Nov. 28, 2024
How can the same substance be a coating, comfortable foam and an incredibly strong and dense part such as a wheel or stop? The secret is in the way polyurethane is manufactured. So, let&#;s look at this fascinating process.
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The incredible and unrivalled versatility of polyurethane revolves around the way its fundamental components work together. Change the mix and you change the end result in some dramatic ways. However, creating polyurethane always involves a chemical chain reaction and always produces a lightweight but stable material.
The answer to &#;How is Polyurethane manufactured?&#; is complex. This article aims to provide the basics on how polyurethane can take so many different forms and how it can be so resistant to friction, abrasion, pressure and environmental factors such as oil, heat and moisture. But it won&#;t stop there. As a leading UK supplier of polyurethane, we&#;ll try to delve a bit deeper.
The two core components of polyurethane include a polyol. This is an organic compound and it contains multiple reactive hydroxyl groups (OH radicals) in each of its molecules. The second central component is a diisocyanate (or polymeric isocyanate). This is a chemical building block, that is highly reactive.
By mixing these two reactive compounds together in differing quantities &#; and by varying the catalysts and additives &#; you can produce a diverse end result. One that is lightweight, yet highly durable.
That&#;s because one of the common traits of all forms of polyurethane is how incredibly well bonded the components become. Their structural integrity is unparalleled. Which is why polyurethane can bounce back to shape when used in cushions or can repel corrosion or abrasion when moulded into parts.
This amazing chain reaction also explains why polyurethane can be strong and durable, yet much lighter than alternative materials.
Varying the mix of the polyurethane components will always create a harmless and inert substance. You can then process the material to create a huge variety of coverings, components, parts and structures.
For example, you could put it into moulds to create customised polyurethane wheels, rollers, stops, linings, discs, hooks, rings, bars and rods. The incredible structural integrity means it is possible to engrave, cut, emboss and otherwise alter this substance to shape even the most complicated bespoke part.
Any shape, any dimensions and with any choice of custom detailing for polyurethane components.
Not all polyurethane gets pressed, shaped and cut into solid parts though of course.
By amending the diisocyanates and polyols used, the substrate could become rigid or flexible foam or a coating. You can produce polyurethanes with adhesive properties, or manufacture ideal sealants that dry to a 100% reliable finish.
Related article: Polyurethane product manufacturing 101
Thermoplastic refers to the polyurethane that is heated to shape it before it cools to become a durable form. This classification of polyurethane is one of the most common and finds its way into homes, cars and electrical devices.
It has been developed for its elasticity and resistance factors. In other words, it is incredibly flexible but also incredibly strong! Making it the perfect way to create a substrate as pliable as rubber, but as tough as metal.
Thermoplastic polyurethane can be shaped on extrusion, injection or compression moulding machines, and can be used in film, sheet and profile applications. TPU can be manufactured to be transparent or produced in a colour, and it offers a smooth to the touch finish.
You would find thermoplastic polyurethane moulded into sheaths to protect wires and cables, or as sheets and insulators used in construction. It is also used in manufacturing footwear, medical devices, instrument panels and mobile phones. Showing just how versatile it is!
The wide-ranging advantages of this metal, rubber and plastic alternative are well known, but knowing how to cast polyurethane gives insights into the variety of polyurethane services available.
If you have ever wondered how to cast polyurethane, the starting point is probably to decide if there is a difference between moulding and casting in manufacturing terms.
When some substances are involved, the two processes are distinct. For example, you could pour liquid metal into a design template that is then a one-off &#;cast&#;.
However, when dealing with polyurethane, you would usually transfer it in its liquid state to a mould (that can be reused multiple times). The item that is then extracted from the mould is a cast, but one you can reproduce as many times as you wish.
To cast polyurethane parts you would generally rely on various types of moulding, which we outline further below. To complicate things a little more, you can use a one-off cast as the basis for producing a new mould, which can then help you to replicate a 3D part in a fast and cost-effective way!
Keep reading: The benefits of product prototyping
The formulation of the polyurethane mix dictates its final tensile properties and performance features; from soft foam to a substrate hard as stone.
