Stig Arne Mattsson

The implications of fit between planning environments and manufacturing planning and control methods

The applicability of manufacturing planning and control methods differs between environments. This paper explains the fit between the planning environment and material and capacity planning on the detailed material planning and shop‐floor planning levels. The study is based on a conceptual discussion and a survey of 84 Swedish manufacturing companies. Results show the use of planning methods and their levels of user satisfaction in complex customer order production, configure to order production, batch production of standardized products and repetitive mass production, respectively.

Framework for Characterizing the Design of VMI Systems

– The purpose of this study is to provide for the research community as well as for the practitioners measures that enable the evaluation, categorization and comparison of vendor managed inventory (VMI) systems., – In this paper, a framework is developed for characterizing the design of VMI systems based on a review of prior research and an empirical investigation of industry‐to‐industry VMI relationships in Sweden., – The proposed framework incorporates the main characteristics of VMI systems and serves as a tool for profiling VMI system designs and for facilitating the comparison and analysis of different VMI system configurations., – The Swedish industrial context in which the framework was tested should be taken into consideration when generalizing upon the findings., – VMI systems come in various shapes and setups, as a result of which the challenges related to their operation and management may differ significantly. This study addresses the issue by providing practitioners with a tool that helps them in the design and management of VMI systems., – While categorizations and measures for the VMI systems exist in prior research, this study contributes by synthesizing the existing measures and testing them in empirical setting. The study contributes particularly to the research on VMI systems but also more broadly to the supply chain management research.

Inventory management practices and their implications on perceived planning performance

This paper focuses on the use of material planning methods to control material flow to inventories of purchased items. The first sub-objective is to evaluate the perceived planning performance of material planning methods used to control material flows in different inventory types in manufacturing and distribution companies. The second sub-objective is to evaluate the difference in perceived planning performance depending on the way planning parameters are determined and the methods used. Five material planning methods are studied: the re-order point method, the fixed order interval method, run-out time planning, Kanban and MRP. Our analysis is based on survey data from 153 manufacturing and 53 distribution companies. Findings conclude that the use of material planning methods differs depending on where along the material flow they are applied, whether the inventory is located in manufacturing or in distribution operations and between companies of various sizes. The modes of applying a material planning method affect its perceived performance. In particular, the way of determining and the review frequency of safety stocks and lead times have great importance for the planning performance of MRP methods, while the determination and review of order points, review frequencies and run-out times were important for re-order point methods.

A longitudinal study of material planning applications in manufacturing companies

Purpose – The paper seeks to describe the state-of-the-art, reasons for selecting various material planning methods, and modes of applying methods for initiating inventory replenishment of purchased items. It also identifies trends from 1993 to 2005. Design/methodology/approach – Empirical survey data are collected from Swedish manufacturing companies in 1993, 1999 and 2005. The MRP, re-order point, fixed interval ordering, run-out time, and Kanban methods are studied. Findings – MRP is the most commonly used method and its position has strengthened since 1993. A common way of determining parameters such as order quantities and safety stocks is to use judgment and experience. Parameters used in material planning methods are reviewed relatively infrequently. The planning frequency has increased, with daily planning now being typical. Research limitations/implications – The major limitation is that different data collection techniques were used in 1993 compared with 1999 and 2005. An important research implication is that the state-of-the-art applications differ from theoretically appropriate application modes. The trends are towards less appropriate modes among the most widespread applications. Practical implications – The frequency of reviewing planning variables is relatively low in industry, and should in most situations be increased. The paper implies that more user-friendly software applications need to be developed and implemented. It could serve as guidelines when designing and developing training and education programs and function as a benchmark. Originality/value – The paper provides a longitudinal state-of-the-art description of materials planning usage and identifies application modes with positive and negative performance impact.

