Dynamic card number adjusting strategy in card-based production system

Abstract

In a production line, throughput rate changes according to WIP (work in process) level and WIP is controlled through the number of production cards in a card-based production system. This paper presents a fast tuning card adjusting procedure using the CONWIP system, which can adjust the number of production cards to ensure desirable throughput rate. The method, termed DTC (difference throughput control), is based on the concept of classic automatic control theory. Whenever a TTH (target throughput value) is set, the difference between TTH and RTH (real time throughput value) is used to adjusting the number of cards. We test this procedure with an existing one in a variety of scenarios; the results show that the proposed procedure is competitive. We also analyse how processing time impacts on the performance of CONWIP system through simulation data.

Keywords:

• CONWIP
• pull system
• throughput rate
• card controlling
• production control