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...

background: obesity may lead to various morbidity including liver diseases. the present study was done to determine which obesity indices, including body mass index (bmi), waist circumference (wc), waist to hip ratio (whr), and waist to height ratio (whtr) have the stronger association with rising levels of alanine aminotransferase (alt). material and methods: of 6143 subjects aged ≥ 10 years o...

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...

Process capability indices (PCIs) have been widely used in industries for assessing the capability of manufacturing processes. Castagliola and Castellanos (Quality Technology and Quantitative Management 2005, 2(2):201–220), viewing that there were no clear links between the definition of the existing multivariate PCIs and theoretical proportion of nonconforming product items, defined a bivariat...

Statistical techniques are effective and powerful means of quantifying the variability of processes, analyzing this variability with reference to product requirements, and eliminating this variability in product manufacturing. Many process capability indices have been effectively and widely used to determine whether the quality of a process meets preset targets. However, conventional process ca...

Capability indices compare the actual performance of a manufacturing process to the desired performance. In practice these indices are estimated using sample data, often with quite small sample sizes. Thus, it is of interest to obtain confidence limits for actual capability index given a sample estimate. Most of the traditional methods for assessing the capability of manufacturing process are d...

The classical method of process capability analysis necessarily assumes that collected data are independent; nonetheless, some processes such as biological and chemical processes are autocorrelated and violate the independency assumption. Many processes exhibit a certain degree of correlation and can be treated by autoregressive models, among which the autoregressive model of order one (AR (1))...