States that, under certain circumstances, a single • control chart with tightened control limits may be more effective for detecting process shifts than the combination of • and s control charts, while the type I error can be kept at the same level. A computer program is developed to decide...

The mean shifts (or range shifts, standard deviation shifts) of a process may be classified into a set of modes (or classifications), each of which is characterized by the shift magnitude (δ) and the occurrence probability, f. The knowledge relating to the shift modes is useful to the...

Following an alarm signal from a control chart it may be necessary to conduct an adjustment to bring the process mean towards a target value. Addresses the problem of how such an adjustment should be made, based on the use of an EWMA control chart, including the special case in which the EWMA is...

The double exponentially weighted moving average (DEWMA), which is known in the literature as Brown′s one‐parameter linear method for forecasting is proposed as a control tool for process monitoring and detecting shifts in the process mean. Obtains a closed‐form expression for the...

When there is a change in a process, the MaxMin exponentially weighted moving average (EWMA) control chart shows which parameters have increased or decreased. The MaxMin EWMA may also be viewed as smoothed tolerance limits. Tolerance limits are limits that include a specific proportion of the...

Purpose – The purpose of this paper is to present the application of a procedure for the quality control of stainless steel tubes produced for automotive exhaust systems from a leading company in the steel sector, based on the Delphi method in accordance with the ISO/TS 16949:2009 and the ISO...

Presents a modification of Saniga′s model for joint economic design of process control parameters, i.e. sample size, sampling frequency and critical regions for X and R charts. The objective is to minimize the total system cost, which consists of the cost of sampling and charting, the cost of...

Presents two production models for maintaining current control of an industrial process under the surveillance of an np ‐control chart. The first model assumes that the process is not allowed to continue in operation during the search for the assignable cause. The second assumes that the...

Studies the economic design of x ‐ control charts in a situation in which the duration time that the process remains in the in‐control state follows a general distribution which has an increasing hazard rate. In this situation, the active and persistent action for quality control is to...