Stator core lamination

The most critical factor is the grade of electrical steel (silicon steel). You must specify whether you require Cold-Rolled Non-Oriented (CRNO) or Grain-Oriented (CRGO) steel. Pay close attention to the lamination thickness (typically 0.2mm, 0.35mm, or 0.5mm), as thinner sheets reduce eddy current losses but increase manufacturing costs. Ensure the material meets international standards such as AISI, DIN, or JIS.

Insulation coatings are vital for preventing short circuits between layers. Common options include C3 (organic) for improved punchability, C5 (inorganic) for excellent heat resistance and weldability, and C6 (mineral filled) for high insulation. For high-efficiency motors, ensure the coating can withstand annealing temperatures if post-stamping heat treatment is required.

Top-tier suppliers should utilize high-speed progressive die stamping for high-volume consistency or laser cutting for low-volume prototyping. Inquire about their stacking methods, such as interlocking (cleating), welding, riveting, or back-lap (bonding) technology. Bonded cores are increasingly popular for EV motors as they minimize vibration and noise while maintaining magnetic integrity.

Suppliers must provide reports on dimensional accuracy (tolerances within ±0.02mm) and burr height control (typically kept under 0.02mm to prevent insulation piercing). Request Iron Loss Testing (W/kg) and Stacking Factor verification. Certification to IATF 16949 is mandatory if you are sourcing for the automotive industry, while ISO 9001 is the baseline for industrial applications.

Yes, most professional manufacturers on Made-in-China.com offer OEM/ODM services. You should provide CAD or DWG drawings specifying slot geometry, outer diameter (OD), and inner diameter (ID). Discuss tooling costs (die charges) upfront, as custom progressive dies represent a significant initial investment but lower the unit price for long-term production.

Material fraud is a common risk. Always request a Mill Test Certificate (MTC) that matches the heat number of the steel used. For large orders, hire a third-party inspector (like SGS or Intertek) to perform a spectrometer analysis and magnetic property test before the goods leave the factory.

Since electrical steel prices fluctuate, negotiate a formula-based pricing model linked to a public steel index. To secure better rates, consider longer-term contracts or larger MOQs, as suppliers often offer 10-15% discounts when production runs exceed 5 tons due to reduced setup times.

Stator laminations are heavy and prone to rust. Insist on VCI (Volatile Corrosion Inhibitor) paper or vacuum sealing, followed by heavy-duty wooden crates (IPPC heat-treated). Ensure the cores are tightly packed to prevent lamination shifting or edge deformation caused by sea freight vibrations.

Use Secured Trading Services provided by Made-in-China.com to ensure payment is only released upon proof of shipment. For initial orders, utilize a 30% deposit and 70% balance against the Bill of Lading (B/L) structure to maintain leverage over quality and delivery timelines.