Before a housing can see the light of day, the right choice of materials is very important, in addition to the pure planning and manufacturing process. As mentec® has many years of experience in this field, the processes used have been optimized to perfection, as has the selection of the materials. This article reports on materials science. It deals with the high-quality plastics that mentec® uses in the production of its plastic housings. We provide a brief insight into how much know-how about the material is necessary to produce a high-quality, durable housing.
Which materials are used for mentec® housings?
The most important material used in the production of mentec® housings is an impact-resistant plastic called polystyrene. This is ideally suited to the requirements that mentec® places on the material in order to manufacture plastic housings based on K-Box technology. The individual parts, which are cut out of sheet material in the manufacturing process, are joined together to form a compact housing. To ensure that these are permanently and strongly bonded, the connection is made using the tongue and groove principle and a solvent. The solvent is applied to the groove. The polystyrene is softened in the applied areas to allow the surfaces to stick together. This process has to be carried out quickly after application, as the softened material sticks as fast as superglue. The connection then needs 48h to harden completely and can only be broken with brute force. The drop test from a height of one meter is an important criterion, especially in medical technology, where a housing must survive undamaged.
What do you need to know about materials?
In order to be able to produce a housing in various solid designs, the plate blanks used by mentec® are available in thicknesses of 3mm, 4mm, 6mm, 8mm and 10mm, which is of great importance for the stability of the housing. Plastics are available in different colours for the production of coloured housings. mentec® has a pool of about thirty colours, standardized according to RAL and available at short notice. Before a project starts, fire behaviour must be clarified. Products may generally only be used if the material is flame-retardant. Of course, this also applies to the housing used. This is introduced into the polystyrene by a granulate additive which ensures that the housing is no longer flammable. The plastic plates used by mentec® have a so-called fine structure side, which is used on the outside of the housing and a smooth side on the inside. The fine structure is resistant to scratches and shocks and gives the housing a longer service life. Glossy surfaces are very much in demand in the field of medical enclosures. Here, material mixes of acrylic glass and polystyrene are frequently used.
How is the raw material polycarbonate applied?
Polycarbonate is a material with an enormously high impact strength. These advantages are evident in the production of outdoor housings, which are subject to high temperature fluctuations (cold / heat) and strong UV radiation. Polycarbonate is also used for sealing and IP protection (protection against contact, dust and water). In the sealing area, for example, injected seals are used to seal the housing parts against penetrating liquidity. Shatter- and splinter-resistant protective covers made of polycarbonate are often used in the medical sector, e.g. in laser systems or laboratory centrifuges. Transparent machine covers, in the form of hoods, are also frequently made of polycarbonate.
Are there alternatives to polystyrene?
The alternative to polystyrene is an acrylonitrile-butadine-styrene co-polymer – ABS for short. Compared to polystyrene, ABS has a higher temperature resistance of up to 90° Celsius. The properties of ABS make this material ideal for processing, milling and bending. Individual parts must be glued together with an adhesive.
What is a semi-finished plastic product?
Semi-finished products are plastics such as PVC or polycarbonate sheets, which have different properties. Compared to other materials, polystyrene is an inexpensive semi-finished product. The chemical resistance of PS is very high. The material can be formed cold and hot. Compared to a sheet metal housing, the plastic housing is much lighter and does not have to be painted because the material is already coloured.
What is the electromagnetic compatibility with electronic housings?
There are two processes that are used by mentec® to ensure so-called electromagnetic compatibility (EMC):
- Process 1: the plate material is coated on the inside with a silver conductive lacquer. The housing is connected to the tongue and groove system to form a conductive connection.
- Process 2: the housing is built and completely assembled. The interior is subsequently coated with silver conductive lacquer. This process is much more complex, but results in a higher shielding.
Are sustainable materials for housings available?
mentec® can also use regenerated materials. These include polystyrene and polycarbonate made from 100% recycled raw materials, which are discarded in the manufacturing process. We send excess material, such as the waste, to the manufacturer, who returns this material to the manufacturing process thus ensuring a raw material cycle