PROCESSING PLASTICS
heat treatment
Due to the manufacturing-related material stresses that have already been mentioned several times, it is often necessary to intermediate or post-treat the plastics thermally.
Material stresses arise from the rapid cooling of the outer skin of a plastic that is still hot in the core. A correctly carried out heat treatment cannot avoid the stresses completely, but they can be significantly reduced. For this reason, semi-finished plastic basically thermally posttreated.
However, the heat treatment can certainly also lead to disadvantages. A heat treatment that is too hot can permanently damage the plastic. In addition, dimensional changes due to the process must be expected. During the thermal treatment of hygroscopic plastics, it must be taken into account that the material can be dried. After heat treatment, the material will absorb moisture again until it is equilibrated. As a result, there is an additional dimensional effect.
In the case of complex components to be produced by machining, it sometimes makes sense to prefabricate the desired shape, to treat the material thermally and then to finish the component. This can accelerate the process of stress release so that the component remains dimensionally stable.
The heat treatment of the polyamidimide Torlon® is of particular importance. To ensure its outstanding mechanical and chemical properties, Torlon® has to undergo special heat treatment. In particular, the extraordinarily high wear resistance of Torlon® can only be achieved through thermal post-treatment.
In this thermal process called "postcuring", a precise temperature control triggers a chemical process. This is what gives Torlon® its unique features. In addition to wear resistance, other mechanical properties are also positively influenced by the heat treatment. Strength and elasticity increase, as well as heat resistance and glass transition temperature (TG) are significantly increased by postcuring.
However, the process requires an exact, ± 2K accurate temperature control which is dependent on the material cross-section temperature control and should only be carried out by specialized companies.
Summary
When manufacturing technical components from high-performance plastics, the selection of a suitable processing method is of particular importance. Besides the aspects of production technology, economic considerations must also be taken into account.
Various methods are available, differing in their advantages and disadvantages. Before designing technical tcomponents made of high-performance plastics, the necessary processing method should be selected are selected and the construction accordingly matched. Our experienced application technology consultants offer support in every respect!
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