Aims and Purposes of Lean Production
Lean production is an approach to operations that aims to produce goods and services efficiently while minimising waste.
→ Produce only what is needed
→ Produce when it is needed
→ Reduce unnecessary activities
→ Reduce defects and errors
→ Minimise inventory
→ Improve quality
→ Make better use of employees and resources
→ Reduce production time
→ Reduce costs
→ Increase efficiency and productivity
→ Respond more quickly to customer demand
What is waste?
In lean production, waste means any activity or resource that does not add value for the customer.
Examples include:
→ Producing goods that are not needed
→ Holding excessive inventory
→ Waiting for materials or machinery
→ Unnecessary movement of employees or materials
→ Defective products
→ Excessive processing
→ Unnecessary transportation
→ Underusing employees’ skills
Core idea
Identify waste → remove or reduce waste → improve processes → reduce costs → improve efficiency → increase customer value
Operational Strategies for Lean Production
Kaizen
Kaizen means continuous improvement.
→ Employees at all levels are encouraged to identify small improvements to production processes.
→ Improvements are made continuously rather than waiting for one major change.
Examples:
→ Rearranging equipment to reduce movement
→ Improving the layout of a workplace
→ Reducing the time needed to change machinery
→ Improving a production procedure
→ Reducing unnecessary paperwork
Benefits:
→ Small improvements accumulate over time
→ Reduces waste
→ Improves productivity
→ Encourages employee involvement
→ Can improve quality
→ Usually involves less risk than major changes
Limitation:
→ Improvements may be small and take time to produce significant results.
Quality Circles
A quality circle is a small group of employees who meet regularly to identify and solve work-related problems, particularly problems involving quality and efficiency.
→ Employees closest to the production process often understand operational problems well.
Process:
Identify problem → discuss causes → suggest solutions → implement improvement → monitor results
Benefits:
→ Employees contribute ideas
→ Improves communication
→ Identifies problems quickly
→ Improves quality
→ Reduces waste
→ Increases employee involvement and motivation
Limitations:
→ Meetings take time
→ Employees may need training
→ Suggestions may not always be practical
→ Employees may become frustrated if management does not act on their ideas
Simultaneous Engineering
Simultaneous engineering involves different departments working together on product development at the same time, rather than completing each stage separately.
For example:
→ Designers
→ Production staff
→ Marketing
→ Finance
→ Purchasing
→ Quality specialists
may work together while a product is being developed.
Benefits:
→ Problems identified earlier
→ Less time between product design and production
→ Better communication between departments
→ Fewer design changes later
→ Lower development costs
→ Faster product launch
→ Product can be designed with production efficiency in mind
Example:
→ Production employees may tell designers that a particular component is difficult to manufacture.
→ The design can be changed before large-scale production begins.
Limitation:
→ Requires strong communication and coordination.
→ Conflicts may occur because departments have different priorities.
Cell Production
Cell production involves organising production into small teams or work areas called cells, with each cell responsible for producing a particular product or part of the production process.
→ Employees and equipment needed for a particular product are grouped together.
→ A product can move through a cell with less unnecessary movement.
Benefits:
→ Less movement of materials
→ Faster production
→ Better communication
→ Greater employee responsibility
→ Improved teamwork
→ Easier identification of quality problems
→ Greater flexibility
Example:
Instead of moving a product between separate departments for cutting, assembly and finishing, a cell may contain the equipment and employees needed to complete most or all of these stages.
Limitations:
→ Equipment may need to be duplicated between cells
→ Employees may require additional training
→ Setting up cells can be expensive
→ Less suitable for some types of mass production
Just-in-Time (JIT) Manufacturing
JIT means materials and components arrive shortly before they are needed for production, rather than being stored in large quantities.
→ Production is based closely on actual customer demand.
Traditional approach:
Large inventory → higher storage costs → greater risk of obsolete or damaged stock
JIT approach:
Low inventory → materials arrive when required → lower storage costs
Benefits:
→ Lower inventory-holding costs
→ Less capital tied up in inventory
→ Less storage space required
→ Lower risk of obsolete stock
→ Less waste
→ Problems with suppliers or quality can be identified quickly
Limitations:
→ Heavy dependence on reliable suppliers
→ Transport delays can stop production
→ Supplier quality problems can affect production
→ Unexpected increases in demand can cause shortages
→ Disruptions can have a major effect because there is little buffer stock
Example:
A car manufacturer may arrange for components to arrive shortly before they are required on the production line instead of storing large quantities of every component.
Waste Management
Waste management involves identifying, reducing, reusing and disposing of waste efficiently.
→ Businesses can examine every stage of production to identify unnecessary waste.
Examples:
→ Reduce excess raw materials
→ Reuse materials where possible
→ Recycle waste
→ Reduce packaging
→ Reduce defective products
→ Reduce unnecessary transportation
→ Reduce energy and water waste
→ Improve production processes
Benefits:
→ Lower material costs
→ Lower disposal costs
→ Less environmental damage
→ Improved efficiency
→ Less resource wastage
→ Improved reputation
Limitation:
→ Recycling systems, new equipment or improved processes may require additional investment.
