150°C and abrasive metal parts: linear bearing in 3D printing machine for metal parts

Aerosol, a company active in the aviation industry, was involved in the development of a highly ambitious new laser-based 3D printing machine: The largest and fastest metal powder bed 3D printing machine in the world.
The machine prints metal parts up to 20 x 6 x 6 metres in size at speeds up to 10 times faster than current 3D printing systems. At the centre of the process is a high-performance laser that melts thin layers of ultra-fine metal powder until a 3D geometry is formed. The metal powder layer must be applied evenly to a thickness of just 50 µm. The desired component is then created layer by layer.
The rails used to guide the laser must function perfectly under extreme temperatures of up to 150 °C and under the influence of the finest abrasive metal powder particles in the environment. The system must also not be lubricated, as the fine powder would otherwise settle on the linear system and impair or completely prevent its function. The system should also be very stable, as any vibration reduces the quality of the powder layer and affects the mechanical specifications of the part to be produced. Conventional bearing systems were therefore not suitable for this harsh environment.

A drylin® rail system was the perfect solution for this application, which now travels over a length of 3.2 metres in the XXL printer. The excellent temperature and wear resistance properties of the polymer bearings provide a durable solution that is easy to maintain in this harsh environment. The design of the bearing allows operation in "dirty" environments and is ideal for use with metal powders.
The quality of the powder layer is extremely critical as any defect in this layer will cause a defect in the part. Adjustable drylin® pillow block bearings have been used to achieve high accuracy and freedom from vibration. However, the biggest advantage of the drylin® system in this application was the fact that no lubrication is required. This not only prevents the linear guide from being blocked by the metal powder. The risk of contamination of the metal powder by any lubricating grease is also completely avoided by the "dry" rail system.
Finally, a high level of downtime could also be guaranteed with the product solution. The requirement for the rail in the metal 3D printer was continuous operation under the specified environmental conditions for at least 2 weeks.
This, together with the other advantages mentioned, ensured that the product solution with polymer bearings was the only reliable and cost-effective solution for our application.