How To Eliminate Burrs in Electric Motor Laminations? Laser Cutting & Welding Solutions

In the last blog we talked about, silicon steel is an electric motor core in the vital components of the material, however, just choose the most suitable material is not enough to create a perfect motor core laminations. Motor manufacturing is constantly evolving, yet the issue of burrs in electric motor lamination remains a persistent headache, demanding innovative solutions. This blog will lead us to discover the causes of burrs and how laser cutting and welding technologies solve motor core lamination burr problems. Learn about precision processing, reduced electromagnetic losses, and CH Laser's 27-year expertise.

一、What Are Electric Motor Lamination Burrs? Causes & Impacts

During the manufacturing process of electric motor laminations, burrs refer to sharp protrusions or irregular defects formed along the edges of silicon steel sheets after stamping or cutting operations. These metallic residues typically range in size from microns to millimeters, predominantly appearing on blanking cross-sections or slot openings of the laminations.

Critical Impacts of Burrs on Motor Performance:

1. Degradation of Electromagnetic Efficiency
Burrs induce poor interlamination contact, exacerbating magnetic hysteresis losses and eddy current losses. Statistical data indicates that excessive burrs can increase core losses by 15%-30%.

2. Insulation Failure Risks
Rotor slot burrs pose puncture hazards to winding insulation layers, potentially triggering short-circuit failures. (One motor manufacturer reported a 22% increase in product recall rates due to burr-related issues.)

3. Compromised Assembly Precision
Burr accumulation causes dimensional deviations in lamination height, adversely affecting air gap uniformity between stator and rotor. (A mere 0.1mm burr can result in a 5% deviation in air gap dimensions.)

（source：WIKIPEDIA）

二、Five Root Causes of Burr Formation in Traditional Motor Core Manufacturing

Given the severe impacts of burrs on motor lamination cores, what are their root causes? According to global data from motor core lamination manufacturers, 80% of burr-related defects originate from the following factors:

1. Physical Limitations of Stamping Dies

Die clearance deviations: Excessive clearance (>12% material thickness) creates tensile burrs.

Insufficient clearance (<5% material thickness) induces compressive burrs. (Case study: A 0.02mm clearance deviation caused 300% excess burr height at one manufacturer.)

Edge wear and blunting: After 100,000 consecutive stamping cycles, the die edge radius increases by 0.1mm, raising burr occurrence by 47%.

2. Material Properties of Silicon Steel

While silicon steel remains the preferred material for laminations, its softness increases burr susceptibility during processing:

Thickness tolerance variations: ±0.05mm thickness fluctuations (exceeding the ±0.03mm tolerance per GB/T 2521) result in 40% burr height discrepancies.

Non-uniform grain orientation: Hi-B steel exhibits 25% shear force disparity between transverse/longitudinal directions, aggravating edge irregularities.

3. Equipment Precision Degradation

Press guideway wear: Every 0.01mm loss in parallelism expands burr-affected zones by 18%.

Hydraulic pressure fluctuations: ±5bar pressure variations induce 22% burr height instability.

4. Process Parameter Mismatch

Punching speed-material yield strength incompatibility: Q235 steel shows a 3x surge in burr occurrence at punching rates >30 strokes/minute.

Insufficient lubricant film thickness: Oil films <2μm cause die sticking, increasing burr height by 50%.

4. Post-Processing Limitations

Traditional deburring methods face critical inefficiencies: Vibratory tumbling/chemical etching; Low throughput with residual burr rates up to 12% post-processing; Risk of secondary burrs from abrasive re-deposition.

三、Laser Technology: A Revolutionary Solution to Eliminate Burr Challenges

In response to the inherent limitations of traditional stamping processes, laser cutting and laser welding technologies are redefining manufacturing standards for electric motor laminations.

Advantages of Laser Cutting in Preventing Lamination Burrs:

1. High-Precision Cutting with Smooth Edges
Laser cutting utilizes a focused high-energy laser beam to achieve micron-level precision, producing smooth cuts free from mechanical stress. This eliminates edge burrs caused by die wear or mechanical pressure in traditional stamping. For instance, silicon steel sheets cut by laser can be directly assembled into laminations without secondary grinding.

