Anil Kumar Agrawal is currently working as Dean, (Academics) in Apex Institute of Engineering & Technology, Jaipur. He has more than 19 years of experience in the field of education.
He has completed his Bachelor of Engineering (B.E.) in Mechanical Engineering from NIT, Rourkela (Formerly known as R.E.C. Rourkela) and than after Master of Technology (M.Tech.) in Mechanical Engineering with specialization in Manufacturing Systems Engineering from MNIT, Jaipur.
Presently he is pursuing Doctor of Philosophy (PhD) from Shri JJT University. He has published number of research papers in the field of Production Engineering in various National and International journals. He has conducted number of STTP/FDP/Workshop/Seminar/Conference etc. He is actively Life Member of “Indian Society of Technical Education (ISTE)” and Associate Member of ” Institute of Engineers (IE)”.
In this world of competition, without proper production management, a company cannot survive. Using a manu-facturing concept for competitive advantage is relatively a new concept. Lean manufacturing is a concept actually brought up by the Toyota Motor Company, Japan. But it was popularized to the world by the book “The Machine That Changed The World” by Womack, Jones and Roos of MIT in 1990.
Adding value by eliminating waste, being responsive to changes, focusing on quality and enhancing effectiveness of workforce is achieved by lean manufacturing. It needs a systematic and continuing search for non value added activities.
The term lean manufacturing is a more generic term and refers to the general principles and further develop-ments of becoming lean. The term lean is very apt because in lean manufacturing the emphasis is on cutting out “Fat” or wastes in manufacturing process.
Lean manufacturing, an approach that depends greatly on flexibility and workplace organization, is an excellent starting point for companies wanting to take a fresh look at their current manufacturing methods.
Lean manufacturing principles
Lean manufacturing has endeavoured to rationalize production by 9 principles. They are:
(i) Continuous Flow
(ii) Lean machines/Simplicity
(iii) Workplace organization
(iv) Parts presentation
(v) Reconfigurability
(vi) Product quality
(vii) Maintainability
(viii) Ease of access
(i) Continuous Flow: The preferred shape of the lean workcell is U-shaped. Each sub process is connected to the next in order of process. With the worker in the interior of the U, minimum movement is required to move the work piece or assembly from one workstation to the next. Ultimately, one of the goals of the lean workcell is to eliminate all non-value-added movement; hence it’s U-shaped. When the worker has finished the process, he simply turns around and is back at step one.
(ii) Lean Machines/Simplicity: Since continuous-flow, one-at-a-time manufacturing is another goal of lean manufactur-ing, it is important that each workstation or machine be designed to fit within a minimal envelope. The minimal envelope ensures the elimination of excess flat space at the workstation or machine.
This is done to avoid the possibility of storing parts or subassemblies at the machine. Storing parts increases work in process and results in “batch” processing, which subsequently defeats the purpose of lean manufacturing. In addition, smaller, minimal size workstations and machines eliminate unnecessary steps taken by the worker between sub processes.
(iii) Workplace Organization: A smooth, uninterrupted flow of completed work pieces is the desired result of a properly designed lean workcell. Nothing can slow or stop this flow faster than the loss or misplacement of tools. Thus, all tools used at a workstation should have their own holder.
There should be exactly as many holders as there are tools so that the absence of a tool is quickly noticed. Using a modular tool holder system with a specific holder for each tool is ideal. If holders can easily be added to or taken away from a workstation, this simply adds to the flexibility of the workstation and increases its usefulness in a lean manufacturing process.
(iv) Parts Presentation: Naturally, during the average work shift, additional parts will be required for the workcell. Traditional methods of resupplying workstations are not useful in a lean workcell. Each worker should go about his work with the minimum number of interruptions. Therefore, all parts should be supplied to each work-station from outside the workcell. The use of gravity feed conveyors or bins fit the simplified design of the lean workcell.
(v) Reconfigurability: A properly designed lean workcell must be easy to reconfigure. In fact, the ability to change the process and go from good part to good part as quickly as possible is a must. The faster the changeover, the less production time is lost.
(vi) Product Quality: One of the results of one-at-a-time manufacturing is a decrease in quality problems. As each part is produced, visual inspection by the worker can verify that it is correctly assembled. If verification is required through gages, they should be mounted to the machine or workstation and be easily replaced. Quick release of fixtures using star knobs or locking levers is a necessity.
(vii) Maintainability: Ease of service is another requirement of a lean cell. Long downtimes can-not be tolerated in a pull-through system. When customer demand exists, the product must be produced. A modular structural framing system provides the ultimate in maintainability. Components can be replaced or reconfigured in a matter of minutes.
(viii) Ease Of Access: Using an aluminium framing system as the foundation of a lean cell, all necessary work components can be mounted in easily accessible locations because each surface is a potential mounting surface. Parts bins, tools, shelves, and fixtures can all be positioned in the optimum location for efficient work. The T-slot on the framing system’s surface also allows quick repositioning of pneumatic or hydraulic components if clearance space is critical.
(ix) Ergonomics: It includes height, lifting, etc. Finally, the worker must be protected from ergonomic problems. Any properly designed lean workcell must, by definition, be ergonomically designed. Maintaining the work at the ergonomically correct height throughout the workcell is always important. Although it is frequently not taken into consideration, designing for the average worker height is also a necessity. Since average heights vary from country to country, the height of a machine or workstation must be easily changed if there is any chance that a workstation may be shipped from country to country.
Thus lean manufacturing increases the production by completely eliminating waste in the production process, to build quality into the process, to reduce costs – productivity improvements, to develop its own unique approach toward corporate management, to create and develop integrated techniques that will contribute to corporate operation.