Japanese for Waste

  • Inventory
  • Motion
  • Defects
  • Over-Processing
  • Waiting
  • Over-Production
  • Unnecessary Transport

Kanban – including Little’s Law

From pluralsight video and link here

Interesting link between manufacturing and IT. I have been aware of the ideas of Little’s Law for some years in manufacturing, although would not have known it’s name:
“The average time in the system is equal to the average time in queue plus the average time it takes to receive service” which leads to, two ways to reduce cycle time. Same/same manufacturing:

  1. Increase Throughput
    • normally requires investment or hire of additional resources
  2. Reduce WIP
    • simply a policy decision

Little’s Law L = ƛW

L = Length of Queue
ƛ = Arrival rate
Q = Average Wait Time

Wait Time = Lenght of Queue / Arrival Rate
Cycle Time = WIP / Throughput

Lead time clock starts when the request is made and ends at delivery. Cycle time clock starts when work begins on the request and ends when the item is ready for delivery. Cycle time is a more mechanical measure of process capability. Lead time is what the customer sees.
Lead time depends on cycle time, but also depends on your willingness to keep a backlog, the customer’s patience, and the customer’s readiness for delivery.
Another way to think about it is: cycle time measures the completion rate, lead time measures the arrival rate. A producer has limited strategies to influence lead time. One is pricing (managing the arrival rate), another is managing cycle time (completing work faster/slower than the arrival rate).
Corey Ladas

The pluralsight kanban video then goes onto to talk about value stream Ready, Doing, Done limiting WIP in Ready. Other options of columns

Electronic Tools (just list from pluralsight not used any):

  1. AgileZen
  2. Trello
  3. LeanKit Kanban
  4. TargetProcess


Kanban by David Anderson

Theory of Constraints – TOC – The Goal – Eliyahu M. Goldratt

Great book on Theory of Constraints told as a piece of fiction with a story of a Production Manager who is always expediting jobs.

At the end of the book the ‘hero’ asks the consultant, paraphrased here ‘.. and would you have not been able to have told these conclusions at the beginning’
The answer to this was that no, if he had done that then you would never truly understood the solution. Too many paradigm shifts to work through.

TOC includes bottleneck management and line-balancing.

The underlying premise of Theory of Constraints is that organizations can be measured and controlled by variations on three measures: throughput, operational expense, and inventory. Throughput is the rate at which the system generates money through sales. Inventory is all the money that the system has invested in purchasing things which it intends to sell. Operational expense is all the money the system spends in order to turn inventory into throughput

Backflush Accounting

If you mke 20 bicycles you must have used 40 wheels, therefore decrement stock of wheels by 40. Problem losses, rejects.