| dc.description.abstract | Purpose The purpose of this thesis is to develop a spreadsheet tool for takt planning in a high-mix/low-volume (HMLV) environment. Ultimately, the objective is to develop tool that the production planner can use to test different scenarios and evaluate flow and utilization performance for different plans. Using the developed tool, this project further examines those parameters in a few scenarios.
Context Takt based production is challenging in the make-to-order or engineer-or-order context for several reasons, one of which is the difficulty of achieving flow and demand due to the diverse components that often comprise the final product. This parts diversity makes it challenging to plan production since there are many unique products a company can have seven or more product families all with the same function. The research is set in the machining work center of a thruster manufacturing company with a high-mix/low-volume (HMLV) attribute. The setting is that of a shared multi-equipment work-center with one function (i.e., machining), limited equipment scope (an equipment can only be used to machine a small portion of components that make up the final product) and increasingly stringent performance requirements. There is currently no available tool customized enough for the case company to evaluate the effects of different product combinations on flow. Common to industries with this attribute, and in the case company used in this research, there is a demand backlog spanning several months and one of the company s goals is to increase flow efficiency and utilization without sacrificing throughput.
Research gap Due to the complicated nature of the planning and control in the manufacturing of these type of complex products, there is a need for a tool that facilitates the production planning process. The literature is silent on product configuration detail that can alter planning dynamics materially in a HMLV production. Furthermore, there is also a knowledge gap into how the products configuration affects production in this type of system: what is the effect on flow efficiency, throughput, delivery flexibility and capacity utilization? Are the results in this setting different from established knowledge in conventional manufacturing systems? The answer to these questions have been researched extensively in make-to-stock production but scarcely in HMLV.
Research design A spreadsheet model was designed, tested and demonstrated following the design science methodology. Using specific product data for three products or two product families, four planning scenarios were examined and further analysis was carried where limitations where met in the sophistication of developed model. evaluate the consequence of certain planning decisions on the operational performance of a machining cell within a plant considering a shift from pure MRP-based control principle to one with takt time control.
Findings For low machine utilization, level scheduling outperforms the unlevelled schedule as expected from literature. In some scenarios of HMLV production where, the perfectly level production sequence for production within the frozen interval (in this case, one week) does not lead to significantly different results when machine utilization is high. This can be the case when final products are shipped to customers from the finished goods storage once a week due to the size or weight of the products and the attendant high cost of shipping. In addition, the tactical use of overnight operations and the high utilization machines lead to a reduction in work-in-process requirement for levelled mix but not for the unlevelled production scenario. This is important because some 5-axial computer numerical control or CNC machines can be programmed to work autonomously without an operator during the night and therefore will not lead to extra resource requirements during the period of operation.
Practical implications There is a scarcity of tools for the planning and control of this type of production system leaving production planners to the use of basic spreadsheet calculations and the whims of shop floor supervisors. Moreover, although stacked production (i.e., completing the production for one product before starting the next) of multiple products yields the best results for throughput and inventory in low capacity utilization scenarios, in capacity-constrained operations, it underperforms. In general, a level product mix will improve flexibility and performance and improve the flow of operations in the long term. However, in the short term and especially within the chosen frozen interval, it appears to be better to sequence production using a long-span batched sequence rather than a levelled product mix (rather than limited) mix yields improved results on both performance measures.
Research limitations The findings of this study cannot be generalized for the reason that it is based on a single case study data. Moreover, since every HMLV production system is unique in some way, care must be taken in expanding the application of the findings beyond production situations markedly dissimilar to this. In addition, the model design did not include an optimization functionality thereby limiting the production sequences used in this research to simple sequences only. For this reasons, there is a need for future research using more extensive product configurations and attribute dimensions. Examples of dimensions that could serve practical and academic research interests include variation in frozen intervals, number of machines, and route complexity including multi-stage planning.
Originality/value This research work fills a gap in the application of takt-based production in a high-mix low volume production system and highlights factors that practitioners must consider when considering takt production. The findings provide valuable insights for managers operating within the relevant context and researchers seeking to expand knowledge in this field.
Keywords make-to-order, high-mix/low-volume, takt, pull production, planning horizon | en |
