Process capability indices (PCIs), Cp, Ca, Cpk, Cpm, and Cpmk have been developed in certain manufacturing industry as capability measures based on various criteria, including process consistency, process departure from a target, process yield, and process loss. It is noted in certain recent quality assurance and capability analysis works that the three indices, Cpk, Cpm, and Cpmk provide the s...

Over the past few years continuously new process capability indices have been developed, most of them with the aim to add some feature missed in former process capability indices. Thus, for nearly any thinkable situation now a special index exists which makes choosing a certain index as difficult as interpreting and comparing index values correctly. In this paper we propose the use of the expec...

Process-capability indices are effective tools for the continuous improvement of quality, productivity and managerial decisions. Statistical process-control techniques improve the quality in mass production. In this study, a process-capability analysis was carried out in the machining line of a medium-sized company that produces machine and spare parts. For this purpose, normal probability plot...

In this paper we propose the use of design capability indices for use in robust design. These indices allow the design requirements to vary within a certain range. Design capability indices are based on process capability indices from statistical process control and provide an alternate approach to the use of Taguchi’s signal-to-noise ratio which is often used for robust design. Successful impl...

Engineering tolerance plays an important role in the process capability analysis for determining whether a manufacturing process is capable of making good quality products. In contrast with the engineering tolerance region in a multivariate manufacturing process, the multidimensional machining process or the nano-cutting process has a special engineering tolerance called the positional toleranc...

Process capability indices (PCI) can be viewed as effective and excellent means of measuring product quality and performance. Several capability indices including Cp, Cpk, and Cpm are well accepted and the implementation of these techniques is successful. The indices Cpu, Cpl, and Cpk have been used previously for evaluating a multi-process product with smallerthe-better, larger-the-better, and...

Process capability indices are widely regarded as a flexible means of evaluating the quality and performance of a process. Accreditation by the Quality System Requirement QS9000 requires an agent to conduct a global evaluation on the process capability over the entire product family from a plant. Generally, the process capability of the whole product family is an important reference for evaluat...

The production of a process is expected to meet customer demands, specifications or engineering tolerances. The ability of a process to meet these expectations is expresed as a single number using a process capability index. When the quality of the products relates to more than one characteristic, multivariate process capability indices are applied. As it is known, in some circumstances we are ...

Generally, an industrialproduct hasmore thanone quality characteristic. In order toestablish performance measures for evaluating the capability of a multivariate manufacturing process, several multivariate process capability indices have been developed in the past few years. Among them, Taam’s MCp and MCpm indices have the drawback of overestimation and Hubele’s three-component capability vecto...