Rubber Mold Making

Chapter One – What is Rubber Molding?

Rubber molding is the process of transforming uncured rubber or an elastomer into a usable product by transferring, compressing, or injecting raw rubber material into a metal mold cavity. The applied pressure in the presence of heat creates a chemical reaction, such as curing or vulcanization, which causes the polymer chains in the material to cross-link.

 

All rubber manufacturers use heat and pressure to produce their products. The most common methods for rubber molding are injection, compression, and transfer. With the constant evolution of products, rubber mold producers are continually adjusting to meet the ever-growing demand for grommets, gaskets, o-rings, and seals.

Chapter Two – Uses for Rubber Molding

Rubber, synthetic or natural, can be shaped and molded into complex forms, shapes, and configurations, which enhances its usefulness. Rubber’s flexibility and durability offer engineers different ways to design seals and cushioning components. The stability of rubber is seen in its use as a method for cushioning machinery to reduce impact and vibrations.

While natural rubber is still widely used, manufacturers have developed synthetic versions of rubber that have similar strength as natural rubber with greater durability and longevity. Manufactured materials such as neoprene, silicone, ethylene propylene diene monomer (EPDM), and various types of elastomers have the same properties as rubber but have greater flexibility and endurance.

Rubber Bumpers

Rubber bumpers come in a variety of shapes and sizes to be used in manufacturing specific products such as recessed, mushroom, stem, grommet, and tack bumpers. Bumpers reduce vibration and movement in equipment to protect rigid parts from damage caused by vibrations and impact. They protect furniture, work surfaces, circuit boards, displays, and packaging.

The materials used to produce bumpers include various polymers that are a mixture of rubber and plastics.

 

Rubber Bushings

Rubber bushings are somewhat like rubber bumpers since they are designed to absorb vibrations and impact on machinery. They are shaped and configured to fit specific applications, though the most common form is a cylinder. Rubber bushings can be placed on a machine to reduce vibrations or between two pieces of equipment to prevent vibration transfer. A particular use of rubber bushings is on automobiles, trucks, bicycles, and motorcycles as a way of containing the excessive vibrations from deformities in roads.

 

Rubber Diaphragms

Rubber diaphragms are sealing materials used to prevent leakage or friction. They are designed to withstand the effects of pressure while preventing any form of liquid from escaping. Rubber diaphragms are a barrier between two enclosures or chambers to prevent contaminants from entering. They can be static or dynamic, where a dynamic diaphragm can be activated by the slightest amount of pressure.

 

Rubber Grommets

Rubber grommets are rings placed around metal openings to protect objects or materials that pass through the opening. A normal use for grommets is for openings where wires pass through. They are made of synthetic or natural rubber and are produced by various types of molding. Electrical cables are vulnerable to abrasions from the surface of a metal opening, which, when damaged, can short out the wiring. Rubber grommets prevent this and protect wiring.

 

Rubber Isolators

Rubber vibration isolators are used to protect machines and appliances from vibration damage and keep them level and stationary. The term isolator includes mounts, leveling pads, bumpers, shock mounts, and bushings. The control of vibrations is an important aspect of equipment operation since vibrations can lead to equipment malfunction and poor-quality products. Uncontrolled vibrations can result in unnecessary wear and damage to machine components. A common use of isolators is on residential air conditioning units to suppress noise from the unit’s operation.

 

Rubber Mounts

Rubber mounts are closely associated with isolators. The two parts of a rubber mount are the fastening mechanism and the isolator. The fastener is threaded metal. The isolator is made from synthetic or natural rubber. Much like isolators, rubber mounts control vibrations that may damage equipment. Rubber mounts come in a wide variety of sizes, shapes, and designs, with the majority custom-made to fit a specific application.

Cylindrical mounts can be found as supports for conveying lines and transfer equipment. Other types of rubber mounts serve as supports for tabletop equipment such as computers and printers. The simple design of rubber mounts makes them easy to install and maintain. The metal threads are designed to quickly fasten to the supported and protected device.

