14-04-2014, 02:39 PM
VALUE STREAM MAPPING. AN ADEQUATE METHOD FOR GOING LEAN?
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Abstract
The paper addresses the method of value stream analysis, which is a tool for
helping manufacturing companies to go lean and to achieve larger control of
their value stream. It is a qualitative tool that is supposed to give an
understanding of the value stream/value chain as a basis for reducing the
pipeline of inventory and time compress the throughput time. Both physical
flow and information flow are dealt with. The approach is informed by and
conceptualised on basis of experiences in the Japanese automotive industry
and just-in-time production. Focus is product families and it includes suppliers
and customers. A subcontractor case in the automobile industry is analysed.
The research is financed by the Productivity 2005 program (BiN) at the
Norwegian university of science and technology (NTNU).
INTRODUCTION
Since the 1980-s just-in-time production and related paradigms, such as lean
production, have been source of reference for restructuring manufacturing
industry. To a large extent the paradigms are empirical generalisations based
on the success of Japanese automobile industry in the 1980-s and later. Their
way of organising production and the supply chain proved to be much more
flexible and competitive compared to the old technological paradigm (Lipietz
1986). Just-in-time production makes up a set of principles related to the
material flow and the control of it, quality control, industrial relationships,
relationships to suppliers, etc. (Kalsaas 1995).
The paper discusses results from the study of a subcontractor in the
automobile industry that is restructuring the production inspired by the lean
production paradigm. In that regard they apply the tools named value stream
mapping or value stream analysis (Brunt 2001), which application in a case
study is analysed in the paper. The main question addressed is whether the
method is an adequate method in the process of going lean.
VALUE STREAM MAPPING
Rother and Shook (1999, p. 3) limits the focus of value stream mapping to the
“door-to-door” production flow inside a plant. Both the material and
information flows have to be considered, and the mapping address one product
family at time. The object in Lean manufacturing is to get one process to make
only what the next process needs when it needs it.
In accordance with the “pull”-thinking the mapping start at the shipping end
and proceed upstream. Each process on the material flow path is object of
being mapped in accordance to the later description in the empirical section of
the paper. The point is to uncover the value-adding time and the waste of non-
value adding time. A central point is to synchronize pace of production to that
of sales, hence it is making efforts to design work processes with a balanced
cycle time to that of customer takt time (available work time per
shift/customer demand rate per shift).
HYDRO AUTOMOTIVE STRUCTURES (HAST)
The automotive division in Hydro, HAST, manufactures structural parts and
components in aluminium for the automobile industry in Europe and North
America3. Their main product is bumper reinforcements (Crash Management)
in aluminium for the automobile market. Carmakers with a global present as
Ford (Volvo Car, Jaguar) and GM (Saab) are on the customer list. Others are
Porsche, Audi, Volkswagen and BMW. HAST operates eight plants in
Norway (Raufoss), Sweden, Denmark, Germany, France, England and in the
US. HAST’s Raufoss plant (HARA) creates 60 percentage of the turn over
(2500 million NOK in 2001). The number of employees is about 2000.
THE MAPPING PROCESS OF PORSCHE REAR
Then the value stream analysis of Porsche Rear took place; HARA could draw
on the experience from similar assessment of two BMW-product families in
2001. These led to savings in production costs of US$ 300 000. According to
HARA’s own assessments the implementation effort of Hydro Production
System, has lead to considerable improvement on indicators such as customer
rejects, on time delivery and operating margin.
Social security for work is a point of departure for the restructuring process to
be lean, which is guarantied by the plant manager. This is believed to be
crucial for the motivation of the workers to participate in the bottom-up
approach to achieve lean production.