Replacement 3D gears for an e-bike - Increased performance with tribologically optimised materials

• What was needed: new gears for a planetary gearbox for an electric bicycle
• Manufacturing process: selective laser sintering
• Requirements: Accuracy of detail, accuracy of fit, abrasion resistance
• Material: iglidur ® i3
• Industry: Bicycle industry
• Success through collaboration: 30 times better abrasion resistance than conventional SLS materials, high wear resistance, higher efficiency

The application at a glance:
Replacement gears were needed for the heavily worn gears of a planetary gearbox in an e-bike. As the manufacturer of the electric bike was unable to supply replacement gears, the customer turned to the 3D printing department at igus® GmbH in Cologne for a solution. The new gears were modelled on the old, worn components and printed using the laser sintering process. The customer was able to install the gears immediately upon receipt and noticed an improvement in the performance of the gearbox after just a short time.

The gearbox of an electric bike no longer delivered the initial performance and a quick look inside the planetary gearbox revealed the reason: the gears were badly worn. Original spare parts could not be supplied by the manufacturer, which is why the customer looked elsewhere for replacement gears. The gears had to fit precisely in the gearbox and have a significantly higher abrasion resistance than the previous components in order to withstand the load.

The customer turned to the 3D printing department at igus® GmbH. Here he was able to send in the worn gears to have them redrawn and printed. The gears were manufactured from the tribologically optimised material iglidur® i3 using the laser sintering process. Components made of iglidur® i3 are very accurate in detail and have good mechanical characteristics. The decisive factor for this project was the 30 times improved abrasion resistance compared to conventional materials for laser sintering. In addition to the low wear rate, the gears have high strength. The customer reported increased gear performance after just a short time.

One of the biggest advantages of additive manufacturing is the high speed at which components can be produced. Together with the low production costs for small quantities, 3D printing is an unbeatable tool for the production of prototypes in the test phase of many applications. In this case, it was also possible to trace, print and send the gears of the planetary gearbox to the customer in a short space of time. However, the printed gears initially jammed on the retaining bolts, which is why a pinion broke when it was removed again. After a brief consultation, the CAD model was adapted and printed in a very short time. The new gears fitted exactly on the bolts in the gearbox and met the requirements. The customer reports increased performance and great satisfaction.

plastic for longer life® - the goal for every component and material that leaves the igus® gates is to improve the technology and, ideally, reduce costs. This also applies to the materials that have been specially developed for 3D printing in order to produce components with optimised sliding properties. In addition to SLS powders, igus® offers a large selection of materials with different filaments that can be individually optimised for every application. For example, iglidur® i3 is the ideal material for sliding applications and gears. The SLS powder can be processed down to the last detail with precise surfaces and exhibits extremely low wear with maximum strength. The results from the igus® test laboratory speak for themselves: Compared to conventional SLS materials, components made of iglidur® i3 have up to 30 times better abrasion resistance. This material is very well suited for gears as well as for rollers, gear racks, spur gears and bevel gears. In addition to iglidur® i3, the SLS powder iglidur® i6 is also suitable for any sliding applications. The material is characterised by its high abrasion resistance and high toughness as well as its certified food conformity in accordance with FDA and EU Regulation 10/2011. The material is particularly suitable for worm gears and for customised applications in the food industry.