Inner Runner Laminations
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Inner runner laminations are precision electrical steel laminations used in inner rotor motors, high-speed BLDC motors, servo motors, spindle drives, pumps, compressors and compact industrial drives. The lamination stack forms the magnetic core for the stator or rotor structure, helping control iron loss, torque output, temperature rise, noise and motor efficiency.
Compared with outer runner designs, inner runner motors usually require tighter control of shaft bore, slot geometry, air-gap surface, stack concentricity and high-speed mechanical stability. Lamination material, sheet thickness, slot opening, tooth width, yoke thickness, insulation coating and stacking method must be matched with the magnet rotor, winding scheme and operating speed.
Ningbo Vanguard Technologies supplies custom inner runner laminations and lamination stacks using silicon steel, non-oriented electrical steel and custom low-loss materials. We support laser-cut prototypes, stamping, progressive die production, interlocking, welding, bonding, stack height control, burr inspection and dimensional validation.
Whether you need prototype laminations for motor development or production-ready lamination stacks for inner runner motor assembly, Vanguard can provide engineering review and sample production within 10-25 days after drawing, material grade, stack height and tolerance requirements are confirmed.
The following lamination structures are commonly used in inner runner motor projects. Final material, bore size, slot geometry, stack height and tolerance are confirmed according to drawing and motor performance requirements.
| Lamination Type | Typical Material | Sheet Thickness | Stacking Method | Key Feature | Typical Application |
|---|---|---|---|---|---|
| Inner Runner Stator Core | Non-oriented silicon steel | 0.20-0.50 mm | Interlock, weld, bond | Stable slot geometry and controlled air-gap surface | BLDC motors, servo motors, pumps |
| High-Speed Rotor Lamination | 20W / 27W / 35W series steel | 0.20-0.35 mm | Bonded or welded stack | Low loss and strong stack integrity for high RPM | Spindles, compressors, turbo drives |
| Shaft-Bore Lamination Stack | 35W / 50W series steel | 0.35-0.50 mm | Interlock, weld, rivet | Tight bore control for shaft or sleeve assembly | Inner rotor motors, actuators, pumps |
| Segmented Stator Lamination | Electrical steel segment | 0.20-0.50 mm | Segment bonding or fixture assembly | Improves winding access and material utilization | Servo motors, high-fill winding designs |
| Prototype Laser-Cut Lamination | Silicon steel / custom alloy | 0.20-0.50 mm | Loose or bonded prototype stack | Fast validation before progressive die tooling | Motor R&D, sample testing, design iteration |
| Insulated Lamination Stack | Coated electrical steel | 0.20-0.50 mm | Bonding, interlock, weld | Controlled interlaminar insulation and stack height | Efficient BLDC motors and generators |
Vanguard can customize lamination profiles, prototype stacks and production lamination stacks. The table below summarizes common specification items for engineering review.
| Item | Available Options | Engineering Notes |
|---|---|---|
| Material | Non-oriented silicon steel, low-loss electrical steel, custom alloy | Selected according to iron loss, saturation flux density, frequency and cost target. |
| Thickness | 0.20 mm, 0.27 mm, 0.35 mm, 0.50 mm or custom | Thinner sheets reduce eddy current loss but increase stacking complexity and cost. |
| Manufacturing Process | Laser cutting, wire cutting, stamping, progressive die production | Laser cutting is suitable for prototypes; progressive tooling is preferred for volume production. |
| Stacking Method | Loose stack, interlock, riveting, welding, bonding, self-bonding steel | Stacking method affects strength, insulation, dimensional stability and magnetic loss. |
| Geometry | Outer diameter, inner diameter, bore, slot number, tooth width, yoke thickness | Geometry should be matched with winding, magnet pole count, air gap and shaft structure. |
| Surface / Insulation | Factory insulation coating, oxide layer, varnish, bonding coating | Interlaminar insulation reduces eddy current paths and improves core performance. |
| Inspection | Dimension, bore, burr height, flatness, stack height, runout, coating condition | Inspection method is customized by motor speed, air gap and assembly process. |
| Factor | Influence on Performance | Recommended Check |
|---|---|---|
| Steel Grade | Controls iron loss, saturation and efficiency at working frequency. | Choose material based on speed, frequency and thermal target. |
| Bore Accuracy | Bore error can affect shaft fit, balance and rotor-stator clearance. | Confirm bore tolerance, roundness and stack alignment after assembly. |
| Sheet Thickness | Thinner sheets reduce eddy current loss but increase cost and stack count. | Balance efficiency target, speed and manufacturing budget. |
| Burr Height | High burr may damage insulation and create interlaminar short paths. | Define burr limit and deburring requirement for production. |
| Stack Method | Welding, riveting, interlock and bonding affect strength and magnetic loss differently. | Select the method according to motor speed, assembly and efficiency requirement. |
Vanguard can customize outer diameter, inner diameter, shaft bore, slot number, tooth profile, yoke thickness, keyway, material grade, sheet thickness, stack height, stacking method and inspection standard. For new motor projects, we can support prototype lamination sets before stamping tooling investment.
Process support: We provide laser-cut samples, stamping production, progressive die development, interlocking, welding, bonding, stack height control and protective packaging.
Engineering review: If the project involves high speed, tight air gap, low noise or high efficiency, our engineering team can review material, burr control, insulation and stack process before sampling.
Production begins with drawing review, material selection and process planning. Prototype laminations can be laser cut or wire cut, while mass-production laminations are usually produced by stamping or progressive die tooling for stable dimensions and cost control.
Finished laminations are stacked by interlocking, welding, bonding, riveting or customer-specified methods, then inspected for dimensions, bore accuracy, burr, stack height, flatness and appearance before packing.
Dimensional inspection: OD, ID, bore, slot shape, tooth width, yoke thickness, keyway, stack height, roundness and runout are checked per drawing.
Process inspection: Burr height, flatness, stacking direction, weld position, bonding condition and interlock quality can be inspected by requirement.
Material verification: Electrical steel grade, sheet thickness, insulation coating and material certificate can be provided for production traceability.
Documentation: Material certificate, inspection report, dimensional report, RoHS/REACH declaration and lot traceability records are available.
To speed up engineering review, please provide a 2D/3D drawing or confirm the specifications below. If the design is still under development, Vanguard can help compare laser-cut prototype and stamping production options.
