Principles of Lean-Flow and PULL Flashcards
What is single-piece flow?
Single Piece Flow is the movement of products or services through the process one unit at a time (as opposed to batch processing)
What does single-piece flow ensure?
- It ensures employees are focused on the value-adding elements of the process, rather than the waste: waiting, transportation, etc
- It also smoothes the flow of the process creating a consistent workload, which improves employee performance
What are the advantages of single-piece flow?
- Reduced lead time
- Eliminates over-production (the mother of all wastes)
- Reduces inventory
- Identifies defects early within the process
- Provides agility to rapidly respond to changing customer requirements
For Single Piece Flow to be effective it must be linked to other Lean improvements. What are they?
- The product changeover times must be short
- Process volumes need to be linked to customer demand
- The facility layout should support single-piece flow (u-shaped cells)
- The layout should include in-process control (or inspection) to avoid defects being passed forward
- The product should be pulled through the system, not pushed
What is parallel processing?
- Process steps that are currently being completed in series can be re-engineered to work in parallel
- Another possibility is to take out some process steps from the series & conduct them in parallel to other process steps
- This is often called concurrent engineering; the idea being that you can design the different parts of a product at the same time.
Two elements are required for parallel processing. What are they?
- The customer (or the business) would value the reduction in lead time
- Only process steps which are independent of each other can be done in parallel
Multi-Skilling
- Multi-skilling supports flow because it ensures there are enough sufficiently skilled employees to carry out the process
- Multi-skilling employees also improves quality because all team members are aware of up & down-stream processes & can immediately identify defects
- However, multi-skilling is dependent on standard operations and training team members to the standard process
Traditional layout
- Complex flows of material & information
- Bottleneck steps
- Reduced vision and ownership of the total value chain
- Operators concentrate on islands of efficiency
- Reduces the value-adding capability
Cell layout
- Typically u-shaped (no doubling back)
- Operations combined & single piece flow adopted
- The flow of materials becomes smoother.
- There is no queuing between processes.
- Throughput time is reduced.
- Operators are trained in more than one task.
- Value stream visibility is much higher
What are the guidelines for layout & cells?
- Utilize a U-shaped layout to minimize transportation and motion (no doubling back)
- Organise process steps close to each other so there are no locations for inventory
- Consider ergonomics & safety during cell design
- Use 5S to improve layout efficiency and sustain improvements
What is changeover time?
The time between the last good item and the first good item after a product changeover
What is quick changeover?
The process used to reduce changeover times
What is the key to quick changeover?
- Attempt to make all of the changeover tasks external in order that value adding is maximized.
- The majority of activities can be altered to be external tasks.
What are the 8 steps for quick changeover?
- Observe & measure the current process
- Separate internal & external activities
- Convert internal to external activities
- Create parallel activities
- Minimise internal & external activities
- Implement the new process & validate
- Document the new process
- Chart changeover time
How does quick changeover look in non-manufacturing areas?
- Changing from one customer order to another
- Moving someone from one program to another
- Gaining access to your e-mails or the server from another location
- Switching from one service provider to another
- Changing from one Business Unit leader to another
