If you are in the manufacturing industry, you have most likely heard the words “urethane” and “polyurethane” before. But the thing is, most people use these two terms interchangeably. If you experience confusion about urethane vs. polyurethane, this post will help clear up any misunderstanding.

Urethane vs. Polyurethane: Is There Any Difference?

Actually, there is no real difference between these two. The term “polyurethane” simply means that multiple urethane monomers make up this material.

Polyurethane is a simple polymer. It is a chemical compound that a scientific process known as polymerization forms. This combination of chemical compounds consists of repeating structural units. These structural units (or “groups”) are urethane.

The purpose of urethanes or polyurethanes is to produce parts that are used in countless industrial and commercial products and processes. To be more specific, the usage of polyurethanes occurs in the creation of extremely durable and long-lasting products. These products can adapt to a wide variety of situations. For example, acute cold or heat, chemical exposure, and impingement.

Polyurethanes can withstand pretty much any environment, making them the first choice for many manufacturers around the world. For nearly any industry in the world, the usage of polyurethane is quite common.

Many people have this misconception that urethane and polyurethane are different. However, there is no difference between the two products. Dedicated manufacturers and their marketing teams will educate their customers about the facts related to polyurethane. They will do this in order to help them make informed choices.

It’s true that the overall chemical structure of urethane and polyurethane can vary sometimes depending on how they are used (e.g. for varnish, elastomers, padding, or something else). But they are all called urethanes.

The term “polyurethane” only means that there are many urethane monomers linked together in a chain called a polymer (the end product). This is why it can be misleading to use this term. This is because it essentially means it is nothing more than a chemical group that has a bunch of urethane monomers within it.

The Final Verdict

The main difference – if you can call it that – between urethane and polyurethane is the number of urethane monomers linked together. Combining a number of urethanes monomers together in a polymerization reaction to produce one of the many products, such as cast urethane elastomers (as seen in our parts), forms polyurethane at a molecular level.

These multiple layers of urethane actually make polyurethane much more durable and flexible than urethane itself, which essentially has no use until its polymerization happens. If you’re looking to make solid, resilient, and long-lasting products, polyurethane can be an excellent material for you.

Its usage occurs in products such as solid elastomers for industrial use, padding for car seats, home furnishing and upholstery, and much more. Moreover, we can use polyurethane to make gaskets, seals, bushings, pads, rollers, bumpers, etc. And, it can also help create hard “plastics” which are more durable and resilient than synthetic rubber or regular plastic.

Still Have Questions? Feel Free to Ask Uniflex Inc.

At Uniflex Inc., we have been a leading supplier of custom molded urethane and polyurethane products in the country for over 40 years. If you want to reduce your manufacturing costs or upgrade your materials to a more durable option, we’ll be happy to talk! Call us at 248-486-6000 or complete this contact form. Our knowledgeable team will address your requirements in the best way possible.

Are you confused about the industry jargon when dealing with cast urethane products? Well, here is a comprehensive glossary of commonly used cast urethane terms that will help you make judicious decisions.


Wear and tear caused by friction

Abrasion Test

A test that calculates the rate of wearing away by friction (a machine called an Abrasion Tester performs this test)

Accelerated Life Test

A technique designed to estimate in a short time the failing/weakening effects produced under normal service conditions.

Accelerated Aging

To obtain an early change in the physical properties of urethane or polyurethane, intensive exposure to operating conditions is used.


A material (like a flame retardant or filler) is included to change the final product, but it doesn’t affect the chemical reaction.

After Cure

A prolongation of the stabilization process after the “cure” has been performed to the desired degree for a certain duration. 

Banbury Mixer

An internal mixer used to incorporate ingredients like fillers in plastic or polyurethane operations.


A change in the appearance or discoloration of the surface of a polyurethane product caused by the migration of a solid or liquid to the surface.

Breaking Strength

The tensile at which polyurethane is at when it ruptures.


