• Abhi Shejul

Rubber Manufacturing Process

We are all aware of the revolution happening around vehicles. EVs are taking over the IC engines, but one thing has not changed. That is the tyres of the vehicle. They are still made from rubber.


Table of contents

Introduction

What is rubber?

Is rubber a natural material?

What is Vulcanization?

Types of rubber product manufacturing processes

Injection Molding

Compression Molding

Transfer Molding

Rubber Extrusion

Rubber to Metal Bonding

Summary

Short Video


For centuries, rubber has been the most versatile material. It is used most extensively in tyres and as insulators, but has many other applications.


What is rubber?

Rubber is an elastic, non-abrasive material. The primary property of rubber is that it can stretch and shrink. Other properties include rubber is resistant of heat and electricity making it an ideal insulating material.

 

Is rubber a natural material?

Yes and no. Rubber can be sourced from both, natural and synthetic processes. Interestingly, both of these are in high demand by manufactures and hold a very important place.


Natural - Natural rubber is an elastomer, meaning it is an elastic substance and can recover back to its original shape when stretched. Natural rubber is typically sourced from Hevea brasiliensis or the Pará rubber tree.

Synthetic - Synthetic rubber can be produced artificially via the polymerisation of monomers into polymers. This can be done in two ways, either by solution polymerisation or emulsion polymerisation.


Rubber is elastic and will restore to it's original shape and form.

Then the question comes, if the rubber always restores to it's original shape then how do we manufacture different products from this? Almost all rubber products needs to undergo vulcanization.

 

What is Vulcanization?

It is the enhancement of the properties via chemical process. Vulcanization is performed on most of the elastomers including natural and synthetic rubber products. It is considered as the most revolutionized invention in the polymer industry.


 

Types of rubber product manufacturing processes

Lets take a look at what are the different methods to manufacture rubber products.

The different rubber manufacturing processes are

  • Injection Molding

  • Compression Molding

  • Transfer Molding

  • Rubber Extrusion

  • Rubber to Metal Bonding

Injection Molding

A modified version of the plastics technique is used to manufacture rubber injection moulded items. Rubber is heated during this procedure, which also puts it under much more pressure in the moulding. In contrast, materials used in plastic injection moulding are chilled and put under a lot less pressure.


Over time, there have been numerous advances made to the injection moulding procedure. Injection moulding is presently one of the most effective methods for producing rubber parts for a wide range of products, uses, and industries.


The Injection Molding Rubber Parts Manufacturing Process

  1. The preparation of the materials is the first step in the rubber injection moulding process.

  2. placement of uncured rubber using a screw feeder mechanism in the machinery. No performing is necessary for this process.

  3. The screw feeder is used by machinery to feed as much material into the mould as is required. By doing so, all ambiguities are removed, as well as the creation of material waste.

  4. Rubber is moved to the barrel, heated to make it more flexible, and then pushed into the runner system.

  5. Material begins filling the mould cavities and begins the curing process.

  6. The components can be taken out after the curing process is finished to make way for the incoming materials.


Compression Molding

Preforms made from a rubber compound or a combination of raw materials are loosely moulded to resemble the target result during the compression moulding process. To achieve a complete fill of the cavity, these preforms need a lot of material.


This method is perfect for medium-hard compounds, low-volume operations, or applications requiring pricey raw materials. Compression moulding also aids in minimising excess produced during the moulding process.


The Compression Molding Rubber Parts Manufacturing Process

  1. The quantity of material required to fill each cavity is determined by the operators.

  2. The uncured rubber is then preformed to these measurements by operators.

  3. the rubber is inserted into the mould chamber.

  4. covering the rubber components with the mold's lid.

  5. Depending on the materials and components, applying heat and pressure to the material for a predetermined period of time.

  6. Taking the fully-cured component out of the mould after opening it.

  7. Trimming excess material or flash can be done manually or with a deflasher.


Transfer Molding

Similar to compression moulding, transfer moulding calls for the fabrication of preforms using secondary source materials. The key distinction is how ingredients are added to a pot between the top plate and plunger.


The Making of Rubber Parts via Transfer Molding

  1. The quantity of material required for a component is determined by operators.

  2. With these measurements, operators do the rubber.

  3. Preform is inserted into a mold's cavity.

  4. Mold should be closed and pressed.

  5. pushing rubber through a sprue, a small aperture.

  6. Mold cavities are filled with substance.

  7. While the rubber dries, additional heating and pressure should be applied to the mould.

  8. Mold eradication and component release.

  9. Flash or overflow material is eliminated.


Rubber Extrusion

Depending on the components used, rubber extrusion can take many different forms. The procedure entails pushing the components through the cross-sectional die while it is being compressed by an extruder. Soft, unvulcanized rubber compounds are also a part of it. As a result, the extrusion produces rubber that is supple and malleable. To transform these materials into usable components, such as vulcanization or hardening, post-processing is necessary.


Process of extrusion

  1. Whether hot or cold extrusion is necessary is decided by designers and operators.

  2. Fill the hopper with the rubber before it is vulcanised. The conveyor contains a container called a hopper.

  3. The rubber is then guided onto the conveyor by gravity after passing through the hopper's bottom.

  4. Rubber is sent to the die while being heated and compressed by a screw.

  5. The rubber is softened before it enters the die at the end of the conveyor.

  6. The rubber starts to shape itself inside the die.

  7. The rubber is then forced through the die in the finished form of the component.

  8. The optimal post-processing techniques for the component are chosen by operators. These procedures include drilling, coiling, dusting, and vulcanization. In the post-processing stage of rubber extrusion, vulcanization is essential.

 

Summary

  • Rubber is softened before going through any manufacturing process.

  • Rubber is recyclable material and can be repurposed after some curing process.

  • Rubber to metal bonded parts range in size from smaller inserts to larger components. Overmolded components are also applicable in a wide variety of applications and industries.


 

Short Video

 

The interesting thing about rubber is that it has long durability. And to get more of such durable content, be sure to subscribe to Mech n Flow!

109 views0 comments

Related Posts

See All

Chips