Limitations of Lean Production Strategies
Lean production can improve efficiency, but it is not automatically suitable for every business.
Dependence on suppliers
→ JIT requires reliable suppliers.
→ A delayed delivery can stop production.
→ Strikes, extreme weather, transport problems or supplier failure can therefore cause major disruption.
Initial costs
→ New equipment, training, technology and production layouts may require significant investment.
→ Benefits may take time to appear.
Employee resistance
→ Employees may resist changes to working methods.
→ Increased involvement and responsibility can also create additional pressure.
→ Successful lean production requires employee training and cooperation.
Risk of low inventory
→ Very low inventory reduces storage costs but also reduces the buffer available when demand or supply changes unexpectedly.
→ A sudden increase in demand may lead to stockouts.
Quality problems
→ JIT and low inventory make quality particularly important.
→ If defective materials arrive, there may not be enough alternative stock to continue production.
Less suitable for unpredictable demand
→ Lean systems work particularly well when production and supply can be planned effectively.
→ Highly unpredictable demand can make very low inventory levels risky.
Implementation complexity
→ Lean production often requires changes to:
→ Production methods
→ Supplier relationships
→ Employee roles
→ Quality systems
→ Inventory systems
→ Management practices
→ Poor implementation can reduce efficiency rather than improve it.
Employee pressure
→ Continuous improvement and efficiency targets may increase pressure on employees.
→ If poorly managed, this may reduce motivation rather than improve it.
Lean Production and Inventory Control
Lean production aims to minimise unnecessary inventory.
→ JIT reduces the amount of raw materials and finished goods held.
→ Better forecasting and production planning reduce excess stock.
→ Waste reduction reduces unnecessary materials.
→ Quality improvement reduces the need to hold extra stock to replace defective products.
Result:
→ Lower storage costs
→ Less capital tied up
→ Less obsolete stock
→ Less waste
→ Greater inventory efficiency
However:
→ Very low inventory + unreliable suppliers → greater risk of production stoppages.
Therefore, the business must balance low inventory with supply reliability.
Lean Production and Quality
Quality is essential to lean production.
→ Defective products are waste.
→ Poor quality creates:
- Rework
- Returns
- Repairs
- Refunds
- Customer complaints
- Wasted materials
- Wasted labour
Lean production therefore focuses on preventing defects rather than simply detecting them after production.
Link with Kaizen
→ Employees continuously identify ways to improve quality.
Link with quality circles
→ Employees work together to identify causes of quality problems.
Link with JIT
→ Poor-quality materials can quickly disrupt production because there is little spare inventory.
Overall:
Better quality → fewer defects → less waste → lower costs → greater efficiency
Lean Production and Employee Roles
Lean production changes the role of employees.
→ Employees are not simply expected to follow instructions.
→ They may be encouraged to:
- Identify problems
- Suggest improvements
- Participate in quality circles
- Take greater responsibility for quality
- Work in teams
- Perform several tasks
- Solve operational problems
- Make some decisions
Multi-skilling
Employees may be trained to perform several different tasks.
→ This increases workforce flexibility.
→ Employees can be moved between activities when demand changes.
Example:
→ If demand increases in one production cell, trained employees can be moved from another cell to support it.
Employee involvement
Employee involvement → more ideas → continuous improvement → less waste → greater efficiency
However:
→ Training costs increase.
→ Employees may initially resist changes.
→ Greater responsibility can increase pressure.
Lean Production and Capacity Management
Capacity management involves making effective use of the business’s available production capacity.
Lean production can improve capacity utilisation by:
→ Reducing waiting time
→ Reducing unnecessary movement
→ Reducing production delays
→ Improving production flow
→ Reducing machine downtime
→ Improving employee flexibility
→ Matching production more closely with demand
Example
A factory has machinery that spends significant time waiting for materials.
→ JIT ensures materials arrive when required.
→ Production waiting time falls.
→ Machines can be used more effectively.
→ Capacity utilisation increases.
However:
→ Extremely low inventory can create shortages.
→ A machine breakdown or supplier delay may leave production capacity unused.
Therefore:
Lean production → better coordination → less downtime/waiting → better capacity utilisation
but
Very low inventory → greater vulnerability to disruption → possible unused capacity.
Lean Production and Overall Efficiency
The different strategies work together rather than operating independently.
Kaizen
→ Continuous improvement
Quality circles
→ Employee involvement in solving problems
Simultaneous engineering
→ Departments cooperate from the design stage
Cell production
→ Better production flow and teamwork
JIT
→ Low inventory and reduced storage waste
Waste management
→ Reduction and reuse of unnecessary resources
Together:
Less waste → fewer defects → lower inventory → better use of employees and machinery → lower costs → higher productivity → greater efficiency → improved competitiveness