Process variability and its effect on plant performance

Abstract

This report presents the preliminary findings of a research study to determine the factors which enable a manufacturing plant to simultaneously achieve high labour productivity, fast, reliable delivery and high quality consistency. The conclusions are based on analysis of a database containing details of 953 manufacturing plants in the UK. Based on the performance measures mentioned above, a composite performance measure was calculated for each plant in the database. The plants were then divided into groups of high performers, medium performers and low performers. Using statistical analysis, those differences between the high and lowperforming plants that were significant were identified. The main factors differentiating highperforming plants from the rest were those associated with low process variability, high schedule stability and more reliable deliveries by suppliers.

A joint pricing, lot-sizing, and supplier selection model

“…With regard to late delivery, inconsistency is the percentage of time delayed, whereas in the case of wrong delivery it is the percentage of goods returned (Beamon, 1998;Mapes et al, 2000;Chan, 2003). Service level is defined as the percentage of lots that are completed before or on the due date, while inconsistency rate is a measure that is broader than the measure of service level that has thus far been used in multi-objective supplier selection literature (e.g.…”

The quest for process operations variability reduction in manufacturing firms in South Africa

“…Xinlin, Tang and Rai-Arun (2014), Vanpoucke, Vereeckeb and Wetzels (2014), and Mapes et al (2000) suggest that manufacturing firms should develop customer-suppliers relationships so that suppliers could provide on-time delivery. The result of on-time delivery would be not only the reduction of the throughput time and an increase in delivery reliability, but also a reduction in the amount of inventory that should be held.…”

“…Hafner (1991) and WuaKan and McGinnis (2012) conclude that the reduction of the standard deviation of the processing and inter-arrival times has a similar effect on throughput times, which results in an increase in manufacturing capacity. Mapes et al (2000) state that, the lower the variability in the output at each manufacturing step, the higher the percentage of adherence to quality conformance, and the lower the reject rate. The overall effect is an improvement in throughput rates, cost and delivery reliability.…”

“…According to Plossl (1991), all the benefits are directly in proportion to the speed of flow of materials and information within the process operations. Mapes et al (2000) mention that low throughput times and high stock turns are intermediate measures. However, they are a major source of competitive capability; they are themselves the outcome of earlier actions by the organisation (Hall, 1987;Ohno, 1988).…”

“…The current research study attempts to correct this deficiency. Mapes et al (2000) in their study of "Process variability and its effect on plant performance", developed the mechanisms between performance drivers and performance capabilities, using crosssectional data. The purpose of this study is, therefore, to examine the fundamentals drivers and the performance capabilities, as well as the mechanisms within manufacturing firms that would lead to multiple competitive capabilities using longitudinal data.…”