Improving operational effectiveness in the job-shop environment through discrete event simulation and innovative process design

Abstract

A key value stream for Company X is a manufacturing area dedicated to production of precision electro-mechanical systems, of which they are contracted to service during the complete lifecycle. Currently, the production system is dedicated to the refurbishment of these electro-mechanical systems; it could be characterized as a high-mix low volume production system with a-job-shop layout. The operations team is being pressured to increase both production volumes and the product mix, while maintaining a competitive cost structure in a highly constrained environment, in terms of both space and resources. This thesis proposes two distinct projects to address the challenges faced. First, develop a framework to analyze the value stream, utilizing a discrete event simulation (DES) tool to characterize the production system.

The method will validate the DES tool against the current state production system and key performance indicators (KPI's) then conduct what-if analyses and studies based upon anticipated contractual obligations. This effort will identify risks within the value stream related to the transition from current state to future state, while studying the impact of changes in shipment volumes, product mix, direct labor, and capital equipment. This model supported conclusions and recommendations drawn, based upon the results of the DES, to build confidence in the production system and enable the value stream to meet the requirements of the increased volumes and complexity through making informed operational decisions. Second, to improve a key subassembly within the value stream identified as problematic with respect to labor content, cycle time, and ergonomics. A project has been identified to develop a new process to join two components with a tightly controlled radial bond.

Currently, the components are bonded, and the bond material must cure for several days. Upon curing, the joint contains excess bond material that must be removed for several reasons. The excess material is removed through a manual cutting process that is physically taxing on operators. After cutting, a cleanup process is initiated where an operator fills the void left from cutting with additional material; this additional bond material needs several additional days to cure. The new process utilizes an inflatable vessel that will apply pressure during the bond process to direct excess material away from the joint, eliminating the need for secondary processing in the joint, favorably impacting labor content, cycle time, and the ergonomics of operators. To speed validation and adoption, this project leveraged the 3D printing capabilities of the manufacturer.

Both the testing fixture and test articles were 3D printed in order to accelerate development and reduce risk associated with investment in the development process. Testing of the new process has indicated that the new method produces bonds of acceptable quality with markedly reduced labor content, resulting in a projected annual savings of $950k.