Lean supply is closely associated with enabling flow and the elimination of wasteful variation within the supply chain. However, lean operations depend on level scheduling, and the growing need to accommodate variety and demand uncertainty has resulted in the emergence of the concept of agility.This paper explores the role of inventory and capacity in accommodating such variation and identifies how TRIZ separation principles and TOC tools may be combined in the integrated development of responsive and efficient supply chains. A detailed apparel industry case study is used to illustrate the application of these concepts and tools.
The Bullwhip Effect is problematic: order variability increases as orders propagate along the supply chain. The fundamental differential delay equations for a retailer's inventory reacting to a surge in demand are solved exactly. Much of the rich and complex inventory behavior is determined by the replenishment delay. The analytical solutions agree with numerical integrations and previous control theory results. Managerially useful ordering strategies are proposed. Exact expressions are derived for the retailer's orders to the manufacturer, and the Bullwhip Effect arises naturally. The approach is quite general and applicable to a wide variety of supply chain problems.
We calculate the range of a projectile experiencing air resistance in the asymptotic region of large velocities by introducing the Lambert W function. From the exact solution for the range in terms of the Lambert W function, we derive an approximation for the maximum range in the limit of large velocities. Analysis of the result confirms an independent numerical result observed in an introductory physics class that the angle at which the maximum range occurs, θmax, goes rapidly to zero for increasing initial firing speeds v0≫1. We show that θmax∼(ln v0)/v0.
The last twenty years has seen a relentless shift to offshore manufacturing as retailers chase ever-lower labor costs. The results of this strategy can now be evaluated and we propose that some adjustments are in order. We analyze the case of a North American apparel manufacturer that has successfully emerged from a period of major change with a strong and strategic position in the apparel supply chain.Griffin Manufacturing, Inc., is a U.S. garment contactor manufacturing athletic wear for major national and international brands. For a decade, the strategic goal of one of Griffin's major customers has been to eliminate U.S. factories, and to replace Griffin with offshore manufacturing. While 80% of the manufacturing has indeed moved offshore, a critical mass remains. This case study documents Griffin's survival through evolution in capabilities, technology, and especially attitude. The Griffin case study suggests that keeping a portion of the manufacturing onshore at an agile, quick response factory is cost effective: It increases sales and improves margins. However, the new relationship between the parties is much more complex and requires commitment on both sides.
The Offshore Crisis at GriffinIn 1990, foreseeing competitive offshore pressures, Griffin changed its mission to the production of athletic apparel, and working with a small, innovative company, Griffin produced some of the first-ever jogging bras. Griffin invested in new sewing machines and by 1993 was producing 20,000 garments per week. Since then, Griffin has steadily grown 20% annually to a current volume of $20 million.A dramatic change occurred in 1993 when our small, innovative customer was taken over by a large, multinational corporation that immediately attempted to move the manufacturing to Honduras. We can now look back on several cycles in which new managers visited Griffin with the goal of eliminating the last "irritating amount" of domestic manufacturing. After these meetings orders would abruptly fall to zero, but within weeks would start to flow
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