The RIM Manufacturing Process

RIM Manufacturing Process

RIM Manufacturing is well-known for helping our customers design molds, or “tools,” for the greatest efficiency, uniformity, and production productivity. During our RIM product design and manufacturing processes, we also consider including after-mixers and gating to maximize your part’s quality.

Planning & Communication

Our experience in the industry means we can help you achieve the ideal mold design by taking multiple factors into consideration:

The Right RIM System

Part size is the primary factor for determining the size of the dispensing machine used to inject the polyurethane into the mold. RIM Manufacturing offers a wide range of capability with three of the largest machines made, two mid-size, and two small machines.

RIM parts are often light but can weigh as much as 100 pounds. The largest part RIM Manufacturing currently produces weighs approximately 50 pounds.

Mold Clamping Pressure

This is determined by the amount of chemical and the type of RIM system injected into the mold. Generally, clamping pressure can range upwards of 200 tons, but typical molding pressure is less than 100 psi.

Mold Cost

RIM molds (aluminum) can be as much as 70% less than injection molding (steel molds). Lower in-mold pressures allow molds to be created from lower-cost materials, and these lower pressures often lead to less wear and tear, allowing the mold to be used for longer, saving more in mold costs.

Part Shrinkage

All plastics, including RIM materials, shrink during molding. The amount of shrinkage characteristic of the particular RIM system is factored into the tool’s design.

Dimensional Tolerances

This is usually geared toward form, fit, and function, allowing molds to be built to absolute dimensions. Because this is more costly, designing parts for more practical dimensional tolerances generally saves money.

Quality & Dependability

RIM Manufacturing is known throughout the industry for producing parts that reduce cost without any reduction in dependability or quality. For decades, our customers have relied on us because they need parts to be defect-free while they strictly conform to form, fit, and function requirements.

Our process goes a long way to ensure that we spend whatever time is necessary with customers assisting with and reviewing the final part design. Collaborative GoTo, WebEx, or in-person meetings are essential to designing parts that exceed everyone’s expectations.

After part drawings are finalized and the mold is designed and constructed, the Production Part Approval Process (PPAP) begins.

  1. First Article parts are produced, and our Quality Department inspects them for conforming to the part drawing. They measure all critical dimensions and callouts and review them for cosmetic conformance.
  2. Once approved, the polyurethane parts are sent to the customer for First Article Approval and sign-off.
  3. Once final approval has been obtained, our Quality Department produces Work Instructions for each relevant area of the part’s production – molding, secondary operations, painting, assembly, quality assurance, and packaging.

Our customers can count on us for quality and consistency, as evidenced by our ISO 9001:2015 and ISO 13485:2016 certifications. And we will continue to improve our processes, capabilities, equipment, facilities, and staff to sustain the highest level of customer satisfaction – that’s our guarantee.

Contact RIM Manufacturing for more information

Reaction Injection Molding Process VS. Other Processes

Reaction Injection Molding Process part

Reaction injection molding is cost-effective for the production of a few hundred to several thousand parts. Benefits include low-to-moderate tooling costs, short lead times, the ability to produce large and lightweight parts, parts with tight tolerances, enhanced design finishes, chemical resistance properties, 94V-0 and HB ratings, customized part properties, and wall thickness, as well as the ability to mold over metal, wood, glass, computer chips, and other parts.

RIM Advantages VS. Injection Molding

Reaction Injection Molding Advantages

Large, lightweight parts
Varying wall thickness with no sink
Deep draw
Can combine multiple designed parts into one part within a single mold
Low-to-moderate cost tooling – machined aluminum
Short lead-time
Tooling can be used for prototype and easily modified for production parts
Material flexibility – elastomers, solid RIM, structural foam, flexible foam, DCPD, etc.
Encapsulation of component materials including metals, electronics, plastic, valves, circuitry, etc.
Low-to-high production volume
Tight tolerances
Injection Molding

Small-to-mid size parts
Requires uniform wall thickness
Limited draw
Multiple mid-size parts generally require multiple molds
High-cost tooling – steel
Long lead-time
Prototypes require different tooling and tooling modifications are expensive
Limited material options
Limited encapsulation
Moderate-to-high production volume
Tight tolerances

