Lean production processes based on optimization analysis

Summary: draw on the concept of lean production to subcontract parts of a business organization of production process as an example, to optimize their production processes, and optimize the effectiveness of the evaluation of the production process of China's manufacturing enterprises have a lean management reference.

Keywords: Lean production process optimization

With the development of economic globalization and China's accelerated integration into the global economy, companies and broader market, while also facing increased competition, increased costs, profit margins decline, the market demand for personalized and diversified, and many other challenges, this making the average profit level of the business decline in the production process of organization, to choose their product characteristics of production processes, cost control is the key to business, but also for enterprises to improve production efficiency, improve product quality and competitiveness of the market played a key important role, while lean production is to optimize production processes to solve business survival and development is currently the best way.

1 the basic connotation of lean production
Lean Manufacturing (Lean Production, LP), also known as excellent production, which "fine," said the sophisticated, precision, fine; "benefits" means benefits, benefits, etc. Lean manufacturing is to maximize profits as the goal, in time manufacturing eliminate the raw material procurement, storage, production, packaging and other production processes in all the waste.

Lean production is a kind of production to minimize occupied resources and reduce management and operating costs as the main objective of production, but also a philosophy, a culture of lean production implementation of JIT is determined pursuit of perfection, the pursuit of excellence is excellence, perfect for the realization of the ultimate goal of seven to zero and continuous efforts it is supporting the individual and corporate life as a spiritual force, but also in the never-ending learning process to obtain self-satisfaction of a the kind of state.

Lean production using traditional industrial engineering techniques to eliminate waste, focus on the entire production process, not just individual or several steps. Lean production and mass production mode contrary, in the pursuit of inter-process products, semi-finished inventory, but it not forced to inter-process inventory reduction, we can not rely mainly on the traditional process of cluster-type arrangement, because this process too far distance between the processes, goods passed it is unrealistic to implement single pass, so it emphasizes the value of stream flow, This use of a flow in, the device according to the flow in the direction according to the order of arrangement of manufacturing processes, thereby greatly reducing the distance between production processes, reducing handling, making the implementation process between the products, semi-zero inventory as possible.

Lean production includes all the basic things - 5S on-site management, JIT (Just In Time lean production and automation are the two pillars and 6σ quality management principles, visualization, management, and constantly striving for perfection, support system, such as shown.

2 based on lean manufacturing process optimization case study
2.1 Case Study Background Electrical Manufacturing Co., Ltd. under the South China Southern Airlines Power Machinery Company, in the mechanical and electrical product development and manufacturing has a good foundation, the company is mainly engaged in mechanical and electrical products abroad, "three to fill a" subcontracting production to export-oriented production-based, customer orders, production model based primarily on the requirements of the organization.

Produced mainly as a production-driven to customer orders, product series, such as: brush rod holder, mandril bracket, rocker, shaft, etc. similar products very similar structure, organization of production process with multiple varieties of small batch production features. To brush rod holder, for example, the annual order quantity of 2800, requires delivery of 150 per month, but according to company's existing production capacity can not meet demand on the one hand, due to more extensive production management, production and irrational organizational processes, resulting in the low productivity, long life cycle, such shortcomings can not be delivered on time very prominent business monthly, 30% to 50% of orders shipped on time, on the other hand, long-term workers to work overtime, the performance was a serious shortage of production capacity, so that enterprises in the Rapid response to market to meet customer demand, performance was more and more powerless.

2.2 Problems and main business analysis through the production and management for observation, the cause of the problem can generally be concluded that: ① the development of the monthly volume put unreasonable. Not in order to organize production, the products take a long time, long production cycle (about a month production cycle, the lack of flexible capacity, poor market response. ② lack of standardized operating procedures. Process equipment and staffing is not quite reasonable, often more equipment and personnel to wait at idle time, and fellow process practices, significant differences between operating time, product quality, production progress control difficult. and can not establish an effective working hours of assessment criteria, there is a big production capacity uncertainty. ③ lack of basic market prediction mechanism, to order the production of temporary orders inserted a single production, often causing confusion in the overall production process, on time delivery often occurs. ④ due process equipment and staffing is not rational. appear idle and various equipment staff waiting time, resulting in waste of production capacity. ⑤ production site layout confusing. there is no safe and reliable location appliance parts store and transport parts protection, resulting in parts of bumps and scratches, resulting in rework or scrap parts.

2.3 According to the lean production methods to develop optimal solutions based on the above analysis, the current business problems in the production process is divided into machining Technology issues and their overall production site layout problems. Combined with lean production and business future trends, proposed establish a more complete modern processing Technology and process management systems, enterprise organization and management of existing traditional production process for transformation, the content of the product manufacturing processes, equipment and personnel to re-adjust the layout by increasing the necessary advanced equipment and components more flexible way to connect small units of production lines to achieve the elimination of waste, improve efficiency, reduce costs, lean manufacturing goals, and between the production site to establish a "continuous process", the entire value stream optimization, and the use of pull production control ways to enhance productivity. work out improvement measures such as the following:
2.3.1 Adjust the amount of lean production on batch input focus on the entire production process, in the pursuit of inter-process products, semi-zero-library, while the original investment amount of 80 per batch, the excessive number of single-batch, resulting in a single batch flow period is too long, often equipment, personnel downtime to be expected in the case. The analysis estimated that a single batch in volume adjusted to 30 monthly investment in 5-6 batches in order to adapt the frequency of the processing chain, to better control the production site in a reasonable flow of products to ensure that the production process continuity.

