Process capability control procedure for electrical machines by using a six-sigma process for achieving six-sigma quality level

An overall six-sigma process (SSP) that includes a novel process capability control (PCC) procedure is presented for satisfying a six-sigma level for a Z-value as well as a mean value of target performance. An example of this process is present for the efficiency and torque ripple in a spoke-type permanent magnet motor considering the manufacturing tolerances of five rotor dimensions. In this context, six-sigma means that the probability of failure of the product or system is 0.00034%. A novel SSP with a PCC procedure is suggested for designing electrical machines. In this procedure, three possible PCC methods were determined based on the definition of the Z-value. Next, each method was carried out to achieve the target Z-value and to illustrate the advantages and possible issues associated with each method. Finally, the authors showed that the suggested PCC procedure effectively achieves the target Z-value of the motor and can be widely used for the design of electrical machines.