Push-Pull & Kanban Production System

 Pull System

 Definition: 

A method of controlling the flow of resources by replacing only what has been consumed.

Push System 

Definition: 

Resources are provided to the consumer based on forecasts or schedules. 

 

Where do you pull from?

Places you might pull from:

• A supplier 
• Other sister plant
• An upstream process
• A kanban Quantity
• Feeder Cell 
• Supermarkets

 What do you pull?

You may pull nay of the following:

• Single part
• Sub assemblies parts 
• Finished products
• Complete customer order

The basic types of Pull Production systems 

The concept of pull production is simple enough, but implementing these principles to numerous types of businesses is not as easy as it may seem. The reason for this is that Many managers fail to recognize that there are different types of pull production system to choose from and that the best system for their own manufacturing company will depend on the type of environment that they function in.

 

 Pull Systems Must Fit Your Production Needs

 Pull production sounds simple enough:downstream activities signal their needs to upstream activities. Which system is best depends on the manufacturing environment. Here is an overview, along with the pros and cons of each system.

TWO ASPECTS OF PULL PRODUCTION 

• In manufacturing, Pull production is the production of items only as demanded or consumed by the customer.

• In material control, Pull production is the withdrawal of inventory only as demanded by the using operation. Materials is used only when a signal comes from the downstream user.

Pull System 

• In a Pull system --

•  the customer is the trigger of production and material withdrawal.

 Advantages of Pull Systems

• Low Unit Cost:

  -Low inventory

  -reduced space

  -little rework

   High External Quality:

  -high internal quality
  

  -pressure for good quality
  

  -promotion of good quality(e.g. defect detection)

   Good Customer Service:

  -short cycle time
  

  -steady,predictable output stream
  

   Flexibility:

  -avoids committing jobs too early
  

  -encourages floating capacity
  

  
  

   THREE UNIQUE ASPECTS OF PULL

   Production is Music: 

  1. In a factory the melody is the flow of work pieces down the line Kanban and  Single Piece flow  create the melodic result.

  The next process is Your Customer: 

  1. The downstream process is the customer of the Upstream process Creates reliability, consistency and just in time compare to the PUSH system. 
  2. Stop & Go versus Process & Go Production
     

   

  FOUR PRIMARY CATEGORIES IN THE FLOW OF MATERIALS THROUGH THE PRODUCTION LINE

  1.  Retention/Waiting - Waiting between processes points or transfer points, warehouse time.
  2. Transfer - moving materials from one retention to another 
  3. Processing - the Value added activities (that eats up the least amount of Lead-time) 
  4. Inspection - defects are removed 

   

  REQUIREMENTS FOR CONTINUOUS FLOW 

  There ate 7 requirements for achieving continuous flow-

  1. Arrange the production processes and machines in the sequence of their process-line or U-shaped cell.
  2. Install smaller, Slower, and more specialized equipment,keep in general-purpose equipment to facilitate flexible reorganization where needed.
  3. Establish One-Piece flow 
  4.  . Synchronize Processes to keep pace with client needs and the needs of the next process
  5. Use multi-process handling so that one worker can move from process to Process down the line
  6. Train workers in the multiple skills they will  need for multi-process handling. 
  7. Change work position from sitting to standing to create mobility through several operations.

   

   THE RULES OF QUALITY IN PULL PRODUCTION

  1. Never allow a defective product to be pulled into your workstation
  2. Never produce a defective product at your workstation. 
  3. Never allow a defective part to be pulled from your workstation 

  Kanban

  • The kanban system determines the production quanury in i:: evefy proCeSS. t.' It is known as the nervous system of Lean Production. t;:a:,. i;. I(anban ts a Japanese word that means "insttuction cafd".