Stamping is an established process for producing shaped laminations. Bayraktar & Turgut [] and Jayarama [] both investigate the effect of stamping on the quality of the cut edge. M400-50A (Bayraktar & Turgut) and HYPERCO 50 (Jayarama) are the materials tested. In these trials the evidence suggests that stamping does not always generate a clean, full shear cut. These results also demonstrate some deformation and rounding in the upper region of the cut.

　　One of the main competitor processes to stamping for this application is laser cutting. A laser works by focusing a high intensity light source into a very narrow beam. The laser beam is amplified by passing through a medium which can be either a solid, such as a crystal, or an assist gas []. The high energy of the laser beam melts the workpiece at the contact point, and this action of melting away material creates the cut in laser cutting. Separate to the assist gas there is an auxiliary gas which blows away molten material from the workpiece. The auxiliary gas can be inert or active. An inert auxiliary gas protects the surface from oxidation, whereas an active gas (usually oxygen) generates an exothermic reaction at the workpiece, which increases the temperature at the cutting area, allowing thicker cuts to be produced []. Laser cutting is capable of dimensional tolerances in the region of 0.01mm [].

　　Gaworska-Koniarek [] has studied the effect of using different cutting gases on the electromagnetic performance of electrical steels. Gaworska-Koniarek concluded that the use of compressed air had a more detrimental impact on the magnetic properties of the sheet than cutting with a nitrogen atmosphere. Gaworska-Koniarek proposes that the reduction in electro-magnetic performance may be as a result of iron oxides forming on the cut edge, although it appears unlikely that these would penetrate very deeply into the material. Gaworska-Koniarek also compared laser cut samples with punched samples, with results showing that for 1.5T induction, punched samples had total energy losses of 5% whereas for the samples laser cut with air the loss was 20% and samples laser cut with nitrogen showed 17% total energy losses. Salvador [] has similarly compared the performance of laser cut and guillotined (a cutting method mechanically very similar to stamping) samples, again concluding that laser cutting introduces greater losses than stamping-like processes. Bayraktar & Turgut [] compare four different cutting methods. On visual inspection of those results the stamped samples appear slightly better than the laser cut samples. The electromagnetic performance was measured, with a punched stator providing 85.16% motor efficiency and a laser cut stator 83.47%.

　　Krings [] compared the performance of punched and laser cut nickel-iron samples after annealing. The results from that research show similar levels of performance between the stamped and laser cut laminates. Krings reports that the laser cut samples reach a slightly higher saturation flux density at the cost of a slightly larger magnetic coercivity and iron losses. Interestingly, Krings concludes that there is real potential to reduce iron losses by adjusting the manufacturing processes used, suggesting that some form of optimisation can be incorporated into the manufacturing and assembly processes to increase the quality of parts produced. With laser cutting being less established, it may be that there is more potential for optimisation leading to further improvement of the method than there is for stamping. Bali & Muetze [] investigated the degradation effects of punching and laser cutting and showed that further research is required to understand effects that laser cutting has on the degradation of cut laminates, and the mechanisms by which these occur.

　　The research consistently demonstrates that laser cutting laminates introduces greater losses when used to produce stators for electric machines than punching laminates. In the best instances, the difference in performance is small, but not negligible. Miljavec [] states that punching (or stamping) is the process which should be used, citing concerns that laser cutting will increase magnetic losses, but approves of the use of laser cutting in the production of prototypes. Research is beginning to be published which considers the effects of cutting sheets simultaneously in a single operation, noting further applications in automotive industry if the process can be sufficiently optimized []. The current research however does not consider the economic and wider operations effects of using laser cutting as an alternative manufacturing process, and the performance of the material that results from the operation is another critical factor which must be understood. This research reports on the results of an experimental study where we address the potential of cutting multiple laminates in one operation using laser cutting.