Non-metallic and low-friction linear bearings for MRI scanners

Profile

• What was needed: Lead screws and nuts from the drylin portfolio, drylin SLW linear systems, Easy Tube linear units
• Requirements: High-performance, non-metallic bearings that can also be used in the MRT were needed.
• Industry: medical equipment
• Success for the customer: The high-performance iglidur plastics enable the device to work in the difficult environment without interacting with the magnetic field. The bearing components are also used in the application to generate a smooth and low-friction shaft rotation to drive the robot's joints.

Problem

This robot was developed to perform an interventional focussed ultrasound (FUS) on a child's brain. This procedure can be used for the non-invasive treatment of epilepsy and stroke in children without the need to make an incision in the patient's skull. This allows for a less damaging procedure and faster recovery compared to traditional brain surgery, which requires the patient's skull and brain to be opened. The robot is a manipulator with five degrees of freedom that works in a magnetic resonance imaging (MRI) machine. Bearings, lead screws and lead screw nuts must be used on each axis of this machine, whereby there are linear travelling axes and rotary axes. As the robot has to work in the strong magnetic field of the MRI machine, metal bearings cannot be used here.

Solution

Today, iglidur plastic bearings are used in the robot instead of metal bearings. The high-performance iglidur plastics enable the device to work in the difficult environment without interacting with the magnetic field.
They drive the translation and rotation axes of the robot. In addition, lead screws and nuts from the drylin portfolio as well as drylin SLW linear systems and easytube linear units are used. The bearing components are also used in the application to generate a smooth and low-friction shaft rotation to drive the robot's joints. This is because the MRI-compatible motors used developed a relatively low torque, which also generated friction when propelling the heavy payload.