Lean Manufacturing:strategiesfor measureable success Christopher R. Fox, MSEd., M.Ed. Manufacturing & Industrial Technology University of Maryland Eastern Shore Facilitator of Career and Technical Education The Howard County Public School System
Lean Manufacturing is… A way to eliminate waste and improve efficiency in a manufacturing environment. • “Lean” focuses on efficient flow, a consistent value stream and eliminating waste. • Lean manufacturing is the production of goods using lessof everything compared to traditional mass production: less waste, less human effort, less manufacturing space, and less investment in tools, inventory, and engineering time to develop a new product.
What I Consider Waste • Waste is anything that happens to a product that does not add value from the customer’s perspective. • Waste includes: products being stored, inspected or delayed, waiting in queues, and defective products.
Seven Common Wastes • Over-Production – Producing more than the customer orders or producing early. Inventory of any kind is usually waste. • Queues – Idle time, storage, and waiting are wastes. • Transportation – Moving material between plants, between work centers, and handling more than once is waste. • Inventory – Unnecessary raw material, work-in-process (WIP), finished goods, and excess operating supplies.
Seven Common Wastes (Cont.) 5. Motion – Movement of equipment or people. 6. Over-processing/machining – Work performed on product that adds no value to the customer. 7. Defective product – returns, warranty claims, rework and scrap.
Lean ManufacturingToyota Production System Lean Manufacturing is also referred to as the Toyota Production System (TPS).
Underlying Principles of TPS • Work shall be completely specified as to content, sequence, timing, and outcome. • Every customer-supplier connection, both internal and external, must be direct and must specify personnel, methods, timing, and the quantity of goods or services to be provided. • Product and service flows must be simple and direct, that is, goods and services must be directed to a specific person or machine. • Any improvement in the system must be made in accordance with the “scientific method” And it must begin at the lowest possible level in the organization .
Underlying Principles from TPS (Cont.) 5. Since the Toyota Production System requires that activities, connections, and flow paths have built-in tests to signal problems automatically, gaps become immediately evident. Results of the TPS are improvements in reliability, flexibility, safety, and efficiency. These lead to increase in market share and profitability.
Lean Manufacturing and Just-in-Time (JIT) Just-in-Time (JIT) is supplying customers/clients with exactly what they want when they want it. With JIT, supplies and components for a product are “pulled” through a system to arrive where they are needed, when they are needed. Lean Manufacturing was generated from the Just-in-Time (JIT) philosophy of continuous and forced problem solving.
Lean Manufacturing Techniques focus on the following strategies: 5S Single Minute Exchange of Dies Kanban Cellular Manufacturing
5S 5S is a strategy for creating a well organized, smoothly flowing manufacturing process.
Benefits of 5S • Increases organization and efficiency • Avoids wasted motion • Increases safety • Eliminates unnecessary inventory • Offers improvements at an inexpensive cost Before After
5S Drawbacks • If not fully implemented, may result in “Jive S”. • Store things (too much focus and energy devoted to creating more space and order) • Stick to the rules (excessive focus on more and more standardization) • Superficially clean • Switching to new fixtures • Serve reluctantly (some individuals in the process are not promoting the 5S strategy) 5S can not be considered an end goal. It is a continuous improvement process.
Single Minute Exchange of Dies (SMED) Method that focuses on the rapid conversion from manufacturing one product to the next.
Benefits of SMED • Increases throughput by reducing setup times • Eliminates setup errors • Increases safety • Reduces the cost of setups • Reduces waiting times and inventory buildups • Decreases the required skill level of the operators
Kanban A system that uses replenishment signals to simplify inventory management. Signals (usually cards) hold product details: What to make, when to make it, how much to make, and where to send it. Cards stay attached to a bin that holds the product.
Kanban When the bin is empty, it is returned to the start of the assembly line for replenishment. Full bins are returned to the customer, and the cycle continues.
Benefits of Kanban • Highly visible systems • Simple, effective, and inexpensive • Reduces inventory and eliminates stock-outs • Improves the quality of service • Improves lead times
Cellular Manufacturing Dividing the manufacture of products into semi-autonomous and multi-skilled teams known as work cells throughout a factory. Functional Plant Layout Cellular Plant Layout
Benefits of Cellular Manufacturing • Simplifies material flow and management • Reduces interdepartmental travel • Reduces throughput time • Reduces lot sizes • Simplifies scheduling
Lean Manufacturing Advantages and Disadvantages • Advantages: • Increased overall productivity • Reduced amount of floor space required • Reduced manufacturing lead time • Improved flexibility to react to changes • Improved quality • Disadvantages: • Difficulty involved with changing processes to implement lean principals • Long term commitment required • Very risky process - expect supply chain issues while changing over to lean
Lean using CNC Applications and Automation • Machining using multiple axis and multiple tooling, increasing speed of manufacture. • Use of single fixture for multiple operations, less human error in set-up due to fixture design and accuracy. • Single operator for multiple processes reduces error, and increases safety.
Using the best of Lean Manufacturing strategies insures measurable success • Toyota Production System (TPS), Just-in-Time (JIT), 5S, Single Minute Exchange of Dies, Kanban, and Cellular Manufacturing target the elimination of the seven common wastes which include: • Over-production • Queues • Transportation • Inventory • Motion • Over-processing/machining • Defective product • Lean Manufacturing using CNC Applications and Automation target : • Increased speed, accuracy, safety and production • Use of single fixture for multiple operations • Single operator for multiple processes