Benefits of Lean Manufacturing:
To benefit from Lean Manufacturing, the processes must be maintained consistently
and correctly. Everyone involved must be educated and committed to the system.
Benefits are typically lower costs, higher quality, and short lead time.
Safety
6S
The seven key wastes which are attacked in Lean thinking derive from the original seven
wastes defined in the Toyota Production System. These seven sources of waste are:
Transportation (moving products that is not actually required to perform the processing)
Inventory (all components, work-in-progress and finished product not being processed)
Motion (people or equipment moving or walking more than is required to perform the processing)
Waiting (waiting for the next production step)
Overproduction (production ahead of demand)
Over Processing (due to poor tool or product design creating activity)
Defects (the effort involved in inspecting for and fixing defects) [2]
Various Tools of Lean Manufacturing:
Five S’s: sort, simplify, sweep, standardize, and sustain
Just In Time Inventory/ Kanban: Producing and delivering the correct items at the correct time and in the correct amounts.
Kaizen: Continuous improvements
Jidoka: As a quality assurance measure, using mechanics which will stop production when a malfunction occurs.
Various Concepts of Lean Manufacturing:
Single-piece production: A situation in which products proceed, one complete product at a time, through various
operations in design, order-taking, and production without interruptions, back flows, or scrap.
Batch & Queue: The mass production practice of making large lots of a part and then sending the batch to wait in
the queue before the next operation in the production process.
Production Improvement: Individual employees seek ways to do things better
Cycle Time: The time it takes to complete one cycle of an operation. If cycle time can be reduced to Takt-time,
products can be made in Single Piece Flow
Cells: layout of machines of different types performing different operations in a tight sequence, typically in a
U-shape, to permit single-piece flow and flexible deployment of human effort by means of Multi-Machine working.
Elimination of Waste: Examples of waste can be overproduction, inventory, transportation, processing, scrap, motion
and waiting.
Five Why’s: Taiichi Ohno’s practice of asking “why” five times whenever a problem occurs in order to identify the
root-cause of the problem so effective countermeasures can be developed and implemented.
Takt-time: The accessible production time divided by the rate of customer demand. For example, if the customer
ordered 250 widgets and there were 500 minutes of production operation, it would take 2 minutes to
produce each widget.
Visual control: The placement of everything visual, such as signs, charts, and tools, all positioned in clear view
where everyone can observe the status of the system just by glancing.
Why JIT?
In Kaizen, JIT is a is a collection of concepts and techniques for improving productivity.
JIT is a process aimed at increasing value-added and eliminating waste by providing the
environment to perfect and simplify the processes.
What is JIT?
Just-in-time manufacturing means producing the necessary items in necessary
quantities at the necessary time. It is a philosophy of continuous improvement
in which non-value-adding activities (or wastes) are identified and removed.
Putting this concept into practice means a reversal of the traditional thinking
process. In conventional production processes, units are transported to the
next production stage as soon as they are ready. In JIT, each stage is required
to go back to the previous stage to pick up the exact number of units needed.
Kamban - a Communication Tool in JIT Production System
Being a very important tool for just-in-time production, kamban has become
synonymous with the JIT production system.
Kamban, meaning label or signboard, is used as a communication tool in JIT
system. A kamban is attached to each box of parts as they go to the assembly
line. A worker from the following process goes to collect parts from the previous
process leaving a kamban signifying the delivery of a given quantity of specific
parts. Having all the parts funneled to the line and used as required, the same
kamban is returned back to serve as both a record of work done and an order
for new parts. Thus kamban coordinates the inflow of parts and components
to the assembly line, minimizing the processes.
Benefits:
Reduced operating costs
Greater performance and throughput
Higher quality
Improved delivery
Increased flexibility and innovativeness
JIT Components:
Production Leveling
Pull System
Kamban (label or signboard) system
Good Housekeeping
Small Lot Production
Setup Time Reduction
Total Preventive Maintenance (TPM)
Total Quality Control (TQC)
JIT Purchasing
Line Balancing
Flexible Manufacturing
Small-group Activities (SGA)
TPS
Toyota
Production
System
The primary difference between Lean and the
TPS is the focus of efforts. In Lean thinking, the
focus is on the set of tools used to assist in the
identification and steady elimination of waste.
These tools include Value Stream Mapping,
Five S, Kanban (pull systems), and Poka Yoke
(error proofing), among others. Conversely, in
the Toyota Production System, the focus is on
maintaining smooth flow of parts through the
system. The idea is that a more smooth flow
reduces the amount of time parts spend
waiting in the system as well as the time
machines spend waiting for parts to work on.
This in turn reduces waste. The tools used in
both ideologies are very similar and a great
many of them overlap.
Lean
Manufacturing