RIM Advantages VS. Thermoforming & Vacuum Forming

Reaction Injection Molding Advantages

Complex geometry and cosmetically appealing parts
Deep draw with structural integrity
Varied wall thickness throughout the part
Structural integrity molded into parts
Molded-in attachment points
Tight tolerances
Low-to-moderate cost tooling
Low-to-moderate production
Material flexibility – elastomers, solid RIM, structural foam, flexible foam, DCPD
Encapsulation of component materials including metals, electronics, plastic, valves, circuitry, etc.
Thermoforming & Vacuum Forming

Simple part design and geometry
Draw limited and requires post-molding structural features
Requires uniform wall thickness
Post-molding gluing of ribs
Glued attachment points
Low-to-moderate cost tooling
Limited material flexibility
No encapsulation capability

RIM Advantages VS. Sheet Metal

Reaction Injection Molding Advantages

Tremendous design flexibility
Large and light-weight parts
Structurally strong and durable
Molding in color an in-mold painting
Variable wall thickness within the same part
Affordable part cost
Capable of combining multiple parts into one integrated part
Provide sound and vibration insulation
Corrosion and rust-resistant
Part cost is more stable 
Sheet Metal

Limited design flexibility
Parts are heavy
Post-painting required
High part cost
Varied wall thickness requires welding multiple parts
Multiple parts require labor and assembly costs
Structurally stronger parts
Part pricing is less stable due to the commodity’s market

RIM Advantages VS. Cast Molding

Reaction Injection Molding Advantages

Cosmetically appealing parts right out of the mold
Prototype tooling can be used for production parts
Tight consistent part tolerances
Variable wall thickness without sink
Tooling lasts the lifetime of the project
Short lead-time on tooling
Cast Molding

Cosmetic inconsistencies of parts of the mold
Prototype and production tooling are different
Part tolerance varies from part to part
Variable wall thickness generally includes sink
Short lead-time on tooling

Contact RIM Manufacturing to Start Your Next Project

When You Consider All the RIM Advantages, We Know You’ll Have the Best Reaction. RIM Manufacturing is the Partner Uniquely Positioned to Accelerate Your Company’s Success!

RIM Manufacturing | Our Story & Experience

RIM Manufacturing work

RIM was founded in 1979, giving us over 40 years of experience in the reaction injection molding industry. We have grown over the last four decades to become one of the largest independently owned plants in the country specializing in custom Reaction Injection Molding.

We are ISO 9001:2015 and ISO 13485:2016 Certified for Reaction InejctionMolding and  Assembly. Additionally, RIM Manufacturing offers the widest range of chemistries to exactly meet your manufacturing needs. We are recognized as industry experts who have been optimizing our Reaction Injection Molding processes for decades in order to best serve our clients.

With over 40 years in the industry, we bring design expertise and experience to every project and with every client.

RIM Manufacturing | Our Team

Each member of RIM Manufacturing is dedicated to making our clients successful in every phase of their production process – from part and CAD design to mold design and manufacturing, part production, secondary processing, painting and silk screening, assembly, packaging, even shipping.

This makes us a top choice for reaction injection molding from start to finish, as we have the experience to help at every stage of your design, fabrication, and final product.

RIM Manufacturing | Our Growth

We are not only one of the most experienced leaders in the business, but our operating plant floor space exceeds 45,000 square feet and our three-acre site allows us to be flexible in our processes and nimble in our response to our client’s unique needs.

Our location near Dallas and Fort Worth, some of the world’s most significant air and land transportation hubs, helps us streamline our schedules and delivery, as well as cost – making our size and location some of the best benefits in our market.

When you consider all of the advantages you gain with RIM Manufacturing, it’s easy to see that we are your top partner every step of the way. Our unique position and experience are poised to accelerate your company’s success!

RIM Manufacturing | Our Designs & Advantages

With RIM Manufacturing, you can choose your parts’ precise characteristics:
  • Structural integrity and tolerances
  • Impact resistance, dimensional stability
  • Strength, wear- and corrosion-resistance
  • Thermal and electrical insulation
  • Sound absorption and natural adhesion
  • Solid, elastomeric, rigid- or flexible-foam
With RIM Manufacturing, you can create more than individual parts:
  • Combine several parts into one
  • Over-mold metal, wood, glass, and more
  • Encapsulate parts – cable, valves, circuits

RIM Manufacturing | Contact Us

Contact RIM Manufacturing today to learn more about our team, our personalized services, and our processes.

