Metrics for Lean 231
Metrics for Lean provides an introduction to the information and data used to track processes in lean manufacturing facilities, including takt time, cycle time, total time of operations, overall equipment effectiveness (OEE), and first-time quality.
Metrics are measurable variables that can be tracked over time in order to identify errors or gauge progress. In lean facilities, metrics are tools manufacturers use to identify non-value added activities, streamline operations, and improve operations. After taking this class, users will be able to distinguish between broad and narrow metrics and calculate key values such as takt time and OEE. Understanding this information will help users contribute to lean initiatives and everyday continuous improvement efforts.
Number of Lessons 20
- Understanding Lean Metrics
- Traditional Metrics vs. Lean Metrics
- Levels of Value
- Metrics Review
- Choosing Metrics
- Cost of Operations
- Time Metrics
- Total Time of Operations
- Takt Time
- Determining Takt Time
- Cycle Time
- Using Metrics: Cell Balancing
- Time Metrics Review
- Overall Equipment Effectiveness
- Determining OEE
- First-Time Quality
- Time and Quality Metrics Review
- Using Metrics: Narrowing and Comparing Metrics
- Describe the importance of lean metrics.
- Distinguish between traditional and lean manufacturing metrics.
- Define the three levels of value in manufacturing.
- Distinguish between broad metrics and narrow metrics.
- Describe the purpose of cost of operations.
- Define total time of operations, takt time, and cycle time.
- Describe total time of operations.
- Explain how to calculate takt time.
- Explain how to calculate takt time.
- Describe cycle time.
- Describe cell balancing.
- Describe how to calculate overall equipment effectiveness.
- Describe the purpose of OEE.
- Explain how to calculate first-time quality.
- Describe the role of deviation in lean manufacturing.
- Describe how variation relates to lean manufacturing metrics.
- Describe how to identify special cause variation.
The percentage of time a machine is available for production. Availability time is measured in seconds and does not include planned downtime or breaks.
A graph of continuous data characterized by a high center, tapered sides, and flared edges. A bell curve reflects conditions that exhibit natural variation.
The production process with the longest cycle time. A bottleneck process limits the flow of production and is easily identified when compared to takt time.
A method of matching a cell's cycle time to takt time. During cell balancing, tasks that take longer are divided and redistributed until each task requires the same amount of time.
common cause variation
A deviation that is normal and expected and that cannot be traced back to a single source. Common cause variations are sometimes called natural variations.
The belief that an organization must constantly measure the effectiveness of its processes and strive to meet more difficult objectives to satisfy customers. Continuous improvement is a foundational concept in lean manufacturing.
cost of operations
A metric that looks at the overall cost of doing business across all departments rather than by individual departments. Cost of operations focuses on wise investment rather than cost cutting.
The time it takes to perform a task and forward it to the next step. Cycle times are often tracked and monitored in lean facilities.
The time it takes to perform a task and forward it to the next step. One of the major goals of lean is to match cycle time to takt time.
Factual information that is used for analysis and problem solving. Data is often in the form of values or numbers.
The difference between a standard and a result. Lean strives for zero deviation from perfection, or zero errors.
The total time that elapses from the moment raw materials are delivered to the dock to the moment that the finished product is shipped to the customer. Dock-to-dock time, which is also known as total time of operations, is considered a broad metric.
A final process performed on a part. Finishing processes include cleaning, final sizing, polishing, and applying coatings.
A lean metric that indicates to what extent parts are manufactured correctly the first time without the need for rework, re-inspection, or replacement. First-time quality is considered a narrow metric.
A lean metric that indicates what percentage of parts are manufactured correctly without the need for rework, re-inspection, or replacement. First-time quality is considered a narrow metric.
The use of an abrasive to wear away at the surface of a workpiece and change its shape. Grinding operations commonly use abrasive grains bonded into a wheel shape.
The examination of a part to determine if it conforms to specifications. Inspection is considered a non-value added but essential activity in lean manufacturing.
The storage of raw material, in-process parts, and completed, manufactured products. Excess inventory is considered waste in lean manufacturing.
Expenses associated with employees, including wages, insurance, taxes, and workers's compensation. Labor costs are a priority metric for traditional manufacturing companies.
An approach to manufacturing that seeks to reduce the cycle time of processes, increase flexibility, and improve quality. Lean approaches help to eliminate waste in all its forms.
The process of removing material from a workpiece using cutting tools. Machining is considered a value added process in lean manufacturing.
The methods and devices used to move and store materials during the production cycle. Material handling is considered a non-value added but essential activity in lean manufacturing.
Measured variables that are tracked and can be used to detect errors or variation and make improvements. Metrics can include cycle times, inspection data, and other forms of information.
Activities that do not contribute to the product or the process and should therefore be eliminated. Non-value added steps are waste.
non-value added but essential
Activities that support value added steps but that do not directly contribute to the product. Non-value added but essential activities can include inspection, material handling, and machine setup.
overall equipment effectiveness
OEE. A lean metric that measures how effectively equipment is being used. Overall equipment effectiveness is determined by multiplying the percentage of an equipment's availability, quality, and performance together.
Expenses associated with operating buildings and equipment, including rent, insurance, utilities, and repairs. Traditional manufacturing companies try to reduce overhead as much as possible.
The rate parts are produced divided by the machine capacity. Performance rate includes the number of parts produced in a given time, reduced speeds, idling, and short-term stoppage for jams and other problems.
Data used to gauge performance. Metrics can be used to detect errors and track an operation's progress.
A material management system in which parts are not delivered to machines until they are needed. Pull systems are based on actual demand for parts.
The percentage of good parts out of the total number of parts produced. Quality rate includes time lost to defects and the time it takes from startup to normal production.
Changing machinery, fixtures, and tools for the production of a new product. Retooling takes place before new product runs begin.
The origin of an error problem. To identify root causes, manufacturers must study narrow metrics.
single minute exchange of dies
SMED. A theory of setup reduction that strives to reduce the time it takes to perform product changeover to under ten minutes. Single-minute-exchange of dies can help reduce cycle time.
special cause variation
A deviation that causes an undesirable, fundamental change in a process. Special cause variation, which is also known as unnatural variation, can be traced back to a single source.
The rate at which a customer requires a company to manufacture products. Takt time is the number of work minutes per day divided by the number of orders per day.
The rate at which a customer requires a company to manufacture products. Takt time is the number of work minutes per day divided by the number of units ordered per day.
The rate at which a customer requires a company to manufacture products. Takt time is the number of work minutes per day divided by the number of work orders.
total time of operations
The total time that elapses from the moment raw materials are delivered to the dock to the moment that the finished product is shipped to the customer. Total time of operations, which is also known as dock-to-dock time, is considered a broad metric.
A real or perceived quality that satisfies the needs and wants of a customer. Value includes the features of a product, as well as other qualities associated with the product.
Any part of the production process that improves the product for the customer. For a process to be considered value added, a customer must be willing to pay for it.
Any change from what is normal and consistent. Variation can be identified as either common cause variation or special cause variation.
Any thing or process that does not add value to a product. Scrap is the most common form of waste.
A sharp, elongated tool that is held against a spinning grinding wheel for sharpening. Wheel dressers are often embedded with diamonds.
An arrangement of machines, tooling, materials, and operators structured around the design of similar products. Work cells encourage smooth product flows and use space efficiently.