Table of Contents:-
- Meaning of Lean Manufacturing Production
- Features of Lean Manufacturing Production
- Components of Lean Manufacturing Production
- Steps in Lean Manufacturing Production
Meaning of Lean Manufacturing Production
The term “lean” as Womack and his colleagues define it denotes a system that utilizes less, in terms of all inputs, to create the same outputs as those created by a traditional mass production system, while contributing increased varieties for the end customer.
Lean production is a manufacturing methodology based on a novel system design. It has empowered companies to enhance productivity continually (resulting in low unit costs), meeting customer expectations for superior quality and prompt delivery. These advantages stem from a well-planned, agile, and flexible lean manufacturing system. The guiding principles of the Toyota Production System (TPS) are “better,” “faster,” and “less expensive.”
The lean manufacturing production system results in productivity advancements by highlighting waste. It results in quality gains by making problems visible when and where they occur and then by having the internal customer take measures to solve the problems to prevent recurrence. Lean manufacturers learn how to get continuous improvements in productivity and quality by continuously re-designing and making the manufacturing system simpler. The essential element in that redesign is the internal customers who are genuinely empowered and trained to analyze. resolve, and prevent problems. Everyone in the lean production system can understand how the system works.
Features of Lean Manufacturing Production
The following are the features of lean Manufacturing production:
1) Supplier Involvement
The manufacturer treats its suppliers as a long-term partner. They often must be trained in ways to reduce set-up times, inventories, defects, machine break-downs, etc., to enable them to take responsibility for delivering the best.
2) Employee Involvement and Empowerment
Employee Involvement and  Empowerment involve:
- Organizing workers into teams.
- Providing them with training and responsibilities for various specialized tasks such as housekeeping.
- Quality inspection.
- Minor equipment repair.
- Rework.
Additionally, employees can meet to discuss problems and identify ways to enhance the overall process.
3) Short Set-Up Time
A key feature of streamlined production is the emphasis on minimizing set-up time, assuming minimal time loss between various changeovers. The goal is to satisfy the customer by producing only the ordered products. Complaints about die-exchange frequency are addressed by reducing the time spent on die-exchanges. Ongoing efforts, including using quality circle, have significantly reduced set-up times, achieving single-digit or even less than one-minute durations, known as single set-ups and one-touch set-ups, respectively.
4) Improved Quality through Immediate Feedback
A batch production method was utilized before adopting lean manufacturing. In this process, errors in machining operations or material defects were identified only after the completion of a particular stage. Defective components were often machined to the final stage before errors were detected. This practice led to the rejection of the entire batch quantity and the wastage of resources.
5) Multi-Skilled Workforce
Achieving smooth production requires workers to be skilled in multiple functions. Utilizing workers with more than one skill or function in the industry often results in significant underutilization of labour and machinery. Lean production can effectively address small fluctuations in demand by implementing extended shift working and deploying skilled workers. Work is completed ahead of schedule in slightly lower demand, allowing for rest periods for workers or engagement in activities such as practising set-ups or preventive maintenance.
Because of lean manufacturing, a smooth flow of material and production results. The error or defect in a previous manufacturing operation is immediately identified by the operator and he gives feedback. In this way, batch and continuous rejections are avoided. Effects in materials like cracks blow holes, and excess are pointed out quickly. Thus there is continuous quality improvement due to lean manufacturing. The overall effect is less rejection.
Components of Lean Manufacturing Production
The following are the components of production:
- Pull Production System
- Push Production System
Pull Production System
Lean production is based on the pull system of process flow. A pull system utilizes customer demand as the primary driver for production  planning, avoiding pushing products into the marketplace to maximize the use of production resources. Ordering a sandwich at the fast-service restaurant Subway provides an excellent example of a pull system. The sandwich assembly begins with each customer selecting the bread, meat, vegetables, cheese, and other ingredients. Customers can follow the assembly of their custom sandwich in the aisle as it is created.
Pizza home delivery companies such as Pizza Hut and Domino’s also employ pull production approaches. While these restaurants keep necessary ingredients on site, they initiate the production of a pizza of a specific size only after receiving customer orders, specifying the type of crust, cheese, and toppings.
Examples of the pull production system can be observed in various industries. For example, Walmart has reduced costs by transmitting Point-of-Sale (POS) data to all its vendors and replenishing store supplies twice a week, ensuring goods do not linger in inventory. Consequently, additional items destined for Walmart shelves are pulled from suppliers only when customer demand justifies it.
Many products, such as Dell computers, are ordered directly from manufacturers after customers place an order on the company’s website. Because each computer can be configured in numerous combinations (e.g., with different CPU speeds, amounts of memory, media, screen size, etc.), Dell advertises components available in its inventory and produces only what the customer orders. This close connection between customer demand and pull production allows Dell to operate under lean conditions.
Push Production System
The push system focuses on maximizing the use of production capacity and, therefore, relies heavily on estimated customer demand. The push system enables companies to produce in large volumes, thereby reducing the cost of production per unit. An example of push production is the doughnut production by Dunkin’ Donuts. Based on past data and estimated demand, the store determines how many doughnuts of each type (glazed, cream-filled, chocolate-coated, etc.) can be sold in the next few hours. The store then decides on the production quantity and the product mix.
When an individual customer walks into the store, they see the types of doughnuts available and place an order based on the existing variety. Many products sold in supermarkets, such as bread, milk, fruits, vegetables, and meats, are also produced according to the push system.
Steps in Lean Manufacturing Production
There are five essential steps in lean:
1) Identify the Value Stream
Activities contributing value are recognized once identified. The entire sequence of activities is referred to as the value stream. Then, a determination is made regarding whether activities that do not contribute value to the product or service are necessary. Necessary operations are defined as prerequisites to other value-added activities or as essential parts of the business. An example of a non-value-added but necessary process is payroll since people need to be paid. Finally, the impact of necessary, non-value-added activities on the process is minimized. All other non-value-added activities are eliminated from the process.
2) Work toward Perfection
This effort involves the repeated and constant attempt to eliminate non-value activities, enhance flow, and meet customer delivery needs. While lean focuses on removing waste and improving flow, it also yields secondary benefits. Quality is enhanced as the product spends less time in the process, reducing the chances of damage or obsolescence. The simplification of processes results in a reduction of variation. As the company examines all activities in the value stream, the system constraint is eliminated, and overall performance is improved.
3) Identify Value
Determining which features create value in the product is made from internal and external customer standpoints. Value is expressed regarding how the specific product meets the customer’s needs—considering a specific price and time. Specific products or services are evaluated based on features that add value. The determination of value can be from the perspective of the ultimate customer or a subsequent process.
4) Allow Customer Pull
After removing waste and establishing flow, efforts turn to enable the customer to pull the product or service through the process. The company must make the process responsive to providing the product or service only when the customer needs it—neither before nor after.
5) Improve Flow
Once value-added activities and necessary non-value activities are identified, improvement efforts are directed toward facilitating the flow of activities. Flow is the uninterrupted movement of a product or service through the system to reach the customer. Major flow inhibitors include work in a queue, batch processing, and transportation. These buffers slow down the time from the initiation of the service or product to delivery. Buffers also tie up money that could be used elsewhere in the organization and mask the effects of system restraints and other wasteful activities.