RIM Manufacturing, LLC

(817) 599-6521

Benefits of Reaction Injection Molding

orange polyurethane reaction injection molding part

RIM Molding is an excellent process for producing large, lightweight parts. The sweet spot for volumes ranges from a few hundred to several thousand parts per year.  And because of the wide variety of chemistries offered, parts produced can be structural foam, flexible foam, elastomeric, or solid RIM.  What’s more, the low temperatures and low pressures incorporated within the RIM process,  offer design opportunities that are superior to other processes such as injection molding, thermoforming, vacuum molding, and cast molding.

Additional Advantages of Reaction Injection Molding:

  • Variable wall thickness
  • Molded-in bosses, ribs, inserts, tabs, or undercuts
  • Flexible cosmetic surfaces or part design
  • Encapsulation (over-molding) capabilities
  • Dimensional stability
  • Chemical resistance
  • In-mold painting or post-paint
  • Low tooling cost

Technical Properties include:

  • Impact resistance
  • Dimensional stability and strength
  • Design tolerance
  • Wear- and corrosion-resistance
  • Thermal insulation
  • Electrical non-conduction
  • Sound absorption
  • Natural adhesion

Longer Cycle Times

To achieve creative and uniquely designed parts using RIM Molding, the production process requires longer cycle times.  The liquid chemicals used in RIM molding will more easily flow within complex tools to fully fill the cavity of the mold and, therefore, take longer to become a finished part.  A process like injection molding, which incorporates high temperatures and high pressures to quickly fill the mold cavity, has a much shorter cycle time. 

Contact RIM Manufacturing for Your Next Project and Experience the Difference!

RIM Manufacturing is known throughout the industry for its commitment to excellence and producing quality parts at a reasonable cost.  

Contact RIM Manufacturing to learn more about who we are and how the RIM process can deliver the parts you need.

What are the Benefits of Reaction Injection Molding?

new green reaction injection molding part
“Reaction Injection Molding “RIM” is a Thermoset process where low-viscosity liquid polymers and isocyanates are mixed at high-pressure (2000 psi) and injected into temperature-controlled molds at low-pressure (150 psi). An exothermic reaction occurs as the temperature of the liquids reaches 350 degrees Fahrenheit before cooling to become a solid polyurethane part.”

When Should You Use RIM Molding?

RIM Molding is good for low volume and large, lightweight parts. The RIM process may be a better solution in certain situations because of the chemistries offered, or because of the low temperatures and low pressures used in RIM versus other injection molding processes.

RIM Molding for Over-Molding

RIM Molding uses lower temperatures and lower pressures, which make it the most effective process for over-molding production parts.  Over-molding materials like sheet metal, steel, and other substrates allow the combining of multiple parts into a single part.  RIM Molding is also perfect for over-molding sensitive materials, like circuitry or valves, that would otherwise be destroyed by the high operating temperatures and pressures of injection molding.   

RIM Molding for Varying Thickness

The RIM Molding process provides greater design flexibility because it allows varying wall thickness within the same part and without sink or deformities.  Wall thickness throughout an injection molded part must be uniform, otherwise, the part will deform as it cools.

RIM Molding for Various Sizes

Injection molded parts are typically small in size. To produce one large part generally requires producing several smaller parts and then assembling to create the larger part. Tooling costs will be significantly higher than building one large RIM tool. And the single RIM molded part eliminates assembly costs associated with combining the smaller injection molded parts into one larger part.

Reaction Injection Molding for Colors

Large RIM molded parts can be molded in color, which is cosmetically appealing, and can be shipped to the customers immediately upon demolding with some minor trimming of flashing – or excess material. Whereas large injection molded parts often have significant, visible, and unappealing ‘flow lines’, which require painting for cosmetic acceptance.

