooling depending on the complexity of the tool. We are generally faster than others in the industry.

Machine & Material Specifics

Looking to see what machines, materials and inspection devices we use? Check out the technical specs on our Machines & Materials page..

Video: RSP Plastic Injection Molding

RSP plastic molding department Shenzhen, China.

Request a Quote

If you are like many of our customers, you think about your product 24/7. You dream of how it will change the market, or maybe you’re creating a brand-new market. But when it comes to executing the product, you’ve realized you need some help. That’s where we come in.

Interested in learning more about our plastic, ocean plastic and bioplastic injection molding process and what we can do to help manufacture your product? Start by filling out the information below so we can get a good understanding of what you may need from us. We will respond as quickly as possible to your request; however, please allow at least 24 business hours.

Need immediate assistance? Call our sales professionals directly based on the time zone that works best for you. English speakers are available at all locations.

USA: +1-866-329-1804 - UTC-6: Central Standard Time

China: +86-0755-8366-3414 - UTC +8: China Standard Time

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