LEAN MANUFECTURING
PREPARED BY : JYOTI BASERA
WHAT IS LEAN
MANUFECTURING
Lean manufacturing is a production process based on an ideology of maximising
productivity while simultaneously minimising waste within a manufacturing operation. The
lean principle sees waste is anything that doesn’t add value that the customers are willing to
pay for.
The term, lean manufacturing was detailed further by James Womack, Daniel T. Jones and
Daniel RooS in the 1990 book ‘The Machine that Changed the World.’ Womack and Jones
further defined this in their 1996 book, ‘Lean Thinking. Womack and Jones defined lean as, “a
way to do more and more with less and less - less human effort, less equipment, less time,
and less space - while coming closer and closer to providing customers exactly what they
want."
The basis of lean is often translated into five core principles.
LEAN MANUFECTURING PRINCIPLES
The five core principles of lean manufacturing are defined as value, the
value stream, flow, pull and perfection. These are now used as the basis to
implement lean.
1. Value:
Value is determined from the perspective of the customer and
relates to how much they are willing to pay for products or
services. This value is then created by the manufacturer or
service provider who should seek to eliminate waste and costs
to meet the optimal price for the customer while also
maximising profits.
LEAN MANUFECTURING PRINCIPLES
2. Map the Value Stream:
The value stream covers the entire lifecycle of a product, from
raw materials to disposal. Each stage of the production cycle
needs to be examined for waste and anything that doesn’t add
value should be removed. Chain alignment is often
recommended as a means to achieve this step.
LEAN MANUFECTURING PRINCIPLES
3. Create Flow:
Creating flow is about removing functional barriers to improve
lead times. This ensures that processes flow smoothly and can
be undertaken with minimal delay or other waste. Interrupted
and disharmonious production processes incur costs and
creating flow means ensuring a constant stream for the
production or service delivery.
LEAN MANUFECTURING PRINCIPLES
4. Establish a Pull System:
A pull system works by only commencing work when there is
demand. This is the opposite of push systems, which are used
in manufacturing resource planning (MRP) systems. Push
systems determine inventories in advance with production set
to meet these sales or production forecasts. However, due to
the inaccuracy of many forecasts, this can result in either too
much or not enough of a product being produced to meet
demand. This can lead to additional warehousing costs,
disrupted schedules or poor customer satisfaction.
The pull system can involve teams only moving onto new tasks
as the previous steps have been completed, allowing the team
to adapt to challenges as they arise in the knowledge that the
prior work is mostly still applicable to delivering the product or
service.
LEAN MANUFECTURING PRINCIPLES
5. Perfection:
The pursuit of perfection via continued process improvements
is also known as ‘Kaizen’ as created by Toyota Motor
Corporation founder Kiichiro Toyoda.
Lean manufacturing requires ongoing assessment and
improvement of processes and procedures to continually
eliminate waste in an effort to find the perfect system for the
value stream. To make a meaningful and lasting difference, the
notion of continuous improvement should be integrated
through the culture of an organisation and requires the
measurement of metrics such as lead-times, production cycles,
throughput and cumulative flow.
8 Wastes of Lean Manufacturing
1. Defects that require costly correction.
2. Over-production of a product.
3. Waiting – either people or idle equipment.
4. Non – utilized talent.(People’s Talent ,
Knowledge & Skills).
5. Unnecessary transportation.
6. Excess inventory
7. Unnecessary movement of people, equipment or
machinery.
8. Over processing or adding unnecessary
features to a product.
3m (mura, muri, muda)
These types of waste can be broadly split into three specific
types:
1. Muda: This is process-related waste and work that
adds no value.
If an activity doesn’t add value, or directly support one
that adds value, then it is unnecessary and should be
eliminated.
2. Mura: Unevenness or waste as a result of fluctuating
demand, whether from customer requests or new
services (and thereby additional work) being added by an
organisation.
3. Muri: Overburden or waste due to trying to do too
much. This relates to resource allocation and involves
people being asked to do too much. Time can be wasted
as people switch tasks or even lose motivation due to
being overburdened.
Lean Manufacturing Tools
There are a variety of tools that can be used to help implement a lean management
system, these include:
Control Charts – to check workflows
Kanban Boards – to visualise the workflows
5S – a methodology for organising the workplace
Multi-Process Handling
Error Proofing (also known as ‘Poka-Yoke’)
Rank Order Clustering – to aid production flow analysis
Single-Point Scheduling
Single-Minute Exchange of Die (SMED) – a fast method to move between
manufacturing processes
Total Productive Maintenance – to improve manufacturing integrity and quality
Value Stream Mapping
Work Cell Redesign
Advantages and Disadvantages
Advantages:
1. Saves Time and Money
2. Environment Friendly
3. Improved Customer Satisfaction
Disadvantages:
1. Employee Safety and Wellbeing
2. Hinders Future Development
3. Difficult to Standardise
