Silicone Extrusion: A Novice’s Guide To Understanding The Manufacturing Process

Silicone is one of the most versatile materials in the world. With functionality across multiple fields, this material provides a great deal of functionality across the board. And, advancements in technology have also led to growth in manufacturing processes with silicone at the center. 

In this article, we’ll look into the silicone extrusion process, where rubber silicone variants can be manufactured.  

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Understanding Silicone Extrusion

Manufacturers are already very familiar with silicone – the synthetic polymer with a rubber-like material that is composed of Silicon (Si), Hydrogen (H), Carbon (C) , Oxygen (O), and other components that give it a distinct set of mechanical and chemical properties. 

Today, silicone is one of the most versatile materials for manufacturing. The material offers impressive temperature resistance, easily holding its own across a broad temperature range that can easily span between  -60°C (-76°F) and 230°C (446°F). Its varying melting point also means that it can easily operate across different industries. Add that to its flexibility, biocompatibility, and ability to resist both corrosion and chemicals, and you see why it is so popular.

As part of the overall manufacturing processes for silicone, it is important to understand the silicone extrusion procedure. Here, manufacturers use an intricate process to create different products and components with the original silicone rubber product.

With extrusion, you essentially use a silicone extruder to manipulate the rubber material, forcing molten silicone through a bespoke die or mold in order to create particular shapes, profiles, or lengths of products. 

All in all, you use this process to push or pull the solid silicone rubber through a die of a specific cross-section to form continuous silicone extrusion profiles. Thanks to the inherent flexibility of the rubber material, you will be able to make different intricate shapes – much of which you probably wouldn’t be able to achieve with other materials. 

In most cases, it is important for you to get a silicone compound that resists vibration, thermal shock, and temperature when embarking on the silicone rubber extrusion process. This way, you can guarantee that the material will be able to be manipulated properly without any blemishes – and, it will go a long way in ensuring the efficiency of your process overall. 

When done right, you will find that extruded silicone will be able to serve different purposes across multiple fields – some of which we will examine in a later section. 

How The Silicone Extrusion Process Works

Like pretty much everything that has to do with silicone, it is important for you to follow the  right guidelines when handling silicone extrusion. Manufacturers easily handle the process in their own way, but we at WeProFab believe in following this structure: 

An Overview Of SIlicone Extrusion

So, how does this process work in general?

Raw Material Preparation:

Every extrusion process starts with the preparation of the right raw materials. In this case, you get the silicone rubber in the form of solid pellets. Or, in some cases, a compound in the form of gum. 

Remember that silicone can always contain additives such as colorants, fillers, and more. So, keep an eye on your wants and requirements before going ahead.

Material Mixing and Compounding:

This isn’t necessarily compulsory. However, there are instances when the silicone material will need to undergo compounding and mixing in order for it to achieve the right properties. 

Essentially, this step in silicone extrusions will involve combining the raw silicone with different additives. These can be curing agents, reinforcing fillers (such as silica) and more. The objective is to enhance and optimize the material’s overall properties so it is able to perform better for its intended purpose. 

Just as well, mixing provides an avenue for consistent additive distribution through the raw silicone. 

Extrusion Process Setup:

Now that you have your materials ready, you immediately set up your entire workspace. In most cases, you make use of the silicone extruder and the die. We will look into these later. 

Heating and Extrusion:

With your workspace intact, you can begin with the silicone tube extrusion process. Take the silicone material and feed it into the extruder’s hopper. Here, the material is heated to an appropriate temperature- which, in most cases, lies somewhere between 150°C and 250°C (302°F and 482°F). 

With appropriate heating, the silicone is melted. Then, the extruder’s piston rotates, applying appropriate pressure to the molten silicone and forcing it through the die directly.  

Cooling and Curing:

Upon getting out of the die, you want to apply cool air to the silicone. This process ensures that the material is able to take the right shape and conform to the right silicone extrusion profiles

For custom silicone extrusion, this is very important. You can take the silicone material through a curing or cooling process, depending on your specific formulation and what you’re looking to achieve. 

  • Cooling Bath: When the extruded silicone is taken through a cooling bath, you essentially pass it through water. This action causes the material to cool quickly, solidifying it and helping it to take shape. For silicone tube extrusion, this process is ideal.
  • Curing Oven: In the event that you’re handling more complex applications, you can put the extruded silicone through a curing oven. This oven allows you to control the heat parameters, as well as how long the process will take. With appropriate heat, the curing process is immediately activated, and the silicone polymer chains are properly cross-linked to achieve the right properties.