 

Rubber Seals

Rubber seals seal gaps, insulate spaces from water or liquids, and protect surfaces. Since sealing materials is an essential part of a wide variety of equipment and processes, they are easily customizable and can be installed in multiple types of equipment. An important use of rubber seals is in processes that involve pressurized liquids or gasses. A rubber seal can be a gel, film, putty, or strip and be able to adhere to glass, ceramics, concrete, paper, and other materials or porous surfaces.

 

Rubber Suction Cups

Rubber suction or vacuum cups are used as a handling system for manipulating items with a flat surface, such as glass, metal sheets, wood paneling, molded pieces, or tubes. They come in several sizes, shapes, diameters, and types of rubber material.

Two types of suction cups are flat and bellows. Flat rubber suction cups are used for plain or flat surfaces. Bellows suction cups can handle irregular surfaces such as vehicle panels, tubes, and various types of molded products. They are more adaptable and versatile than flat suction cups.

 

Rubber Washers

Rubber washers are flat disks with a hole in the middle used to distribute a load, spacers, wear pads, lock a seal, or reduce vibrations. The dimensions of a rubber washer are determined by its outer diameter (OD) and inner diameter (ID), which vary according to the use of the washer.

When rubber washers are used for pipe connections, they generally serve as a means of preventing leaks and help to secure the joint or connection. Rubber washers are chosen for a variety of conditions because they form a tight seal.

 

Rubber O-Rings

Rubber O-rings are round ring-shaped rubber seals used to prevent leaks of lubricants, liquids, and substances from mechanical devices. They are used to seal gas lines and chemical feeding lines. Aside from their ability to prevent leaks, they serve as a way of sealing connections. O-rings are widely used by aerospace, hydraulic and pneumatic equipment, vacuum flow lines, and petrochemical piping.

When choosing an O-ring, it is important to determine the maximum amount of pressure that it will have to endure. They are designed to naturally compress between two surfaces to prevent air and fluid leaks. If a greater amount of pressure is placed on an O-ring than it is designed to endure, it will likely fail.

O-rings are made of various elastomers, including silicone rubber, ethylene propylene diene monomers, thermoplastic polyurethane, and fluoroelastomers. They can be found in every possible area of life, from gas pumps and hoses to refrigerators and complex hydraulic machinery.

The standard sizes for O-rings are determined by International Standard ISO 3601-1:2002, with the G series designed for general purpose use while the A series is for aerospace applications. The sealing capacity of O-rings is based on the volume relationship between the O-ring and the gland.

For all applications, O-rings with a large cross-section diameter have better resistance to compression sets and less volume swell in liquids. Smaller cross-section O-rings have better physical properties, resist explosive decompression, and require less space. Components with tight tolerances or rigidity and smooth or ground surfaces can use O-rings with the smallest cross-sectional diameter regardless of the pressure.

 

Chapter Three – How Rubber Moldings are Made

Rubber products and components are produced, shaped, and formed using the molding process. The reason for using molding, aside from shaping parts, is to subject the rubber material to chemical processes that toughen or harden the polymer chains of the raw rubber. The chemical reaction forces the long polymer chains to cross-link, which prevents them from moving independently. The rubber material expands and contracts as stress is applied or eliminated.

In the majority of cases, heat is involved in rubber molding to reduce curing time. The three most common types of rubber molding are compression, injection, and transfer. A fourth process, extrusion, is also used to produce rubber parts and components but does not involve using a mold.

There are several steps that need to be taken prior to initiating the molding process.

Designing Rubber Molds

Rubber can be molded into complex shapes, geometries, and designs. During the design process, configurations are included in the rubber geometry that are used to make the production of the final product more economical. In molding part design, engineers have to account for the parting line and its location, which needs to have a minimum draft angle. The design of the mold is the foundation of part development and can determine the success or failure of the production of the parts.

