1 Body quality management
1.1 Incoming inspection and quality management of parts There are many parts that make up the body in white. In order to achieve large-scale production, about 50% of our company's sheet metal stamping parts have spread to cooperative manufacturers. Due to the uneven quality assurance capabilities of the cooperative manufacturers, the mold processing and forming conditions of each manufacturer are not uniform, resulting in certain deviations in the size of the parts. In addition, these parts are assembled and welded on the same welding tool of our company. How to make the parts coordinate and unify during the assembly and welding process to achieve a good assembly and welding effect, this puts forward higher requirements for the incoming inspection of the parts . Firstly, the inspection technicians prepare detailed inspection standards for each part according to the product drawings, combined with the assembly and welding requirements and the assembly process, which we call the Part Inspection Standard (HTS-P). The inspection standard gives the tolerance range of each dimension. The inspection workers carry out sampling inspection on the parts according to the inspection standard. The parts of all cooperative manufacturers must be within the tolerance range. The parts that are out of tolerance are limited to the manufacturer to make corrections within the specified time limit. Through meticulous incoming inspection, the parts of various manufacturers are coordinated to meet the assembly and welding production requirements.
1.2 Welding quality management
The composition of the body is welded into sub-assemblies by single-piece assembly, each sub-assembly is then assembled and welded to form the body assembly. The above work is prepared by the welding technician for each station according to the product drawing and welding process. mark
Standard, we call it Part Operating Standard (HOS). The operating standard stipulates the order of parts placement, clamping and welding process, and the operating specifications of employees, so that employees can establish the concept of "the next process is the user". Employees implement the "three-inspection system" for the products they operate, that is, first-article inspection, intermediate inspection, and unfinished article inspection. At the same time, they inspect the workpieces delivered by the previous process, and operate after they believe that there are no quality problems. In the management of the workshop, the "5S" management method is implemented. The so-called "5S" means sorting (SEIRI), rectifying (SEITON), cleaning (SEISO), cleaning (SEIKETSU), and quality (SHTTSUKE). Through the "5S" activities, the corporate image is improved, employees' sense of belonging is enhanced, waste is reduced, logistics is smooth, and work efficiency is improved. More importantly, "5S" removes carelessness, enhances the sense of responsibility of employees, and enhances product quality. Strong guarantee. At the same time, the relevant departments conduct various quality index assessments on the workshop from time to time, so as to truly achieve "everyone shoulders the burden of quality, and everyone has indicators on their heads."
2 process control
2.1 Process equipment
Good process equipment is the premise of quality assurance. Process equipment includes welding fixtures, welding equipment, operating equipment, etc. There are a large number of resistance welding machines in our welding equipment, such as suspension spot welding machines, fixed spot welding machines, etc. Most of these equipments are products from the 1990s, equipped with microcomputer programming control boxes, and the welding process is controlled by a microcomputer for closed-loop control. Therefore, this equipment can not only control various welding specifications, but also can automatically perform secondary welding and step compensation under the condition of power grid, voltage fluctuation and welding load change, so as to ensure a constant output welding current, thus ensuring spot welding quality.
2.2 Process
Good workmanship is the main control factor to ensure the reliability and stability of product quality, and is the basis for ensuring product quality. Over the past few years, we have been improving the production process of the product. For example, after the front wall slanting pillar and the front claw of the top cover are assembled and welded, the gap between the joints here was filled by coating sealant in the past, resulting in uneven appearance; Metal arc welding, heat concentration, local deformation is small, arc surface trimming and grinding method is used after welding, so that the weld seam and the body of the car body are integrated, and the appearance quality of the product is improved. Another example is the welding of the upper frame and the inner and outer panels of the door in the workshop. In the past, the traditional copper brazing process was used. After welding, the welding powder and welding slag deposited on the surface of the weld seam were difficult to remove. The pre-treatment of the primer will affect the local phosphating film and affect the spraying effect of the whole vehicle;
The deposition of powder and wine has been greatly improved, and it is easy to remove.
