Lean Manufacturing
Pages Appendix1 Appendix2 References
 

 

Lean Manufacturing

 

Lean Manufacturing (also known as the Toyota Production System) is, in its most basic form, the systematic elimination of waste - overproduction, waiting, transportation, inventory, motion, over-processing, defective units, knowledge disconnection and the implementation of the concepts of continuous flow and customer pull. Lean is about doing more with less: less time, inventory, space people and money while giving customers what they want.

 

 

Taiichi Ohno, who is considered to be the creator of the Toyota Production System and the Father of the Kanban System, discovered that in addition to eliminating waste, his methodology led to improved product flow and better quality. Much of lean manufacturing’s terminology came from Taiichi Ohno’s Toyota Production System - 5S, kaizen, kanban, and just-in-time (JIT).

Hoshin Kanri means strategic policy deployment. Hoshin Kanri or Hoshin Planning is the short-term (one year) and long-term (three to five year) process used to identify and address critical business needs and develop the capability of our people, achieved by aligning company resources at all levels and applying the PDCA cycle to consistently achieve critical results.

Value stream mapping is a language that helps us grasp our current condition and identify kaizen opportunities.Satisfying customer demand without excessive inventory calls for strict attention to cycle time reduction and throughput. Any waste (muda) or activity that does not add value to the product is eliminated. Improving throughput involves value stream mapping,where a process flow diagram is made, material flow is analyzed, and the production system reengineered.

Kaizen is a continuous improvement process. Small improvements are made often, wherever opportunities are found for bettering quality and productivity. Team involvement is important to continuous process improvement, and lean manufacturing training makes teams more effective.

5S is a system of workplace organization and standardization whose goal is to support visual management. 5S is based on five Japanese words : Seiri - (sort) means to sort out what you don’t need. Seiton – (set in order) means to neatly arrange and identify parts and tools for ease of use. Seiso – (shine) means to clean. Seiketsu – (standardize) means to use the first three steps of the 5S system at frequent intervals to maintain a workplace in perfect condition, and to make use of visual control systems. Shitsuke – (sustain) means to keep these gains by forming the habit of always following the first four Ss. Stability starts with visual management and the 5S system. 5S supports standardized work and total productive maintenance (TPM).

Visual workplace is a work environment that is self-explaining, self-ordering, and self-improving. In a visual workplace out-of-standard conditions are immediately obvious and can be quickly corrected.

Total Productive Maintenance (TPM) is the key to machine stability and effectiveness. TPM is a series of methods to ensure that every machine or process is always able to perform its required tasks so that defect-free production is never interrupted or slowed.The key measure of machine effectiveness is overall equipment effectiveness (OEE).TPM entails involving all team members to eliminate the six big losses that downgrade machine effectiveness. With TPM, machines and equipment are kept in top condition.

 

 

Standardized work is a precise description of each work activity that specifies takt time, cycle time, the work sequence of specific tasks and, the minimum inventory (WIP) of parts on hand needed to conduct the activity.We cannot work to standards when there are continuous line stoppages and slowdowns. Lean activities support stability in the 4Ms: man/woman, machine, material and method. Stability means repeatability. We need to meet our productivity, quality, cost, lead-time, safety and environmental targets everytime.

Cell is an arrangement of people, machines, materials, and methods such that processing steps are adjacent and in sequential order so that parts can be processed one at a time (or in some cases in a consistent small batch that is maintained through the process sequence). The purpose of a cell is to achieve and maintain efficient continuous flow.

In its purest form, continuous flow means that items are processed and moved directly to the next process one piece at a time. Each processing step completes its work just before the next process needs the item, and the transfer batch size is one. Also known as one-piece flow and “make one, move one.”

Multi-process handling is a production process in which employees operate and maintain different types of production equipment and perform a variety of functions within a cell or cells. Multi-process handling is essential in production cells with many types of machines. It ensures worker flexibility, causes less fatigue, and permits easy adjustments to fluctuations in demand.

