The lean is a production system whose base is the complete elimination of waste. The two pillars needed to sustain this system are: just-in-time and autonomation, or automation with a human touch. (Ohno, cited by Bernárdez)
Just in Time
Just in Time means that, in a process flow, only the parts or pieces necessary for the correct assembly arrive on the assembly line, at the precise moment they are needed and only in the necessary quantity. (Oh no)
The Just-in-Time system is defined as a manufacturing philosophy based on the planned elimination of any waste and continuous improvement of productivity. It covers all manufacturing activities, from design to delivery and emphasizes zero inventory, zero defects, and reduced lead times. (Hernández and Téllez)
The fundamental objective of the Just-in-Time production philosophy is to achieve a continuous flow of the production process, from the receipt of materials to the final sale; this equates to the proper number being produced at the required time. (Muñoz)
Just-in-Time manufacturing is a traction system, where parts are produced to order, and production is matched to demand for assemblies or finished products. There is no stockpile, and the ideal production quantity is one (zero inventories, production out of stock, timing with demand). Also, parts are inspected by the worker as they are manufactured, and are used after a short time. (Kalpakjian and Schmid)
Here is a fairly educational video explaining the concept of just-in-time through its application in a British car manufacturer.
Lean Manufacturing
It is a systematic process to find and eliminate waste (activities with non-added value) through continuous improvement, producing a flow according to the client's requirement in search of perfection. (The Mid America Manufacturing Technology Center)
It is a set of techniques focused on the continuous search for improvement and optimization of operating processes of the manufacturing system. The improvements must be focused on the elimination of waste or activities that do not add value to the final product, since they are not part of what the client is willing to pay for, achieving increased productivity and profitability of the company. (Maguiña)
It is a methodology that allows to comprehensively improve the productive processes of a company, with the purpose that all have an added value and that within its various techniques allow, with simple adaptations and resources, to achieve substantial optimizations that lead to an increase in productivity. (Womack and Jones)
The main idea of lean manufacturing is to maximize customer value while minimizing waste. Lean simply means creating more value for customers using fewer resources. A lean organization understands what customer value means and focuses on its key processes to continually improve them. The ultimate goal is to deliver the perfect product / service to the customer through a perfect value creation process that has zero waste. (Lean Enterprise Institute)
Taking into consideration the previous definitions, it can be inferred that the just-in-time system is a fundamental piece within the concept of lean manufacturing.
In the following figure, known as the TPS House, the Toyota Production System is shown, in it it is clearly appreciated how Just-in-Time forms one of the pillars of the system:
TPS house. Just-in-Time as the foundation of lean manufacturing
As a complement, the following video is suggested in which the main concepts of lean manufacturing are explained, what it is, how it is implemented and what are its most used tools.
Bibliography
- Bernárdez, Mariano L., Human Performance: Consultancy Manual. AuthorHouse, 2009. Pág. 349Hernández, S. and Téllez, SC, Laboratory of just in time Kalpakjian, Serope and Schmid, Steven R. Manufacturing, engineering and technology. Pearson Education. 2002. P. 1091Maguiña, Hedwin. Improvement in the processes of a company that manufactures automation machines. Thesis, Faculty of Sciences and Engineering PUCP, 2013. Page 12 Muerza, Servando. TPS House Muñoz Negrón, David. Operative administration. Business process management approach. Cengage Learning Editors. 2009. Page 58 Ohno, Taiichi. Toyota Production System. Productivity Press. 1988 Socconini, Luis. Lean manufacturing step by step. Rule. 2008 What is lean? Lean Enterprise Institute. Womack, J. and Jones, D., Lean Thinking. Simon & Schuster. nineteen ninety six