The process of pouring open molds with uncured/liquid polyurethane.

Chute Lining

Elastomeric (polyurethane) lining in a chute that is highly resistant to abrasion and its usage is to protect the metal chute from abrasion wear and tear.


The process that marks the completion of a chemical reaction.  

Curing Agent

An additive used to increase chemical activity between different components, leading to a decrease or increase in the speed of cure.

Cycle Time

The duration of time needed to finish a molding cycle which includes:

  • Preparing the mold
  • Insert loading
  • Releasing an agent application
  • Combination of components
  • Curing
  • De-molding.

Durometer Gauge 

A tool used to measure the hardness of polyurethane. Moreover, a Durometer measures the resistance to the penetration of an indenter point into the rubber’s surface.


Measure of a materials hardness. Learn more.


A rubber-like elastic material such as synthetic rubber or polyurethane.


A material mixed with a polymer; its function is to reduce the cost or improve the quality of a compound.

Flame Retardant

An additive or a substance that can be an addition to a polymer formulation to lower its tendency to burn.

Injection Molding 

A method frequently used in the high-volume manufacturing of polyurethane products.


A mixture of two or more compounds to achieve better processing or more thorough dispersion. Moreover, this later becomes part of the final compound in a succeeding mixing process.

Oxygen Bomb

A chamber that can hold oxygen at elevated pressure. This can be heated to an equally elevated temperature to be used for accelerated aging tests.


Measurement of resistance to shear of an uncured/liquid elastomer like urethane.


This is a macromolecular substance formed by chemically combining monomers that have the same or different chemical composition.


A material produced via the process of chemical synthesis.

Tensile Strength

The maximum stress or force applied to a material at rupture


It refers to the flow property of a substance, the lower the viscosity number, the thinner the liquid.

Have Any Questions? We are Here to Help!

So, if you have come across a strange term you don’t see listed here, or you want to know more about custom molded polyurethane or cast urethane parts, please call our knowledgeable Uniflex Inc. representatives at 248-486-6000 or contact us online and we will get back to you shortly.

The performance and lifespan of your custom molded polyurethane parts depend on factors like quality. But it also includes others such as design, tolerance, and formulation. If any of these factors are lacking, your product performance will be shoddy as well.

To get the top-quality custom urethane products, it is important to choose a reputable polyurethane producer who takes pride in their work. But with so many manufacturers in the market, it can be difficult to pick the one who checks all the right boxes. That’s why we created this guide to help you find the best polyurethane manufacturer.

5 Things to Look for When Choosing A Polyurethane Manufacturer 

They Use Custom Formulations with Premium Materials 

Not all urethane is created equal. In other words, if you want your custom urethane parts to have the longest lifespan possible, work with a polyurethane manufacturer who can create custom formulations that meet your unique needs.

Do they use premium grade raw materials? Remember, it may be tempting to use lower-grade materials to drive the costs down. But, it will cost you a lot more in the end. Urethane made from cheap materials will have a shorter life, and less resistance to abrasion and corrosion.

They Offer Complimentary Product Design Assistance

You may have a design that looks good to you, but it may not be feasible to produce.  Alternatively, there might be a more cost-effective way to design your desired polyurethane parts.

Go with a polyurethane manufacturer who is willing to give you the strategic expertise and guidance to ensure your custom parts will be very durable and made in the most cost-effective way possible. They should be open to examining your product drawings and understanding how your product will work.

They Have Strict Standard Tolerances

When creating custom molded polyurethane products, precision is the key. Tight tolerances may not be important with some products, but some require little to no tolerance flexibility. 

What does small standard tolerance mean? It simply means that the actual polyurethane part’s dimensions must be held very close to drawing’s dimensions. This is something that takes decades of experience to perfect, especially when accurately estimating urethane shrink upon cooling. 

Some custom urethane products, on the other hand, will require tighter tolerances than the more standard parts like bumpers and pads. Choose a polyurethane manufacturer who has the machining capability required to meet these tight tolerances if needed.

