Micromilling Using A High-Speed Spindle

inspire AG performs research on various project topics. Some of our current research topics include advanced and additive manufacturing, laser machining, and Industry 4.0. The scope of our research also extends to micromachinery. Our primary research objective in micromachinery is to provide a reliable micromilling strategy for microstructuring electrodes. These electrodes are applied in subsequent die-sinking EDM operations. For experimentation, milling tools with a diameter as low as 200 µm are used. To guarantee a proper cutting speed, and thus a stable process, a spindle speed as high as 200.000 rpm is required.

Micro Milling

The ability to machine microstructures is desirable for many applications ranging from miniaturization to functionalization of large surfaces. This includes the microstructuring of electrodes for die-sinking EDM applications, the micromachining of hierarchal structures for self-cleaning surfaces, and the use in the watch- and jewelry industry. In order to machine microstructures, high demands are placed on machine accuracy, spindle speed, the inverter, tools, and so on.

Machine Setup

Micromilling experiments are conducted with a Mikron HSM 400 U 5-axis-machining center from GFMS in Switzerland. A Mach Serie 200 spindle from MachSwiss provides a rotation speed as high as nmax = 200.000 rpm and is controlled by a ACO5000A inverter from Ornika SA.
As extreme spindle speeds and high spindle efficiency are required, the ACO5000A is equipped with a Pulse Amplitude Modulation (PAM). Furthermore, PAM has low switching losses compared to Pulse Width Modulation (PWM). The PWM is usually employed if low spindle speeds are desired. The ACO5000A provides an output frequency of 5000 Hz, thus covering the necessary frequency up to ~3330 Hz, and a voltage of 200 V. Both are required for a spindle speed of nmax = 200.000 rpm.

Micro Structures

Micromilling is carried out using a 200 µm diameter tungsten carbide micro-end milling tool from Dixi Polytools in Switzerland. In tungsten reinforced copper (WCu), defined structures with a height of 200 µm and width of 60 µm are feasible to machine. To avoid burr formation and to guarantee low surface roughness, the cutting speed – and respectively the spindle speed – must be set as high as possible for such small tools.

End of a micro-rib in WCu with a total length of 5 mm, a height of 200 µm and width of 60 µm

An ACO5000A inverter with a control panel for spindle speed regulation

inspire AG was founded by ETH, Swissmem and the Swiss Federation with the mission to transfer research insights from the university to the industry

As a strategic partner of ETH Zurich, inspire AG is the leading Swiss competence centre for technology transfer to the mechanical, electrical and metal (MEM) industries. It conducts research for the industry, develops state- of- the- art technologies, methods and processes and solves problems in all areas of product innovation and production technology. inspire brings together the best partners from industry, universities and technical colleges for joint projects and has the brains, knowledge and experience to successfully turn ideas into innovations. inspire can provide new solutions wherever new territory is to be broken, where technical or project management skills are lacking and where unbiased judgement is required. inspire is a technology competence centre funded by the Swiss Confederation, created by a joint initiative of Swissmem and the Swiss Federal Institute of Technology, Zurich.

Henning Büttner
Doctoral Student in Mechanical Engineering

Register to our newsletter ( max 4 x year )

© 2018 -2019  Ornika SA

Cookies make it easier for us to provide you with our services. With the usage of our services you permit us to use cookies.
More information Ok