High-precision thermoset piston - robust, lightweight and heat-resistant.
Materials

Thermosets are only plastically deformable at high temperatures during the shaping process. Once they have hardened, they retain their shape and hardness even when exposed to heat. This is due to their unique molecular cross-linking, which gives them distinct physical properties. Their strength, weight and cost-effectiveness make thermosets ideal for technological applications.

Thermosets are increasingly being used in areas that were previously reserved for metallic materials. This is because they are dimensionally stable, thermally stable, chemically resistant and hard. The possible range of applications is constantly expanding thanks to advances in materials research and processing technology. In many areas, thermosets now offer clear technical, structural and cost advantages over metals.

There are two main types of thermosets: free-flowing thermosets and doughy, pasty BMC/SMC moulding compounds. SMC and BMC moulding compounds are based on a styrene-containing polyester resin. The delivery form is pasty. Special feeding equipment is therefore required for processing (e.g. so-called tampers).

Free-flowing thermoset moulding compounds are granulated and can be fed via standard hoppers.

Fields of application:

Replacement of technical metal parts as a lightweight construction variant, replacement of metals with the same linear expansion factors, use for highly stressed, extremely smooth and precise surfaces.

Epoxy resins (EP)

Epoxy resins have very good mechanical properties and good chemical resistance. EP resins are used in combination with glass fibre, carbon fibre or aramid fibre for products subject to high mechanical loads and for encapsulating electronics and sensors.

Compared to other thermosets, melamine resins are highly resistant to weathering and light and have good mechanical stability. They have good surface hardness and are therefore scratch-resistant with a high surface gloss. Certain MF types are also approved for use in the food sector.

Unsaturated polyester resins are processed as so-called “moulding compounds (SMC)”. As a rule, these moulding compounds have a high filler content, which gives them greater strength and makes them suitable for high mechanical loads. Applications include switch and connector parts, appliance housings and vehicle parts.

Urea resins, also known as aminoplastics, were already being used as thermosets in the 1920s: The materials have the advantage of being both highly dyeable and food safe. Today, urea resins are used predominantly as adhesives and binders within the furniture industry, but are also used as housings for household appliances, as sanitary products or as technical parts such as switch housings or contact strips.

These resins are characterised by their very good heat resistance and excellent mechanical and electrical properties.

Phenolic resin moulding compounds were the first fully synthetic plastics and were introduced to the market at the beginning of the 19th century.

The moulding compounds are reinforced with glass, organic fibres or inorganic fillers. They have excellent electrical properties, good heat resistance, very good chemical resistance and dimensional stability. Due to their low processing shrinkage, very good mechanical properties, high surface hardness and excellent surface quality, phenolic resin moulding compounds are used in a wide variety of areas for housings or functional components as a substitute for metallic materials.

A thermoset produced by polycondensation, also known on the market under the trade name Bakelite.

Thermoset or thermoplastic: we will be happy to advise you on choosing the right material

Thermoplastic

These plastics become malleable at higher temperatures and liquefy. After shaping, they cool down and retain the required shape of the finished component with the corresponding material properties. Thermoplastics can be processed using a variety of methods, the most common being injection molding, extrusion, blow molding, film blowing and calendering. Thermoplastics can also be joined using ultrasonic, friction and laser welding processes.

Hybrid and multi-component parts

In instances where plastic is not the optimal material, we utilise combinations of materials. For instance, metal components can be incorporated to ensure stability or to facilitate the conduction of electrical signals or currents as required. Injected or overmoulded elastomers provide flexibility and tightness where needed.
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Injection moulding machines are available for the processing of thermosets.
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... is the maximum temperature load a thermoset part can withstand for a short time.
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Shrinkage factor achievable under optimum conditions for thermoset components

Plastics and their properties

Density and strength

Precise density measurement for light and stable plastics.

Most plastics have a density of between 0,8 and 2,2 g/cm3. They are therefore considerably lighter than metall or ceramic materials.

Chemical resistance - robust plastic solutions for the highest requirements.

Many plastics are highly resistant to inorganic substances, including acids, alkalis, oil, petrol and salt solutions. This justifies their use in a wide variety of areas such as household, automotive and mechanical engineering.

Plastic ageing: effects of environmental influences and mechanical stress.

Plastics age due to external environmental influences, exposure to chemicals, radiation, thermal or mechanical influences. This ageing manifests itself in swelling, embrittlement, loss of strength or cracking.

High-quality plastic insulation for electrical safety.

Plastics generally have minimal electrical an thermal conductivity and are therefore particularly suitable for insulating against both electricity and thermal energy.

Flammability of plastics: protection through flame-retardant additives

Thermoplastics are usually highly flammable. However, this can be regulated by flame-retardant additives. Thermosets are not flammable due to their molecular structure.

Reinforced plastics: More stability through glass and carbon fibres.

The physical properties of plastics can be optimised by adding additives to increase their mechanical strength. This is done, for example, by adding glass fibre or carbon fibre.

High-quality finishing for perfect plastic surfaces.

Many processes are available for the technical and visual enhancement of plastics, for example painting, metallising, vapour deposition, laser marking or printing.

Refinement

The most important advantages of thermosetting plastic at a glance

  • very low, linear coefficient of linear expansion
  • very dimensionally stable even at temperatures above 180 °C
  • very good dynamic features even at temperature changes
  • no corrosion protection required
  • low cold flow under static load and high temperature
  • large differences in wall thickness possible
  • resistant to chemicals and aggressive media (fuel, engine oil, transmission oil, glycol/water, brake fluid), even at high temperatures
  • very UV-stable

Your direct contact for thermoset solutions

Ingo Höfner

Project Management
07721 7509-8521
ingo.hoefner@ke-technik.de

Plastic granules: Wide range of design options in terms of colour and surface.
Design

Variety in appearance and surface finish

Hardly any other material is as versatile as plastic: apart from its physical properties, plastic offers an enormous range of possibilities in terms of shape, colour, haptics and surface design.

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