They Have Dedicated Customer Service Representatives 

It may seem irrelevant, but you should never overlook how a manufacturer treats you and interacts with you. If their customer service reps are unable to answer your questions or concerns or they seem unresponsive, uninterested, or unfriendly, it’s a red flag. Choose a polyurethane manufacturer that responds to your inquiries within 24 hours. And, the one who is committed to addressing your concerns with accurate answers to your questions. 

They Offer In-House Mold Making

There are several benefits of working with a manufacturer that provides in-house mold making. This eliminates the need to use a third-party company, reducing the cost and the turnaround time for custom molded urethane products. 

#1 Polyurethane Manufacturer & Supplier in Midwest

Uniflex Inc. has been a leading manufacturer of custom molded polyurethane products since 1979. If you’re looking for a reliable supplier who can meet all your needs and help you take your business to new heights, let’s talk. You can call us at 248-486-6000 or simply use this online form and our representatives will respond to your requirements right away.

Cast urethane provides end-use, flexible, and rigid parts with production-level quality. The process of casting urethane utilizes a machined master pattern to create a soft mold. The mold delivers cost-effective short to medium-run volumes and high-quality parts (hard molds used as well). This is an excellent alternative to a high-volume injection molding process. In this post, we are going to discuss exactly what cast urethane is and how its usage in manufacturing happens.

Cast Urethane: The What and How

Urethane casting is like injection molding in that the former requires a tool with a cavity in the silhouette of the final product. The biggest difference is that the urethane casting process involves pouring liquid urethane resin into an open mold. Whereas injection molding forces material into a closed mold through a port. Open cast urethane also involves using thermoset plastics. They have very favorable properties when compared with the thermoplastic materials used in the injection molding process.

If you’re looking for a cost-effective option for producing a prototype or low to medium volume runs of urethane parts with production-level surface finishes and properties, cast urethane will be a wise choice.

Casting urethane involves 3 major steps:

Creating the Mold

First things first, it is decided whether a mold or a hobb (master pattern) will be made for the desired part. A mold is generally used for parts that need to hold strict tolerances on all dimensions. For example, urethane seals, gaskets, and other critical parts. Hobbs, on the other hand, are used for parts that are not as critical such as urethane bumpers, pads, covers, bushings, etc. Hobbs, or master patterns, are the most commonly used method for manufacturing most urethane parts due to their economical pricing. If you want to learn more about Hobbs, click here.


Next, the pouring of a compounded urethane material into the mold occurs. Then the placement of the mold into an oven or on a hot table happens in order to speed along the curing process. This is where the liquid material begins to harden in the shape of the mold cavity.


Demolding and Curing

Finally, once the mold has been filled with material, it will harden to an extent. This allows a production worker to remove the freshly poured urethane part from the mold so that they can pour another part. Although the part has hardened enough so its removal from the mold is possible, it still needs to cure in the oven for at least another hour or two depending on the formulation. This ensures that the reaction is complete, and the part is ready for end use.


Benefits of Using Cast Urethane

Urethane casting has a quick turnaround and a low-cost for superior quality plastic parts. This is especially if compared to that of injection molding. While a cast urethane mold is economical and easy to produce off the master pattern, injection molding requires expensive investment up-front for the machining of the mold.

This is why cast urethane has become the go-to solution for manufacturers. And, for business owners looking to do low to medium volume production or on-demand prototyping. Whether you need to make rubber-like, colored, clear, flexible, or rigid plastic parts, the urethane casting process can handle it all.

Speak To Us For High Quality Cast Urethane and Polyurethane Parts Made in the USA

As one of the leading manufacturers of cast urethane products and parts in the country, Uniflex Inc. offers a wide range of possible combinations of materials, finishes, and markings for your required specifications. Our experienced team can help you make the most appropriate and cost-effective buying decisions. To know more, please call us at 248-486-6000 or contact us online to get started.