 

Producing the Mold

Once the design is completed, it is transformed into a metal mold. The manufacturing and production of molds involve the use of hardened steel, beryllium hardened copper, or some forms of aluminum. Steel is the most common material used to make molds since it lasts the longest, making it an economical choice even though it is initially more expensive. Hardened steel measures 38 to 45 on the Rockwell hardness scale. Included in the construction of the mold are the mold cavity and surface finish of the cavity that has to be correctly adjusted for the proper finish on the final part.

Included in the construction of the mold are the mold cavity and surface finish of the cavity that has to be correctly adjusted for the proper finish on the final part.

The creation of the mold involves the use of computer programs that precisely produce molds that exactly match the parameters of the design. The computerization process cuts down on the amount of time necessary to produce the rubber mold for production.

Once the mold has been cast and made, it is tested for dimensional accuracy and compliance with the original design.

 

When the mold is completed and approved, the production process begins using one of the three manufacturing methods

Vulcanization in Rubber Molding

A key aspect of rubber molding is vulcanization, which changes the thermoplastic properties of rubber into strong, elastic, and durable materials. Each of the molding processes uses some form of vulcanized rubber. There are various vulcanization techniques that are used to complete the process. Each method involves using sulfur with some other agent containing an accelerator, activator, and retarder to form the cross-linked molecular network.

When vulcanization is completed using just sulfur, the process is slow and leads to oxidative degradation creating poor mechanical properties. Accelerators added to the sulfur are more efficient in lowering the temperature and reducing the amount of sulfur, which improves the rubber’s aging properties.

The cross-linking from the vulcanization process creates a netlike structure that gives rubber stable elasticity that cannot be broken down, referred to as thermoset. It is through cross-linking that rubber gets its tensile strength.

Compression Molding

Compression molding is the simplest type of rubber molding process. A two-part clamshell-style mold is used to shape the final part. Once unvulcanized rubber is placed in the mold cavity, the mold is closed and heated. Pressure is applied using a hydraulic press.

As the rubber in the mold heats up, it fills the mold cavity. During the heating process, the viscosity of the rubber lowers, which allows it to flow freely under the increased pressure to fill the die cavity. When the proper temperature is reached, the rubber vulcanizes or hardens, which ensures that the rubber will keep its shape as it cools in the mold.

 

 

Transfer Molding

The transfer molding process is similar to the compression molding process but uses a transfer system that is on top of the mold that feeds raw rubber into multiple mold cavities after the press has been closed. Before being forced into the mold cavity, the rubber compound is placed in the part of the mold called the pot. From the pot, the compound is forced by a heated plunger or piston into the mold cavity through a small section called the sprue.

Transfer molding is a highly efficient process with short tool loading times. Though parts do not have tight tolerances, the process allows for high production runs. When curing is completed, the mold is split, and the parts are released.

 

 

Injection Molding

The injection molding process is used for products that require tight tolerances with high precision and accuracy. The injection process begins by heating raw rubber to form a liquid that flows more freely and readily into the mold cavity. The preheating process shortens curing time and allows for higher curing temperatures.

The nature of injection molding requires that the mold be tightly clamped, which helps to avoid or limit flashing. The rubber for injection molding is supplied to the mold through a nozzle and barrel assembly that provides a continuous flow. The consistency of the rubber is referred to as gum stock, which enters the mold cavity through a gate after having traveled through a system of sprues and runners. The liquified rubber fills the mold cavity and packs tightly to the walls of the mold to form the desired shape.

 

Though injection, compression, and transfer molding are the most common forms of rubber molding, each manufacturer has a different way of completing the process. Regardless of any variations, all rubber molding involves the use of heat and pressure.

Rubber to Metal (RTM) Molding

The process of rubber to metal molding is a way to bond vulcanized rubber to metal in order to isolate noise and vibrations. Each form of RTM is designed, engineered, and configured to meet the needs of a specific application and includes high fatigue strength, resistance to aging and temperature, and the ability to be recycled.

