Extruded rubber

Types of Extruded Rubber

Extruded rubber products are custom-made on-demand with the help of a high-quality rubber extrusion machine. In this process, the materials are then force-fed or pushed through a mold or die in the shape of specialized products. Several rubber materials and compounds can be used for this manufacturing process.

Some common examples of extruded rubber goods are seals, gaskets, strips, tubes, custom profiles, foam profiles, sponge profiles, wiping seals, lip seals, co-extrusions, double shots, flocked seals, and sealing assemblies. In the diagram below, one can see some of the more common types of rubber extrusions. Advanced technology has made it possible for more complex geometrical profiles to be produced.

Generally, rubber extrusion is a low-cost method of making products as long as the volume is decent enough. One can find volumes of up to hundreds of kilometers of seal strips produced in Europe for the extrusion method.

Some items created from this method include:

• Rubber co-extrusions: are profiles created when two or more materials are simultaneously extruded and bonded together. For example, a hard PVC groove with an EPDM lip used for the sealing of a car window. This technique is widely used in the automotive market for advanced design criteria in cars.
• Double-shot extrusions: are also called "over-mold" or "two-shot" molding, which refers to the use of two different materials in a single molding process. Usually, soft and hard materials are combined to make example sealing applications with different kinds of materials meeting distinct functional and aesthetic requirements.
• Flocked seal: A flocked seal is a type of seal that is used to prevent the unwanted passage of air or water between two objects. The flock consists of a base material coated with short piles of fiber that resembles a soft texture. It is usually used for car, bus, and truck sealing applications between the chassis and the window area.
• Sealing assemblys: These assemblies are used to prevent dust and unwanted material from entering an area that needs to be clean. The assembly is manipulated to create a defect-free surface as required by the application. Usually, this type of assembly is employed in the electrical switchgear and rail markets, including trains and high-speed trains.
• Wiper seals: are seals that are usually semi-exposed dynamic seals that wipe dirt and water away from an articulating element, such as a post, shaft, or rod. In simple terms, they are seals that keep water and foreign material away from critical articulation areas, such as in hydraulic cylinders. Wiper seals are usually made of rubber or plastic. They perform two main functions: to wipe off any dirt or water from the element to keep it clean and to prevent any dirt or water from getting into the sealing area.
• Lip seals: are also exactly what they sound like. They have an open groove and a lip that is shaped like a human lip. These are dynamic seals that are used to keep rotating shafts in oil and grease. SKF, a leading bearing manufacturer, offers lip seals that can be used in light and heavy-duty conditions, such as heavy-duty lip seals designed for diesel engines. The operating temperature range of a lip seal varies from approximately -40°C to -70°C.

Specification and maintenance of extruded rubbers

Specifications

• Temperature:

  Extruded rubber seals are usually manufactured to operate within a specific temperature range. This might be anything from -40°C to +120°C, for instance. Outside of this temperature range, the rubber might either harden or become too soft.

• Durometer:

  This is a measurement of the hardness of rubber. An extruded rubber with a low durometer is soft and flexible, while one with a high durometer is hard and resilient. The application will usually dictate the durometer of rubber to use.

• Length:

  Many manufacturers can produce long lengths of rubber extrusions, but the most common length is usually around 3m to 6m. When longer lengths are required, joints or continuous lengths can be used to make them.

• Cross-sectional:

  This refers to the shape of the rubber, which could be circular, rectangular, or even custom shapes. The size will, of course, depend on the specific requirements of a project.

• Material:

  Several types of rubber exist, each with its own unique properties. For example, Neoprene is popular for its excellent UV resistance. Nitrile might be used where an oil-resistant rubber is needed, and EPDM is often chosen for applications requiring high resistance to heat and oxygen.

Maintenance

• Cleaning:

  A clean, damp cloth should be used regularly to remove any extruded rubber buildup of dirt or grime. This will help prevent scratches and other damage to the rubber. When cleaning, users should ensure that they don't use harsh chemicals or abrasives that could damage the rubber.