When it comes to selecting the right material for your industrial roller applications, you probably have a lot of questions. This is especially about the polyurethane vs. rubber rollers debate. If your current equipment originally came with rubber rollers, would it be acceptable for you to use polyurethane rollers instead of the rubber ones? Let’s take a closer look at both so that you can make a well-informed choice.

Polyurethane vs. Rubber Rollers: Is There Any Difference?

Before we talk about the differences, let’s consider the commonalities between the polyurethane vs. rubber rollers.

  • Both are elastomers, i.e., both have elastic properties.
  • Moreover, both are excellent in terms of adhering to metal cores.
  • Both are resistant to acid, whether it is concentrated or diluted.
  • Also, both offer poor resistance to lacquer solvents.
  • And, both are machinable when you need a pattern on the outer diameter of a roller to perform a particular task.

So clearly, there are a lot of similarities between polyurethane vs. rubber rollers. However, there are quite a few differences as well:

Chemical Composition

Polyurethane can be formulated in hundreds of different ways to give you the required properties your application needs. It is possible to add fillers to the sap-derived rubber to change its properties but there’s a limit to how much you can customize it.

Wet Environments

If you need a material that will be exposed or submerged into wet environments for extended periods, polyurethane will outperform rubber every time. Polyurethane doesn’t rot. Rubber, on the other hand, will rot.

Durometer (Hardness)

While processing of rubber in 30-Shore A to 90-Shore A is possible, polyurethane has a much wider range from 10-Shore “OO” to 70-Shore “D”.

Unwanted Pigmentation

Rubber manufacturers add carbon to rubber, which can leave black marks on products it comes in contact with. Polyurethane, on the other hand, does not leave any marks or color on any product even when pigment is added to the polyurethane.

Abrasion Resistance

When a combination of high friction and dynamic loads happens, rollers can experience a great deal of abrasion. Polyurethane again surpasses rubber since polyurethane is extremely resistant to abrasion, corrosion, and high pressures.

Final Decision

The above analysis doesn’t cover all the differences between polyurethane vs. rubber rollers. But, they are significant enough to affect your decision. Just remember, these differences can add up in manpower and downtime if you’re not using the best material for your specific application.

Reduce Your Cost & Lead Time with Polyurethane Rollers

Due to the considerable chemical capabilities of polyurethane and the range of hardness/durometers, this material can keep your machinery up and running to a degree that rubber simply cannot. Polyurethane may not be suitable for every roller application, but if you’re looking for the highest quality urethane that will meet your precise specifications, it’s worth considering.

Contact Uniflex Inc. to Learn More About Polyurethane

If you want to know more about polyurethane vs. rubber rollers and whether the former will be the right choice for you, we will be happy to answer all your questions and concerns. We have been making custom molded polyurethane rollers for over 40 years and can advise you on the best option. You can reach us at 248-486-6000 or complete this online contact form to discuss your requirements with us.

Over the last few years, the safety standards in the food and beverage industry have improved dramatically. In fact, the manufacturers are now more focused on safety and sanitation in their production processes to prevent contamination.

Being one of the decisive components in almost all food processing systems and equipment, the seals and gaskets have also undergone multiple modifications over time. Moreover, instead of standard plastic, today’s seals and gaskets are made from safe and proven FDA compliant polyurethane.

In fact, this significant move was based on the realization that a considerable part of the sanitary issues and food contamination is caused from gasket or sealing units made from poor quality materials. So, with the growing consciousness about health and hygiene across all product segments, it makes sound business sense to choose FDA compliant polyurethane.

What is FDA Compliant Polyurethane?

