Plastic Injection Moulding
Production Technique
Injection moulding is a method to obtain moulded products by injecting plastic materials molten by heat into a mould, and then cooling and solidifying them. The method is suitable for the mass production of products with complicated shapes, and takes a large part in the area of plastic processing. There are many different materials that can be used and our material scientists can advise you on the most suitable plastic for your application.
Technical details
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The dimensional tolerances depend on the plastic that is chosen. In general, tolerances are smaller for stiffer materials. Specific values for each material are available on request.
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The weight can vary from a couple of grams to approximately 5 kg.
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Surface roughness depends also on the plastic and is in most cases below Ra = 0.8 µm
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Minimum wall thickness depends on the design but it thicknesses below 1 mm should be avoided.
Materials
Acrylonitrile Butadiene Styrene (ABS)
ABS is a light but hard and impact-resistant polymer. ABS is also a dimensionally stable material and has little tendency to creep. Depending on the blend, the maximum operating temperature is between 85 °C and 100 °C. The minimum operating temperature, on the other hand, is -35 °C. ABS itself is a flammable polymer. That is why it is often decided to add flame retardants.
The most well-known product made in ABS are Lego blocks, but ABS is also often used in many other applications where dimensional stability is very important such as housings for mobile phones.
Low Density Polyethylene (LDPE)
Low Density Polyethylene (LDPE) is a form of Polyethylene (PE), just like HDPE (high density polyethylene). Both forms of polyethylene are thermoplastics. In general, LDPE is produced at lower temperatures.
LDPE is translucent, just like most other plastics of the PE or PP family. It has a glossy and smooth surface. Therefore, printing and gluing is difficult without suitable surface treatment.
LDPE is very flexible, has good chemical resistance and good electrical properties.
Low density Polyethylene is used for the plastic injection molding of films, containers, toys, pipes and hoses.
High Density Polyethylene (HDPE)
High Density Polyethylene (HDPE) is a milky, tough and impact-resistant plastic. HDPE has good insulation properties and is quite wear-resistant. It is also odorless and tasteless (FDA approved). Thanks to its excellent price-quality ratio, HDPE is one of the most widely used plastics in the industry.
HDPE is translucent white and can easily be colored. The surface is glossy and very smooth in structure. Without pre-treatment, HDPE cannot be glued or painted. It has limited UV and weather resistance.
High-density Polyethylene is commonly used for the injection moulding of: guide profiles for machine construction, drinking water pipes and tanks, sheathing of high-voltage cables and food packaging material.
Polycarbonate (PC)
Polycarbonate (PC) is a transparent (crystal clear), stiff and impact-resistant material with low notch impact resistance. Various blends with HPVC, ABS and ASA create plastics with specific properties.
Polycarbonate is easy to color. The surface is glossy as standard and with the addition of additives it can be made opal. A satin-finished surface is also possible. It has good UV resistance but limited weather resistance.
Polycarbonate is used, for the plastic injection molding of: covers for lighting fixtures, conductor rail profiles, baby milk bottles, lenses in electrical appliances, power distribution cabinets.
Polyamide 66 (Nylon)
In addition to ABS and PP, polyamides are among the most commonly used plastics. In mechanical engineering and precision mechanics, polyamide is even the undisputed number one among polymers. Polyamide 66 has good stiffness, scratch resistance and hardness. In addition, Polyamide 66 has excellent properties of wear resistance and low friction. It has a moisture-absorbing capacity and has good sliding and rolling properties. Polyamide 66 is excellent for mechanical processing.
Polyamide 66 is commonly used in parts for strollers, wheelchairs, switches, control buttons.
Polyvinyl Chloride (PVC)
Polyvinyl chloride (PVC) is one of the oldest plastics that is still used in many variants today. By adding various additives, hard PVC, soft PVC or even transparent PVC can be produced. All with the same basic material. This is unique to PVC compared to other thermoplastics. PVC is very easy to recycle and reprocess. PVC is also easy to color.
Products made from PVC have good UV and weather resistance due to the addition of appropriate additives. In addition, PVC has good chemical resistance. It is resistant to dilute acids and alkalis, salt solutions, petrol and oil.
Polyvinyl chloride belongs to the group of thermoplastics and is used for the plastic injection molding of: pipes for sewerage and rainwater drainage, plastic frames, gutters, facade cladding, ceilings, cable ducts, roller shutters, decorative frames, furniture finishing profiles, insulation parts for electronics, mounting profiles, cover caps.
Polypropylene (PP)
Polypropylene (PP) is available in many versions, both pure and in blends and/or with fillers and reinforcing substances. The material is lightweight and has a high temperature range. By adding EPDM, higher impact resistance, weather resistance and lower operating temperatures are achieved.
PP is easy to color. The surface is slightly shiny. Without pre-treatment, PP cannot be glued or painted. It has limited UV and weather resistance.
Because PP is one of the most versatile plastics, it can be used for many different applications. Polypropylene belongs to the group of thermoplastics. PP is used, among other things, for plastic injection molding of: housings of kitchen appliances, parts in dishwashers, bread bins, drinking cups, garden furniture.
Fibre Reinforced Plastics
Fibre-reinforced plastics are a category of composite plastics that specifically use fibre materials to mechanically enhance the strength and elasticity of plastics. The original plastic material without fibre reinforcement is known as the matrix or binding agent. We only use short glass fibre in combination with the plastics listed above. By adding glass fibre to the plastic, mechanical properties such as tensile strength and wear resistance can be improved significantly at a very reasonable price. Fibre reinforcement is used in all cases where the plastic in itself needs to be improved in order to make it suitable for the application.