Key Takeaways
Traditional cleating, riveting, and welding processes induce magnetic degradation, high mechanical stress, and micro-vibrations, severely bottlenecking next-generation motor designs. Rivet-free self-bonding (Backlack) cores eliminate these issues through full-surface insulation bonding, delivering stress-free magnetic performance, ultra-low eddy current loss, and superior NVH characteristics.
1. Three Major Bottlenecks of Traditional Lamination Methods
In ultra-high-speed BLDC motors, humanoid robot joint actuators, and eVTOL propulsion units, traditional mechanical interlocking (cleating), side-welding, or bolting methods introduce distinct operational drawbacks:
- Increased Eddy Current Loss (Pfe): Stamping interlocks puncture the surface insulation of electrical steel, creating localized short circuits that dramatically elevate iron losses at high frequencies.
- Residual Mechanical Stress: Interlocking deformation and welding heat introduce severe stress fields into the silicon steel, reducing magnetic permeability and raising coercivity.
- NVH & Structural Imperfections: Micro-gaps between mechanically locked laminations vibrate under high rotational speeds, generating audible noise and failing strict stiffness and miniaturization requirements.
2. Technical Comparison: Backlack vs. Traditional Methods
Self-bonding technology uses electrical steel pre-coated with a thermoplastic or thermosetting adhesive layer. After precision stamping, the stack is cured under controlled heat and pressure to achieve molecular-level adhesion across every lamination.
| Evaluation Metric | Traditional Interlocking / Welding | Self-Bonding (Backlack) Cores | Engineering Benefit |
|---|---|---|---|
| Joining Method | Localized rivets / side weld seams | Full-surface interlaminar bonding | Eliminates short circuits & minimizes core loss |
| Stress State | High mechanical / thermal stress | 100% Stress-Free | Fully preserves raw magnetic permeability |
| Interlaminar Insulation | Pierced at interlocking points | Continuous 100% insulation | Drastically reduces high-frequency eddy currents |
| NVH Performance | Prone to micro-vibrations & resonance | Solid block structure; suppresses vibration | Whisper-quiet operation & high rigidity |
| Slot Fill & Heat Dissipation | Interlocks consume internal space | No interlocks; maximum slot utilization | Increases slot fill factor & evens heat dissipation |
3. Engineering Implementation: From R&D to Mass Production
Custom lamination is more than executing a CAD drawing; it requires deep tooling strategies, material expertise, and cost optimization.
Existing Stamping Die Library
We maintain an extensive in-house library of standard stamping dies covering various outer diameters, slot counts, and shaft configurations. During early-stage R&D, clients can leverage existing dies to produce prototype samples without paying upfront tooling fees, significantly shortening time-to-market.
Progressive Tandem Dies & In-Die Bonding
For high-volume production, single- or double-row progressive tandem dies punch stators and rotors from the same strip, increasing raw material utilization by over 15%. Integrated precision thermal controls enable high-speed stamping at 200+ SPM with shear bond strength exceeding 100N.
Ultra-Thin Gauge Processing (0.1mm - 0.2mm)
As lamination thickness decreases from 0.35mm down to 0.2mm, 0.15mm, and 0.1mm, stamping difficulty escalates exponentially. Our micron-level clearance control ensures burr-free, high-precision laminations across ultra-thin alloys.
4. Core Applications Driving Backlack Adoption
- Humanoid Robotics: Dexterous hands and compact joint actuators demand high torque density, low heat generation, and minimal noise in ultra-compact footprints.
- eVTOL & Aerospace Propulsion: Weight reduction and low iron loss directly dictate hover time and flight range under continuous high-load operations.
- High-Performance Automotive & Servo Motors: To meet demanding high-speed stress requirements and strict NVH standards, market leaders are rapidly transitioning to Backlack lamination designs.
About Youyou Company
As a premier custom motor lamination manufacturer, Youyou Company specializes in solving core loss, NVH, and heat dissipation bottlenecks in next-generation electric motors. By combining ultra-thin 0.10mm–0.20mm silicon steel processing with rivet-free In-Mold Bonding (Backlack Technology), we engineer high-efficiency, stress-free stator and rotor cores. Leveraging our extensive in-house stamping die library, we help motor developers transition seamlessly from rapid prototyping to automated high-volume production for humanoid robot joint actuators, eVTOL propulsion motors, and frameless servo systems.
Ready to eliminate eddy current loss and accelerate your motor development?
Contact our engineering team to request Backlack stator samples using our existing die library or get a free In-Mold Bonding DFM & Tooling evaluation today!
