Bonding varnish (Backlack)

Bonding varnish (Backlack): New motor concepts and fast bonding in minutes

Lamination stacks made with bonding varnish (Backlack) improve performance as well as thermal conductivity, strength, and cleanliness. They also cause fewer short circuits, vibrations, and noise. This allows you to improve your motors or implement completely new motor concepts. Bonding varnish (Backlack) also makes it possible to reduce the use of materials with segmentation.

Technology leader for innovations in bonding varnish (Backlack) technology

Bonding varnish (Backlack) technology for stator and rotor stacks was developed before the turn of the millennium. Over the last 25 years, enormous developments and many series productions have resulted from this. SWD AG has shaped these developments from the very beginning. Today, we are the technology leader in the processing of electrical sheet coated with bonding varnish (Backlack). To this end, we are constantly developing new tools, processes and procedures. Our technologies are widely established and are being used in industrial series manufacturing.

BPS® technology

BPS® technology for stator segments is revolutionizing bonding varnish (Backlack) processing. This results in minimal material usage, maximum process reliability, and improved magnetic properties in the lamination stack. A digital twin is used for tracking, analyzing, and improving processes.

Find out more

EPS® technology

EPS® technology for full stators and rotors is a precise, fast, always identical and documented bonding process. Thanks to a precise coordination of bonding varnish (Backlack) layer thickness, degree of pre-curing, and controlled bonding pressure, the stacking factor is optimal. Your benefits: Reliable bonding processes and 100% traceability.

Find out more

DKS® rotary cavity system

The DKS® technology for segmented stators and rotors saves a lot of material. Segments are punched and stacked overlapping like a brick wall. After the quick bonding process, the stator or rotor is ready.

Find out more

Excellence in production and processing

We have already produced millions of parts with our fully automated systems. Our “high-speed” bonding makes cycles of a few minutes possible. We use fully finished and coated electrical sheet from various manufacturers all over the world. Our technologies for manufacturing bonding varnish (Backlack) stacks are always based on the principle of the complete separation of punching and bonding. This means that we don’t have to make any compromises and can get the best out of each sub-process.

Quality | Processes & Industrialization
10.03.2023 - Reading time: about 3 minutes
The technologies for bonding electrical sheet are different and have a major impact on the stator and rotor stacks.
Read full article

Why you should use bonding varnish (Backlack) for your lamination stacks

Functional integration

With bonding varnish (Backlack), several functions can be integrated into the lamination stack. This saves on components when assembling the electric motor.

Maximum precision

Bonding varnish (Backlack) makes it possible to manufacture lamination stacks with maximum precision. Thanks to the full-surface connection, even filigree geometries can be precisely punched, stacked, and bonded.

Optimum stability

Bonding varnish (Backlack) stacks are very stable. This simplifies further processing and assembly. Thanks to the wide-area connection, the stack can be handled like a milled part. (Further) mechanical processing is easily possible.

Virtually no short circuits

Unlike punch-stacking or welding, bonding does not cause any direct short circuits between the laminations, resulting in better magnetic properties and fewer losses.

Reduced noise

The laminations do not fan out and the full-surface connection reduces both vibration and noise. Ideal for meeting the increasing demands.

Cleanliness

Dirt and particles are firmly bonded thanks to the wide-area connection. The cleanliness is higher. No liquid is drawn in between the laminations.

Optimal thermal conductivity

Full-surface bonding improves thermal conductivity within the lamination stack, as bonding varnish (Backlack) has better thermal conductivity than air. Even optimized bonding varnishes (Backlack) with higher thermal conductivity can be achieved.

Reliability

Bonded lamination stacks can be mass-produced using state-of-the-art processes and with maximum process reliability. Our fully digitalized processes provide more transparency than any other process.

What our employees have to say

“Bonding varnish (Backlack) technology will help your motor concepts achieve greater stability and performance.”

Thomas Stäuble

CEO

Future prospects with bonding varnish (Backlack)

We work with bonding varnish manufacturers to improve various parameters in the lamination stack, such as thinner coatings for a higher stacking factor, new formulations such as fast and rapid for faster bonding, different curing behavior for narrower height tolerances, higher temperature resistance, etc.

Impressions

Our specialist will be happy to answer any questions you may have.

Fact box

  • Bonding varnish (Backlack) improves the performance of your electric motor
  • Bonding varnish (Backlack) enables new motor concepts
  • Reduced use of materials
  • Maximum process reliability in series manufacturing
Scroll to Top