Chapter 12. Lean Production. Lean Production The Toyota Production System Lean Implementation Requirements Lean Services. OBJECTIVES. Lean Production.
Based on two philosophies:
These are small specialized plants that limit the range of products produced (sometimes only one type of product for an entire facility)
Most plants in Japan have between 30 and 1000 employees
Quality at the Source means doing it right the first time and, when something goes wrong, stop the process or assembly line immediately.JIT Production means producing what is needed when needed and no more. Inventory hides problems.
Suppose we operate a production plant that produces a single product. The schedule of production for this product could be accomplished using either of the two plant loading schedules below.
Not uniform Jan. Units Feb. Units Mar. Units Total
1,200 3,500 4,300 9,000
Uniform Jan. Units Feb. Units Mar. Units Total
3,000 3,000 3,000 9,000
How does the uniform loading help save labor costs?
k = Number of kanban card sets (a set is a card)
D = Average number of units demanded over some time period
L = lead time to replenish an order (same units of time as demand)
S = Safety stock expressed as a percentage of demand during lead time
C = Container size
k = DL(1+S)/C
A local hospital wants to set up a kanban system to manage its supply of blood with the regional blood bank. Blood is measured by the pint and is shipped in containers that contain six pints each. For a particular blood type, the hospital uses an average of 12 pints per day. The hospital also carries a safety stock of two days’ expected demand. How many kanban cards should the hospital use for the type of blood?
D = 12 pints per day, L = 1 day, S = 200%, C = 6 pints
k = DL(1+S)/C=12*1*(1+200%)/6=6
This means that six kanban cards are needed. Each time a new container of blood is opened, a card should be sent to purchasing and another six pints of blood be ordered. When the blood is received, the card is attached to its container.
Four unwritten rules: