Complete tool package for machining small electric motor housings.

E-mobility: Solutions for small motor housings

Electrified mobility has long since found its way into everyday life. The general public was first introduced to electric drives on bicycles. The motor housings, among other things, pose a challenge in their production - they have to be small and light and at the same time highly accurate. MAPAL offers economical, precise and process-reliable complete packages for the machining of these housings.
The motor housings of electric bicycles are also machined with MAPAL tools.
Most manufacturers of small electric motors manufacture their motor housings from diecast aluminium - more often than diecast magnesium. The housings are very thin-walled, unstable and therefore prone to vibration. Multi-level contours within the housing provide space for the various functional motor components. The geometrical and dimensional requirements are high - tight form, running and position tolerances are specified.

Over the past decades, MAPAL has gained extensive experience in the machining of small motor housings made of both aluminium and magnesium, for example housings for chainsaws, mopeds or lawnmowers. However accuracy requirements have increased yet again with electrification.

MAPAL offers an all-round package for the machining of small housings made of aluminium or magnesium. First and foremost, PCD and solid carbide tools are ideal for machining both materials. The tool manufacturer designs the best concept including all tools and chucks depending on the requirements and complexity. Combination tools, each covering several work steps, make the process more economical.

PCD tool machines bearing and position bores on magnesium housing

MAPAL PCD tool for the bearing and position bores on a magnesium housing.

Strong vibrations in particular present a challenge when machining bearing and position bores on a specific magnesium housing because the component is extremely thin-walled in the area of the third bearing bore. The tool must remove 0.6-1 mm of material from the pre-cast bores. 

The following parameters must be observed:
  • Roundness < 0.01 mm
  • Diameter tolerance IT7
  • Average roughness depth Rz < 10 µm

​​​​For this, MAPAL designed a complex, multi-step PCD combination tool which machines the three bearing bores and the bearing seat position bore in one shot - reliably and within the required tolerances.  

​​The tool works with the following cutting data:
  • Spindle speed 8,000 rpm
  • Feed rate 3,200 - 4,800 mm/min
  • Feed 0.1-0.15 mm

Drilling and milling combined in a single tool

 A combined drilling and milling tool from MAPAL for machining an electric motor housing made of die-cast magnesium.

Another tool combines milling and drilling on a magnesium housing. While drilling steps machine the bearing bore and the position bore, a milling step is used to produce the sealing groove. It was also important for this tool to prevent vibration and keep the cutting pressure low. The tool experts achieved this by optimally coordinating the number of teeth and the geometry of the milling step. This also avoids chips in the groove.​​​​​​​

Milling step cutting data:
  • Spindle speed 8,000 rpm
  • Feed rate 7,200 mm/min
  • Feed 0.15 mm

Your direct contact

Matthias Winter from the Automotive Market Segment Management at MAPAL.

Contact person

Matthias Winter Market segment management Automotive matthias.winter@mapal.com +49 7361 585 3360