Riveting, welding, and interlocking all hold electrical-steel laminations together, but they do so in different ways. Riveting uses mechanical fasteners, welding joins selected points or edges with heat, and interlocking forms small mechanical connections in the laminations themselves. For motor core buyers, the best method depends on the required magnetic performance, core geometry, production volume, dimensional control, and assembly process—not on a single universally superior option.
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As a general starting point, consider interlocking for designs where integrated joining and production efficiency are priorities; riveting when mechanical fastening and accessible tooling suit the design; and welding when a robust fixed assembly is needed and the thermal effect is acceptable. These are screening guidelines, not substitutes for design validation. Below, we compare the methods and outline what to confirm with a motor core supplier.
A motor core is commonly built by stacking thin electrical-steel laminations to limit circulating eddy currents compared with a solid steel component. The joining method keeps the stack together during handling and subsequent motor assembly. Each joining approach changes the core in a different way, so a decision should account for both the joint and the surrounding magnetic material.
Sheet thickness is one relevant design input. For example, a drawing may specify laminations of 0.20 mm, 0.35 mm, or 0.50 mm; these are illustrative values, not a recommendation for every motor. Thinner sheets can be used in some designs to manage core losses, but material choice and the complete magnetic circuit determine suitability. The joining process should therefore be evaluated against the specified material and lamination design.
| Method | How it joins the stack | Potential advantage | Key consideration |
|---|---|---|---|
| Riveting | Fasteners pass through prepared locations in the laminations. | Mechanical fastening without a welded joint. | Fastener placement, holes, stack access, and assembly time. |
| Welding | Heat joins selected areas, often at stack edges or designated points. | A fixed assembly with no separate rivets. | Heat-affected areas, distortion, and possible magnetic impact. |
| Interlocking | Formed features in adjacent laminations mechanically engage. | Joining features can be integrated into the lamination process. | Feature design, local deformation, tooling, and stack consistency. |
In a riveted core, the laminations are aligned and secured with rivets through planned locations. Depending on the core design, rivets may be positioned inside or outside critical regions, subject to available space and assembly requirements. The method creates a recognizable mechanical joint that can be reviewed against the motor’s structural and manufacturing needs.
Riveting avoids the direct heat input associated with welding and may suit designs where the stack must be firmly retained using separate fasteners. It can also be considered when interlocking features are not feasible in the lamination geometry or tooling plan. However, rivet holes take up material and may affect the magnetic path, while the fasteners add components and require suitable access and assembly controls.
When reviewing a riveted design, ask where fasteners will sit relative to the flux path, how the holes will be produced, and how the stack will be held during assembly. Confirm whether the rivets could interfere with winding, housing, or other motor components. Riveting is most appropriate when those design details can be accommodated without compromising the required core function.
Welding joins parts of the lamination stack by applying heat at selected locations. The weld pattern and location depend on the design and manufacturing process. Buyers should specify which areas may be joined and review how the process will control the finished stack’s shape and dimensions.
A welded stack does not require separate rivets, and welding may be suitable when a rigid, fixed assembly is important. The main trade-off is that heat can alter material properties near the weld, and joining laminations can affect the electrical separation that helps limit eddy currents. The practical impact depends on the material, weld location and extent, and operating requirements, so it should be assessed for the specific core rather than assumed.
Discuss potential distortion and dimensional requirements with the supplier, particularly for cores that must fit closely with a shaft, housing, or other assembled parts. Ask how weld locations will be defined and controlled, and whether the proposed process can be evaluated on representative parts. Welding can be a workable choice when its structural benefit is needed and its thermal effects are acceptable for the application.
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Interlocking uses formed features, often called interlocks or projections, that engage with adjacent laminations as they are stacked. Because the joining feature is created in the lamination rather than added as a separate fastener, the method can integrate joining with the lamination production sequence. Feature position and geometry need to suit the core design and the available tooling.
Interlocking can reduce the need for separate joining components and may support efficient, repeatable production when the design and process are well matched. Its limitations include local deformation around the interlock and possible effects on magnetic performance, stack height, or flatness. An interlock pattern that works for one lamination shape or volume may not transfer directly to another.
Ask the supplier to review interlock placement against the active magnetic area and required stack dimensions. Consider how the design will be punched, stacked, and inspected, and whether the feature count and locations are compatible with the core geometry. Interlocking is a strong candidate when integrated joining is desirable and the resulting mechanical and magnetic performance can be validated.
For a design where minimizing separate components is important, evaluate interlocking first, while checking local effects and tooling feasibility. If the design benefits from mechanical fastening without thermal joining, compare riveting against the available space and hole locations. If a fixed joint is the leading requirement, assess welding while paying particular attention to heat exposure and dimensional control.
Operating conditions matter as well. A motor intended for a 50 Hz or 60 Hz supply may have different design priorities from a variable-speed motor whose electrical frequency changes with operating speed and control. Frequency alone does not determine the joining method, but it is useful context when discussing losses and core performance with a supplier. Share the application and operating range rather than asking for a joining recommendation in isolation.
There is no reliable universal cost ranking among these methods. Riveting adds fasteners and assembly operations; welding requires an appropriate joining process and control plan; interlocking may require dedicated features in the lamination design and suitable tooling. Volume, geometry, inspection requirements, material availability, and existing production setup can all influence total cost and lead time.
For early sourcing discussions, provide the core drawings, material and thickness requirements, expected annual volume, sample requirements, and any critical dimensional or performance criteria. If the design is not finalized, identify which details remain open. Request a method comparison based on the actual part and ask what validation steps are recommended before production release.
In summary, riveting, welding, and interlocking solve the same basic problem—retaining a motor core stack—but create different mechanical, thermal, and production trade-offs. Interlocking is often worth evaluating for integrated production, riveting for mechanical fastening without weld heat, and welding when a fixed joint is needed and its effects are acceptable. The final choice should follow a design-specific comparison rather than a general rule.
Onlink can support B2B buyers with motor core part discussions focused on the drawing, lamination material, joining requirements, and intended application. Send your specifications and production expectations so our team can review which stacking method is practical for your project and identify the details to confirm before sampling or quotation.
For more information, please visit Motor Core Stacking Methods Compared: Riveting, Welding and Interlocking.