3D Printing With High-performance Polymers Replaces Metal Parts

2023 Author: Hannah Pearcy | [email protected]. Last modified: 2023-11-26 11:39

In the automotive sector, materials are required that are not only highly resilient, but also have other properties such as chemical resistance, temperature resistance or wear resistance. This ensures that parts are much more durable and have to be replaced less frequently. So far, metals have been the material of choice because they combine all the important properties. A big disadvantage here is the weight. A lower weight saves fuel and thus reduces CO ₂ emissions.

PEEK as a metal replacement

This is made possible by the high-performance polymer PEEK (polyether ether ketone). Thanks to its semi-crystalline structure, it can be used at temperatures above its glass transition temperature of 143 ° C and is therefore ideal for the automotive industry, where the parts in the drive trains and engines usually have to work at 150 ° C or more. Even at higher temperatures, PEEK can be used thanks to its melting temperature of 343 ° C and a service temperature of up to 260 ° C.

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In addition to its mechanical strength, the polymer is also chemically inert. This is particularly important for parts in the drive train, as they do not suffer damage from the various liquids, such as oils or fuels. Specific applications are wear parts that were previously made from metal. With PEEK instead of metal, up to 70% of the weight can be reduced, which leads to a saving of 1 to 2% fuel overall. In addition, the wear of the parts is 25 to 75% below the value of the metals; the parts are also more resistant to too little lubricant. Another plus compared to metals is noise reduction.

PEEK parts from the 3D printer

The most effective way to process PEEK is 3D printing. This makes it possible to manufacture parts that would not be possible with conventional processes due to their complex geometry. However, the potential to save material is much more important. In FFF (Fused Filament Fabrication) technology, a plastic strand, the filament, is melted through a nozzle and applied in layers. This means that only the material that lands in the component is used. Compared to CNC milling, in which up to 90% of the material ends up as chips, depending on the application, 3D printing offers a significant saving in material costs.

The company Indmatec offers PEEK in filament form commercially and has developed the Indmatec HPP 155, a fused filament fabrication 3D printer specially tailored for industrial high-performance polymers.

Even if the FFF process cannot be used for mass production, it is a process for research and development that provides prototypes with little effort. It can also be used to manufacture special, individual parts; small series are also conceivable, such as gears and sealing rings.

The main advantage of PEEK gearwheels is their wear resistance to the forces acting between the gearwheels. Sealing rings made of PEEK have the advantage of being resistant to the fluids in automobiles, which makes them more durable. In addition to the possibility of producing complex geometries, lightweight components can also be manufactured with a 3D printer. Thanks to the honeycomb structure, there is approximately the same strength as a fully printed part, but with significant material and weight savings. Such constructions are not possible with the injection molding process.

Strengths similar to injection molding

A decisive criterion in the production of functional parts using the additive process is the question of whether the part can match the strength of conventionally manufactured products.

The PEEK tensile test comparison, made with Selective Laser Sintering (SLS), Indmatec's Fused Filament Fabrication Technology (FFF) and Powder Injection Molding (PIM), shows that the FFF process is in the area of injection molding when it comes to strength. The tests were carried out in the X / Y direction, the strength in the Z direction is approx. 30% lower due to the layering process. (qui)

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