Cutting and Final Processing:

Once you’re done with the curing or cooling process, you can go ahead to cut the final product into the appropriate lengths. This allows you to apply any final processing steps to ensure that the silicone meets your requirements. 

Quality Control:

As it is with every other manufacturing process, you want to ensure optimal quality control here. If you’re making food grade silicone, then see to it that the product you have meets biocompatibility and other safety standards. 

Set up the right quality control parameters and monitor all characteristics of the final product to ensure that it meets your needs. 

Packaging and Distribution:

At this point, you’re pretty much good to go. Take the finished product and send it out to the right distributors and end users. 

All in all, the process of making custom silicone extrusions is quite straightforward. As long as you’re able to keep up with the right parameters, you shouldn’t have much of an issue across the board. 

Materials & Machinery Needed For The Process

For the silicone extrusion process to be successful, it is important for you to have the right tools. As you optimize your setup, be sure to have all of the following equipment available: 

Raw Material: 

To begin with, you want to get your silicone rubber. This is the primary raw material used in the process, and you want to be careful with it. 

Keep in mind that this product comes in different forms and grades – from pellets to compounds and more. Your choice here will depend significantly on what you’re trying to achieve. Are you looking to conduct medical silicone extrusion? Then ensure that the product meets your specifications.

Additives: 

In general, you might not need additives. They are usually added to the compound to ensure that it meets your specific functionalities and requirements, and they’re generally a “nice-to-have.”

From curing agents to reinforcing fillers and more, these additives help to provide additional backing for the raw material to meet your requirements. So, once again, your choice of additives will depend primarily on what you’re trying to achieve. 

Extruder: 

The silicone extruder is one of the primary tools used in this process. The component consists of a barrel, a hopper, and a processing system made of either screws or pistons.

With the silicone extruder, you work by applying heat to the silicone material. This heat brings pressure, which forces the raw material through a die or tool to create the shape you have in mind. 

Die or Tooling: 

This brings us to the die or tool – essentially, the second critical component of the entire extrusion silicone process. This component is especially built to mold the raw material into the shape you desire as it comes out of the silicone extruder

In most cases, you have dies being custom-made to produce different profiles. So, if you’re looking to make silicone tubing medical applications, you need to ensure that the die is in the shape of that. 

Cooling System:

As part of the silicone extrusion process, you might need to also implement a cooling mechanism. As expected, this tool helps to quickly cool the material down after it has been subjected to considerable heat in the silicone extrusions. 

Cooling systems can be flexible – as long as they are compatible with the product itself.

Curing Equipment: 

If you will need additional curing after the silicone sponge extrusion, then you’d need to get the right tools for that. These could be curing tunnels, ovens, or any other product. 

The job of your curing equipment is to provide the right levels of heat that reinforce the initial silicone extrusions. Just as well, they provide cross-linking functionalities, strengthening the bonds within the polymer chains.

Cutting and Processing Tools: 

Once the main silicone extrusion process – as well as any additional post-processing procedure – is done, you’d need to shape the final product based on your specifications. Hole punches, cutting tools, and more will help you to achieve this task. 

Quality Control Equipment: 

We already pointed out the need for proper quality control when it comes to silicone extrusion. And, you need to always keep it in mind. Get your measurement tools and keep an eye on factors such as color, hardness and other properties of the final product. This way, you can guarantee that it’ll meet your needs. 

Safety Gear: 

While custom silicone foam extrusion is a straightforward process, it also requires a great deal of work and close proximity to machinery. So, you shouldn’t forget the place of safety. 

See to it that everyone working on the process has safety goggles, gloves, and other gear that can help them stay safe across the board. 

At the end of the day, your choice of materials will vary based on the process complexity, the type of raw material, and what you’re looking to achieve. However, always remember to sort the critical components and ensure the safety of everyone working on the process. 

Types of Silicone Extrusion Processes

Silicone extrusion is a versatile process that helps in the creation of different materials across the board. However, as a manufacturer, it is also important for you to understand which of the processes you’re engaging in. 

Generally, silicone nose extrusion can be broken down into some of the following

Tubing Extrusion:

Perhaps the most common of the available processes is tubing extrusion. Here, you create silicone hoses or tubes, which can be used across different functions. 

With tubing extrusion, silicone tubing suppliers have the freedom to create tubes that offer different properties – thicknesses, diameters, and much more. These tubes go on to work in different fields, from food to medical and industrial applications. 

Profile Extrusion:

In profile extrusion, the focus is on creating silicone products that offer different cross-sectional shapes. These products are quite intricate, and making them with other processes might not necessarily be convenient. 

