Pull Production Systems 生産システムを引いて- The benefits and a brief description.

Push Production Systems: a forecast of future demand drives production

scheduling and material replenishment.  Planned orders are used to authorize

production or move materials – usually in batch mode

Push Production Systems are…

• Inherently complex and inflexible
• Usually computer based (no visible system)
• Labor intensive, requiring significant labor-hours to keep the system accurate and up-to-date
• Incapable of reacting quickly or accurately to the frequent, small demand changes common to production operations

A Pull Production System has three major tasks:

• Get materials to the shop floor based on actual consumption
• Move work-in-process (WIP) through the shop based on actual customer demand
• Provide a mechanism for continuously improving the production processes

If the meaning of production control is truly understood, inventory control is unnecessary.

                                              -- Taiichi Ohno

Safety Stock is WASTE

Safety stock is excess inventory in a system to account for variations

in:

• Demand
• Lead time
• Supplier performance
• Poor quality
• Differences between calendar days and work days
• E.g., Production works on Saturday, but suppliers don’t deliver on Saturday

Kanban:

Kanban is a Japanese word, which loosely translated means sign or card

We use Kanban signals to pull product through the process, AND to

replenish raw material

Use Kanban when processes are separated

• Lines with multiple back ends
• Outside suppliers
• Feeder cells
• Semi-finished goods
• Finished goods with our customers!

2-Bin Replenishment System

Goals of a 2-bin system:

• Ensure operator always has parts
• Ensure operator does not have to leave bench to find parts
• Ensure material availability status is VISIBLE
• Minimize the amount of raw material kept on the production floor

Kanban and Materials Management

Small parts: use the container/bin as Kanban signal

• It is the container that goes back and forth for replenishment

Large / expensive parts: use Kanban card Where possible raw

material should be removed from stores (warehouse) and put on the

production floor in point-of-use (POU) locations.  Strive to eliminate

stores.

• Appropriate quantities in POU depends on:
• physical size
• material cost
• frequency of usage
• frequency of replenishment

Material Handling Function

In a continuous flow cell, if operators abandon their stations to retrieve parts, the adjacent operations will quickly shut down.  A separate material handling role will need to be responsible for part retrieval, removal of empty part containers, and handling of part scrap/fallout

Principles:

Consumption is the signal for activity

Signal is located in the producing

area

Producing area is buffered from

extreme variation in demand

Benefits:

Simplifies planning and control system

Converts shop floor into an assembly line

Controls production through adherence to

pull rules

• standard containers
• standard quantities
• authorized production