Waste separating robot application that uses 3D printed iglide® plain bearings

Application Overview:

• What was needed: plain bearings with special geometries
• Manufacturing method: selective laser sintering and print2mold
• Requirements: good sliding properties with aluminium as a counter partner, high abrasion resistance at high speeds, complex geometry
• Material:
• ​​​​​​iglide i3 (laser sintering)
• iglide J2 (p2m)
• Industry: waste separation plants
• Success from the collaboration: long service life under heavy load, significantly reduced unit costs, high design freedom

Problem:
During the test phase of a new "FastPicker" waste separation system by ZenRobotics, a Finnish company, it quickly became clear that classic plain bearings cannot withstand the torsional forces during axial acceleration if the centre of mass is not located in the centre of the moving axis. The rotation was initially to be stopped by stopper elements. However, they quickly failed due to the heavy load. In addition to the stopper elements, standard plain bearings from igus were first used to withstand the radial and axial acceleration.

Solution:
Ultimately, special-geometry igus plain bearings were used. They were first made from the iglide i3 high-performance plastic using the laser sintering process in order to fit onto the grooved aluminium axis and thus stop the rotation. The company then switched to Rapid Tooling in order to use the material diversity of the injection moulding process. The Rapid Tooling or print2mold process can also reduce costs by up to 80%. The mold for injection molding can be produced within a few days and is immediately ready for use. The design freedom 3D printing offers made it ideal for the plain bearings' special geometry.

The decisive factors were the variety of materials and the low unit costs associated with injection molding. The final plain bearings were made of iglide J2. In this case, the print2mold component cost only a tenth of the laser sintering component (approx. €49/piece) at approx. €5/piece, and from 100 pieces onwards, the tool had also paid for itself. The tough plastic has good mechanical properties, is cost-effective and has good media resistance. In addition, the integrated solid lubricants make external lubrication of the plain bearings superfluous.

When speed is of the essence, 3D printing is the solution for manufacturing an injection mold. Depending on the geometry, printing takes about 12-24 hours, and the tool is ready for use immediately afterwards. The print2mold process known as Rapid Tooling enables cost-effective production of advanced prototypes and small volumes. It is more profitable in quantities of up to 10,000 (no minimum quantity) than machine-produced injection molds. Wear-resistant parts can be produced with a cost reduction of up to 80%.

The quality of print2mold injection moulded parts is the same as with the conventional injection moulding process. Development processes can be greatly accelerated using the print2mold process and the material variety of regular injection moulding is also retained.