Rubber for RTM molding uses vulcanized rubber to form an elastomer, which is bonded to the metal substrate during vulcanization. The metal is primed and given a topcoat of polymer solutions with other ingredients. The rubber and additive blend is mixed with sulfur used as a catalyst and molded with the metal substrate under heat and pressure.

During vulcanization, the metal interacts with the primer, topcoat, and rubber to form a layer next to the metal substrate creating a strong bond that is 10 to 20 microns (µ) thick. The polymer molecules of the rubber cross-link, removing their ability to move independently and allowing the rubber to withstand stress and retain its original shape.

 

Chapter Four – Types of Rubber Used for Rubber Molding

There is a long and ever-growing list of the different types of rubber used for rubber molding. There is a wide variation in the types of rubber used for the rubber molding process, the majority of which are synthetic and formed by a chemical process involving polymers, which enhance the durability and elasticity for the forming and shaping process.

To understand the materials used in the rubber manufacturing process, it is important to know the difference between natural rubber and synthetic rubber. Natural rubber comes from the rubber tree plant from which latex is taken to produce rubber.

Synthetic rubber is made artificially by the polymerization of monomers into polymers. The process can be done by solution or emulsion polymerization. The solution method involves dissolving the monomer in a solvent that contains a catalyst, with the result being a polymer. The emulsion process uses an emulsion that contains water, a monomer, and surfactant, a compound that lowers surface tension.

Natural Rubber

Natural rubber comes from the latex produced by the rubber tree. It has high tensile strength with abrasion and surface friction properties, which makes it the ideal material for vibration dampers, seals, O-rings, mountings, diaphragms, and bumpers. Since natural rubber bonds well with metal, it can be used as a coating.

This unique combination of elasticity and resilience makes natural rubber a valuable material in various applications, including the manufacturing of tires, footwear, automotive parts, industrial products, and a wide range of consumer goods.

Nitrile or Buna-N (NBR)

Nitrile rubber is made from acrylonitrile and butadiene. It is made using the emulsifier process where acrylonitrile, a butadiene monomer, an activator, and a catalyst are mixed in a polymerization container. For the various compounds to mix, the container has to be heated to 104 °F (40 °C). NBR is the most used of the synthetic rubbers in the rubber molding process due to its resistance to water, oil, various fluids, and solvents. It is resistant to abrasion and tearing and has excellent mechanical properties.

Due to its excellent oil and chemical resistance, nitrile rubber is commonly used in the manufacturing of O-rings, gaskets, seals, hoses, diaphragms, and other components in industries where exposure to oil and fuel is common. It is also used in gloves and other protective equipment due to its resistance to oil and chemicals.

Hydrogenated Nitrile Butadiene (HNBR)

HNBR is produced by the hydrogenation of NBR, which removes the olefinic that are vulnerable to degradation. It is known for its strength and resistance to heat. HNBR rubber compounds are resistant to petroleum-based oils and fuels, aliphatic hydrocarbons, vegetable oils, silicone oils and greases, ethylene glycol, water and steam, dilute acids, bases, and salt solutions. In addition, it is extensively used in the auto industry.

In the automotive sector, HNBR seals and gaskets are essential components, ensuring reliability in engines, transmissions, and air conditioning systems. Its durability also makes HNBR a crucial material in the oil and gas industry for seals and hoses, withstanding harsh conditions and preventing leaks. HNBR is also used in the aerospace field for critical components such as O-rings and fuel system seals, guaranteeing safety and performance at high altitudes and extreme temperatures.

Ethylene Propylene Diene Monomer (EPDM)

EPDM is made by combining ethylene, propylene, and a diene comonomer that allows for cross-linking. The structure of EPDM makes it resistant to heat, light, and ozone as well as capable of withstanding temperatures up to 302 °F (150 °C). EPDM is highly durable and lasts in an application for a long time. It is used for steam systems, panels on cars and trucks, and braking systems

EPDM’s remarkable resistance to heat, weathering, ozone, and UV radiation makes it a staple in the automotive sector for weather seals, gaskets, and radiator hoses. In the construction industry, EPDM roofing membranes provide durable, waterproof solutions. It also finds extensive use in the manufacturing of electrical insulation, ensuring safety and longevity in electrical systems. EPDM’s flexibility and durability also serve the marine and HVAC industries for gaskets and seals, where maintaining environmental resistance is crucial.

