2,Implementation
1.Improvement of Production Processes
Lean production utilizes traditional industrial engineering techniques to eliminate waste by focusing on the entire production process, not just a few individual steps or processes.
(1) Eliminate quality inspection and rework. If the product quality from the product design program, until the entire product from the assembly line out of manufacturing, which each link of the quality can do 100% guarantee, then the phenomenon of quality testing and rework naturally become redundant. Therefore, the idea of "Poka-Yoke" must be applied throughout the entire production process, i.e. from the beginning of the product design, the quality issue is already taken into account to ensure that each product can only be processed and installed in a strictly correct manner, thus avoiding the possibility of errors in the production process. This ensures that each product can only be processed and installed in a strictly correct way, thus avoiding possible errors in the production process.
(2) Eliminate unnecessary movement of parts. Production layout is not reasonable is the root cause of parts moving back and forth. In the form of process specialization in the organization of the workshop, parts often need to be moved around in several workshops, making the production line is long, the production cycle is long, and take up a lot of in-process inventory, resulting in high production costs. By changing this unreasonable layout, the production of products required by the equipment in accordance with the processing sequence, and to do as compact as possible, which is conducive to shorten the transportation route, eliminating the parts unnecessary moving, saving production time.
(3) eliminate inventory. Inventory as a solution to the production and sales of urgent practice is like drinking hemlock to quench their thirst. Inventory masks many production problems, fosters worker inertia, and, worse, ties up a lot of capital. In a lean organization, inventory is considered the biggest waste and must be eliminated. A powerful measure to reduce inventory is to change from "mass production and queuing" to a "l-piece-flow" process. In the l-piece-flow process, basically only one production piece flows between processes, and the entire production process remains in perpetual flow as the l-piece-flow process proceeds. Ideally, there is no work-in-process inventory between neighboring processes. Achieving a one-piece production process and maintaining the flow of the production process must also be done in two ways: Synchronizing a continuous, uninterrupted production process must balance each process within the production cell, requiring each operation to take approximately the same amount of time to complete.
Balancing a rationalization of work schedules and staff to avoid one process being overloaded and underloaded at the same time. However, in some cases, a certain amount of work-in-process inventory must be maintained, and this amount depends on the turnaround time between two adjacent processes.
The goal of implementing a one-piece production process, synchronizing and balancing these measures, is to match each operation or group of operations to the production line's one-piece production time (Tact time). Tact time is the amount of production time required to satisfy user demand and can also be thought of as the beat or rhythm of the market. When production is organized in strict accordance with the Tact time, the inventory of finished goods is reduced to a minimum (in the following.). Tact time will be examined in depth in the following example).
2. Improvement of production activities
It is not enough to continuously improve the production process to achieve lean manufacturing, but to further improve individual activities in the production process to better match the improved production process. With little or no inventory, the reliability of the production process is critical. Continuity of production must be ensured by reducing production lead times, machine overhauls, downtime for awaiting material and reducing scrap.
(l) Reducing production lead time. Reduce the production lead time general practice is to carefully and meticulously do a good job before the start of all the preparatory activities to eliminate the production process may occur in a variety of hidden dangers.
-enumerate each element or step of the production preparation procedure;
-identify which factors are intrinsic (requiring downtime to deal with) and which are creative, intrinsic factors (which can be dealt with during the production process)
-convert intrinsic factors into extrinsic factors as far as possible;
-utilize industrial engineering methods to improve technology and streamline all factors affecting the preparation of production. of intrinsic and extrinsic factors, leading to increased efficiency.
(2) Elimination of downtime. TotalProductive Maintenance (TPM) is the most powerful measure for eliminating downtime, and consists of four basic types of maintenance: routine maintenance, pre-visualized personalized maintenance, preventive maintenance, and immediate maintenance.
Routine Maintenance - a maintenance activity done daily by operators and maintenance workers that requires regular maintenance of machines.
Predictive maintenance - the use of measuring hand four analytical techniques to predict potential failures, to ensure that the production equipment will not be caused by machine failure and loss of time. The significance of this is to save for a rainy day and prevent problems before they occur.
Preventive maintenance - a for each machine to prepare a file, record all the maintenance program and maintenance records. Thorough and rigorous maintenance is done on every part of the machine, and parts are replaced at the right time to ensure that the machine does not break down unexpectedly.
Immediate maintenance - a when there is a failure, maintenance personnel to call Z that is, on call, timely treatment.
Because in a continuous production process, there is little inventory between processes, and if a machine breaks down, the entire production line is paralyzed, so eliminating downtime is significant to maintaining continuous production.The goal of TPM is zero defects and no downtime. To achieve this goal, it is important to work on eliminating the root causes of breakdowns, rather than just dealing with the symptoms that manifest themselves on a day-to-day basis.
(3) Reduce scrap generation. By closely monitoring the various phenomena that produce scrap (such as equipment, staff, materials, and operating methods), we identify the root causes and then thoroughly address them. In addition, those measures to eliminate rework are also conducive to reducing scrap.
3. Improve labor utilization
Improve labor utilization, there are two aspects, one is to improve direct labor utilization, and the other is to improve indirect labor utilization.
The key to improve the utilization of direct labor in the dry one person in charge of multiple machines, which requires cross-training of operators, cross-training is designed to make the production line operators can adapt to any type of work on the production line. Cross-training gives workers great flexibility and facilitates the coordination of abnormal problems in the production process. The prerequisite for the realization of one-person-multi-machine is the establishment of a work standardization system. Work standardization is the process of studying a large number of work methods and movements to determine the most efficient and repeatable methods. Employees must work in strict accordance with the standardization, which is significant not only in terms of increased utilization of direct labor, but also in terms of improved product quality, since the adoption of a series of technical measures such as error protection and prevention of scrap ensures that each operation can only be carried out according to the only correct method.
Installation of automatic inspection devices in production equipment can also increase the direct labor utilization rate. The production process is closely monitored from start to finish by automatic detection devices, which sound an alarm or shut down the machine automatically if they detect any abnormalities in the production process. These automatic inspection devices to some extent replace the activities of quality inspection workers, eliminating the causes of quality problems, rework phenomenon is greatly reduced, labor utilization rate naturally increased.
Indirect labor utilization rate with the improvement of production processes and the elimination of inventory, inspection, rework and other phenomena, those measures that help to improve the direct labor utilization rate can also improve the indirect labor rate. Inventory, inspection, rework and other aspects of the human and material resources consumed does not increase the value of the product, so these labor is usually considered indirect labor, if the elimination of indirect activities in the product value chain can not value-added indirect activities, then by these indirect activities caused by the indirect cost will be significantly reduced, the utilization of labor can be improved accordingly. In short, lean manufacturing is a never-ending process of excellence, which is committed to improving the production process and every process in the process, eliminating all activities in the value chain that do not add value to the maximum extent possible, improving labor utilization, eliminating waste, and producing according to customer orders while minimizing inventory. Lean is a new corporate culture, not the latest management fad. The transition from a traditional to a lean enterprise cannot be made overnight, it takes a price to pay, and sometimes unexpected problems can arise, allowing those who are enthusiastic about traditional production methods and skeptical of lean to cite one reason or another for their refutation. However, those who are determined to take the lean road, most of the enterprises in six months, some even less than three months, can recover the full cost of transformation, and enjoy the benefits of lean production.