Beyond the scientific formulas used to create this essential polymer, let&#;s move on to exploring some of the moulding processes involved in casting parts from polyurethane.
This option to cast polyurethane involves both a heated mould and a heated polyurethane blend. Compression is used to ensure all of the mixture spreads evenly into all parts of the mould, and the whole process cures the polyurethane swiftly.
This makes compression moulding a great option for casting multiple polyurethane parts quickly and cheaply, especially if you choose the right manufacturer.
This is another common way to cast polyurethane, as it too provides a quick turnaround on part production. It is also an excellent polyurethane casting method for more complex designs. As the name suggests, liquid PU is injected precisely into the mould, and the pressure involved delivers the correct amount across the entire shape outline.
Related article: Polyurethane for the Boat Industry
For highly complex parts made from polyurethane, extrusion moulding can be the best option. It involves transferring liquid polyurethane into a shaped mould &#; usually a cross-section of the desired target item &#; to fill a specific space or series of spaces if numerous elements are needed.
If you want to know how to cast polyurethane to produce a hollow part, then this is your answer!
Blow moulds have a single point of entry for liquid PU, and pressure is used to blow it to the sides of the preformed shape.
This is a general term applied to injecting heated liquid polyurethane into a soft mould, so it can cure into a specific shape that is pinpoint accurate, including when any curves are required.
The way polyurethane is moulded is not the only consideration, when you need a structure, part or component engineered to match a very specific brief. There are other specialist processes involved to create an accurate, perfectly functioning and sometimes aesthetically attractive result.
For more Custom Polurethane Productsinformation, please contact us. We will provide professional answers.
Mention has already been made of the fact that what you put into polyurethane mixes &#; including different catalysts and dyes &#; dictates its function and appearance. If you need parts in a specific colour tint, that too is part of the initial formulation process.
Also, how the PU is cured can affect its properties. Various levels of heat &#; and an exothermic reaction &#; produce different results.
Clearly, moulding polyurethane to produce 100% accurate outcomes is a highly specialist task, particularly as both moisture levels and shrinkage need to be carefully calculated for often intricate designs.
Making it essential to find a leading supplier of polyurethane services.
Also read:Industrial Wheels: The Benefits of Polyurethane
From a basic chemical reaction to a vital part that performs flawlessly, the methods used to produce high-performance polyurethane items are surprisingly simple. The skill is in the detail, and getting both the blend and mould right, to create the ideal outcome.
The team at Custom Moulded Polyurethane have the technological and traditional abilities needed to offer exacting prototypes and to achieve 100% consistency across high volume orders. Including when a complex bespoke part is needed and there is a lot riding on its accuracy and performance.
The following step by step guide to custom polyurethane part manufacturing shows how we stay so successful.
The most crucial stage is the initial discussion between our technicians and the client. Finding a product form that matches often exacting specifications can include everything from varying the tensile and resistant properties to custom shapes, colours and details. Does this part need specific tear or impact resistance perimeters, or to be especially good at dampening noises and vibrations? We also consider whether the part must exhibit strong electrical insulating properties or cope with extreme temperatures and proximity to pollutants.
The brief will also dictate the level of completion of the product. In some cases, the spec calls for an unfinished part that will undergo separate production techniques.
This collaborative approach means the brief for custom polyurethane parts can be in many guises. From data supplied in computer code to a rough sketch. We are often presented with an existing part and asked if we can replicate it in high-performance polyurethane. Or, if we can scale up or scale down an item or produce it in a different colour or with tiny improvements.
Read more: 5 incredible polyurethane facts
To meet client requirements flawlessly, our technicians decide the proper blend of basic urethane components that will produce the ideal outcome. By varying the high-quality resins, curatives, pigments and other additives, we can form polyurethane into everything from an adhesive that becomes rock hard, to soft foam, to polyurethane parts with the strength of metal. Our shore hardness range for custom polyurethane parts is 10°A to 85°D.
Working together, our knowledgeable chemists and designers then add the blend to a suitable mould and heat the formula to bind the molecules.