Line Balancing is a useful tool for determining how many operators we need and making visible the muda of waiting. Operator Balance Chart shows process cycle time in relation to Takt time. and identifies where operators are underutilized and where cycle time is greater than the Takt time. Throughput is governed by the slowest machine or operation in the chain, called the bottleneck or constraint.

Pull production means that nobody upstream should produce a goods or service until the customer downstream asks for it. There are three types of pull system used depending on order frequency - frequent or low, and customer lead time – long or short and stable.

Just-in-time (JIT) production means producing the right item at the right time in the right quantity. The objective of JIT is to produce a continuous flow of value so that the customer can pull. The components of the JIT system are Kanban, Heijunka (production leveling).

Kanban is a visual tool (signal) used to achieve JIT production. Usually, it is a card and an authorization to produce or withdraw and may also contain related information such as the kind and quantity of product, the supplier of the part or product, customer, where to store it, how to transport it. There are two kinds of kanban : Production kanban, which specifies the kind and quantity of product that the upstream process (supplier) must produce, Withdrawal kanban, which specifies the kind and the quantity of product that the downstream process (customer) may withdraw.

Mistake-Proofing is about a way to manufacture or assemble products that have zero defects by catching and fixing human mistakes and machine errors before they can cause defects. Zero Quality Control (ZQC) does not mean no quality control, however it is a quality control approach to make products with zero defects. Main reasons for producing zero-defect products are: to maintain customer satisfaction and loyalty, to avoid the unnecessary costs of scrap, rework, downtime and to adopt lean production methods with smaller inventories. ZQC prevents defects by combining four approaches: source inspection, 100 percent inspection, immediate feedback, and the use of poka-yoke devices. Poka-yoke means implementing simple low-cost devices that either detect abnormal situations before they occur, or once they occur, stop the line to prevent defects.

Each production operator becomes part of the quality process. If a worker finds a problem, anandon light (like the flashing lights used at supermarket cashier stations) at his or her workstation is turned on to call a manufacturing engineer or maintenance person to respond immediately. Andon is an example of jidoka.

Lean activities support stability. Machine stability requires 5S and TPM. Quality is strengthened with Jidoka. Just-in-time techniques attack parts shortage problems. 5S, TPM, and standardized work improve safety.

Three Phases of Lean and Tools

The ten rules of lean production can be summarized:

1. Eliminate waste 
2. Minimize inventory 
3. Maximize flow 
4. Pull production from customer demand 
5. Meet customer requirements 
6. Do it right the first time 
7. Empower workers 
8. Design for rapid changeover 
9. Partner with suppliers 
10. Create a culture of continuous improvement

Lean Manufacturing vs. Traditional Manufacturing

 

Traditional

Lean

Manufacturing

Manufacturing

Organization

Functional (Silo)

Focused/Cellular/ Lean

Scheduling

Forecast - push

Customer Order - pull

Production

Stock

Customer Order

Lead Time

Long

Short

Batch Size

Large - Batch & Queue

Small - Continuous Flow

Inspection

Sampling - by inspectors

100% - at source by workers

Layout

Functional

Product Flow

Machinery

Maintenance when a breakdown occurs

Preventative maintenance

Empowerment

Low

High

Inventory Turns

Low - <7 turns

High - 10+

Flexibility

Low

High

COGS

High and Rising

Lower and Decreasing

Just as mass production is recognized as the production system of the 20th century, lean production is viewed as the production system of the 21st century. Instead of devoting resources to planning what would be required for future manufacturing, Toyota focused on reducing system response time so that the production system was capable of immediately changing and adapting to market demands. In effect, their automobiles became made-to-order. The principles of lean production enabled the company to deliver on demand, minimize inventory, maximize the use of multi-skilled employees, flatten the management structure, and focus resources where they were needed.

The principles and practices of Lean are simplistic and developed over a 90-year period of time, however they are not easily to implement. Implementation requires a commitment and support by management, and participation of the all personnel within an organization to be successful.

 
 

Lean Manufacturing System 

  • Both strategies empower workers on the assembly line, in the belief that those closest to production have the greatest knowledge of how the production systemshould work. In a lean manufacturing system, suppliers deliver small lots on a daily basis, and machines are not necessarily run at full capacity.
  • The position requires creative and innovative approaches to analysis and design through the implementation of lean manufacturing methods. Ideally, each client will experience plateaus of success through approaches and solutions specially designed for their products, production environments, and customers.
 

Lean Production Manufacturing 

  • Tools and materials are neatly arranged and put in their proper location following the sequence of production. Manufacturing organizations commonly use shadow boards where the shape of each tool is painted on a board to guide workers in returning the tools to their proper places.
  • These solutions may require drastic changes in the design and execution of the production system that involve revamping operations from the shop floor through processing and information and material flows. Experience in manufacturing, engineering, or production is essential for success as a lean manufacturing consultant. The ability to confidently lead and communicate with employees at various levels is important as production changes are normally implemented throughout the manufacturing operations.
 

Lean Manufacturing Inventory 

  • Originally a Japanese methodology known as the Toyota Production System designed by Sakichi Toyoda, lean manufacturing centers around placing small stockpiles of inventory in strategic locations around the assembly line, instead of in centralized warehouses.
  • Thus, Lean Six Sigma provides a method to accelerate a company's decision-making processes, while both reducing production inefficiencies as well as increasing product quality. The lean manufacturing business management strategy strives to optimize an organization's production process by reducing costs during product development.
 

Lean Manufacturing Methods 

  • In addition to eliminating waste, lean manufacturing seeks to provide optimum quality by building in a method whereby each part is examined immediately after manufacture, and if there is a defect, the production line stops so that the problem can be detected at the earliest possible time. The lean manufacturing method has much in common with the Total Quality Management (TQM) strategy.
  • The position requires creative and innovative approaches to analysis and design through the implementation of lean manufacturing methods. Ideally, each client will experience plateaus of success through approaches and solutions specially designed for their products, production environments, and customers.
 

Lean Manufacturing Waste 

  • These small stockpiles are known as kanban, and the use of the kanban significantly lowers waste and enhances productivity on the factory floor. In addition to eliminating waste, lean manufacturing seeks to provide optimum quality by building in a method whereby each part is examined immediately after manufacture, and if there is a defect, the production line stops so that the problem can be detected at the earliest possible time.
  • Because the overall goal of lean business practices is to optimize the manner in which a company functions, there are specific educational requirements for those interested in lean manufacturing jobs. Most companies prefer to employ or contract individuals who have a background and degree in manufacturing or industrial engineering.
 

Lean Manufacturing Flow 

  • Additionally, supply chain management factors heavily into lean manufacturing, and a tight partnership with suppliers is necessary; this facilitates the rapid flow of product and parts to the shop floor. Lean manufacturing strategies can save millions of dollars and produce excellent results.
  • Businesses of all sizes can adapt these basic tools to any situation, whether the focus is on a production line or the way that tasks are carried out in an office setting. Lean manufacturing in general has to do with making sure there is no waste of resources as quality products are created for eventual sale to consumers.
 

Lean Manufacturing Quality

  • These small stockpiles are known as kanban, and the use of the kanban significantly lowers waste and enhances productivity on the factory floor. In addition to eliminating waste, lean manufacturing seeks to provide optimumquality by building in a method whereby each part is examined immediately after manufacture, and if there is a defect, the production line stops so that the problem can be detected at the earliest possible time.
  • The financial future of a company is at times in the hands of a lean engineer whose sole job is to cut costs and improve quality. Lean manufacturing jobs are often found in such places as automobile factories and mattress producers
Top of page
 
Site Policy Contact Us Disclosure Policy Suggested Operating Environment