During the continuous process of silicone rubber extrusion, a screw transports the material into the die, involving the introduction of a catalysed compound (often continuous strips) in the feeding system.
To achieve the necessary viscosity level, pressure and temperature rise close to the die.
One of the most popular manufacturing processes for various applications is silicone rubber extrusion. With the silicone rubber extrusion process explained, you can create complex profiles and cross-sectional parts, as well as longer pieces like hoses and cords.
Frequently, complementary elastomeric or reinforcement components are used to combine multiple layers of material. Large-scale, high-performance parts for industries, such as oven seals, electrical cables, wire insulation, and seals, are made from extruded parts.
The rubber extrusion process is also beneficial in medical settings for items like drains and catheters, and in homes for food-grade plumbing. This intricate process is typically handled by experienced companies, such as Formgummigruppen, who specialise in silicone rubber extrusion.
For more detailed information, you can read further about their expertise and rubber manufacturing services here.
Preparation: The material and tools required for silicone rubber extrusion
Having the proper instruments is essential for the success of the silicone rubber extrusion process. The silicone rubber extrusion process explained includes the following tools or instruments:
Raw material
Firstly, you need to obtain silicone rubber. Since it’s the main raw material used in the procedure, handle it with caution. This product is available in several grades and forms, such as pellets, compounds, and more. Your choice will depend on your specific goals.
For instance, if you want to perform silicone extrusion for medical purposes, ensure the product meets your requirements. Read more about rubber and extrusion here: gummilist.com
Additives
Additives are often not necessary but can be added to ensure the compound meets your unique functionality and requirements.
These can include strengthening fillers and curing agents, which aid in giving the basic material more support.
Extruder
One of the main instruments in this process is the silicone extruder. The extruder operates with a hopper, a barrel, and a screw- or piston-based processing system.
The heat generated during operation pushes the raw material through a die to form the desired shape.
Die or instrumentation
This is the second crucial part of the process. It shapes the raw material as it exits the extruder into the desired form. Dies are often custom-made to produce various profiles.
Cooling system
A cooling system rapidly cools down the material after it has been exposed to high heat during extrusion. It ensures the product maintains its shape.
Curing equipment
Further curing might be required post-extrusion. This can include ovens and curing tunnels, which apply the proper amounts of heat to fortify the original extrusions.
Cutting and processing tools
These tools are used to shape the finished product according to your requirements. They include hole punches and cutting tools.
Quality control equipment
Careful quality control is essential. Measuring equipment is used to monitor characteristics like colour and hardness to ensure the product meets your specifications.
Safety equipment
Ensure all personnel involved in the process are equipped with protective eyewear, gloves, and other safety gear to maintain a safe working environment.
The silicone rubber extrusion process
- Raw material preparation: Prepare the proper raw materials before beginning any extrusion operation. Silicone rubber is usually provided as solid pellets or sometimes as a gum-like substance. It may also include additives like colourants and fillers.
- Silicone rubber compounding: This step involves mixing the raw silicone with various additives to improve its properties for the intended use.
- Extrusion process setup: Arrange your workplace and set up the die and silicone extruder.
- Heating and extrusion: Transfer the silicone material into the extruder’s hopper and heat it to a proper temperature, typically between 150°C and 250°C (302°F and 482°F). The heated silicone is then forced through the die by the extruder.
- Cooling and curing: Expose the extruded silicone to cool air to ensure it maintains its shape. Apply a cooling or curing process as needed based on your specific composition and desired outcome.
- Cutting and final processing: Cut the end product into proper lengths and carry out any additional processing steps to meet your requirements.
- Quality control: Ensure the product satisfies biocompatibility and other safety requirements, especially if producing food-grade silicone.
- Distribution and packaging: Once complete, distribute the product to the appropriate end users and distributors.
Learn more about industrial manufacturing on www.industriteknik.net.
Die design and co-extrusion shape function
Die design – shape wizardry
The die is a finely machined mould through which molten silicon is formed. The complexity of the die design affects the profile’s complexity.
Simple designs are needed for tubes and flat strips, while more complex shapes require multi-component die setups.
Types of die – a taste of variety
- Single-hole dies: Provide a solid profile.
- Multi-hole dies: Generate numerous identical profiles simultaneously.
- Multi-flow path dies: Used for medical tubing and catheters to create profiles with internal channels or hollow parts.
- Co-extrusion dies: Shape various silicone materials simultaneously for multi-layered products.
Adding function layer by layer using co-extrusion
Co-extrusion creates multi-layered silicone products by extruding two or more silicone compounds through a die, enhancing the product’s functions and properties.
Applications for co-extrusion
This technique is used in various industries, such as medical tubing, electrical cables, food-grade housing, and automotive gaskets.
The silicone rubber extrusion process in short
The silicone rubber extrusion process explained is a straightforward operation. By maintaining the appropriate parameters, the process is widely utilised by numerous industries.
As silicone applications continue to progress, we anticipate further advancements in this process.
