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FMI Motors Engineering

The FMI series motors by Rozum Robotics rely on the advanced brushless technology to meet the requirements of robotics and other precision drive applications. Minimized wearable parts, increased efficiency, enhanced controllability and safety—those are major advantages of the engine setup. What places the FMI drives on a par with similar competitor products?

Up to benchmark standards  

In the basic configuration, FMI engines are sold as frameless encoder-ready stator and rotor kits. Suitable for use either as direct drives or embedded motion hubs. With the frameless kit design and a hollow shaft, the actuators allow for remarkable mounting flexibility and space-saving integration.

FMI motors
FMI series frameless rotor and stator kits

Best R&D practices

The company boasts a staff of experienced hardware and embedded engineers who use advanced software tools to make design calculations and optimize engine performance.

So far, the R&D team’s efforts have helped to achieve the following:

  1. Improved geometry | The improvement entailed low cogging to provide enhanced dynamics and reduced product size to enable wider integration and usage options.
  2. Optimized winding | A dense copper fill factor accounts for higher torque density—i.e., more capacity in a smaller size. In addition, concentrated coils help to minimize thermal losses.
  3. Upgraded thermal characteristics | Casting the stator with an epoxy compound leads to better heat dissipation and superior motor performance. An in-built NTC sensor ensures thermal overload protection.
rozum robotics team
R&D team discussing ideas

Quality raw materials    

Rozum Robotics knows it firsthand that finding reliable suppliers is key to building a smooth manufacturing flow. Counting in the factor is crucial to provide quality output and meet delivery deadlines.

A database of reputable suppliers was created, comprising those who have proven expertise and extensive experience in related fields. Simultaneously, a strategy was adopted, aiming at localization of component production within the company’s own premises. For now, the components of FMI engines are mostly manufactured and assembled in-house, whereas suppliers act as vendors of consumables—metal, magnets, wiring, etc.

To manufacture its frameless motor and stator kits, Rozum Robotics utilizes first-rate raw materials. These include copper wiring and rare-earth rotor magnets contributing to magnetic field strength, as well as electrical steel plates making up the stator lamination stack.

Own production      

From design to shipment, the entire manufacturing process is under Rozum Robotics’ stringent control. The company has introduced a multistage product delivery flow, with each stage completed in three to five iterations. The production management method enables to deliver fast, while improving the output on-the-go.

At the end of each iteration, the team verifies acquired results against predefined objectives and makes changes when and as needed. The final and obligatory step at every stage is quality control. The last milestone in the delivery flow is acceptance testing in a specialized stand to confirm motor compliance with requirements and specifications.

Process insights

After R&D calculations are refined and drawings are revised as appropriate, the FMI manufacturing flow migrates to the company’s workshop. Below is a general sequence of how an FMI motor “rolls off the conveyor.” The starting operation is precision laser cutting in a CNC machine to get stator plates with a specific tooth profile. Varying the profile of the coil-supporting teeth in the stator allows to optimize performance of FMI engines.

servo motor
Laser-cut stator plates

Once the stator plates are cut, they are assembled and welded into a lamination stack. In standard FMI models, the stack is 20 mm high. On the upper and lower side, isolation pads are installed to prevent any damage to copper coils in the course of winding.

servo motors
Stator stack and copper coils on the teeth

The next step is winding copper coils onto the stator teeth. The winding pattern, method, and total turns play a role. The denser the coiling, the higher torque an actuator can generate.

stator plates
Welding stator plates

As soon as the winding operation is complete, the stack is rolled up into a ring and welded along the mating line. The wiring ends from the coils on the stator teeth are laid to form a three-phase Y-configuration power output, enabling to pack more power into the engine. For thermal protection, an NTC thermistor is embedded into the FMI stator winding, enabling overtemperature cutoff.

stator rings
Rolled up stator rings

The assembled stack with copper winding is then cast with a compound, which is intended to upgrade thermal performance of the FMI frameless engines. Compound casting is the last operation to deliver the stator in its ready-for-use form.

FMI series motors by Rozum Robotics

FMI series motors by Rozum Robotics

FMI series motors by Rozum Robotics

FMI series motors by Rozum Robotics

FMI series motors by Rozum Robotics

The next workflow stage is assembling the rotor—i.e., gluing magnets onto a support ring, observing the pole alternation sequence.

Magnets glued to a rotor

Keeping the entire production flow within in-house workshops, Rozum Robotics can track compliance with quality standards end-to-end. Whether it is purchasing consumables, or assembling components, or after-sales servicing, each stage is under the spotlight. As a result,  we can state proudly—our motors deliver reliable power, at the state-of-the-art level.