Medical diagnostics benefit from polymer ball bearings

What was needed? 
Bidirectionally compatible ball bearings 

Requirements:
Reduction of friction, no lubrication and maintenance

Industry:
Medical equipment

Success for the customer:
The non-magnetic ball bearings made of plastic with glass balls from igus are ideal for magnetic resonance imaging and score with perfect bidirectional compatibility.

This system is designed as a rehabilitation device that is operated during functional magnetic resonance imaging (fMRI). MRI-compatible rehabilitation devices can be used in the strong magnetic field of MRI equipment to permit physiotherapeutic exercises. This allows the MRI machine to map the activated regions of the brain, from which conclusions can be drawn to guide physiotherapy in a way that increases the effectiveness of treatment, which can have a positive impact on the quality of life of millions of people suffering from neurological disorders such as a stroke. The device is capable of successfully transmitting controlled forces, measured by fibre-optic encoders that are attached to flexible elements. Patients are optimally supported, while also ensuring their safety. This elastic force control architecture, which achieves excellent force control performance within the required frequency ranges, essentially transforms the force measurement problem into a position sensing problem. This force measurement is necessary due to the unavoidable friction caused by the Bowden cables.

Problem

The most important aspect of MRI-compatible rehabilitation is thebidirectional compatibility problems between the MRI device and the rehab equipment. To ensure bidirectional compatibility, the device must not disturb the imaging process or cause image interferences. At the same time, the performance of the device must not be affected by the imaging process. The Sabancı University searched fornon-magnetic, non-conductive polymer ball bearings that were not only maintenance-free but also had a long service life.

Solution

The components located in the MRI area must be MRI-compatible due to the strong magnetic field. This also applies to the bearings, which must have low friction. A xirodur B180 polymer ball bearing with glass balls is used in this application. In addition to the aforementioned requirements - non-magnetic and low friction - they are lubrication-free, maintenance-free and durable. Because excessive friction has negative consequences for transmitting the assisting forces to the patient, the xiros polymer ball bearings ensure that the patient is optimally supported.