Rapid Injection Molding: Definition, Components, and Materials

Rapid Injection Molding- Definition, Components, and Materials

Rapid Injection Molding (RIM) is similar to  other injection molding process. The mechanism and equipment used in the process are the same except for a few modifications.

The RIM catalyzes production by integrating specifically designed molds, ensuring speedy fabrication at significantly lower costs.

Interested in reducing injection molding costs? You can utilize rapid injection molding to cut your capital expenditure by half. The RIM doesn’t require conventional molds; instead, it uses cheaper and quickly manufactured rapid molds.

This smaller modification in the injection molding process takes production efficiency to the next level. Resultantly, you can save both money and time.

Can Rapid Injection Moulding do wonders?

Products manufactured in the aerospace industry using RIM are already in space, and that’s a wonder for sure.

This blog will help you visualize the Rapid Injection Molding process. You’ll have a clear picture of the entire process—make sure you don’t skip anything!

What is Rapid Injection Molding?

What is Rapid Injection Molding

Rapid Injection Molding is an injection molding technique that employs special rapid molds to manufacture a variety of plastic products.

These molds are easy-to-design and much cheaper because of their material. The usage of such molds expedites the manufacturing process and reduces overall expenditure.

However, the process is only feasible for limited production, given the poor durability of the molds.

Three essential considerations for rapid injection molding are highlighted underneath.

  • Production Volume: The process is only recommended for low-volume production of about (500 – 1,000) pieces.
  • Production Rate: The process shall opt for projects requiring a higher production rate.
  • Design Specifics: This process is only feasible for simple mold designs to ensure rapid mold making.

The practicality of the RIM comes into question for some inevitable reasons. Still, the process’ feasibility in manufacturing is beyond doubt. The specific molds used in the process can only be produced by CNC machining.

Otherwise, the molds are not considered for rapid injection molding. It is because the speed and economics of the process largely depend on these molds.

What makes mold-making so significant in RIM? The speed of the process depends upon mold-making. It differentiates RIM from similar injection molding techniques.

Further, this condition limits the production of parts having complex design features. Only certain types of products qualify for rapid injection molding to keep the process fast-paced.

When is Rapid Injection Molding Being Used?

When is Rapid Injection Molding Being Used

Wherever injection molding is used, the RIM process can also be utilized there. It’s essentially a manufacturing method for plastic products, but a faster one.

It is mainly implemented in the research and development phase to test the products in small batches before upscaling to high-volume production. Resultantly, initial-stage products are developed in a shorter time frame in a much more cost-effective way.

Rapid injection saves manufacturers substantial capital traditionally spent on prototype research and development.Making molds is a costly undertaking, whereas the molds used in RIM are inexpensive and develop very quickly within a week or two.

Moreover, the process has also proven to help manufacturers efficiently meet short-term demand increases. With RIM, the products could be developed faster without erecting a conventional production line with expensive tooling equipment.

The manufacturers have the flexibility to choose RIM as per their needs. In most cases, rapid injection molding caters to the needs of low-cost and short-term manufacturing in industries.

How Does Rapid Injection Molding Work?

The process kickstarts with the design and fabrication of rapid molds. A rapid mold is an easy-to-design and quick-to-manufacture mold type. It is produced from inexpensive materials like aluminum.

Where production-grade molds take months to develop, a rapid mold is created within a week. Hence, significantly reducing the production time and overall expenditure of manufacturing.

 Rapid Molds vs. Production Molds

  • Rapid molds are simple; however, production molds may be complex in design with added features.
  • In cost comparison, rapid molds are cheap and produced from standard materials without considering any specific resistances for long-term usage.
  • Rapid molds offer short-term advantages, whereas production molds offer long-term benefits.

The next step in line is the installation of molds on the injection molding machine. Remember, the regular injection molding machine uses rapid molds for the RIM process. No specialized equipment is required to complete the process.

The injection molding machine has two plates, i.e., stationary plate and moving plate, and the two parts of the rapid mold are installed on these plates.

These parts are then adjoined with the help of the moving plate pushed by a hydraulic system. It ensures that the mold stays together during the injection molding process without any spill out.

The final manufacturing process begins once the rapid mold is fitted on the machine properly. It is the same as the traditional injection molding process. The raw material is filled in the barrel through the hopper.

When external heating is provided, the temperature inside the barrel rises to the point when raw material starts to melt. A clockwise movement is ensured with the help of a frictionless screw-type rod to easily draw the liquified material.

The liquified material is then filled in the mold through a nozzle at high temperature and pressure. The material takes the shape of the pre-installed mold.

Finally, the end product is obtained after the process completes. The machine returns to its initial state so that the process is repeated.

What Are the Components of a Rapid Injection Molding?

Rapid Injection Molding can be divided into three main components: the injection molding machine, injection molds, and a material feeder. We’ll briefly explain each of the components and their operations.

Injection Molding Machine

Injection Molding Machine

A molding machine is based on an injection technique used to manufacture plastic products. Tooling equipment is installed on the machine to shape the product.