There is a myriad of choices when it comes to gasket material including Viton, silicone, EPDM, PTFE, and polyurethane. Want to have a go with any results best live blackjack casinos. However, polyurethane is the only material out of these that’s used to make FDA compliant seals and gaskets. In fact, there are many reasons why polyurethane tends to be the most suitable material for making food-grade equipment:

  • It meets all the NSF regulations and FDA requirements for food processing applications and is non-allergenic, non-marking, and non-toxic
  • Polyurethane has high abrasion and impact resistance
  • It is resistant to breaking, tearing, and cracking
  • Moreover, it is tear-resistant and has high tensile properties
  • It is an extremely versatile elastomer, known for its high load-bearing capacity
  • FDA compliant polyurethane is resistant to extreme environmental factors involving acids, oils, solvents, and heat
  • It lasts longer compared to other gasket and sealing materials
  • It has incredibly high mechanical strength even at super low temperatures
  • Polyurethane performs really well at temperatures ranging from -30 F to 220 F
  • It is resistant to aromatic hydrocarbons, and vegetable and mineral oils, making it ideal for food-grade applications
  • Also, it doesn’t allow mildew, mold, and fungi to grow when in constant contact with edible items
  • It can be formulated with different color pigments to create many types of sanitary seals and gaskets

When it comes to sanitation requirements, the food processing industry is probably the most demanding industry. Therefore, using FDA compliant polyurethane maximizes health and safety and can give you a competitive edge.

Where You Can Get the Best FDA Compliant Polyurethane Components

Uniflex Inc. is the leading manufacturer of FDA approved urethane parts including FDA approved:

  • Urethane sprockets
  • Pads
  • Sheets
  • Washers
  • Gaskets
  • And more

So, we understand that improving detectability in FDA approved polyurethane parts is critical to prevent contamination – minor and major – which will ultimately save you a lot of time and money in the process.

Moreover, we can help you if you need US-made FDA compliant polyurethane for:

  • Inspection tables
  • Conveyor belts
  • Chutes
  • Chute liners
  • Wheels
  • Rollers
  • Bumpers
  • Seals
  • Gaskets
  • Custom molded parts

Our rapid prototyping capabilities allow us to go from “print” to “part” within 8-12 business days.

Call Uniflex Inc. Today For Quality FDA Compliant Polyurethane Components

For over 40 years, Uniflex Inc has focused on precision and speed to manufacture the premium-quality cast and molded polyurethane parts. If you have any questions or concerns, please call us at 248-486-6000 or contact us online and our representatives will get back to you promptly.

There are few industries that depend more on machinery and equipment than mining. If you work in the mining industry, you know that your equipment is going to be pushed to the limits, as far as Mother Nature and the law will allow. So, it goes without saying that the mining tools and equipment used must be resilient and durable above all else.

In the dusty, dirty, hazardous, and harsh environments of mining, the equipment designers and manufacturers are increasingly paying more attention to the “little things”; like machine components that help the big machines perform better and for longer.

This is where cast urethane mining parts come in. (And the key is to find a dependable manufacturer to work with.)

Urethane Mining Industry: Why the Modern Mining Industry Prefers Urethane

Urethane or to be more specific, cast polyurethane parts have always been known for their incredible properties, such as:

  • Abrasion resistance
  • Unmatched resilience
  • High load-bearing capacity
  • Impact strength.

Now, as mining designers and manufacturers are looking for ways to increase the longevity and performance of mining equipment, urethane has naturally become a preferred choice.

One of the biggest advantages of using urethane mining parts is that it’s super flexible; not just in physical performance (like rubber), but also because it comes in a liquid form. Liquid urethane allows the combination of different formulations, in addition to metering, and dispensing it with unparalleled precision.

This unique process allows the making of urethane mining parts into any form, density, or weight. This is while still ensuring the component stays completely uniform and consistent throughout the entire run. In addition, when compared to plastics and other elastomers, urethane offers far more versatility, durability, toughness, and strength in reduced costs.

Imagine the flexibility and resiliency of rubber combined with the performance benefits of metals and engineered plastics – that’s urethane. Tweaking of this material due to its sheer adjustable nature of the chemical properties is easy in order to provide several new opportunities to address performance problems that other materials simply can’t solve.

