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Undercutting machines for the partial removal of mica between big DC motor commutator bars.

Rimac undercutters are available in several configurations and with different degrees of automation.

  • Rimac | Undercutting 1
  • Rimac | Undercutting 2
  • Rimac | Undercutting 3

Technical features:

Rimac offers a wide range of undercutters, benefiting from advanced technology and guaranteeing excellent results on any type of commutator

For instance, having an automatic bar indexing means that you can easily work on the most difficult commutators.

We supply a wide range of undercutting tools (cutters), capable of creating any undercutting profile on the commutator.
The linear interpolation of the electrical axis enables the machine to have linear changes in the undercutting depth, at the beginning and at the end of the commutator.

Technical solutions refined over 30 years of experience make our machines capable of undercutting commutator of all sizes. Skewed bars are not a problem: the operator can choose the most suitable program among four undercutting modes.

The integration of an easy and user-friendly HMI completes the offer when it comes to DC motor undercutting machines.

Generally speaking, the undercutting function can be integrated in multi-function machines performing multiple operations on the armature, such as turning, armature banding, TIG welding and electrical testing.


Via Doberdò 39 – 21046 Malnate (VA) – Italy | Ph: +39 0332 429963 Fax: +39 0332 424639 | Email:

© 2019 Rimac Machines – Rimac S.r.l. – VAT nr. IT02569340132