2. Minimal Heat-Affected Zone (HAZ), Reduced Material Deformation
The heat-affected zone in laser cutting is extremely narrow (typically 0.1–0.5 mm), mitigating edge warping or micro-cracks induced by thermal expansion. This characteristic is particularly advantageous for precision processing of thin silicon steel sheets.

3. Non-Contact Processing, Zero Mechanical Damage
As a non-contact method, laser cutting avoids burrs and debris generated by friction between traditional tools (e.g., stamping dies) and materials.

4. Automated Control for Superior Consistency
Computer Numerical Control (CNC) programming enables fully automated cutting, ensuring dimensional and geometric uniformity across all laminations. This minimizes burr risks associated with human operational errors.

Advantages of Laser Welding in Preventing Lamination Burrs:

1. Precision Welding, Minimizing Post-Processing
Laser welding leverages its high energy density and micron-level controllability (e.g., adjustable spot size down to microns) to achieve precise fusion between core laminations. The resulting weld seams are uniform and spatter-free, eliminating burrs caused by unstable molten pools or splatter in traditional welding methods (e.g., TIG welding).

2. Controlled Heat Input, Reduced Deformation Risks
Laser welding delivers localized and controllable heat input, with a heat-affected zone (HAZ) only 10%–20% of conventional welding. This significantly minimizes thermal deformation in the weld zone, preventing localized warping or burrs induced by thermal stress in laminations.

3. Non-Contact Welding, Zero Mechanical Compression
As a non-contact process, laser welding eliminates the need for mechanical pressure, avoiding surface damage or burrs caused by fixture compression or physical contact from welding torches in traditional methods.

4. Automation Integration, Enhanced Process Stability
Laser welding seamlessly integrates with automated systems. Real-time monitoring tools (e.g., infrared thermography, spectral analysis) optimize welding parameters to ensure consistent seam quality, reducing defects (e.g., porosity, cracks) and subsequent burrs caused by process fluctuations.

四、Why Choose CH Laser Prototyping Service

CH Laser has developed into the field of laser processing for 27 years, and has accumulated rich experience in the application of laser equipment. For the prototyping difficulties and pain points in the motor industry, we can realize the mold-less processing of motor core to meet the rapid and high-precision sampling needs of motor customers.

We have:

High precision and complex shape machining capability

1.1 Micron-level precision: the positioning accuracy of laser cutting can reach ±0.01mm, which is suitable for fine cutting of high magnetic permeability materials such as silicon steel sheet, ensuring even air gap after motor core laminations and reducing magnetic loss;

1.2 Complex contour realization: it can easily process complex structures such as shaped grooves, teeth, curved edges, etc., to meet the special needs of high-performance motors or transformers on the shape of iron cores;

1.3 No mechanical stress: non-contact machining avoids material deformation or burrs caused by traditional stamping, and reduces subsequent grinding processes.

Rapid response and moldless production

2.1 No need to make molds: traditional stamping requires customized molds (long cycle time and high cost), while laser cutting is directly programmed and processed according to CAD drawings, which is suitable for small-lot and multi-variety sampling;

2.2 Shorten the R&D cycle: from design to sample delivery takes only a few hours to a few days, accelerating product iteration verification;

High material utilization

3.1 Flexible Adjustment: Only program parameters need to be modified when the design changes, no need to re-mold, reducing the cost of trial and error.

Optimized nesting cutting: maximize the utilization rate of silicon steel sheet through intelligent nesting software, reduce the edge waste, and lower the material cost (especially significant for the higher price of high grade silicon steel sheet);

3.2 High-efficiency processing of thin plates: the cutting efficiency of laser cutting on 0.1~3mm thick silicon steel wafers is much higher than that of traditional processes, and the heat-affected zone is small to avoid degradation of magnetic properties of materials.

If you are worried about motor core lamination burrs or are interested in CH Laser's innovative solutions, please feel free to leave your request and our professional team will be happy to serve you.