Lean Manufacturing

Lean Production System Mapping and Development

Saginaw Metal Casting Operations:

Joe Ruder

Winter 2007

MFGO 633 Project #2

June 15, 2008

Learning Site: Saginaw

Site Code: 43

Table of Contents

1. Introduction

2. Value Stream Map вЂ" Current State Summary

3. Value Stream Map вЂ" Future State Summary

4. Recommendations

5. Conclusion

6. Appendix вЂ" Value Stream Maps

Introduction

Within the Precision Sand aluminum casting process of General Motors Powertrain, there is a consistent effort to continually improve the manufacturing process. Saginaw Metal Casting Operation (SMCO) is in the middle of implementation of the Global Manufacturing System (GMS) in their quest to become a leaner manufacturing facility. GMS is a similar system to the Toyota Manufacturing System. The elimination of muda is the objective of the SMCO organization.

This paper will primarily focus on the Liner Delivery System within the Precision Sand process. The product team receives steel liners from our supplier MPM on a daily basis. There are two types of liners in our current process. We utilize 5.3L and 6.0L liners to build the castings required by our customer, Romulus Engine Assembly.

The liners are required to be baked and then inserted into a sand core within 72 hours to maintain quality specifications. The sand cores are assembled into packages by nine robots and then transported by self guided vehicles to the cast line. The liners are received in pallets containing 288 liners which can produce 48 castings. The department currently produces 900 castings per day but has the capacity to do as much as 1800 castings.

The liners are by far the most expensive aspect of the entire process. The cost of liners is more than 64 dollars for each casting. In additions the liner thermal treatment system is responsible for over 11 percent of the entire product team’s downtime.

Current State

The current process is operational but very expensive due to excessive built in muda. The liners are trucked in daily from our supplier. The shipping dock receives the forecasted order and then transports the liners to various storage locations within our facility. Excess liner scrap contributes to excess cost in the process.

The storage locations include a main plant staging area, elevator holding area, buffer conveyor, liner deck staging area, and the oven conveyor system. The shipping dock fork truck driver delivers the liners from the plant staging area to the elevator staging area and removes the empty dunnage from the elevator holding area. A different driver then loads the elevator with incoming liners which travel up the elevator on the buffer conveyors. As the elevator buffer is being loaded, the liner assembly operator removes the liners from the conveyor and stores the liners in the designated location on the liner deck. The liners are then transported onto the oven conveyors which allow the liners to be loaded into the ovens by two robots.

The liners come in pallets which are traced by lot number and barcode. The liner deck operator scans each pallet of liners as they are loaded on to the oven conveyors to ensure the 72 hour expiration is tracked. The barcode system will reject liners that have expired.

The liners then travel through three ovens and are loaded onto pallets by robots that send the pallets of baked liners to the liner buffer. The assembly elevator pulls from the liner buffer to build the packages.

As the process continues, the liner deck operator continues to load unbaked liners into the process and sends empty dunnage back down the elevator fro the shipping dock truck driver to pick up and return to the plant staging area.

The operator often fails to utilize FIFO in the process and therefore allow liners to expire before they