Mats I. Johansson

Design and performance of kitting and order picking systems

The results from a number of case studies carried out within a research project concerned with the design and performance of materials kitting systems are discussed. The focus is on the design of the kitting systems in terms of location of the order picking activity, work organization, picking method, information system and equipment. These design considerations are related to performance measurements, such as picking efficiency and picking accuracy, and are discussed in relation to the preconditions of the kitting system. In kitting systems, results show that picking efficiency and accuracy can be improved by making better use of the product structure when designing the picking information and when deciding the storage assignment policy. Also, batching of picking orders is cost efficient when extensive sorting and administration can be avoided. In general, combining the work roles of assembly and picking results in less administration.

Storage location assignment: Using the product structure to reduce order picking times

The stock location assignment problem is concerned and a strategy for prestructuring components and information for the picking work in storehouses is described. This classification is derived from the product structures transformed to support a holistic perception aimed at the material handler/picker. The results imply a more efficient material handling through reorganizing the components in the storage system, in order to support the work from the pickers point of view. A storage location assignment strategy emanating from the product structure is proposed, and is exemplified by using empirical data from a case study. The result from this case study was a reduction in picking information of more than 75%, which in turn greatly reduced the amount of information to the picker.

Musculoskeletal Symptoms, Ergonomic Aspects and Psychosocial Factors in Two Different Truck Assembly Concepts

The project was carried out as a multidisciplinary correlational study of two truck-axle assembly systems (System A and B). System A (the old system) could be characterized as an unpaced line assembly system, whereas the change to the new system, System B, involved a parallelized system with longer job cycle time. The study included all permanent assembly workers in the two systems (System A 17 workers, System B 28 workers). The purpose of this study was to evaluate the two systems with respect to ergonomic factors, psychosocial factors and self-reported musculoskeletal symptoms. The job cycles were studied by means of video observation. Each subject answered a questionnaire regarding musculoskeletal symptoms and physical and psychosocial environment. The assemblers in System B were more satisfied with the physical work environment (e.g. noise, air), but less satisfied with the psychosocial environment, and the period prevalence of musculoskeletal symptoms was not lower, compared with the assemblers in System A. Video observation techniques showed that deep forward flexion was less common, but that the work was more hand intense in System B. In System B, neck/shoulder symptoms were associated principally with physical work (load) variables, whereas low back symptoms were associated with psychosocial variables.

Reflective Production in the Final Assembly of Motor Vehicles – An Emerging Swedish Challenge

Presents some theoretical principles and empirical evidence relating to the new Swedish production systems for final assembly of motor vehicles. Contends that in these production systems it is possible simultaneously to enhance efficiency and quality of working life. Briefly sketches three production forms as they apply to the final assembly of automobiles and discusses the societal environments in which these different forms of production have evolved. Focuses on Volvo′s Swedish Uddevalla plant as one of the main examples so far of a reflective production system for final assembly of automobiles. Amplifies the analysis of different production flow patterns for final assembly and in particular addresses the issue of semi‐parallel mechanistic production flow and parallel organic production flow as alternatives to serial flow on a conventional line assembly.

A Methodology for Evaluation of Order Picking Systems as a Base for System Design and Managerial Decisions

Presents a methodology useful when analysing the efficiency of order picking systems. The main feature of the analysis is the ability to compare different system designs. The methodology has earlier been applied mainly to assembly production systems, and has in these cases proved to be an effective management tool in discussions concerning the choice of production system.

Materials supply systems design in product development projects

Purpose - This research aims to develop a model for describing and analysing materials supply systems (MSSs) design in product development projects (PDPs). Design/methodology/approach - Literature on materials supply and production systems design is reviewed in order to derive a MSSs design model. The model is applied to empirical data from a qualitative case study, which exemplifies how the model can serve to describe MSSs design in PDPs. Moreover, the model is used to analyse the empirical data related to the focus and characteristics of the design issues. Findings - The model developed contains six areas: materials feeding, storage, transportation, handling, packaging, and manufacturing planning and control at four levels: supply chain, plant, sub-unit, and utility. Research limitations/implications - Future research could complement the model by developing a design process to enable systematic design of the MSS as well as the integration of materials supply aspects at an early stage of PDPs. Such a design process should also consider the design of the flows of specific components. Practical implications - The importance of considering the relationships between the six design areas as well as evaluating the whole MSS is highlighted. Originality/value - The paper focuses on the materials supply aspects dealt with in PDPs, which have been the subject of little research interest so far, despite the fact that extensive resources are required for materials supply activities.

Sales and operations planning: responding to the needs of industrial food producers

This paper investigates sales and operations planning (S&OP) at four Scandinavian industrial food producers in order to explore how the use of S&OP might help leaders to deal with the challenges set by the planning environment. Variables connected to the product and market, e.g. frequency of new product development, customer service levels and supply uncertainty, were identified as particularly critical for the S&OP process. It was found that there is great potential for S&OP in the food industry, foremost to cope with the imbalances between demand and supply and to create prerequisites for a stable production process.

Fault tolerance strategies in an existing FMS installation

This paper describes a case study of an FMS installation in which fault tolerance is modelled through the use of a description model called the General Recursive System (GRS). The GRS makes it possible to study different system configuration are described, called Hardware Configuration, Mission Configuration and Work Configuration. Fault tolerance, i.e. ways to overcome erroneous situations in the FMS installation, is obtained by choosing alternative system configurations. Alternative ways to describe different fault tolerance strategies within the FMS installation are illustrated through examples.

Influences of process location on materials handling: cases from the automotive industry

During the last few years there has been a change in the physical location of activity in the automotive industry. The main trend has been towards increased outsourcing, and larger modules and more complex components are being delivered to the final-assembly plants, often in sequence. Sequencing, kitting and subassembly are frequently done at the supplier location or at an additional, intermediate facility. The need for materials handling is related to the design of materials flow systems in relation to process localisation. Five cases, having different numbers of process localisations and types of activities, are compared based on actual efficiency and potential of the system design. The results indicate that there is a large difference in the efficiency of the materials handling function depending on the existence of an intermediate facility, primarily connected to the handling of transport packages. No clear difference can be detected in relation to what types of sub-processes are located at an existing intermediate facility.

Evaluation of materials supply systems during product development projects

The aim of this paper is to analyse how materials supply systems can be evaluated during product development projects in a concurrent engineering context. The focus is on performance assessment of materials supply systems and the input data required. A case study was conducted in close cooperation with a company and two performance measures were assessed during the concept definition phase and recalculated during the product and process validation phase. The results show that preliminary input data can be used to calculate performance measures by means of the following approaches: indicators, standards or scenarios. Furthermore, it is discussed how performance assessment can assist the materials supply systems design process in a concurrent engineering context by facilitating early problem discovery, early decision-making, and common understanding.