RIM Molding Tooling Materials & Costs

Reaction injection molding uses aluminum tools instead of steel tools, which translates to lower tooling costs per mold.  Unlike injection molding tools, which are made of steel to sustain the high operating pressures and temperatures, RIM molding uses machined aluminum tools because of the low operating pressures and temperatures.  Therefore, the capital requirement for RIM tools is significantly less than injection molding, by as much as 2 to 3 times!

About RIM Manufacturing

We are industry experts offering a wide range of chemistries and process capabilities designed to meet the needs of our customer’s projects.

Every member of RIM Manufacturing is dedicated to making your project successful at every phase of our production process!

Contact RIM Manufacturing today!

Combining Multiple Parts into One: A Key Advantage of RIM

Metal part from injection molding (RIM)

Advantage of Reaction Injection Molding

Reaction Injection Molding or RIM is a process used to produce a wide variety of polyurethane parts, including: structural foam, solid RIM, elastomeric, flexible foam, and composite parts. These are used in multiple different industries, ranging from automotive to medical.

RIM involves using polymer liquids – polyol and isocyanate. These liquid polymers are dispensed through high-pressure pumps at low pressure into aluminum molds, which are temperature controlled. injected into heated molds. Inside the mold, the combined chemicals produce an exothermic reaction transforming the liquids into a molded part. This process allows you to easily create products that are customizable according to your desired tolerance, density, weight, thickness, and hardness.

Because the RIM process is perfect for larger, lightweight parts, designing several parts into one part can reduce the need for multiple molds and the labor required for assembling multiple parts. Additionally, over-molding sheet metal or steel can eliminate the need for hinges or attachment points creating additional cost savings.

Contact Us for Your Next RIM Manufactured Part

RIM (Reaction Injection Molding) vs. Plastic Injection Molding: What Are the Differences?

Trilogy Accelerator Machine from reaction injection molding

Product manufacturers may look to injection molding when they need to produce custom parts. However, there are several processes available for producing plastic parts. Depending on the size of the part, the geometric design, the functionality, the quantity required, and the capital expenditure budget, RIM (Reaction Injection Molding) may be a better option.

Though these two molding processes are similar, they are also very different – here are a few of the key differentiations.

The Processes 

The Reaction Injection Molding (RIM) process uses a sophisticated closed circuit dispensing machine to mix two-component non-viscous liquid polyurethane materials (a polyol and isocyanate) at high-pressure within the mix-heads mixing chamber. This combined material is then injected into machined aluminum tooling at low pressure and low temperature.

The Plastic Injection Molding (PIM) process uses an injection machine to melt plastic resin pellets into a viscous molten material which is then injected, at high pressure and high temperature, into steel tooling.

Design Benefits 

Reaction Injection Molding (RIM) is perfect for large, light weight parts with varied wall thickness and unique geometric design. Additionally, RIM’s molding functionality allows for the combining of several parts into one part and easily accommodates over-molding materials like sheet metal, steel, circuitry, valves, etc.

Injection Molding is perfect for small parts and high volumes. The more simplistic the design, the better the efficiency for production.

Cost Benefits 

There are several cost benefits to using the RIM process:

  1. RIM uses machined aluminum tools that can easily be modified for subsequent design changes. The cost of aluminum tooling is significantly less than steel tooling, used in injection molding, and there is little to no maintenance.
  2. Aluminum is easier to machine than steel allowing the RIM process to bring a product to market much faster than injection molding.
  3. The RIM process uses non-viscous liquids which allow for several smaller parts to be molded into one larger part thereby reducing the costs associated with inventory management and assembly.
  4. Unique design features, including over-molding increase the functionality and eliminate potential assembly labor.

However, because the RIM process is better suited for larger parts, the per part cost will be higher than injection molding.

Injection Molding requires steel tools in order to accommodate the process of high pressures, high temperatures and highly viscous material. While the capital expenditures and lead-times are significantly higher and longer than RIM Molding, the rugged steel tools allow for faster processing of parts resulting in a significantly lower part cost than RIM.

Experience the Advantages of RIM Processes

For more than four decades, RIM has been optimizing Reaction Injection Molding for various industries.

We produce high-quality plastic components to help our customers achieve their business goals and objectives.

Get in touch with us for more information about our RIM services.

