Second, implementation
1. Improve the production process
Lean production uses traditional industrial engineering technology to eliminate waste and pays attention to the whole production process, not just one or several processes.
(1) Eliminate quality inspection and rework. If the product quality can be guaranteed 100% from the design scheme to the whole production line, the phenomenon of quality inspection and rework will naturally become redundant. Therefore, the idea of "error prevention" must run through the whole production process, that is to say, the quality problem has been considered from the beginning of product design, so as to ensure that every product can only be processed and installed in the correct way, thus avoiding possible errors in the production process.
(2) Eliminate unnecessary movement of parts. Unreasonable production layout is the root cause of parts moving back and forth. In the workshop organized by process specialization, parts often need to move back and forth between several workshops, which makes the production line long, the production cycle long, takes up a lot of WIP inventory and has high production cost. By changing this unreasonable layout, the equipment needed to produce products is arranged according to the processing sequence, and it is as compact as possible, which is conducive to shortening the transportation route, eliminating unnecessary parts movement and saving production time.
(3) Eliminate inventory. Taking inventory as an urgent need to solve production and sales is tantamount to quenching thirst by drinking poison. Because inventory will cover up many problems in production, it will also increase the inertia of workers, and even worse, it will take up a lot of money. In lean enterprises, inventory is considered as the biggest waste and must be eliminated. A powerful measure to reduce inventory is to change "batch production and queuing supply" into L-piece flow. In the process of single-piece production, basically only one production piece flows between each working procedure, and the whole production process keeps flowing forever with the progress of single-piece production process. Ideally, there is no WIP inventory between adjacent processes. To realize the integrated production process and maintain the fluidity of the production process, the following two points must be achieved: synchronization 1. In the uninterrupted continuous production process, every working procedure in the production unit must be balanced, and the time required to complete each working procedure is roughly the same.
Arrange the work plan and personnel in a balanced and reasonable way to avoid the workload of a process being too high and too low for a while. However, in some cases, it is necessary to maintain a certain amount of WIP inventory, which depends on the handover time of two adjacent processes.
The goal of implementing measures such as single-piece production process, synchronization and balance is to make each working procedure or group of working procedures match the takt time of a single product on the production line. The production time of a single product is the production time needed to meet the needs of users, and it can also be considered as the rhythm or rhythm of the market. Under the condition that production is organized in strict accordance with takt time, the inventory of finished products will be reduced to a minimum (below. In this example, we will study takt time in depth.
2. Improve production activities
It is not enough to achieve lean production only by continuously improving the production process. It is also necessary to further improve individual activities in the production process to better cooperate with the improved production process. The reliability of the production process is very important when there is no or little inventory. In order to ensure the continuity of production, it is necessary to reduce the production preparation time, machine maintenance, downtime of waiting materials and the generation of waste products.
(l) Reduce production preparation time. The general method to reduce the production preparation time is to do all the preparation activities carefully before starting the machine to eliminate all kinds of hidden dangers that may occur in the production process.
List each element or step of the production preparation procedure;
Identify which factors are internal (need to stop and deal with); What are the creative and existential factors (which can be dealt with in the production process)
Turn internal factors into external factors as much as possible;
Using industrial engineering methods to improve technology, straighten out all internal and external factors affecting production preparation and improve efficiency.
(2) Eliminate downtime. Total Productive Maintenance (TPM) is the most powerful measure to eliminate downtime, including daily maintenance, preventive maintenance and immediate maintenance.
Daily maintenance-The daily maintenance activities of operators and maintenance workers require regular maintenance of the machine.
Predictive maintenance-use the measuring hand four analysis technology to predict potential failures and ensure that production equipment will not lose time due to machine failures. Its significance lies in taking precautions and preventing problems before they happen.
Preventive maintenance-the document of each machine, recording all maintenance plans and maintenance records. Make a thorough and strict maintenance of every part of the machine, and replace the parts in time to ensure that the machine does not have unexpected faults.
Immediate maintenance-when something goes wrong, the maintenance personnel should call Z on call and deal with it in time.
In the process of continuous production, there is little inventory between two processes, and if the machine breaks down, the whole production line will be paralyzed, so eliminating downtime is of great significance to maintain continuous production. The goal of total productive maintenance is zero defects and no downtime. In order to achieve this goal, we must devote ourselves to eliminating the root causes of failure, rather than just dealing with the symptoms of daily performance.
(3) Reduce waste products. Pay close attention to various phenomena (such as equipment, personnel, materials and operation methods, etc.). ) produce waste products, find out the root cause, and then solve it completely. In addition, those measures to eliminate rework are also conducive to reducing the generation of waste products.
3. Improve the utilization rate of labor force
There are two ways to improve the utilization rate of labor force, one is to improve the utilization rate of direct labor force, the other is to improve the utilization rate of indirect labor force.
The key to improve the utilization rate of direct labor is that one person is responsible for multiple machines, which requires cross-training of operators. The purpose of cross-training is to make the operators on the production line adapt to any type of work on the production line. Cross-training gives workers great flexibility and is conducive to the coordination and handling of abnormal problems in the production process. The premise of realizing one person with multiple computers is to establish a work standardization system. Work standardization is to determine the most effective and repeatable method by studying a large number of working methods and actions. Employees must strictly follow the standardization in their work, which is not only to improve the utilization rate of direct labor, but also to improve the quality of products. Because of the adoption of a series of technical measures such as error prevention and waste prevention, every operation can only be carried out in a unique and correct way.
Installing automatic detection devices on production equipment can also improve the utilization rate of direct labor. The production process is closely monitored by automatic detection devices from beginning to end. Once there is any abnormal situation in the production process, it will give an alarm or stop automatically. These automatic inspection equipments have replaced the activities of quality inspection workers to a certain extent, eliminated the causes of quality problems, greatly reduced the rework phenomenon, and naturally improved the utilization rate of labor.
The utilization rate of indirect labor increases with the improvement of production technology and the elimination of inventory, inspection and rework, and those measures that are conducive to improving the utilization rate of direct labor can also improve the indirect labor rate. The manpower and material resources consumed by inventory, inspection and rework can not increase the value of products, so these labors are usually regarded as indirect labor. If the indirect activities that can't add value in the product value chain are eliminated, the indirect costs caused by these indirect activities will be significantly reduced and the labor utilization rate will be improved accordingly. In a word, lean production is a never-ending process of pursuing perfection. It is committed to improving the production process and every working procedure in the process, eliminating all activities in the value chain that cannot be added as much as possible, improving the utilization rate of labor force, eliminating waste, and reducing inventory as much as possible while producing according to customer orders. Lean is a brand-new corporate culture, not the latest management fashion. The transformation from traditional enterprises to lean enterprises can't be completed overnight, it needs to pay a certain price, and sometimes unexpected problems will appear, so that those who are keen on traditional production methods and skeptical about lean production can cite one reason or another to refute it. However, those enterprises that are determined to take the lean road can recover all the transformation costs within six months, and some even enjoy the benefits brought by lean production in less than three months.