And if that’s not enough, urethane mining parts are much less likely to fail due to deterioration, abrasion, and other forms of damage. Unlike other materials. Cast polyurethane parts will deliver a much superior long-term value to end customers.

Another great benefit of urethane mining parts is their molding and bonding ability to multiple different kinds of substrates such as fiberglass, aluminum, and steel. This allows for added rigidity and strength if necessary.

Talk to Uniflex Inc., The Industry Experts, About Urethane Mining

Cast urethane mining parts created at Uniflex Inc. can be custom molded for both low and high-volume production. They are also available in a wide range of hardness’s (durometers). We can cast parts that are as small as a few ounces or as large as hundreds of pounds. If you have any questions or concerns about the urethane mining industry and parts, please call us at 248-486-6000 or contact us online and our representatives will get back to you shortly.

Polyurethane is one of the most versatile materials that manufacturers today use. Molding it into almost any shape for utilization across many different industries is possible. You can use custom molded urethane or polyurethane repeatedly in some of the most adverse environments without worrying about it wearing out or being significantly damaged.

Polyurethane is also resistant to high temperatures, electricity, abrasion, corrosion, and many other environmental factors. The versatility of polyurethane has made it a material of choice for a variety of applications across industries.

If you are looking for custom molded polyurethane, it is best to first get a clear idea about the products produced by it and its overall usability. In this short guide, we will break down everything you need to know about this highly useful compound.

What Is Custom Molded Urethane?

When polyurethane undergoes a molding process to take a desired shape and specification, it is referred to as molded urethane or custom molded urethane. Since it can take various forms, the molding process usually varies depending on the end-use of the products produced. Here are a few common techniques that the industry throughout uses:

Compression Molding

In this process, the placement of the liquid polyurethane or millable gum polyurethane into a multiple-plate mold occurs. Once inside the mold, the plates sandwich the urethane compound between them. And, a heated hydraulic press forces the plates together. The extreme pressure and heat of the press force the polyurethane to fill the shape of the enclosed cavity formed by the plates, curing it in the process. This molding process allows for a much more refined end product compared to other techniques; however, it tends to be more expensive as well. Compression molding’s often usage happens in the making of polyurethane seals, bushings, gaskets, and other critical products.

Open Cast Molding

This process involves pouring liquid polyurethane into a mold. It is a relatively inexpensive process that leads to highly durable products. Opencast molding tends to be the most common technique when it comes to making cast urethane elastomer products.

Centrifugal Molding

Also known as spin casting, this process occurs when the liquid polyurethane material is placed inside the center pot of a spinning mold. Channels allow the material to flow to mold cavities using centrifugal force, eliminating air in the process through vents. This process is not suitable for molding large-sized components and parts, and it can be expensive. However, it does produce bubble-free parts if there is a requirement.


custom molded urethane

In this injection method, the liquid (or the hardened droplets) of polyurethane material will shoot into a mold at a very high pressure using an injection molding press. By injecting the liquid into the mold, shaping the polyurethane into almost any design is possible. This process can be cost-efficient because injecting liquid thermoplastic urethane resin is quick and automatization is attainable. Plus, any material waste that occurs in the process can go through the recycling process and its repeated usage is possible. However, injection molds tend to be very expensive and their usage only happens when production volume is incredibly high (e.g., 20,000+ pieces)


During the foaming process, the mixed polyurethane material will set and fill out a mold. While the process can take a long time to complete, the end result is a material that is full of air and fiber. And, its usage is common when it comes to mattresses, pillows, seat cushions, adhesive foam strips, etc.

Want to Know More About Custom Molded Urethane? Call Uniflex Inc!

At Uniflex Inc., we have helped many industries meet their custom molded urethane needs over the course of our 40 years in business. We can cast any kind of urethane product for any purpose, regardless of which industry you work in.

Our unmatched precision, attention to detail, and superior quality have helped us become a leading manufacturer and supplier of molded polyurethane in the US. If you have questions or concerns you can call us at 248-486-6000 or fill out this online contact form.

