Applicability of Lean and Value Stream Mapping Techniques in Turbulent High-Variety, Low-Volume Manufacturing Environments - A Multiple Case Study
MetadataShow full item record
Many manufacturing companies aspire to achieve performance improvements associated with lean manufacturing to cope with increasingly demanding customers and pressure from global competition. Lean was originally developed for the automotive sector s repetitive and stable manufacturing, which means that it is best suited to industries with similar characteristics. High-variety, low-volume (HVLV) manufacturers are becoming increasingly relevant in today s market due to their ability to deliver more product options and the possibility of customization. This leads to uncertain demand and variable processes, which creates the problem of turbulence, i.e. swift and sudden changes in the production system that disrupt smooth flow. This is not compatible with traditional lean practices, and turbulence is considered an obstacle for HVLV manufacturers that wish to become leaner. The primary objective in this study is to determine how turbulence in demand, process, supply and control systems affects applicability of lean techniques in HVLV manufacturing, with value stream mapping (VSM) as primary focus. The result of the research aims to confirm or disprove the following hypothesis: High degree of turbulence makes value stream mapping techniques less applicable . A second objective is to identify VSM techniques adapted to HVLV manufacturing that are more in this production environment. This study is carried out with a theoretical part and an empirical part. The former consist of a literature review that defines HVLV manufacturing and the phenomena of turbulence, in addition to present VSM techniques adapted to HVLV production. Several shortcomings of the standard techniques are identified and addressed by the modified solutions that have been reinterpreted to fit the turbulent circumstances of this manufacturing environment. The empirical part consists of case studies conducted in five HVLV companies, primarily through semi-structured interviews guided by questionnaires. Degree of turbulence and applicability of lean techniques have been mapped for all cases. Empirical findings were analyzed to confirm or disprove the hypothesis. It is found that the hypothesis is true for the VSM techniques takt time, continuous flow, supermarket pull system, pacemaker process, and leveling, i.e. the applicability of the techniques are largely influenced by turbulence. Turbulence does however appear to have less impact on basic lean techniques, product family grouping and use of first in, first out (FIFO) lanes. The main conclusion in this study is that it is indeed problematic to apply VSM techniques in HVLV manufacturing settings due to its dynamic environment characterized by uncertainty, complexity and variability. The major contribution is a detailed insight to the challenges experienced in turbulent manufacturing environments in this regard. A number of turbulence factors critical for applicability has been identified, whereas all belong to the demand and process category, thus suggesting that these two dimensions of turbulence are of most significance for applicability. Findings from the empirical study also suggest that HVLV manufacturers should attempt to implement adapted VSM techniques, as they have proven to have higher potential than what their standard counterparts do.