Order‐to‐delivery process performance in delivery scheduling environments

Purpose - The purpose of this paper is to generate a performance model for an order-to-delivery (OTD) process in delivery scheduling environments. It aims to do this with a triadic approach, encompassing a customer, a supplier and a logistics service provider. Design/methodology/approach - The paper takes the form of a conceptual analysis and a triadic case study on performance measurement requirements in an OTD process characterized by delivery scheduling, and generating performance models. Findings - Two OTD process performance models, one for the suppliers delivery sub-process and one for the customers delivery scheduling, the logistics service providers transportation and the customers good receipt sub-process, in delivery scheduling environments are generated. Research limitations/implications - A single case study limits the levels of external validity and reliability to analytical generalization. Practical implications - The generated performance models include definitions of four sub-processes and outline ten performance dimensions that should be of relevance for several companies to apply. Originality/value - This is the first approach that generates performance models for a triadic OTD process for use in delivery scheduling environments.

Inventory control in environments with short lead times

Purpose – The objective of this study is to revise and enhance existing inventory control models in a way that allows them to be used more efficiently in environments with short lead times.Design/methodology/approach – A simulation approach has been chosen to assess the efficiency of the developed model. This simulation is based on randomly generated demand data with a compound Poisson type of distribution.Findings – Results from the simulation show that traditionally used inventory control methods fail to ensure that desired service levels are attained in environments with short lead times. The simulation also shows that, by using the developed model, the differences between desired and attained service levels can be reduced to fall within limits acceptable in practice.Originality/value – The study provides an enhanced inventory control model that can be used in environments with short lead time to increase service level performance.

The Selection and Application of Material Planning Methods

Methods for planning and control of the flow of material in the manufacturing enterprise are more or less appropriate to use in a specific situation, mainly depending on the existing planning environment. How well they contribute to an effective material flow is also depending on how they are applied. This paper examines which material planning methods companies are using, to what extent these methods are perceived as efficiently supporting the operation, how the various methods are applied, and how the satisfied users apply the methods. The findings are based on a survey study carried out in 84 manufacturing companies in Sweden in 2000. From the results some conclusions concerning state-of-the-art application of material planning methods in the manufacturing industry are presented. A comparison with a similar study on the same population from 1993 is also conducted. The findings show that material requirements planning is generally the most used method. The most common ways to determine planning parameters are based on judgement and experiences. The majority of companies review the parameters less frequently than once a year. The satisfied users, however, use more analytical approaches and review parameters more frequently than others.

Advanced material planning performance: A contextual examination and research agenda

This research examines the inventory performance effect of advanced material planning modes and analyses how internal and external contextual difficulties moderate this relationship. This study also identifies avenues for future research. The empirical analysis uses a survey of material planning for purchased items in 292 Swedish manufacturing and wholesaling companies. Three dimensions of inventory performance are dependent variables: material planning performance, inventory turnover rate and service level. Advanced material planning modes are directly associated with material planning performance, but this study could not verify direct associations with inventory turnover rate and service level performances. External and internal contextual difficulties have direct effects on all inventory performance dimensions and moderate the inventory performance effect of advanced material planning modes. The moderating effect is stronger in non-difficult contexts, for which advanced material planning has significant inventory performance effects. Demand- and human-related contextual dimensions are especially critical. The study identifies the following guidelines for companies to consider in order to unlock the potential of advanced material planning: consider full implementation of advanced material planning in non-difficult contexts; minimize plan variability effects of high parameter revision and planning frequencies; minimize the need for, and use of, manual modification of planned orders before release; reduce demand uncertainty and variability; and secure appropriate human skills and working time. This study somewhat contradicts the literature on material planning by not finding a direct positive effect on any inventory performance dimension from analytical design of order quantities and safety stocks. Our research adds to the literature by identifying direct and moderating effects of external and internal contextual difficulties on all three inventory performance dimensions. The relative importance of managing automatic order release identified in our study motivates future research as the effect has not been previously highlighted in the literature. Accordingly avenues for future research and an agenda for practice-oriented research are suggested.