Molded urethane is a plastic material whose creation stems from the chemical reaction between prepolymer resins and specialized curing agents. Products and parts made from molded urethane offer incredible chemical resistance, flexibility, and durability. If you’re wondering what custom molded urethane is, you’ve come to the right place! In this short guide, we will provide you useful insights about this versatile material that a wide spectrum of industries uses, in addition to using it for numerous applications.

What Is Custom Molded Urethane?

The usage of custom molded urethane products is common when it comes to using them for several industrial purposes. For example, for seals, bushings, rollers, and bumpers. The usage of this tailorable polymer occurs when making small, molded parts like washers all the way up to large multi-hundred-pound components.

Urethane starts as a viscous, liquid prepolymer that we must heat and mix in with a curing agent so the chemical reaction can occur. Urethane is relatively stable and tends to be resistant to most chemicals as well as impingement.  Many manufacturers also use additives to improve UV resistance, increase flame retardation, and reduce friction.

When liquid urethane is injected or poured into a mold, the “molded” urethane products take shape. A reaction between prepolymer and curing agent causes the urethane to polymerize and harden. Most times, to ensure lasting quality, these molded products are cured in industrial ovens as well as hot on hot tables. To know more about what custom molded urethane is, you should talk to a dedicated manufacturer with expertise in thermoset plastics, such as Uniflex Inc.

Are Custom Molded Urethane Products Customizable?

If you’re looking for a versatile solution for your manufacturing needs, custom-molded urethane can be a great option. It’s unmatchable in terms of:

  • Chemical resistance
  • Scraping abrasion resistance
  • High impact resiliency
  • Vibration dampening
  • And much more

But the best part is, we can mold urethane into a plethora of products due to its liquid starting state. This allows the polyurethane material to fill the cavity of pretty much any mold. In other words, urethane has the ability to take shapes that other materials can’t.

We can customize custom molded urethane parts for specific applications by simply adjusting formulations to change the physical properties and hardness (durometer).

what is custom molded urethane

Compared to other similar compounds like rubber, urethane has the most versatility. While rubber and other compounds are sometimes vital for certain applications, molded urethane serves as the cheaper and more durable option when it comes to most parts.

In addition to customization, there are numerous other benefits of choosing custom molded urethane to manufacture your parts. For starters, it offers lower-cost tooling. This generally makes urethane costs much lower than rubber molding which requires higher-cost compression molds.

The molding process of urethane is capable of forming parts without any need for costly injection molds. It is extremely precise and can work with a wide range of part sizes. Moreover, urethane molded parts need little to no additional finishing so there is an incredibly fast turnaround time as well.

Talk To Our Dedicated Experts At Uniflex Inc.

At Uniflex Inc., we create custom molded urethane parts for your specific needs.

We can cast a variety of tailored, molded urethane products for multiple purposes with meticulous precision and superior quality. If you have more questions related to what custom molded urethane is, or how it can help you save time and money on your project, call us today at 248-486-6000 or contact us online.

Molding Polyurethane: The Cast Urethane Process

Custom cast polyurethane products have become widely adopted throughout the manufacturing, food and beverage, mining, automotive, printing, and robotics industries.  Their relative ease of production, low tooling costs, and longevity have made cast urethane parts a staple of industry and automation. But what is the process behind manufacturing custom molded urethane parts?

The Concept

It all starts with the concept. Generally, a customer will submit a CAD file. Or, some form of drawing file along with a brief description of the uses for the part, the environment where the usage of the part will take place, and quantity of the part they need. This is how the presentation of most inquiries happens, but it is not the only way. Sometimes customers do not have a design and need in-field engineering assistance to come up with a solution.  In this case, an experienced engineer/estimator will drive or fly out to the company that is requesting the urethane product. And, works on the ground floor with the company in order to come up with a solution. Often, the quotation of the job can happen on-site. But, sometimes further engineering is a must in order to come up with an accurate estimate.


