E-bikes become increasingly lighter and in addition very quiet. During operation, there are hardly any motor noises to be heard. However, resourceful inventors, such as Lars Hartmann from Reichshof, are not content with that. The bicycle chain's background noise was too loud and a thorn in his side. A metallic chain sprocket served as guide roller at the chain to prevent it from colliding with the frame, but caused tremendous operating noise. In search of a remedy, he remembered the offer by igus, which he had seen at a trade show: the 3D printing service, which manufactured individual components cost-effectively with a 3D printer.
In the context of his work for VMA Getzmann GmbH, manufacturer of stirring, dispersing and fine grinding systems, machine parts were tested that had been produced with the 3D printing service by igus®. The results were so good that Lars Hartmann considered the printed parts for his e-bike. The perfect solution for the hobbyist: "The standard metal pinion generates a lot of noise when in use. We drew it and had it printed at igus, with iglidur I3 as the material. The way to the part was simple and fast. We used the 3D printing service to upload the corresponding data, chose the material and ordered the quantity." We have been using the chain sprocket in two bikes for two months – and the noise level has decreased significantly, Hartmann is pleased to say.
Left: POM gear wheel, breakdown after 621,000 cycles
Right: iglidur® I6 gear wheel, low wear at 1 million cycles
The material in use, iglidur I3, is of course also suitable for industrial application and mass production. It is especially attractive due to its low coefficients of wear and high stability, and is processed via selective laser sintering (SLS).
In addition, igus has developed the material iglidur® I6 for particularly high demands with regard to wear resistance and for a long service life. In tests, the high-performance plastic beats machined gear wheels made of common materials such as POM and PBT. A worm wheel with 5 Nm tightening torque and 12 rpm was tested. The gear made of the new laser sintering material iglidur I6 showed only minor wear after a million cycles (termination of test) and was still fully functional. Hence, it could prevail significantly compared to machined gear wheels – as gear wheels made of POM showed total wear after 621,000 cycles, while milled PBT gear wheels broke after 155,000 cycles. Also part of the test: a gear wheel made of the laser sintering material PA12. Due to the high coefficient of friction, however, it stopped after 521 cycles.
At the same time, designers can profit from the new igus® gear configurator. It allows you to configure custom gear wheels or chain sprockets, even in special dimensions. In a few steps, the user only needs to enter the specifications of the required gear wheel (such as the tooth module, number of teeth, width and inner diameter). This automatically generated a 3D model that can be exported as a STEP file. If the file is uploaded in the framework of the igus® 3D printing service, the configured gear made of the new extremely durable SLS material iglidur® I6 for gear wheels can be ordered immediately. With one click, the user can order his/her wear-resistant gear with no minimum order quantity or request a quotation. Already within three days, the custom-made part is ready for shipment.