Cold Rolled Motor Laminations Manufacturer

It starts with careful processing of the steel coil, followed by advanced heating techniques that are very important for getting the magnetic qualities we want.

Annealing Technologies

• Continuous Annealing Lines (CALs): Our CALs can lower core loss by up to 15–20% in 0.20–0.35 mm cold-rolled non-oriented electrical steels compared to older heating methods. This is because of even temperatures and controlled cooling. CALs are also 2–3 times faster and save up to 25% energy per ton.
• Vacuum Annealing: We use vacuum annealing to greatly increase initial permeability (up to 30% higher than air-heated samples) and remove almost all carbon (<0.002% C), which is vital for high-frequency motors. This process prevents oxidation between grains, keeping them strong.
• Rapid Thermal Annealing (RTA): For thin-gauge (≤0.18 mm) laminations, RTA helps grow a specific grain structure (Goss texture, {110}<001>). This is linked to lower hysteresis loss and better magnetic induction (B50 up to 1.85 T at 5000 A/m).
• Atmosphere Control: We use controlled H2/N2 atmospheres (e.g., 75% H2, 25% N2) to improve carbon removal and surface quality. This is especially important for very thin laminations (<0.20 mm) where surface oxidation can hurt magnetic qualities.

Microstructural Control

Our heating processes are carefully controlled to improve the material’s internal structure. Continuous annealing at 850–900°C for 2–3 minutes creates a mix of grain sizes (average 30–50 μm), balancing eddy current loss and permeability. We also stop hard particles (Fe3C, MnS) from forming at grain boundaries. This leads to better stress relief and lower magnetostriction, which directly cuts down on noise in high-speed motors.

Sino’s stamping work is designed for the highest accuracy, especially for thin-gauge (<0.2mm) electrical steel, which has its own difficulties.

Reducing Stamping Problems

• Burr Formation and Edge Quality: We keep the die clearance within 2–5% of the material’s thickness and use advanced die materials (e.g., tungsten carbide) to cut down burrs by up to 30%. This is very important because burrs can cause short circuits between layers and increase core losses.
• Die Wear and Tool Life: Using carbide dies makes our tools last 2–3 times longer than high-speed steel. We use progressive dies with swappable parts for quick changes and less downtime.
• Material Springback and Dimensional Accuracy: We use Finite Element Simulation (e.g., AutoForm, DEFORM) to predict and fix springback, making sure dimensions are very accurate (often ±0.01mm). We use special in-die steps to fight springback.
• Stamping-Induced Stresses: Stamping can harm magnetic qualities (increasing core loss by 5–15%), so we use stress-relief annealing after stamping to get performance back. For key uses, we use laser cutting to reduce stress.

Process Control and Tooling Improvements

• In-Line Inspection: For high-volume work (>100,000 laminations/day), we use camera systems (e.g., Cognex, Keyence) to spot burrs, cracks, and size errors at speeds up to 1,000 parts/minute. Some lines also have eddy current or magnetic flux sensors to check material quality right away.
• Lubrication: We use special lubricants (e.g., micro-lubrication with synthetic esters) to lower friction, die wear, and material sticking, balancing tool life with cleanliness.
• Tooling: We use progressive dies for complex shapes and high-volume work, and compound dies for high-accuracy, small-batch jobs. We are looking into 3D-printed die parts with built-in cooling channels.
• Servo-Driven Presses: Our servo-driven presses have programmable strokes, which allow for softer impacts and less stress on thin materials.
• Digital Twins: We are testing digital twin technology to create a virtual model of the whole stamping process. This helps predict tool wear and plan maintenance using real-time data.

Applying high-quality insulation coatings is very important for cutting down on eddy currents between layers and ensuring the motor can handle heat. We use coatings that fit specific needs, from standard C-5/C-6 to advanced high-temperature inorganic silicate or polyimide-based coatings that can handle up to 250°C.

Our manufacturing processes consider the important heat-control needs of motor laminations:

• Core Loss Escalation: We know that core losses go up with temperature (a 20–40% rise from 100°C to 180°C). Our material choice and processing work to reduce this.
• Saturation Flux Density Reduction: We account for the drop in B_sat with heat (0.04–0.06 T per 100°C rise) in our design advice.
• Mechanical Integrity: We make sure our laminations stay strong, resisting bending and stress at high temperatures (>150°C) to stop layers from separating and causing more NVH.
• Coating Degradation: Our advanced coatings are chosen to resist breaking down above 150–180°C, which prevents more eddy currents and hot spots.
• Thermal Conductivity: We consider the overall thermal conductivity of the lamination stack (2–5 W/m·K vs. 50 W/m·K for solid steel) because of the insulation layers. This helps us guide stack design for the best heat removal.

Sino is committed to eco-friendly manufacturing. We know that getting raw materials and making steel cause most of the GHG emissions (70–80% of the total). Our processes work to lessen our environmental impact:

• Energy Efficiency: Our cold rolling and heating processes are designed to save energy, especially where the power grid is cleaner.
• Waste Reduction: Stamping and punching usually create 15–25% scrap. We work hard to reduce this with better methods and recycle all scrap properly.
• Coating Emissions: We choose low-VOC and water-based coatings to reduce chemical and waste issues.
• Operational Phase Impact: We point out that higher-grade, thinner laminations, while maybe having a slightly bigger manufacturing impact, greatly cut down on energy losses (5–10%) during the motor’s life. This leads to a net positive effect on the environment.