Lean Manufacturing and Just-In-Time Philosophy

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 => Just-In-Time (JIT)

• The aforementioned effort should an ongoing process towards continuous improvement rather than one-time/shot effort.

Enabling factors and practices of the lean manufacturing philosophy

• 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

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 => 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

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

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

• 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

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 WIP’s and authorizes new (replacing) production, through a card-based mechanism known as KANBAN.

– Appropriate mainly for repetitive manufacturing environments.