Students at the University of Bremen in Germany have
developed a ‘Smart Drill’ featuring lubrication-free iglidur L500 igus plain
bearings. Led by the young team from Bremen Institute of Measurement
Technology, Automation and Quality Science (BIMAQ), the project sought to fix
bone fractures safely by developing an attachment for a medical drill.
During the drilling process, this attachment measures
the depth of the hole to determine the correct screw. Due to the special
demands on the bearing points of the measuring system such as resistance to
chemicals and moisture as well as trouble-free mounting at high speeds, the
lubrication-free iglidur L500 plain bearings provide an optimal solution.
Fixing a fracture in osteosynthesis requires screw
connections to be made inside the bone. The length of the screw needs to be
precise to avoid injury to the surrounding tissue and to ensure sufficient
strength. The bone diameter and depth of the hole must be determined during the
operation using a gauge. However, the accuracy of this assessment is currently
dependent on the operator’s experience and can lead to errors in the selection
The ‘Smart Drill’ project aims to make this process
safer using an attachment for the existing drilling machine that supports the
length selection of the screw with measuring values. Lubrication-free igus
bearings made of high performance polymers are used at the bearing points of
the drive shaft.
The medical drilling machine required an optimal
bearing to be developed in different speed and vibration frequency ranges
without a negative influence on the system.
According to Michael Sorg of the Bremen Institute of
Measurement Technology, Automation and Quality Science (BIMAQ), the combination
of rotary drive and axial vibration required the use of high-quality plain
bearings not only to implement freedom of movement in the axial direction, but
also to achieve the most accurate signals possible at high vibration
frequencies. To cover all requirements, various igus plain bearings were
compared, and iglidur L500 was selected as the best option.
Key features of iglidur L500 plain bearings include low
friction values and high wear resistance, with both rotary and axial movements;
speeds of up to 900 RPM much below load limit; ability to withstand medical
sterilisation at extreme temperatures; moisture resistance minimising water absorption
to negligible levels; lubrication-free bearing eliminating any risk of
contamination of the wound or premature bearing failure due to washout of the
lubricant; and low installation sizes and very low weight compared to bearings
made of metallic materials.
The iglidur L500 plain bearings meet the hygienic
requirements of medical technology.