2.3.2 create a complete production line Lean value stream flow stress, the use of a stream which flows into the device according to the flow direction of the flow process according to the order placement process, thereby greatly reducing the distance between production processes, reducing handling. According to the requirements of lean production processes and the ability of different processing equipment, adjust the equipment, adding a vertical machining center and milling machine and the two he used a drill to adjust Press the processing of parts "brush rod holder" of the process process to form a flexible small unit connected to the production line, complete all the machining processes the content to produce qualified products must be configured processing equipment and workers, and according to production cycle needs and equipment, processing capacity and reasonable arrangements for personnel shifts Specific adjustment see "the original production of the processing site layout map" (shown in Figure 2 and the optimization of the improved "adjusted production processing site layout map" (shown in Figure 3.

After the above adjustment, the equipment processing capacity has been significantly improved, the production unit is more compact, thus greatly reducing turnaround time and the middle part of the vacant facilities.

2.3.3 Optimization of the processing Technology to improve the standard of lean production process requires staff to work according to the beat production, according to lean production methods, modern processing Technology and process management on the part "brush bar bracket," the processing Technology of consolidation adjustments, of manufacturing processes in 50,60,80,90 processes merged into one process, using machining centers for processing, alone, saving the processing fees, but also shorten the processing time to ensure quality, increase product qualified rate specific process contents shown in Figure 4.

① the production cost analysis. The part (shown in Figure 5 the complexity of the technology medium, physical tolerances required. After adjusting equipment and process adjustments, increased capital investment, the purchase of a vertical machining center, but from Table 1 and Table 2 shows the comparison did not increase processing costs, as well as the lower, more importantly is to enhance the enterprise's production and processing capacity and to expand the production range. Links to free download http://www.hi138 . com A. Original cost: Q processes the original process cost = E50 + E80 + E60 process process process + E90 = 10 +9 +50 +60 = 129 yuan
B. is the cost: Q = E machining center machining center piece H unit process time = 100x0.7 = 70 元
② process capability analysis shown in Table 1, we can see, from a single work process point of view limits the ability of the main bottleneck in 80,90,120 processes, and process 120 can be directly resolved by increasing the inspection staff, as 80, 90 process is more complex, demanding process, due to uneven processing technology workers, resulting in a very unstable product quality, low pass rate, but also lead to the production efficiency is low. Therefore, we must adjust by improving technology and processing equipment, in order to improve production efficiency to ensure processing quality, improve product parts directly to the passing rate, so that process capability has been greatly improved.

③ cycle analysis shown in Table 2, the process takes longer 50,60,80,90, processing contents, there is uncertainty, making it easy to extend the production cycle and confusion, after 50,60,80,90 process of adjustment after the merger, replaced by a process of machining centers processing, process time from 134 minutes / single working hours (before the merger reduced to the present 42 minutes / single working hours (after the merger. single from the total working hours " 80 minutes / one-piece total working hours, "shortened to" 288 minutes / one-piece total working hours ", a significant reduction in processing time process, directly reducing parts processing cycle.

2.3.4 a "Kanban" means
Through the production plan, production schedule, the product flow process, quality control and management draw on lean production and other aspects of the "kanban", better transfer of production and delivery of work orders, to prevent excessive over-production and delivery, for "visual management" and the problems can be improved. enhance product quality control, processing of the part to increase the necessary testing and sampling, to avoid rework and scrap parts of the batch. to increase the necessary equipment to protect parts of the station to avoid parts The bumps and scratches, reduce rework and scrap parts. a good selection of cost-effective tools, fixtures, gages, reduce production costs and production costs.

3, after the implementation of optimization applications results analysis
After a period of practical application, verified by example, through the production of lean production process optimized to obtain the following direct benefits: First, adjust the volume on batch input, after a reasonable volume greatly reduces the process inventory, improve on-site production management order, are the product off the assembly line each week, significantly shortening the production cycle, improve production efficiency more than 10%, followed, after the establishment of small units of production lines, equipment, processing capacity has been significantly improved, the production unit is more is compact, greatly reducing the turnaround time of parts and equipment for the vacant half-way time and reasonable arrangement turns the production, standardization of work processes, setting a quota for posts at least 5% of production efficiency over again, through the improvement of processing technology to optimize and shorten the processing time, lower processing costs, to ensure processing quality, increase product yield. reversing often can not deliver on time, long-term adverse overtime situation, reduce production costs in the case without increasing the cost of production be significantly improved. than before to improve production efficiency improved more than 30% and finally, through the introduction of "Kanban" approach, making the entire production process at a glance. increased processing flexibility and control, combined with other optimization part of the improvement, the production efficiency increased by 15% or more.

In summary, after re-design of the production process is running, the company gradually from traditional mass production to lean production methods change, the establishment of a more complete modern processing technology and process management system, through the enterprise existing traditional production process to transform the organization and management, product manufacturing processes for managing content, re-adjust the layout of equipment and personnel by the above example also illustrates the method of the application process and the actual results, production indicators fully meet the design requirements and also meet not to increase the enterprise's production staff, production efficiency by 50% or more of the requirements, the production site environment has been greatly improved at any time to meet the market demand for product diversity, enhance customer satisfaction, more importantly, improve the overall level of technology and machining capabilities, greatly enhancing the enterprise's market competitiveness.

4 Conclusion
It can be seen from the case under the direction of the lean production, combined with business practice, production process can be cost-efficient continuous processes, its adaptation to the modern fast-changing external environment, new ideas. The use of lean manufacturing, continuous continuous improvement, reduce waste, increase value, enhance the core competitiveness of manufacturing companies to obtain and maintain competitive advantage in an effective way.

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