Quoting is the second step in the process of molding polyurethane. Once the cast polyurethane parts manufacturer has the drawing of the part he will produce, estimating then thoroughly examines it and determines how much the part will cost. This step often requires involvement. And, it takes into account many things such as the best material to use for the part. Also, the cost of the material, the time it will take to make the tool, the time involved in setup processes, the time the job will spend in production. And, the time the part will spend in trimming and inspection.

Every little detail is important. Also, the estimator is often collaborating with all of these departments in order to come up with accurate time estimates so that the proper quotation of the job is possible. It is very important that all of these departments are working with incredible efficiency. This is in order to keep manufacturing costs low by saving time. This is because it ultimately provides the customer with a quality part at an economical price.


Once the quotation of the job and the reception of the order happened, the first step in the production portion of the journey is tooling. Tooling is the process that results in the making of polyurethane molds and hobbs. Here, a machinist receives the drawing of the part in the form of an IGS file. The machinist is then able to take that design and come up with a CNC tool path. The tool path will make a mold for the part that when filled with urethane will form the part with extreme precision (usually within 0.005”). This can often be a very intricate process as urethane parts become more complex.

When complex polyurethane molds are made, they often have to be built in many pieces that come together in sync to form the cavity that will form the finished product.  An alternative option to a cavity-cut mold, as mentioned previously, is a hobb. A hobb is an aluminum replica of the part that has been modified for the purposes of making a urethane mold. A hobb is designed to mimic the part so that when urethane is cast around it. And then its removal from the urethane ensues after a cure cycle. The result is a cavity that will produce the part when filled with urethane.


After the production of the mold or hobb finishes, it then enters the production room. The production room is where molding polyurethane parts in mass takes place. Here, urethane is formulated using different prepolymers, curatives, and ratios to create formulations that are specific to the particular job. These specially formulated mixtures are generally processed in automated dispensers, centrifugal mixers, or hand-batched depending on the job size and requirements.  After the material is processed it is then poured or dispensed into the polyurethane molds and cured in an oven, on a hot table, or in a heated hydraulic press (for compression molded parts). Most parts cure within a few hours because they are run with a more standard polyurethane formulation, but other formulations, such as higher-end Vulkollan substitutes, can take all day.

Trimming and Secondary Machining

In fact, trimming comes after production when the newly cast polyurethane parts have fully cured. Trimming is just removing all of the “flash” from urethane parts that have just come out of production. This is essentially just a clean-up operation where shaving off excess, leftover urethane from the molding process happens, creating the finished product.

Polyurethane parts may also need secondary machining operations, depending on the final use. For this, the urethane parts are moved back into the machine shop. There, they are turned, milled, 3D’d, or grinded (depending on the type of project and tolerances). 


Once the urethane part has made it through every operation, it still has one more step in the journey before its shipment happens: inspection. Inspection consists of checking the durometer of the finished polyurethane parts. Then, checking critical dimensions, checking color to make sure the ratio was correct for every mix, checking for porosity. And, checking for overall cleanliness. Here at Uniflex, we will not ship anything unless it went through a thorough inspection. If a part does not pass any step in the inspection process, we throw it out. And, we manufacture a new one.


The final step in the process of molding polyurethane is shipping. Once the engineering of the polyurethane parts finishes, molds have been made, production has taken place, trimming is complete, and inspection is passed, the parts can finally be shipped out the door to the customer.


As you can see, the process of molding polyurethane requires involvement. There are a lot of steps along the journey from concept to finished part. So, a very professional and well-trained crew is essential for keeping things working efficiently. Without a dedicated staff and years of experience, it is very difficult to produce quality urethane products with speed, efficiency, and ultimately an economical price.

If you have any questions about polyurethane products, molding polyurethane, or the manufacturing process, do not hesitate to give us a call at (248) 486-6000 or send us a message. We have an experienced staff that is always willing to lend support!