 

Neoprene™

Neoprene rubber, also known as polychloroprene or chloroprene, is produced by the emulsion polymerization of chloroprene using a potassium catalyst. It is a multipurpose material with weather, temperature, fire, and abrasion resistance properties. Since neoprene resists degradation, it is used for gaskets, hoses, and various forms of coating. The versatility of neoprene makes it ideal for rubber molding regardless of the type of molding used.

The automotive sector relies on neoprene for gaskets, seals, and hoses, benefiting from its resistance to oils and extreme temperatures. In the sporting goods industry, neoprene’s flexibility, durability, and insulating properties make it a top choice for wetsuits, diving gear, and protective equipment. The medical field also utilizes neoprene for orthopedic supports and braces, owing to its comfortable and hypoallergenic nature. Neoprene’s resistance to chemicals and weathering makes it indispensable in construction for waterproofing materials.

 

Silicone

Silicone rubber is a rubber-like material composed of silicon combined with carbon, hydrogen, and oxygen. The term silicone rubber covers several types of silicone rubbers that are differentiated by their organic grouping and chemical structure. The different types include methyl, methyl phenyl, methyl vinyl, methyl phenyl vinyl, and fluoro vinyl methyl. Silicone rubber is widely used for its resistance to extreme temperature variations, flexibility, and weather resistance.

Silicone is used in the electronics sector for insulating and protecting delicate components from extreme temperatures and moisture. The automotive industry relies on silicone in gaskets, seals, and hoses to ensure durability and performance.

In healthcare, medical-grade silicone is pivotal for manufacturing implants, prosthetics, and medical tubing due to its biocompatibility. The aerospace and aviation industries also utilize silicone-based coatings for aircraft protection against harsh environmental conditions. Construction benefits from silicone sealants and adhesives for weatherproofing, bonding, and its resistance to extreme temperature variations.

Fluorosilicone (FVMQ)

Fluorosilicone is one of the variations of silicone that contains trifluoropropyl, which enhances its resistance to chemicals, non-polar solvents, fuels, oils, acids, and alkaline. Like silicone, it is highly adaptable across a wide range of temperatures. This and its longevity and resistance to petroleum products have made it extensively used in the aerospace industry.

Fluorocarbon (FKM)

FKM is made from VITON or fluororubber and is classified by its chemical composition, fluorine content, or method of cross-linking. The classification of FKMs goes from one to five, with each type having a different type of copolymer. There are three types of cross-linking materials for FKMs, which are diamine, dihydroxy, and peroxide. The characteristics of FKM make it resistant to chemicals and extremely high temperatures, making it ideal for molding hoses, O-rings, gaskets, and fuel lines.

Styrene Butadiene (SBR)

SBR rubber is produced mostly from butadiene with a small percentage of styrene, which is copolymerized using the emulsion process. It has exceptional abrasion, crack, and aging resistance. The many positive characteristics of SBR have made it ideal for the rubber molding of diaphragms, seals, and gaskets.

Butyl or Isobutylene Isoprene (IIR)

IIR rubber is made by copolymerizing isobutylene with isoprene, two compounds that come from natural gas or crude oil. To combine the two materials, they are cooled to -150 °F (-100 °C). IIR is not permeable by gas, making it ideal for the production of seals for high pressure and vacuum applications. Additionally, it has sound dampening qualities to use as a bumper for equipment.

Polarity of Rubber

Many factors affect the permeability of rubber, with the size of the permeant molecules being one of these. The polarity of a molecule is a factor that affects its size. Rubbers have varying polarities that affect how they react to water, gasses, and oils. EPDM and oil are nonpolar. When EPDM is placed in oil, it swells as it absorbs the oil. NBR has high levels of polarity, which makes it repel oils and not swell.