Both low or high volume orders of polyurethane products rely on accurate moulds that produce often challenging forms. For items with standard dimensions, we can use an existing mould for a particularly speedy response of course. However, we can create bespoke moulds quickly too.
In many cases, liquid polyurethane is poured into a relevant open mould. Then, it is put in a heated compression machine to make sure the substance is pressed evenly into the mould features. Sometimes the polyurethane mix is injected into a closed mould (with small air holes) which is often required for cylindrical or larger shapes for instance.
Read more: What can Polyurethane rods be used for?
Using a combination of advanced design software and our experience and skills, we can work with clients to innovate. Often problem-solving and producing a part or component that underpins a new piece of machinery, manufacturing process or productivity improvement.
Moulds for prototypes can sometimes require complex contouring or cut-outs, protrusions, or indentations. There is pretty much nothing we haven&#;t mastered when it comes to precision engineering polyurethane.
Clients often put their polyurethane prototype into action, to test the merits of their own specifications. Once it has proven to be impeccable, they can then commission anything from a short run of these items to a significant production run.
Using advanced equipment such as modern dispensing, trimming and finishing machines, we can switch easily from focusing on prototyping to full-scale production. Including high volume orders for polyurethane parts.
It is important to note that the accuracy, sustainability, and speed of waterjet cutting often makes this technique an integral part of our unrivalled service.
As we hold moulds for clients indefinitely, there is always a possibility of re-ordering in the future. Though polyurethane&#;s unrivalled durability and strength make it unlikely one of our parts will wear out any time soon!
Read more: What is engineered polyurethane?
Whether you need rapid prototyping, model making or bulk manufacture of polyurethane parts, the team at Custom Moulded Polyurethane can help.
We are always happy to talk to clients about the cost savings to be gained by specifying polyurethane, the incredible problem-solving values it offers and the precision tooling and finishing services we provide.
Polyurethane is a polymer compound with many versatile uses. It is employed in the marine, fuel, and manufacturing industries, among countless others. One of the main factors in polyurethane&#;s versatility is that it exists as a liquid before molding and casting. This allows the material to be formed into a wide variety of shapes, from hourglasses for pipe rollers to caps for offshore oil rig wellheads.
Since polyurethane is such a versatile material, it can be molded and cast in a number of different ways to suit individual or industry needs. Some of the most common methods are discussed below.
This method uses a heated mold as well as heated compression material. The material is then put under pressure so that it contacts all parts of the mold. The material is kept under heat and pressure until curing is completed.
Compression molding of polyurethane is ideal for high volume, simple orders as it is fast and inexpensive compared to many other molding methods.
Injection molding offers the benefit of high volume production by using strong, metal molds. It can be utilized for a variety of parts, both large and small. The process is completed under very high pressure where the polyurethane is injected into a mold then allowed to cure. With injection molding, the mold can contain multiple cavities for very intricate shapes.
In this process, polyurethane is shaped into a preform with a hole in a single end. This preform is placed into a mold and air is then blown through it, forcing it to match the dimensions of the mold. Of course, this makes blow molding ideal for forming hollow parts. Once the process is complete, the mold is opened and the part removed.
This method uses a polyurethane blank, or unformed shape, to create a cross section of the desired part. The blank is forced through a shaped die, allowing for an extremely complex final shape. Furthermore, this technique allows for a very long final product, or multiple shorter pieces &#; whatever is needed for the project.
Overall, casting polyurethane is similar to injection molding. A mold, usually made of silicone or a similar soft substance, is injected with hot polyurethane which is then allowed to cure. Since the mold is not as resilient as the metal molds typically used for injection molding, polyurethane casting is not typically used for large volume production. However, very complex and intricate products can be produced with this method. Urethane casting is ideal for prototypes, small custom projects, and single pieces.
With its light weight, overall low production cost, versatility and resistance to corrosion, polyurethane is well suited to a variety of industrial and consumer applications. Since it can be subjected to a variety of molding and casting techniques, it can be employed in almost every conceivable industry. The various molding and casting methods available also allow urethane to be custom designed to provide solutions for even the most specialized jobs.
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