Switching From Hydraulic To Magnetic Actuation

In pursuit of a more efficient PECM tool, a customer sought to replace hydraulic actuators. Conventional hydraulic actuators, while functional, imposed limitations on part production speed that hindered the company’s overarching goal of continuous improvement.

After thorough technical discussions, a single-phase multicoil “ironless” moving magnet actuator with water cooling concept was chosen. Integrated into the customer’s machinery and tested on the production line, the actuator module doubled machine productivity. Our success in transitioning from hydraulic to electromechanical actuation underscores the power of tailored innovations.

Faster
movements

Future
proof

More
accurate

Thermally
stable

Problem and approach

In the pursuit of advancing their next-generation PECM tool, a customer sought to depart from conventional hydraulic actuators due to their limitations in part production speed. They wanted to switch to an electromechanical actuator.

PECM is an electrochemical machining process, which requires a high speed moving platform for contactless electrochemical removing of metal material according to an inverted projection. The tool is required to work with high accuracy and a very small working gap.

Magnetic Innovation was asked to develop a suitable solution – an electromechanical actuator capable of delivering pulse forces up to 10kN to oscillate the tool electrode. Other specifications for the electromechanical actuator included:

  • High accuracy
  • Minimal working gap
  • Reproduction accuracy of 2-5 µm
  • High accelerations of about 35m/s^2 with a 150kg moving mass

The specific requirements demanded a tailored approach. Off-the-shelf solutions could not provide the level of accuracy, pulse force precision and high accelerations necessary to switch from hydraulic to magnetic actuation. By choosing for a custom design they showed their commitment to making an application that is future proof for the industry they operate in.

Custom actuator

Plan of approach

Based on the first technical discussions, it became quite clear that a relative large moving magnet solution was the most viable approach. After studying several actuator topology’s, the decision was made to proceed with a single phase multicoil “ironless” moving magnet actuator.

The moving magnet actuator has the advantage of minimal parasitic force effects within the electromechanics. Next to that, there are highly favourable parameters for control loop dynamics and power electronics integration.

The goal was to design and build an actuator that would achieve optimal performance from the beginning, making it suitable for both performance testing and subsequent series production.

To minimize the size of the electromechanical moving magnet actuator, we decided to incorporate water cooling. This actuator type is very suitable for water cooling, since the coils are located in the static part of the actuator.

When the design phase was finished, dedicated winding and magnet assembly tooling was developed to enable a first prototype build. The prototype was qualified in-house to validate all performance data and customer requirements.

Solution

Upon integration into the customer’s machinery and rigorous production line testing, the actuator proofed itself to be a success. This transformation facilitated cost reductions.

Thanks to the implementation of the custom actuator, the productivity of the machine significantly improved, effectively doubling its output. This enhanced productivity allowed the customer to lower the costs associated with producing existing parts, making them more economically viable. Moreover, the improved productivity enabled the adoption of the PECM process for the creation of new parts, expanding the range of components that could be efficiently manufactured using this advanced method.

Today, the actuator module is now a standard part of a successful PECM production tool. Ultimately, the goal of transitioning from hydraulic to electromechanical actuation was realized, underscoring the power of tailored innovation in engineering advancement.

Details

  • Faster movements possible with respect to hydraulics.
  • More accurate due to use of a high bandwidth control loop.
  • Thermally stable actuator principle with the use of water cooling.
  • Future proofs, further improvements possible.
  • Low contribution of electromagnetic disturbances.
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