It is extensively used in the manufacturing industry around the globe. The machine efficiently produces plastic items from raw plastic in pelleted form. It consists of a hopper, barrel, nozzle, and mold.

  • Hopper: Used to hold raw material and fed the barrel from time to time or as needed.
  • Barrel: A container for melting raw plastic with the help of external heating and clockwise movement.
  • Nozzle: It injects plastic into the mold at high pressure and temperature. It is mounted on the barrel and works by the action of the screw.
  • Mold: A pre-designed tooling equipment used to mold melted plastic into the required shape.

The raw material is fed to the barrel via a hopper. The material melts inside the barrel with the help of heaters.

Then melted material slides into the mold with the push of a screw inside the barrel, passing through the nozzle at high pressure and temperature.

The material sets in the mold and solidifies in the shape of the mold, which is the final product.

Injection Mold

The quality of the end product in RIM exclusively depends upon the mold. Although rapid mold is comparatively less expensive than production-grade molds, it must be well designed to hold the material and perfectly shape the product.

The core and cavity make up a rapid mold. The core is installed on a moving plate, whereas the cavity stays on a fixed side of the injection molding machine.

During the RIM process, a hydraulic ram presses these parts against each other. The melted plastic is injected into the mold and shaped accordingly.

Material Feeder

Material Feeder

The material Feeder is the mechanism of an injection molding machine comprising different components. It converts and transfers raw material within the injection molding setup and completes the process through which the material melts down and sets inside the mold.

A material feeder consists of a hopper, barrel, and nozzle. They feed the mold with the required quantity of material to extract a fine-quality product.

How to Choose the Best Materials for Rapid Injection Molding

How to Choose the Best Materials for Rapid Injection Molding

Choosing the raw material for the RIM process is a crucial step. You must consider your product’s application and budget before making any selection.

Always choose the best material for the best results and top-quality products. Various materials are available in the market for RIM, and choosing the best requires consideration and knowledge.

You have different options of thermoplastics to choose from for rapid injection molding. Please, see what best cater to your needs.

Two commonly used commodity plastics for rapid injection molding are polypropylene and polyethylene. The other two popular plastics are nylon and polycarbonate. Both are used to replicate latex, silk, and rubber products.

Below, we will explore the properties of ‘commodity plastics’ used in rapid injection molding. These plastics include polypropylene, polyethylene, and nylon.


  1. Highly cost-effective and easily available.
  2. Resistant to atmospheric moisture.
  3. Very low internal friction


  1. High tensile strength and stress resistance.
  2. Used for food-grade applications.
  3. Easily recyclable.


  1. Unreactive to chemicals.
  2. Weather resistance.
  3. High melting point.

Lastly, don’t forget to consider the following points before choosing a material for your rapid injection molding project.

  1. Consider your budget—choose a cost-effective material to benefit from the RIM process.
  2. Check if the material’s tensile strength and other mechanical properties match your product’s application.
  3. Note the resistive properties of the material; they may be thermal properties, electrical properties, or chemical properties.
  4. Consider long-term benefits vs. short-term benefits as per your requirements.

What are the Advantages of Rapid Injection Molding?

Rapid injection molding is an effective process that offers a multitude of benefits to manufacturers, including cost-effectiveness, speed of operation, design flexibility, and quality & consistency.



It is an economical process that can be used in different ways to save capital and operational expenses. For instance, a temporary demand increase may be fulfilled with RIM without going towards expensive full-scale production.

Speed of Operation

This process employs rapid molds, which are easier to produce in a much shorter time. Conventional molds take over a month to develop, and rapid molds can be manufactured within a week. Hence, it saves time.

Design Flexibility

Rapid molds are inexpensive, so you can produce multiple designs and test products without expensing huge sums of money. That’s why RIM is highly recommended for prototyping and low-level production.

Quality & Consistency

Quality & Consistency

You can maintain quality and consistency using rapid injection molding. The operation is not different from traditional injection molding; hence, consistency can be ensured. And the quality will depend on your material selection for mold and product.

Applications of Rapid Injection Molding

Rapid injection molding is being used in major industries around the globe and in space too. The products manufactured using rapid injection molding are utilized at the consumer level and for industrial applications.

The major industries using rapid injection molding include aerospace, automotive, electronics, medical, and more.

Many products you see around you or use are developed using the RIM process—for example, laptop or mobile device components, coffee cup holders, or car dashboard parts.

Similarly, panels, housings, conduits, and enclosures for various components are produced using rapid injection molding.


Phew! It took a while to get here, right? Now that we’re here, you must know how effective rapid injection molding is for your manufacturing needs. It offers you a plethora of benefits, saving you time and money too.

Above all, it empowers you with design flexibility, which is challenging when dealing with plastic.

Are you still having second thoughts? If you’re choosing a rapid injection model to cater to your prototyping, research & development, or short-term demand increase needs, it’s the best option and second to none!

Kemal: The Best Choice for Injection Molding Services

Kemal The Best Choice for Injection Molding Services

The next step from here is to contact our team. With more than 28 years of experience in offering high-end services to our clients, we are at your service. We provide the best Injection Molding Services at market-competitive prices.

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