Profile:
Shahrukh A. Irani and Jin Zhou
Department of Industrial, Welding and Systems Engineering
The Ohio State University
Introduction:
Lean Thinking, a concept that is based on the Toyota Production System, extends continuous improvement efforts to reduce the costs of serving customer/s beyond the
physical boundaries of a manufacturing facility, by including the suppliers, distributors
and production system that support the manufacturing function [Womack and Jones,
1996]. These improvements and cost reductions are achieved by eliminating the muda
(wastes) associated with all activities performed to deliver an order to a customer. Wastes
are defined as "all activities that consume resources (add costs to the product) but
contribute zero value to the customer." According to Womack and Jones, there are five
steps for implementing Lean Thinking in an enterprise: 1) Define Value from the
perspective of the Customer, 2) Identify the Value Streams, 3) Achieve Flow, 4)
Schedule production using Pull, and 5) Seek Perfection through Continuous
Improvement. Womack and Jones define a Value Stream as "the set of all the specific
actions required to bring a specific product through the three critical management tasks of
any business: ...problem solving, ...information management, ...physical
transformation". Alternatively, Rother and Shook define a Value Stream as "all the
actions (both value-added and non-value-added) currently required to bring a product
through the main flows essential to every product" [Rother and Shook, 1999, p. 3].
Overview of Value Stream Mapping
Value Stream Mapping (VSM) is the process of mapping the material and information
flows required to coordinate the activities performed by manufacturers, suppliers and
distributors to deliver products to customers. Unlike the traditional process mapping
tools used by IE's, VSM is a mapping tool that maps not only material flows but also
information flows that signal and control the material flows. This enhanced visual
representation facilitates the identification of the value-adding steps in a Value Stream
and elimination of the non-value adding steps, or wastes (muda). Using VSM, many
OEM's and their top-tier suppliers have changed their existing facility layouts, as well as
existing systems for material handling, inventory control, purchasing and scheduling, to
reduce the total throughput times of orders and current levels of work-in-process (WIP)
inventories.
Please click here for the details:
Value Stream Mapping of a Complete Product.pdf