In using rubber, it is important to properly match the type of rubber to the permeant by examining the rubber’s polarity.

Chapter Five – Advantages of Rubber Molding

Rubber molding is an essential part of the rubber production industry since components, parts, configurations, and designs can be produced to exactly fit the needs of an application. The main reason for choosing rubber as a central part of an application is its unique durability and endurance since rubber can withstand abuse for long periods without failing.

Injection Molding

Injection molding heats the rubber material and places it under pressure such that it fills the mold cavity. The process of injection molding is a labor-saving method for molding rubber parts since it is fully automated, which cuts down on labor costs.

Advantages of Injection Molding

• Efficient process
• Fully automated insertion of raw material and ejection of final product
• High-precision products
• Repeatable process
• Allows for molding of complex geometries
• Eliminates preforming labor costs
• Produces little to no flash
• Rapid cycle times
• Significantly reduces waste
• Products are recyclable
• Tight dimensional tolerances
• Uniform parts
• Reduced tooling time

Compression

Compression molding uses a preformed piece of rubber placed in a mold. The mold is heated so that when it is closed, the preformed rubber piece is compressed to the sides of the mold. Products are produced under high pressure and temperature, which activates the curing process.

Advantages of Compression Molding

• Cost-efficient
• Less expensive tooling
• Increased cavity count
• Perfect for larger pieces needing extended curing time
• Accepts all forms of elastomers
• Eliminates the need for runners, sprues, or gates
• Simplified process
• Little to no waste

Transfer Molding

Transfer molding is a closed mold system that uses rubber pellets and preformed rubber. The pellets or preformed rubber are placed in a pot located between the top plate of the mold and the plunger. In the pot, the pellets are heated by the plunger and forced down the sprue into the mold cavities. The plunger remains in place until the material takes the shape of the mold and cures.

Advantages of Transfer Molding

• Economical process
• Cost-effective tooling
• Shorter cycle times
• Highly precise parts
• Tight dimensional tolerances
• Long curing time for larger products
• Accepts all types of elastomers
• Multiple parts produced during each cycle
• Greater design flexibility allowing for sharp edges
• Reduced flash
• Simple process with pot, plunger, and mold

Chapter Six – Industries Served by Rubber Molding

There are limitless uses for rubber molded products, which makes them a valuable part of a wide variety of industries, from auto manufacturing to aeronautics and spacecraft producers. The guaranteed durability of rubber molded components has made them an essential part of several industrial processes.

Aerospace

Rubber components for the aerospace industry must be dependable and meet exacting performance standards that are not required by other industries. Parts must be highly durable, have excellent weathering ability, and be able to withstand sudden variations in temperature. For passenger and aircraft safety, gaskets and seals are resistant to oil, gasses, and fire.

This manufacturing technique is employed to create a wide range of critical components, from sealing gaskets and vibration dampeners to custom seals for aircraft windows and doors. Rubber molding provides a durable and flexible solution that ensures safety and performance in the demanding conditions of flight. Its ability to produce complex, customized shapes with tight tolerances makes it indispensable for achieving peak efficiency and safety standards in aerospace engineering.

Automotive

The auto industry uses rubber parts in many sections of cars, from brakes and clutch seals to gaskets for the battery. The noise suppression capabilities of rubber parts make them ideal for consoles and other parts of a car’s interior. Its ability to withstand extreme temperatures, chemicals, and mechanical stress makes it ideal for applications ranging from engine mounts to tire treads, contributing to the durability, safety, and overall performance of vehicles.

 

Print

An important use of molded rubber products in the printing industry is rubber rollers with three parts: their metal core, rubber bonding material, and rubber covering. These rollers are used in graphic arts and printing and are important for passing ink onto printing plates. Rubber pads are widely used for shock absorption along with rubber mountings.

