Section D: Lean Flashcards
(38 cards)
Lean Production
Lean Production
A philosophy of production that emphasizes the minimization of the amount of all the resources (including time) used in the various activities of the enterprise.
It involves identifying and eliminating non-value-adding activities in design, production, supply chain management, and dealing with customers.
Lean producers employ teams of multiskilled workers at all levels of the organization and use highly flexible, increasingly automated machines to produce volumes of products in potentially enormous variety.
Lean production contains a set of principles and practices to reduce cost through the relentless removal of waste and through the simplification of all manufacturing and support processes.
What are the objectives of Lean
The objectives of lean are to Make only those products and services customers actually want Match the production rate to the demand rate Make products and services with perfect quality Make products and services with the shortest possible lead times Include only features actually in demand, excluding all else Keep labor, equipment, materials, and inventory continually in motion, with no waste or unnecessary movement Build worker learning and growth into each operational activity.
Pull Rather Than Push
one major difference between conventional MPC and lean
Push System
Push System
1) In production, the production of items at times required by a given schedule planned in advance.
2) In material control, the issuing of material according to a given schedule or issuing material to a job order at its start time.
3) In distribution, a system for replenishing field warehouse inventories where replenishment decision making is centralized, usually at the manufacturing site or central supply facility.
Pull System
Pull System
1) In production, the production of items only as demanded for use or to replace those taken for use.
2) In material control, the withdrawal of inventory as demanded by the using operations. Material is not issued until a signal comes from the user.
3) In distribution, a system for replenishing field warehouse inventories where replenishment decisions are made at the field warehouse itself, not at the central warehouse or plant.
The House of Lean
The Roof: Eliminate Waste
Focus on the customer to produce only what is wanted in the best quality, at the lowest cost, and using the shortest lead time possible by eliminating waste in all of its forms.
Waste
Waste
1) Any activity that does not add value to the good or service in the eyes of the consumer.
2) A by-product of a process or task with unique characteristics requiring special management control. Waste production can usually be planned and somewhat controlled. Scrap is typically not planned and may result from the same production run as waste.
Muda
Muda (waste) : In lean manufacturing, costs are reduced by reducing waste within system.
Mura
Mura : A Japanese word meaning unevenness or variability.
Muri
Muri : A Japanese word meaning strain or overburden.
Shingo’s seven wastes
Shingo’s seven wastes :
Shigeo Shingo, a pioneer in the Japanese just-in-time philosophy, identified seven barriers to improving manufacturing.
They are the:
- waste of overproduction,
- waste of waiting,
- waste of transportation,
- waste of stocks,
- waste of motion,
- waste of making defects, and
- waste of the processing itself
The 8th waste:
Waste of Unused people skills
Lean identifies these forms of waste in regular continuous improvement sessions and by getting out on the shop floor and talking to people. This is very important to lean and can be expressed as gemba or genchi genbutsu in Japanese. The Dictionary defines these terms as follows:
Lean identifies these forms of waste in regular continuous improvement sessions and by getting out on the shop floor and talking to people. This is very important to lean and can be expressed as gemba or genchi genbutsu in Japanese. The Dictionary defines these terms as follows:
Gemba : The place where humans create value; the real workplace. Also a philosophy: “Go to the actual place, see the actual work.”
Genchi genbutsu : A Japanese phrase meaning to visit the shop floor to observe what is occurring.
The House of Lean
Pillar One: Just in Time
The primary elements of just in time are to have only the required inventory when needed; to improve quality to zero defects; to reduce lead times by reducing setup times, queue lengths, and lot sizes; to incrementally revise the operations themselves; and to accomplish these activities at minimum cost.
Takt time
Sets the pace of production to match the rate of customer demand and becomes the heartbeat of any lean production system. Computed as the available production time divided by the rate of customer demand.
For example, assume demand is 10,000 units per month, or 500 units per day, and planned available capacity is 420 minutes per day. The takt time = 420 minutes per day ÷ 500 units per day = 0.84 minutes per unit. This takt time means that a unit should be planned to exit the production system on average every 0.84 minutes.
An immediate benefit provided by quick changeovers is a reduction in lead time. Reducing lead time using lean, or by improving lead time in conventional systems, can provide a number of other benefits:
Reducing lead times allow these benefits:
There will be a direct and immediate reduction in product cost, because setup time is a direct cost.
It can eventually reduce lot sizes—and thus order quantities—because setup time will not be as large a component in the tradeoff analysis between the cost of setups and other costs.
Reducing lot sizes will also eventually improve quality because defects will have less chance to be replicated across as many units.
By reducing lot sizes, WIP inventory and queues (orders awaiting production at a work center) will be reduced, because the total amount of inventory in process or waiting to be run at individual work centers is partly a factor of the order size.
When less inventory is held between work centers, it will be easier to establish cellular layouts because the work centers can be physically nearer to each other.
Kanban
A method of just-in-time production that uses standard containers or lot sizes with a single card attached to each.
It is a pull system in which work centers signal with a card that they wish to withdraw parts from feeding operations or suppliers.
The Japanese word kanban, loosely translated, means card, billboard, or sign, but other signaling devices such as colored golf balls have also been used. The term is often used synonymously for the specific scheduling system developed and used by the Toyota Corporation in Japan.
The House of Lean
Pillar One: Jidoka
Jidoka, which can be translated as automation with a human mind, is all about empowering shop floor workers to take ownership of the quality of their processes and to help the organization to improve.
The APICS Dictionary , 16th edition, defines jidoka as “the Japanese term for the practice of stopping the production line when a defect occurs.”
Andon
andon as a sign board with signal lights used to make workers and management aware of a quality, quantity, or process problem.
The House of Lean
The Foundation: Standardization and Operational Stability
Leveling, standardized work, reducing variability, avoiding overburdening processes or employees, and kaizen (a form of improvement) are the main tools that lean organizations use to reduce variation and allow work to be harmonious rather than in a constant state of emergency.
Total productive maintenance and heijunka are important examples of how operational stability are achieved.
The House of Lean
The Foundation: Standardization and Operational Stability
Leveling, standardized work, reducing variability, avoiding overburdening processes or employees, and kaizen (a form of improvement) are the main tools that lean organizations use to reduce variation and allow work to be harmonious rather than in a constant state of emergency.
Total productive maintenance and heijunka are important examples of how operational stability are achieved.
Total productive maintenance (TPM)
Total productive maintenance
Preventive maintenance plus continuing efforts to adapt, modify, and refine equipment to increase flexibility, reduce material handling, and promote continuous flows.
It is operator-oriented maintenance with the involvement of all qualified employees in all maintenance activities.
The House of Lean
The Center: Culture of Involvement and Continuous Improvement
A House of Lean that is built correctly creates a culture of continuous improvement with a high degree of respect for people, in terms of both designing processes so they are safe and maintaining and improving morale.
quality at the source
quality at the source
A producer’s responsibility to provide 100 percent acceptable quality material to the consumer of the material.
The objective is to reduce or eliminate shipping or receiving quality inspections and line stoppages as a result of supplier defects.