Solid Cord Extrusion:

If you’re looking to create a cylindrical silicone rod or cord, then this process is perfect for you. It is quite similar to the process that silicone tubing manufacturers use, although it is better suited for creating seals, o-rings, and more. 

Sponge Cord Extrusion:

This process is also quite similar to the solid cord extrusion. However, it varies as the end products here tend to come with cellular structures – not necessarily cylindrical silicone extrusion profiles.  

Strip Extrusion:

With strip extrusion, you focus on creating silicone tapes or strips. These strips need to have uniform thickness ratings so as to fit their functionalities. 

Wire and Cable Coating:

The name pretty much says it all, doesn’t it? Here, you apply a thin layer of silicone layer on cables and wires, protecting them from harsh environments and overloaded electrical current.

Multi-Lumen Tubing Extrusion:

This extrusion type produces tubes with different channels. It is a form of silicone medical tubing manufacturing that shares similarities to the silicone tubing extrusion process. 

Dual-Durometer Extrusion:

For this extrusion type, you combine two different silicone materials – each with its own hardness rating – to create a single product. The product will have different levels of rigidity or flexibility along its profile, all based on your specifications.

Custom Extrusion:

Finally, we have custom silicone extrusion. This process is very versatile, allowing you to create products that meet your specific requirements. Considering how complex these silicone products can be, laying out the parameters of your custom silicone extrusions will be more than important if you hope to achieve success.

Applications of Silicone Extrusion 

Over the years, advancements in silicone production have led to the material being used across different industries. Just as well, the silicone extrusion process has also grown considerably in terms of where it can be used. 

Here’s a brief breakdown of several areas where silicone rubber extrusion has become especially useful. 

Seals and Gaskets:

Silicone extrusion is used predominantly to manufacture gaskets and seals – which go on to be functional across several industries, ranging from construction to automotive and more. These components help to offer a considerable amount of sealing from chemicals, the infusion of moisture, and any possible changes in temperature. 

Tubing and Hoses:

Of course, there is no way to make a tube or hose with silicone without going through the extrusion process. Whether it’s sterile silicone tubing in the medical space or hoses for transporting fuel in vars, this process is quite flexible. 

Weatherstripping and Window Seals:

You also see this process being used a lot in weatherstripping and the manufacturing of window seals. Once again, insulation is the name of the game here, and silicone has become especially adept at that. 

Electrical Insulation:

Silicone sleeves and coatings that have gone through the extrusion process are great for insulation in cables and wires. Their job, of course, is to protect against any adverse environmental factors and electrical shocks. 

O-Rings and Sealing Rings:

Both of these components work in hydraulic systems and general machinery. They offer resistance to chemicals and temperature, protecting the internal components of these machines as they work. 

Food Industry Applications:

In the case of food-grade application, extrusion helps in making seals, conveyor belts, and other equipment that can easily help in making different foods and beverages. 

Construction:

You can also find this process being used in making tools for architectural sealing, expansion covers, glazing seals, and weatherproofing. 

Appliances & Consumer Goods:

Whether it’s in making tools such as fridges and ovens or consumer goods such as kitchen utensils and baby products, silicone extrusion plays a considerable role.

Industrial Equipment:

Extruded silicone also comes in nifty across different industrial functions. It helps in making industrial equipment and machinery, as well as sealing in the il and gas sector where its chemical resistance comes into play. 

We should also mention the process and its use in the renewables space, where it helps in making solar panels and wind turbines.

Why Choose Silicone Extrusion While Manufacturing?

Of course, the fact that silicone extrusion has become popular these days doesn’t necessarily mean that it was the first – or is the only – way of manufacturing silicone rubber. However, it has pretty much become one of the most popular ways of doing this. 

So, what makes silicone extrusion so popular? 

Temperature Resistance: 

Extruded silicone exhibits an impressive level of temperature resistance. It retains its properties and flexibility across different temperature ranges, from pegs as low as -60°C (-76°F) to those as high as 230°C (446°F). 

Thanks to this characteristic, the material is especially perfect for application regardless of the ambient high temperature. 

Flexibility and Elasticity: 

You also get optimal elasticity from extruded silicone. It is able to seamlessly conform to unconventional shapes, while also maintaining its strength. Even after consistent expansion and compression, extruded silicone easily maintains its properties.

The flexibility in extruded silicone should also extend to its color and transparency. You can make the product transparent or translucent, and you also get different color options to work with. 

Chemical Resistance: 

With its impressive resistance to chemicals, every silicone product made of extrusion works perfectly in applications where exposure to harsh chemicals might be a distinct possibility.