The flexibility of rubber molding allows for the production of intricate and specialized components, enhancing the quality and efficiency of printing equipment. Rubber’s resilience and resistance to wear and tear makes it an ideal choice for long-lasting printing solutions.

Home Appliances

Home appliance rubber parts are subjected to constant use and extreme temperature changes. Rubber molded parts have to be durable and strong enough to take intensive wear.

Rubber molding is used in many home appliances for its flexibility and durability, making it ideal for creating seals and gaskets that prevent water, dust, and other contaminants from infiltrating sensitive electronic components, ensuring the appliance’s longevity.

Rubber molding also enhances safety by providing insulation against electrical currents and shock hazards. Its non-slip properties make it perfect for grip-enhancing surfaces on handles and buttons, enhancing user control and ergonomics. Rubber molding can dampen vibrations and reduce noise levels, contributing to a quieter and more pleasant home environment.

Electrical

An important use for rubber molded products for the electrical industry is safety and protection. The products can include outlet covers, protection from shock, chemical resistance, methods for reducing electromagnetic interference, and sealing connections from dust and moisture. Much like all industries, parts have to be durable, resilient, and easy to use.

The main concern for the electrical industry is meeting the standards and regulations designed to protect workers and ensure safety.

Agriculture

The demands of the agriculture industry may seem dissimilar to those of other production and manufacturing industries. What is important for agriculture is protection from leaks and seepage but also the ability to withstand harsh weather conditions that all agricultural products must endure. A major part of agricultural production is the use of chemical fertilizers and bug repellents, which have to be handled with great care.

Rubber molding produces gaskets and seals that give the necessary protection and safety that are required for handling the variety of chemicals used for agricultural production.

Medicine

There are countless ways that rubber molded products are used in the medical field, from seals and gaskets on equipment to tubing to provide fluids. The durable nature of rubber makes it an ideal partner for medical use. Whether medical research or patient treatment, rubber molded parts and products can be found in every aspect of medical treatment.

The most important feature of rubber molded products is their ability to be recycled since most medical applications allow instruments to be used once and then disposed of.

Another factor of concern with medical instruments is the requirement to meet the exacting standards that have been set for patient treatment. Manufacturers strictly adhere to the legislated requirements and restrictions set for the protection of the public.

Food and Beverage

The standards for rubber molded products for the food and beverage industry have to adhere to the regulations of the Food and Drug Administration (FDA) of the Federal Government. Products are required to be designed for exceptionally hygienic conditions and have the ability to endure regular cleaning and sanitization.

The FDA specifies the types of acceptable rubber compounds that can be used in producing parts and components in the food and beverage industries. The main concerns are that materials be non-toxic and non-carcinogenic.

Chemical

The chemical industry produces a variety of products that include chemicals for agriculture, pharmaceutical use, paints, and the petroleum industry. The many products require a wide assortment of rubber products since rubber is chemically resistant. Hard rubbers are used for products in the chemical industry because they are made with a high percentage of sulfur, which makes them chemically inert and resistant to corrosion.

Rubber molding’s resilience to corrosive chemicals and extreme temperatures makes it an ideal choice for gaskets, seals, and custom components used in chemical processing equipment. Rubber molding ensures a secure and leak-free environment, preventing hazardous substance leaks and promoting safety. The flexibility of rubber allows for the creation of intricate shapes and sizes, accommodating the diverse needs of the chemical sector.

Conclusion

• Rubber molding is a process of transforming uncured rubber or an elastomer into a usable product by transferring, compressing, or injecting raw rubber material into a metal mold cavity.
• The most common methods for rubber molding are injection, compression, and transfer.
• Rubber‘s flexibility and durability offer engineers different ways to design seals and cushioning components.
• The purpose of the molding process, aside from shaping parts, is to subject the rubber material to chemical processes that toughen or harden the polymer chains of the raw rubber.
• Rubber molding is an essential part of the rubber production industry since components, parts, configurations, and designs can be produced to exactly fit the needs of an application.