• Lubrication:

  Though extruded rubber doesn't usually need lubrication, some applications may benefit from it. A thin layer of lubricant can be applied to the rubber if there is a lot of friction or dragging against it.

• Inspection:

  The extruded rubber should be frequently inspected to see if there are any signs of cracks or tears. The earlier these issues are detected, the easier and faster they are to address. Proper alignment should be ensured, and the fittings should be checked to see that they are tight.

• Replacement:

  Once damaged beyond repair, extruded rubber can be replaced. The new rubber should be installed carefully to see that it's not overstretched or pinched during installation. Proper sealing methods should also be used, and the new rubber should be lubricated before use.

Scenarios

Though the main purpose of extrusion rubber is to fill, seal, and insulate, it can be used in many situations. Some examples of industries that use extruded rubber products are as follows:

• Automotive

  The vehicle industry uses rubber extrusion seals for windows and doors. They help to keep out water and noise, create a comfortable interior, and make sure the vehicle has got good fuel economy. Other examples are bumper rubbers, shaft seals, and vibration dampers.

• Construction

  In the building trade, rubber extrusions are used as window seals, neoprene expansion joints, weather-stripping, and door seals. They stop air and water leaks, allow movement in structures, and reduce noise and vibration transmission.

• Transportation

  The transport industry uses rubber extrusions for bus and train windows and doors to stop water and air leaks. They also allow for smooth and safe movements. Moreover, bulkheads and dock fenders also make good use of rubber extrusions.

• Aerospace

  In aerospace applications, highly specialized rubber extrusion seals are functional in aircraft to prevent the entry of wind, moisture, and noise. Also, they provide insulation against extreme temperatures and protect against foreign object damage (FOD).

• Marine

  Marine rubber extrusions are commonly used in boats and ships to serve as fender seals, hatch seals, and docking seals. They absorb impact, prevent water ingress, and allow for smooth and cushioned contact between surfaces.

• Industrial machinery

  Rubber extrusions are employed in CNC machining and 3D printing equipment as vibration dampers and equipment seals. They reduce noise generated by vibrations and prevent contaminants from entering sensitive mechanical parts.

How to Choose Extruded Rubber

The following tips will help buyers when choosing rubber extrusions.

• Determine the Application

  Before anything else, buyers need to determine what they will use the rubber extrusion for. The application will influence other things like shape, profile, size, and sealing requirement. The need to satisfy the application can’t be overemphasized, so buyers should take their time to study the application before moving to the next step.

• Consider Material Properties

  The next step is to consider the properties of the materials used to make the rubber extrusion. Mainly, these materials have different levels of tensile strength, temperature resistance, compression set, and other relevant features. Buyers should match the material's properties with the demands of their application. Also, they should consider how long they want the rubber extrusion to last and its maintenance needs.

• Find a Reliable Supplier

  Finally, buyers need to find a trustworthy supplier with a proven track record. The supplier should have extensive experience in dealing with rubber extrusion products like rubber extrusion seals and should stock a wide range of options to choose from. The supplier should be able to customize the product to the buyer’s exact requirement.

Extruded rubber Q & A

Q1. How is rubber extrusion different from other manufacturing processes?

A1. Rubber extrusion differs from rubber compression and injection molding. In those methods, raw material is forced into a heated chamber to form parts. Another way that is different from extrusion is die-cutting, which cuts material into parts versus forming material into shapes.

Q2. What is the size range for extruded rubber?

A2. Most suppliers can produce thin sections down to 2.5 mm, solid sections up to 75 mm, and hollow sections up to 100 mm in diameter.

Q3. What is the lead time for extruded rubber?

A3. The average lead time for rubber extrusion orders is four to five weeks for standard orders. Please inquire about the timing for custom designs.

Q4. Can buyers get samples of extruded rubber?

A4. Buyers can request samples of standard sections from catalogs. However, there is a minimum order quantity of 100 meters for custom sections with specific profiles.

Q5. Are there custom shapes that a buyer can request?

A5. Yes, buyers can request custom shapes and sections. The buyer will need to provide drawings or sketches. The rubber material will be discussed to see if it is compatible with the shape of the extrusion, and then a quote will be given.