Lean Manufacturing and Just-In-Time Philosophy

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Lean Manufacturing and Just-In-Time Philosophy
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Basic Idea

• Try to eliminate the system operational
  inefficiencies and the resulting waste by
• trying to produce the right items in the right
  quantities and quality at the right time through
  the right procedures.
• In the emerging philosophy, inventories should be
  carefully controlled and they should not function
  as the mechanism for accommodating the system
  inefficiencies gt Just-In-Time (JIT)
• The aforementioned effort should an ongoing
  process towards continuous improvement rather
  than one-time/shot effort.

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Enabling factors and practices of the lean
manufacturing philosophy

• Reduce the variability in the system
• input
• quality of raw material
• delivery times
• operation
• processing times
• process capability
• (smaller) lot sizes
• output
• production volume
• production scope

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Enabling factors and practices of the lean
manufacturing philosophy (cont.)

• Timely and reliable information flow across the
  entire supply chain through
• stable, long-lasting and trustful relationships
  between the different parties in the supply chain
• flexible / electronic ordering mechanisms
• Electronic Data Interchange (EDI), and
• e-commerce practices
• vendor owned and managed inventories

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Enabling factors and practices of the lean
manufacturing philosophy (cont.)

• Reliable and flexible production and transport
  systems
• establishment of well-tuned processes with
  predictable and controllable performance gt
  Statistical Process Control (SPC)
• reduction of set-up times through the adoption of
• flexible equipment
• standardization of designs and production methods
• externalization of set-up tasks
• introduction of mistake-proofing techniques like
• explicit checklists
• integrated machine gages
• real-time linkage of the transport carriers to
  the corporate headquarters / operational planning
  center through mobile telephony and global
  positioning systems

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Enabling factors and practices of the lean
manufacturing philosophy (cont.)

• Well-trained, responsive and responsible /
  empowered personnel
• knowledge management
• quality circles
• employee ownership of the processes and their
  results
• flattened (middle) management structures

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Push versus Pull production control schemes

• Push (MRP-type) control schemes Predict the
  demand and try to initiate and coordinate
  production in order to meet these predictions
  under the available production capacity.
• Pull control schemes Assuming a stable demand
  rate, establish the production capacity and the
  Work-In-Process (WIP) levels that will allow the
  system to meet demand as it occurs.
• Generated demand consumes the existing WIPs and
  authorizes new (replacing) production, through a
  card-based mechanism known as KANBAN.
• Appropriate mainly for repetitive manufacturing
  environments.

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KANBAN-based Production Systems

Station i
Station i1
A material balance equation (Number of Kanbans)
(Container Size) (Demand at Station i1
over a Cycle Period) (Safety Stock)