2.3 Process assessment
The manufacture of automobile products will be disturbed by various external factors, so to ensure product quality, a set of feasible stochastic control methods is needed, and the control of stochastic factors is a necessary condition for quality assurance. In production practice, we implement a dynamic process discipline assessment for the welding workshop. The content of the assessment includes the parameter setting of the welding equipment, the process status of the electrode head of the welding gun, the reliability of the welding tool, and whether the operation of the employees is carried out in accordance with the operating standards, etc. . For this reason, a line inspection system for engineering and technical personnel has been formulated. Through patrol inspections, it is observed whether there are quality risks on the production line, and minor abnormalities are found to be dealt with in a timely manner. Technicians are required to have the "Three Present Principles, Five-Minute Concept", that is, after a problem occurs, the technician needs to rush to the scene within five minutes, and deal with it in a timely, accurate and objective manner according to the concept of "on-site, present, and present". The possibility of batch problems has been eliminated.
2.4 Extensive QC group activities
The QC (QUALITY CONTROL) group is organized by the masses of employees from the reality, through voluntary association or administrative organization, and uses quality management theories and methods around the company's policies and on-site problems to improve quality, reduce consumption, increase A group that conducts activities for the economic benefit of the enterprise. Group activities focus on "small" and "real", "small" means small topics, small projects, and small achievements; "real" means seeking truth and being solid. Through the activities of the QC group, managers, technicians and operators communicate with each other, which promotes employees' interest in work, deepens the understanding between managers and operators, and is conducive to ensuring the improvement of product quality. Now, our company There are about a dozen QC teams in the company, and they solve hundreds of quality problems every year, taking
Obvious practical effect has been obtained.
2.5 Audit inspection
AUDIT CHECK is an internationally popular means of ensuring product quality. It evaluates every small part of the vehicle every day from the user's point of view. In 1997, our company began to carry out Audit inspection of products, aiming at checking and improving product quality, so as to achieve the approval of users. The relevant content of the daily inspection is fed back to the responsible unit. The purpose of this work is to meet the technical requirements of the product, and strive to achieve a better consistency between what the user needs, what the manufacturer can do, and what the technical requirements require (as shown in Figure 1 ).
3 Establish an effective and rapid information feedback system
In actual production, it is inevitable that there will be quality problems. Since our company's production is an assembly line operation, in order to solve these problems in time and control the occurrence of batch quality problems, it is necessary to establish an effective information feedback system. Information feedback and quality tracking are important ways to ensure quality. Based on years of practice, we have gradually established our company's quality information feedback system (as shown in Figure 2).
From the above figure, we can see that the Quality Assurance Department has become the central system for communicating the entire quality information feedback. For example, if there is a quality problem with external cooperation parts, after receiving the quality information from the stamping parts inspection team, the Quality Assurance Department will instruct the corresponding cooperative manufacturer to carry out rectification within the prescribed time limit. At the same time, the information is fed back to the quality inspection room of the welding workshop, and corresponding technological measures are taken to remedy it to ensure product quality. Another example is the Audite assessment and the final assembly workshop report the assembly and welding quality problems of the welding workshop, and timely feedback to the quality inspection room of the welding workshop, and they will take corresponding control measures to prevent the occurrence of quality problems in the next batch. The information microcomputer statistics center conducts microcomputer statistics and records on the quality problems that come from feedback, and publishes regular quality problems through graphs on a regular basis, and urges relevant departments
Make corrections.
4 Conclusion
Our company also often carries out quality month activities to deepen everyone's quality awareness and improve quality. Through the development of the above-mentioned activities, the product quality of our company has jumped to a new level than before, and has been recognized by the majority of Changhe vehicle users. With the development of the times getting higher and higher, this requires us to continuously improve the quality awareness and operation level of all employees. Quality is the life of an enterprise. Changhe people will dedicate good products to users with strict quality management.