F. Frank Chen

Enhancing lean training for the office environment through simulation and gaming

Modern training methods call for active engagement of the trainees in the training process. Simulation games are among the most effective methods of training. As waste elimination concepts become more popular, numerous lean training packages have been developed. Most of these packages include simulation games as a hands-on training tool. So far, lean simulation games have largely focused on manufacturing. However, administrative or office processes also contain a great deal of waste and could benefit from a game aimed at their processes. This paper proposes a lean office simulation game to demonstrate the effect of lean implementation on office processes. The game uses four phases to simulate the impact of several lean tools. Various performance metrics are recorded during the game to capture the impact of these tools. A case study of the game played by administrative personnel is included along with an analysis of the results.

Simulation Studies of Hybrid Pull Systems of Kanban and CONWIP in an Assembly Line

Pull system is an important component of lean manufacturing that can effectively reduce typical wastes associated with push production systems, such as overproduction. Using Toyota’s Kanban system, a production line can be configured as a pull system to avoid unnecessary accumulation of Work in Process (WIP). Another common method to carry out a pull concept is the CONWIP line, which maintains a constant WIP level within a segment of production line. Both methods have proven effective, but they may have different characteristics. The objective of this paper is to explore the potential to combine Kanban and CONWIP methods into a robust hybrid pull system that preserves the advantages of both methods while minimizing the disadvantages of each individual method. A simulation study has been carried out based on a real-world assembly line. Various pull system configurations of the assembly line have been evaluated and compared in terms of WIP level, number of Kanban cards in system, and throughput. The study shows that the productivity of CONWIP configuration outperforms Kanban configuration in majority of scenarios; and the performance of a well designed hybrid system can be more robust to various scenarios, compared to Kanban and CONWIP system.

Rough Cut Machining for Impellers with 3-Axis and 5-Axis NC Machines

In recent times, impeller machining has posed a new challenge to engineers due to demand from aerospace, automobiles, and ship building industries. Various methods are introduced by researchers in machining impellers by using 5-axis milling machine; this is because the 5-axis method has the flexibility of tool orientation to machine the extremely twisted surfaces between the blades of impellers. When impellers are machined by a 5-axis machine, the time consumed is very long and the process creates a bottleneck in the manufacturing line. The problem causes increase in the manufacturing lead time and manufacturing cost. To overcome the problem, this paper introduces a new method of machining impellers by integrating 3-axis and 5-axis machine. This paper opens up a new field in impeller machining with the aim to reduce rough-cut time. The results show that by applying this strategy, total machining time of an impeller can be reduced significantly up to 17%.