4 Cost Benefits of Reaction Injection Molding for Manufacturing

Theranos medical device from reaction injection molding

Manufacturing firms are always looking to lower their overall production costs. Especially now that we’re in the middle of a global economic recession, companies strive to minimize their expenses and maximize their cash reserves.

One of the solutions that can help cut your production costs is reaction injection molding or RIM. Compared to the standard or thermoplastic injection molding, RIM is a more economical plastic manufacturing method. It offers plenty of cost benefits, helping manufacturing firms save on assembly expenditures. 

What is Reaction Injection Molding?

RIM uses thermoset polyurethane liquid chemicals instead of standard thermoplastic resin pellets. The process starts by mixing two base polymers, causing a chemical reaction that thickens and expands the polymers. The polymers are then injected into the mold, where they are heated until they harden.

The polymers used in RIM have a lower viscosity than the ones used in standard plastic injection molding. It’s easy to achieve your desired density, weight, thickness, and hardness with RIM. 

Here are some of the cost benefits you get with reaction injection molding.

1. Lower Machine Costs

RIM features low injection pressures and low processing temperatures, unlike the more intensive plastic injection molding process. The mold also requires less clamping force to form the thermoset plastic materials. There’s little need for external force or pressure in RIM since the polymers used rely on chemical reactions and low processing pressures.

For these reasons, RIM has more economical processing machines than other manufacturing processes of plastic parts. Plastic injection molding, for example, needs high-grade steel machinery to support high pressure and temperature. 

2. Lower Tooling Costs

RIM also offers lower tooling costs. The thermoset polymers expand on their own exerting less stress on the machined aluminum tools.  These are more affordable than the high-grade steel tooling required in thermoplastic injection molding. 

RIM tooling experiences little or no wear because of the non-viscous chemicals used to produce parts.  Therefore, tool maintenance, if any, is minimal thereby eliminating or significantly reducing mold maintenance costs over the life of a project.

Because it uses low-cost tooling, RIM significantly reduces capital costs associated with new projects and is ideal for large productions that require a large number of molds.

3. Shorter Lead Times

Lead time is an important consideration in manufacturing. The shorter your build cycle, the quicker you can get your product to the market.  Because aluminum machines faster than steel, RIM tools require shorter lead times than injection molding tools, which saves you money and time.

You can enjoy shorter tooling lead times with reaction injection molding. The typical build cycle of complex molds is four to six weeks.

4. Lower Finishing Costs

Finally, RIM allows in-mold painting. You can produce aesthetically pleasing finishes, such as high or low glosses or color variety. In-mold painting saves you time, manpower, and even production floor space during the finishing process. It can also reduce the costs that usually come with secondary finishing.

Cost-Efficient Reaction Injection Molding Processes

RIM Manufacturing specializes in custom reaction injection molding. ISO 9001:2015 and 13485:2016-certified, we’re one of the largest and most trusted independently owned manufacturing plants in the country. We help our clients optimize reaction injection molding processes unique for their business needs and goals.

Connect with us today to learn more about reaction injection molding.

Understanding the ‘Reaction’ Process in Reaction Injection Molding

Injection Molding machine for RIM process

Some people assume that the difference between traditional injection molding and reaction injection molding (RIM) is purely superficial. But the two processes are considerably different and provide distinctive results. Although both inject raw materials into a mold, RIM is more complex as it uses chemical reactions to create parts.

Educate yourself on RIM’s “reaction” process to understand how it differs from traditional injection molding. Apart from this, you will discover how chemical reactions create stronger, more durable, and more customizable parts.

The Reaction Process

RIM uses low-viscosity liquid polymers, specifically isocyanate and polyol, which are lightweight and cost-efficient. These liquids are stored in large tanks before high-pressure industrial pumps dispense them into the appropriate molds. The injected liquids slowly expand and thicken through a chemical reaction. Once this is complete, the materials harden into the finished parts.

RIM differs from traditional injection molding in its design process. It is highly customizable, making it easier to select which raw materials and molding techniques to use. It results in finished parts that have custom weight, strength, and density characteristics. The RIM process also allows for more intricate designs.

