EMAG ECM: Non-Contact Manufacturing of E-Bike Drive Shafts

10/05/2018 - Markus Isgro


Technology is becoming more complex while simultaneously time unit volume is rapidly increasing. A perfect example of this can be seen when looking at the e-bike market. Some product innovations even remind us of the automotive industry: The first ABS systems and automatic transmissions for e-bikes have made their debuts this year. Another goal for developers is to introduce smaller and lighter e-drives while meeting growing quality requirements. To meet these demands a new application for electro-chemical machining (ECM) was born. The high-volume, precision production of key drive components is increasingly attracting the attention of industry decision-makers. A CI machine from EMAG ECM is used to quickly, precisely and economically manufacture a thin-walled e-bike drive shaft. Customized configuration of the machine by EMAG’s ECM experts is a major reason for the machines success.

According to the Confederation of the European Bicycle Industry (CONEBI) about two million e-bikes were sold in Europe in the past year – up 19 percent from last year. Unit volumes are growing at similar rates throughout Europe. Experts expect, on average, every other bike sold to have an electric drive. What does this development mean for production? The component supplier production planners are currently turning to electro-chemical machining from EMAG ECM when producing a core component such as a drive shaft. This technology is frequently used in the high precision aerospace and automotive industries. ECM ensures efficient production of complex components with high quality requirements in these industries, the exact same criteria as is needed in the production of e-bike drive shafts. They have small external gearing as well as a cross bore and are designed to have very thin walls. To complicate matters, the drilling process and an additional broaching process must be performed on the hardened component—without any warping. The specialists at EMAG ECM, headquartered in Gaildorf, next to Schwäbisch Hall in Germany, developed a production solution precisely to achieve this. It implements a CI machine that includes ECM drilling and ECM broaching which are performed one after the other. An electrolyte solution flows between the workpiece (positive anode) and the tool (negative cathode) throughout the process. Metal ions detach themselves from the workpiece and the hardness of the material has no effect on the feed rate or on precision. “The process is totally contact-free,” explains Daniel Plattner from the Technical Sales department at EMAG ECM. “The long life of the tool cathode results in reduced production costs.” It is also essential to achieve maximum surface quality and this chipless process requires no additional deburring. In addition, the ECM drilling does not generate any burrs or drill caps. 

Excellent Price-Performance Ratio

When establishing this technology, the expertise of the involved engineering department is vital. EMAG ECM is based on a modular concept in which the generator technology, electrolyte management system, tools and automation are configured individually. With this system, the production of the e-bike shaft involves a tool system with five active cathodes that are used to simultaneously produce five e-bike shafts. An additional advantage for the user is the excellent price-performance ratio of the CI series of machines implemented. Users also save valuable floorspace due to the technology’s small machine footprint of only about 5.5 square meters/59 square feet (including filtration). Our engineers have optimized the basic machine structure as well as the size of the electrical cabinet and of the electrolyte management system. Another benefit is the technologies flexibility - For example, the cycle time can be changed with scalable equipment, the system can be upgraded to full automation or the machine can be linked with additional EMAG machines. This flexibility gives users the ability to grow their machinery with their business.

Focused on the E-Mobility Industry

With all of its benefits, electro-chemical machining is continuing to grow within the e-bike market. Its process reliability plays an important role in this because ECM broaching, drilling and deburring guarantees consistently high quality—even with hardened components. “With current market demands, we are receiving a large number of inquiries from the e-mobility sector,” says Daniel Plattner. “With growing unit requirements, our reliable technology is attracting more attention than ever.”


Markus Isgro

Press and Communication

Phone:+49 7162 17-4658
Fax:+49 7162 17-4027