Quality Assurance for High-Performance E-Motors

Quality Assurance
for High-Performance E‑Motors

Reliable components through inspection and quality data
E-Motor Quality Management in Production

E-motor quality management in production

Highest accuracy for automated processes

Many of the components in compact high-performance electric motors are produced in automated processes. They require checks at every stage of production – though the requirements may vary, precision is a constant need. E-motor performance depends on ensuring proper positioning, accurate dimensions, and high-quality weld seams.

ZEISS excels when it comes to these precision assemblies, which require micrometer-level accuracy and a range of technologies including automated and contact-free solutions.

Full coverage of e-motor applications

Electric motors are the true powerhouses in electric vehicles, combining high speed and enormous torque while being light and compact. In order to achieve maximum performance with little wear, all components must interlock precisely for perfect interaction. Inspecting the hairpins and sheet stacks, checking weld seams on the stators, measuring the rotors and shafts – you can do it all with the ZEISS portfolio. Click the links below to explore our dedicated quality assurance solutions for electric motor applications.
Hairpins: Inspection of dimensions and positions


Inspection of dimensions and positions

Hairpins consist of a bent rectangular copper wire and are coated with an insulating layer. Since they are highly susceptible to deformation and their ends are difficult to weld, it is necessary to inspect the dimensions and positions of hairpins during the stator assembly process.

Sheet Stacks: Inspection of geometry and surface

Sheet stacks

Inspection of geometry and surface

Sheet stacks comprise numerous 2D sheets less than 1 mm thick. Key quality aspects include the cross-section slot geometry for the hairpins, the permanent magnet slots, and the inner and outer diameter of the sheet stack assembly. Micrometer-range tolerances mean the sheets must be flat and burr-free.


Defect inspection and digitization

Among all e-motor components, the stator offers the greatest potential for improving performance, power, and efficiency. Given new raw materials and innovative manufacturing technologies, quality assurance is required across all stator production steps to guarantee e-motor safety, reliability, and performance.

Rotors and shafts

Inspection of shape and location

Due to the high performance and speed of the e-motor, the rotor must meet very tight shape and location tolerances that require inspection. The air gap between the rotor and the stator bore is one of the main parameters defining the safety, reliability, and efficiency of the e-motor.

ZEISS eMobility solutions at every manufacturing step

Blue Line for battery development and production

Click through all quality gates

  • Quality Gate 1: Size, Form, and Position

    Geometrical inspection of hairpin production


    • A large number of hairpins are used as current-carrying conductors in electric motors
    • Difficult to geometrically inspect individual dimensions due to flexible hairpin structure and sensitive coating with insulating lacquer

    Your benefits with ZEISS

    • Overcome structural properties of hairpins via contact-free measurement with optical probes on CMMs
    • Fast full-field digitization of hairpins without pretreatment thanks to laser triangulation using ZEISS LineScan
    • Fully automated contact-free digitization of sensitive structures with ZEISS ScanBox for eMotors
  • Quality Gate 2: Single Sheet and Sheet Stack

    Geometrical inspection in production of sheet stacks


    • Sheet stacks comprise multiple single sheets each just a few millimeters thick
    • 2D geometry, flatness, and absence of burrs must be assessed on individual sheets
    • QA with micrometer-level precision ensures proper fit and e-motor performance

    Your benefits with ZEISS

    • Multisensor ZEISS CMMs combine a large number of tactile and optical probes on a single system
    • This enables automated inspection of component pallets for increased machine utilization and reduced inspection cycle times
    • Quick and effective internal defect detection with ZEISS X-ray solutions
  • Quality Gate 3: Insulation Paper and Hairpin Position

    Stator installation


    • Positioning and excess length of insulation paper between hairpin and stator must be inspected to prevent stator short circuit
    • Inspection of hairpin end positions before and after welding is critical for ensuring e-motor safety, reliability, and performance

    Your benefits with ZEISS

    • Insulation paper positioning performed with optical 3D scanning and ZEISS CMMs
    • Optimum process control and merging of different measurement results via ZEISS PiWeb reporting and statistics software
    • Determine the position of hairpin weld tips using ZEISS PRISMO with tactile styli

  • Quality Gate 4: Weld Seam Inspection

    Stator installation


    • Lacquer residue from sealing can result in weld seam porosity that impairs e-motor performance or causes total failure
    • Non-destructive defect inspection of all weld seams is therefore a critical requirement

    Your benefits with ZEISS

    • Detection, localization, and classification of pores and defects inside weld seam with industrial CT systems such as ZEISS METROTOM
    • Ensures non-destructive quality assurance and monitoring of the weld processes
  • Quality Gate 5: Analysis of Installation Space Dimensions

    Stator installation


    • The e-motor can only be assembled if external stator dimensions do not exceed installation space in e-motor housing
    • Complex geometries and mixed materials of stator also increase difficulty of quality assurance for overall component

    Your benefits with ZEISS

    • Automated switching between different sensors supported by ZEISS CMMs equipped with ZEISS mass technology
    • Full QA of pre-assembled stator thanks to combination of laser triangulation probes and tactile stylus systems
    • Automated inspection of larger quantities with ZEISS Integration Series

Extra insights into quality assurance for e-motors

  • Five measurement steps for optimal quality control
    ZEISS eMobility Solutions at GROB: Success Story
  • Multiple measuring tasks handled by precision ZEISS technology
    Measurement of E-Motor Stator
  • Multiple measuring tasks handled by precision ZEISS technology
    Measurement of E-Motor Stator Features
  • Multiple measuring tasks handled by precision ZEISS technology
    Measurement of E-Motor Winding Head

“That’s why we have to perform constant checks from incoming goods to the fully assembled part: What is the bending behavior of the wire, does the geometry fit, is the paper insulation layer positioned between the hairpins and the sheet metal package, do the welds fit?”

Georg Knoll

Head of Inspection Laboratory, GROB

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