The Advantages of RIM

The chemical reaction utilized in this process has several advantages, including better structural integrity at a low cost. Learn more about it to understand why many businesses prefer the RIM process.

Build Larger Parts

The traditional injection molding process is more expensive, making it difficult to use in manufacturing larger parts. The RIM process for parts molding offers clients a cost-efficient alternative. Additionally, liquid polyurethane is better at filling molds for larger pieces without compromising on its finer details.

Experience Better Durability

The materials used in the RIM process offer better design flexibility, allowing you to design and build parts with varying thicknesses to suit the final product better. Parts created through RIM exhibit better dimensional stability and chemical resistance, letting them withstand internal stress during processing. Polymer-made products are also known for their corrosion resistance, making them ideal for moisture-prone applications and environments.

Enjoy Superior Flexibility

Polymer materials used in RIM are known for their flexibility, especially compared to aluminum and sheet molding compound. Quickly form parts with intricate details without compromising their durability with these materials.

Create In-mold Paintings

RIM provides aesthetic benefits, including in-mold painting. This is achieved by painting the cavity of the mold before it is filled with polymer materials. The paint adheres to the liquid through a chemical bonding process, coating the finished part as it dries. It results in a paint job that is resistant to cracking, flaking, and chipping.

Experience the Advantages of RIM Processes When You Work with RIM Manufacturing

For over four decades, we have worked with businesses across industries, providing them with high-quality parts for their products. We take a hands-on approach to each project, allowing us to create custom parts for any product.

Get in touch with us for more information about our services.

The Applications & Advantages of Reaction Injection Molding (RIM) over Thermoforming

Spacelabs - Akron Thermoforming product

Plastics play a huge role in manufacturing. They are present in virtually every industry. From automotive to medicine, plastic materials are utilized as end products and components for assembling a more complex product.

However, these plastic products are not readily available in the market, and they have to undergo a manufacturing process within a plant dedicated to designing and molding plastics.

RIM Manufacturing is an example, and helping to design and molding plastic end products or components is something we do exceptionally well. To give you a clear picture of what we do, we’ll compare the process we use, Reaction Injection Molding (RIM), with another popular plastic manufacturing method – thermoforming.

What Thermosetting & Thermoforming?

Let’s cover the basics.  Reaction Injection Molding is a Thermoset process whereby low-viscosity liquid polymers and isocyanates are mixed at high-pressure (2000 psi) and injected into temperature-controlled molds at low-pressure (150 psi).   An exothermic reaction occurs as the temperature of the liquids reach 350 degrees Fahrenheit before quickly cooling to become a solid polyurethane part. Thermoforming, on the other hand, draws a pliable plastic sheet stock down onto a heated mold.  A vacuum may be used to evacuate any air and accurately reproduce the details of the mold.

The key difference between the two is significant.  RIM (Thermosetting) allows for tight tolerances, unique design, and molded in ribbing and bosses.  Thermoforming, on the other hand, is good for simple design parts with limited functionality and cosmetic finish.

The Applications of Thermosets & Thermoplastics

The different qualities that thermosets and thermoplastics possess dictate where and how they may be applied.

For example, thermosets are ideal for products exposed to high temperatures because of their incredible heat resistance. For this reason, manufacturers use thermosets for the body and components of household and kitchen appliances. These machines tend to generate excess heat. If thermoplastics are used for these products, they could warp at best and melt and mess up the electricals at worst.

Thermoplastics, on the other hand, are ideal for single-use plasticware like cups, drinking bottles, food containers, and grocery bags. CDs, DVDs, children’s toys, sports equipment, and eyeglass lenses are also made from different thermoplastics.

Thermoset vs. Thermoplastic: Which Should You Choose?

Which is the better material to use for your products? The answer depends on the uses of your products. Our opinion at RIM Manufacturing, however, skews in favor of thermosets. We attest to the quality of thermoset plastic, and its heat-resistance and physical integrity are additional perks. More importantly, it’s easier for us to create intricate details like textures, irregular corners, and protrusions using reaction injection molding. Thermoforming is more acceptable for simpler designs.

Find out if thermoset plastics are compatible with your manufacturing requirements and product design. Talk to our product specialists at RIM Manufacturing. Contact us today.