Turned parts

Various turned-milled parts made of engineering plastics | Application: mechanical engineering

Turned parts from plastic

We specialize in processing only engineering plastics in our production. Unlike many other producers, we do not process metals. This gives us the opportunity to fully optimize our machinery for the machining of plastics. This is essential, especially when manufacturing turned parts, but there are also various points to consider even before production, during development and design.

But don’t worry! We are not only a contract manufacturer, but also your development partner for plastic turned parts. Our large team of experienced engineers is always at your side. Early contact with our development department is recommended, because often costs can be reduced, quality can be increased and process capability is guaranteed.

A turned part made of PEEK, which is currently being manufactured

Production of turned parts from PEEK

Thermal expansion of turned plastic parts

For many types of plastic, the coefficient of thermal expansion is 20 times greater than for most metals. During turning, friction and thus heat is generated, which is transferred to the workpiece and thus already has a greater influence on the accuracy during production.

This influencing factor must also be taken into account during the quality control of the CNC machines during production, as well as during the final inspection of the components. Our CNC machines are essential to counteract this effect. Heat dissipation via cooling lubricants is not permitted with most high-performance plastics.

Especially when using high-temperature plastics, this high coefficient of thermal expansion must be given essential consideration and the design must be adapted as necessary.

Turned parts made of PTFE, which is currently being manufactured

Production of turned parts from PTFE

Tolerancing of plastic turned parts

Precision plastic parts cannot always be produced with the tolerances that are state of the art for metal parts. Plastics processing is much more demanding with the large number of engineering plastics, which is why the tolerances also have to be designed as necessary.

On the one hand, the lower stiffness and greater elasticity play a role, on the other hand, the thermal expansion, which is on average 20 times greater. Added to this is the moisture absorption specific to plastics in many materials.

A decisive factor in plastics technology is residual stresses that can remain in the semi-finished product as a result of production. During machining, they are released and can thus have an influence on accuracy.

For all these challenges, we have developed solutions to still achieve the highest accuracy when machining plastics.

An employee inspecting a red elastomer turned part

Testing of a turned part made of elastomer

Residual stresses of turned parts made of special plastics

During the production of semi-finished products from thermoplastics, residual stresses often arise which remain in the semi-finished product due to the cooling process. Without the necessary safety equipment, these residual tensions are released during CNC machine processing and the component can deform. This deformation can continue for a long time after machining. Plastic parts that have been positively measured may suddenly show dimensional deviations after a certain storage time.

At Hänssler, we counteract this effect by reducing residual tensions with our annealing furnaces before processing, or even between processing steps. Thanks to our know-how and many years of experience, we know the annealing processes for standard plastics as well as for high-performance plastics and can therefore realize essential tolerances.

From the smallest diameter to large plastic turned parts

Due to our diverse machinery in the plastic turning department, we are able to manufacture micro components made of plastic as well as the largest turned parts up to 1500 mm. At our location in Mannheim, we cover a very wide range of plastic solutions through many innovations.

Depending on the requirements, we select the ideal manufacturing process and coordinate the processes for an optimal result with our customers.