Article ID: | iaor1998671 |
Country: | United Kingdom |
Volume: | 35 |
Issue: | 5 |
Start Page Number: | 1213 |
End Page Number: | 1228 |
Publication Date: | May 1997 |
Journal: | International Journal of Production Research |
Authors: | Inman R.R., Bhaskaran S., Blumenfeld D.E. |
Keywords: | manufacturing industries, inventory |
Traditionally automotive assembly plants operate with at least two weeks of frozen vehicle orders enabling them to calculate the amount of material needed for the next two weeks. Implementing a pull system between the plant and its customers, and level-material-shipping between the plant and its suppliers, changes the amount of material buffer needed within the assembly plant. The pull system eliminates the frozen vehicle-order schedule, without which plants cannot calculate the material needed, but must use inventory to buffer the line from random demand. Level-material-shipping, a just-in-time principle that provides suppliers with a constant shipping schedule, forces plants to use material inventory to buffer the line from un-level demand for parts resulting from un-level production or an un-level model mix. We model these effects to derive formulae for the buffer needed to provide a given service level in the face of demand variability, un-level production, and un-level model-mix.