Biocompatibility:

You can easily use extrusion to create silicone rubber products that are biocompatible. From medical silicone tubing to food grade silicone, all of these are compatible for contact with the human body. 

Electrical Insulation: Silicone rubber is an excellent electrical insulator, which is important in applications where electrical conductivity must be minimized. It is commonly used for insulating wires, cables, and electronic components.

Safety Parameters: 

When done right, you’d find that extruded silicone can also adhere to some of the most stringent safety requirements. It resists moisture and ultraviolet light, making it perfect for outdoor and aquatic functions. 

Just as well, the material is non-toxic and doesn’t give off any smells. So, there is a low chance of allergic reactions across the board.

Easy to Clean: 

Maintenance is easy for extruded silicone. Its surface is easy to clean, making it perfect for applications ranging from healthcare to food making. 

Operational Longevity: 

Rest assured that your silicone extrusion product will easily be able to stand the test of time. It withstands wear and tear, and its resistance to different factors makes it perfect for extended use. 

Broad Application Range: 

Thanks to its varying property set, extruded silicone easily works in different fields. As long as you know what you’re looking to create, you shouldn’t have an issue with the material. 

Process Challenges & How To Solve Them

While the process itself can be quite straightforward, silicone extrusion also does come with several possible operational challenges. And, working through those will help to optimize your chances of success as you move forward. 

Here are some things you would want to keep an eye on, as well as a few strategies that could help you overcome the bottlenecks:

Material Handling and Mixing:

For all its benefits, a silicone compound can be a bit of a hassle to handle. Your ability to achieve a uniform mixture – especially considering the incorporation of additives and other components – will be crucial for the quality of the final product. 

To that end, we recommend implementing the right material handling techniques. Just as well, use lubricants and release agents to optimize material flow and ensure that you achieve the right levels of mixing. 

Die Swell:

This is a challenge that mostly describes the outward expansion of the extruded material as it comes out of the die. In the event that die swell happens, you might end up with a final product that has larger dimensions than you anticipated.

To prevent this, work with your engineers to design a die with the right tolerance levels. Also,accommodate possible die swells in the die design and adjust your parameters to control it if it happens. 

Curing Variability:

If you choose to incorporate curing into your overall process, then you might find it challenging to get a consistent curing level throughout the product. In turn, you could find variations in the dimensions and physical properties of your final silicone product. 

The solution to this will be to implement accurate time and temperature controls when you’re curing the extruded silicone product. This way, you can achieve precise cross-linking and consistency. 

Die Wear and Maintenance:

Over time, you’ll find that your die will fall victim to wear and tear. The simple solution to this will be to properly maintain it and inspect its components. If anything needs fixing or replacing, then don’t hesitate to do that. 

Contamination and Cleanliness:

External components such as dust and debris can cause contamination of your die and affect the quality of your resulting product. 

As a precaution, ensure that you have the right hygiene and cleanliness protocols in place to ensure that external component interference can be minimized as much as possible. 

Complex Profile Challenges:

One of the major reasons why silicone extrusion is popular is that it helps in creating components with intricate profiles. However, depending on the complexity of these silicone extrusion profiles, you might need to get special tools. 

By collaborating with top-notch, experienced tool designers, you will be able to develop bespoke dies and tools that help ensure that your final product truly meets your needs. 

Price Considerations:

Everyone has cost implications to deal with. And when you’re working with silicone materials, you can find that they will cost more than most other polymers. Just as well, silicone extrusion processes tend to get more expensive as you require more tools. 

To reduce your cost basis as much as possible, censure that your material selection process is as careful and as precise as possible. You can also focus on optimizing your processing parameters and production process to ensure cost-efficiency.

Environmental and Regulatory Compliance:

Before starting with silicone extrusion, ensure that you have a clear view of industry-specific environmental requirements. Your process should be as eco-friendly as possible, and you also need to know about regulatory requirements for the products you’re making. 

For instance, what does the FDA require for food-grade silicone?

Keeping yourself informed about all of this will be critical. Ensure that your materials are regulatory-compliant, and implement the right quality management systems. If the need arises, speak to an expert and let them help you out. 

Silicone Extrusion 3d Printing

  • It can only be extruded by a pump-nozzle system.

Conclusion 

Silicone extrusion has become one process that many companies and industries use. And thanks to advancements in silicone applications, we expect to see this process expand even more in the future. 

To learn more or get started with buying silicone extrusion, feel free to reach out to us at WeProFab. We have the right skills and competencies to help manufacture your silicone rubber product, so give us a call, and let’s help you out. 

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