By Liz White, UT editor
Teningen, Germany-A new dialysis machine from a leading medical technology manufacturer, has polyurethane housing produced by plastics specialist THIEME GmbH & Co. KG of Teningen. This PU casing contributed to a design prize for the equipment's "elegant and ergonomic design" from the Design-Zentrum Nordrhein-Westfalen.
As well as greater design freedom allowed by polyurethane, the materials offers favourable costs, as Bernhard Schuler, project manager at THIEME, points out, in a company statement. "Particularly in the case of complex moulded parts with integrated functions, the RIM process is a lot simpler than, for example, injection moulding."
Schuler also explained that even considerable wall thickness differentials-which in a dialysis machine is between 4 and 10 mm-"do not lead to sink marks so that stiffening ribs and functional elements on the inside can largely be planned independently of the outer contour."
Compact, modular, pleasing
Dialysis machines treat the blood of those suffering from chronic kidney disorders, and patients can spend four hours on a machine three times a week. Good aesthetics for the equipment can make the experience pleasanter for the patient: hence THIEME's customer wanted a compact and elegant design for its new dialysis model.
To simplify handling and maintenance, the customer also wanted a modular structure. Custom reaction-injection-moulded parts fulfilled these objectives.
Polyurethane offers valuable properties for such products, THIEME said. These include high design freedom, minimum distortion, coatability with conductive paint, good noise absorbtion, low weight and good hygienic properties, added THIEME. Another plus is the strength and toughness of the material which has proven itself in daily use in clinics and dialysis centres, the firm added, in a press statement.
Cost advantages follow from the integral construction in which the functional elements such as bushings and fastening threads can be pre-formed during the moulding process or even foamed in to the part. This considerably reduces the costs of the final assembly, THIEME said. RIM also has low tool costs as a result of the low pressures involved. Hence aluminium moulds can be used rather than steel; at the quantities common in medical technology (hundreds up to one thousand) this generally has a cost-reducing effect, the German company said.
The housing consists of ten custom RIM parts, with rounded forms presenting no problems "thanks to the good flow characteristics of the material used: Baydur 110 FR," said THIEME.
Since the material allows low wall thicknesses, THIEME also found it also possible to make the dialysis machine very compact in accordance with the wishes of the customer. In order to ensure the required stability, some of the parts are equipped with stiffening ribs. Assembly of the machine is very simple with pre-formed bushings, plug connections, fixing and support points. The machine will be on display 15-17 Nov 2006 at the medical trade fair ComPaMED in Düsseldorf, Germany, said THIEME.
Pic: Compact comfortable design for dialysis machine. "