Lean principles
13 important questions on Lean principles
Which two problems should be solved with Toyota Production System?
- small home market required flexible production to manufactore different types of cars: no resources for many plants and too many different products
- short cycle times essential for capital flow: reduce the time between purchasing materials and being paid by the customer
How are the 5 principles seen by Christis & Soepenberg
- specify value as defined by customer is not specifically addressed
- design flows is sen as the main point
- aim for perfection is important last step
How do lean and STSD relate (variability)?
- core aspect of lean and STSD: abandon batch & queue systems and design flows
- ashby: minimises disturbances (attenuating) and enhances regulatory capacity (amplifying)
- reduces functional concentration and separation between performance and control activities
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What does functional de-concentration (formation of value streams) entail?
- market-based grouping
- business segment: product family/customer family
- restricted set of similar orders
- reduces complexity of production structure by placing interdependent activities in the same unit
- this in turn reduces coordination needs and enables simplified planning
How should you design flows?
- abandon functional departments: process improvement by work flow in a product family
- create single piece flow: avoid work-in-progress, batch & queue
- just in time delivery; reduce lead time and reduce inventory
- takt time defined by demand of next process; fewer order --> slower takt time
How can you reduce undesirable sources of variability?
- customers want different things at different times
- demand can fluctuate depending on financial market, currency exchange, competitor activity
- unreliable equipment
- lack of standardised procedures
- uncontrolled of environmental conditions
- late deliveries from suppliers
- large production lots
What does the reduction of variability lead to?
- shorter cycle times
- lower work-in-progress
- faster response time
- better customer service
What possible buffers are there to deal with variability?
- time; demand waits for products
- inventory: product is finished before demand
- capacity: idle resources
Traditional bureaucracy is aimed at resource utilisation through a functional structure: leads to wastes in terms of waiting time in inventory
What are the differences between a bureaucratic organisation and a modular organisation?
- bureaucratic: huge triangle with high functional specialisation --> high coordination needs --> high hierarchical specialisation
- modular: cross trained teams with team ownership and delegated planning
What does the integration fo preparatory & support functions entail?
- womack & jones; spreading overhead costs; hides it
- decentralised planning & support in office cell; reduce coordination needs and enables bottom-up costing based on what team actually does
Why does lean need reliability?
- standard work= best practices
- works write their own job descriptions
- poor maintenance can stop cell flow
--> reduce variability
--> invest in preventive maintenance
--> use routines, but remain alert if they actually work
What does the 5th principle entail?
- Aim for perfection: There is always room for improvement
- Standard work: current gold standard – gets revised when problems occur
- Avoid Kamikaze Kaizen: first install flow production and pull planning, only then start continuous improvement
What are critical voices about lean stating?
- JIT disaster
- Insufficient knowledge about lean philosophy
- Lack of senior management support
- Lean thinking can be part of sustainability programme
- Lean & mean refers to taking away too much
- Does not necessarily lead to meaningful work
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