How to select a Rubber for your application?

                 

    There is nothing called universal rubber

           Rubber is a polymer material which finds wide range of applications starting from the gaskets used in your cooking vessels to aero plane tires where you have demanding requirements. Though from an outsider point of view, all the rubber may look similar, but each rubber has its unique properties and should be used for specific applications only. There is nothing called universal rubber which can work for all applications.

    Selection of rubber is a science

              The selection of rubber needs the knowledge about the structure and property of rubber, application conditions like temperature, pressure, environment and life cycle of the product and so on. So, selection of rubber is science where you need to deep understanding about the application and the chemistry of the rubbers.

    Without complete information, you cannot make right decision.

    Information collection about the application is a very critical step in the material selection. But in practical it's very difficult to collect the data because customers may not share full information or sometimes the infrastructure is not enough to collect the data. So, one must try to collect maximum information as possible to make a right decision.

Customer specification

    3 dominating factors

        

        Though we have myriad number of technical factors while considering the material selection, decision is always a business decision. So, anytime you do a material selection, always needs to consider the decision triangle mentioned below. 

    Any material selected should serve the scope of the function for the intended lifetime without which it doesn't make sense as a product. Meeting the scope of the product within the cost target and timeline is the day in and day out challenge for a designer or a material specialist. One must have a fair idea about the cost of the material before going for the selection. To add further, due to the prevailing supply chain issues, one must check the availability of the materials locally or an import is required. Last but not least, timeline and target dates are inevitable factors because of the competitive environment and demanding business goals. Often it is very difficult to get an ideal material for an application, so it always better to choose to optimum product rather than a poor product or an overengineered product.

 Rubber properties table:

    Below table is a basic guideline or reference for the selection of rubber materials and one must need an expert advice to take a decision on material selection as per the intended use of the rubber parts.

  

Rubber	Operating temperature  (°C)	Applications
NR (Natural Rubber)	-45 to 95	Tyre, adhesives, Load bearings
CR (Chloroprene Rubber)	-35 to 110	Adhesives, gaskets hoses
EPDM (Ethylene Propylene Diene Monomer)	-50 to 120	Electrical insulators, beading
IIR (Butyl Rubber)	-45 to 150	Tyres, tubes
NBR (Nitrile Rubber)	-35 to 125	Gaskets, seals,  o-rings
CSM (Chlorosulphonated polyethylene rubber)	-35 to 150	Hoses, roofing membranes, liners
SBR  (styrene Butadiene Rubber)	-40 to 90	Car tyres, shoe soles, drive couplings
VMQ (Silicone Rubber)	-60 to 300	Pharma, medical, valves in automotives
AEM (Ethylene Acrylic Elastomer)	-35 to 175	Turbo charger hoses, oil resistant dampers, seals in filters
ACM (Alkyl acrylate co polymer)	-30 to 150	O-rings, diaphragms and transmissionseals
FKM (Fluoro-elastomer)	-20 to 250	High temperature oil, chemical and heat resistant hoses, seals and o-rings

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