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

• What was needed: new gears for an electric bicycle planetary gearbox
• Manufacturing method: Selective laser sintering
• Requirements: detail accuracy, fitting accuracy, abrasion resistance
• Material: iglidur i3
• Industry: bicycle sector
• Success through collaboration: thirty times the abrasion resistance of conventional SLS materials, high wear resistance, higher efficiency

The application at a glance:
Replacements were needed for the heavily worn gears of an e-bike planetary gearbox. Because the electric bicycle manufacturer was unable to supply any additional gears, the customer found the solution in the 3D printing department of Cologne-based igus GmbH. The new gears could be traced on the basis of the old, worn components and printed using the laser sintering process. The customer was able to install the gears immediately after receipt and noticed an improvement in gearbox performance after only a short time.

 

The e-bike is now working perfectly again with the replacement gears

Problem

The gearbox of an electric bicycle no longer produced the initial power and a quick look inside the planetary gear showed the reason: the gears were badly worn. Original spare parts could not be supplied by the manufacturer, so the customer looked elsewhere for replacement gears. The gears should fit snugly in the gearbox and have a significantly higher abrasion resistance than the previous components in order to withstand the loads.

Solution

The customer turned to the 3D printing department of igus GmbH. Here he was able to send in the worn gears to have it redrawn and printed. The gears were made of the tribologically optimised material iglidur I3 in the laser sintering process. Components made of iglidur I3 are very detailed and have good mechanical properties. 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 a high strength. After only a short time, the customer reported enhanced performance of the gearbox.

Quick prototype - better effect

One of the biggest advantages of additive manufacturing is the high speed at which components can be produced. Combined with the low manufacturing costs for low volumes, 3D printing is an unbeatable tool for prototyping in the test phase of many applications. It was thus also possible in this case to redraw the planetary gears in a short time, print them and send them to the customer. However, the printed gears initially jammed on the retaining bolts, which is why one sprocket broke when it was removed again. After a short consultation, the CAD model could be 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 utmost satisfaction.
 

After a few tests, the correct dimensions for the replacement gears were found

Especially for gears and the like - iglidur I3 and iglidur I6

plastics for longer life® - the goal for every component and material that leaves the igus gates is to improve technology and ideally reduce costs in the process. This also applies to the materials that have been specially developed for 3D printing in order to produce sliding-optimised components. In addition to laser sintering powders, igus offers a wide range of materials with various filaments that bring individual optimisations for every application. Thus iglidur I3 is the suitable material for sliding applications and gears. The laser sintering powder can be processed with exact surface details and has extremely low wear with maximum strength. The results from the igus test laboratory speak for themselves: Compared to conventional laser sintering materials, components made of iglidur I3 have up to 30 times better abrasion resistance. It is very suitable for gears as well as for rollers, gear racks, spur gears and bevel gears. Besides iglidur I3, the iglidur I6 laser sintering powder is also suitable for any sliding applications. The material is characterised by the fact that, in addition to high abrasion resistance and high toughness, it has certified food conformity according to FDA and EU Regulation 10/2011. The material is particularly suitable for worm wheels and for customised applications in the food industry.
 

In the planetary gear, the good mechanical properties of iglidur I3 take effect