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About the quality control of PCBA multi-variety production
About the quality control of PCBA multi-variety production

About the quality control of PCBA multi-variety production


The production characteristics of PCBA multi-variety and small-batch production increase the difficulty of product quality control. In order to ensure the steady improvement of product quality under the conditions of multi-variety and small-batch production, it is necessary to establish detailed operating instructions and implement the principle of "prevention first". Introduce advanced management concepts to improve management.

1. Establish detailed work instructions and standard operating procedures for the commissioning phase

The work instruction should include the required numerical control program, fixture number, inspection means and all parameters to be adjusted. Prepare work instructions in advance, you can fully consider various factors, through compilation and proofreading, gather the wisdom and experience of multiple people to improve accuracy and feasibility. It can also effectively reduce the online changeover time and increase the utilization rate of the equipment.

The standard operating procedure (SOP) shall determine each execution step of the commissioning work. Determine what to do at each step and how to do it in chronological order. For example, the type of CNC machine tool can be changed according to the sequence of changing the jaws-calling the program-according to the tool number used in the program-checking-tool setting-positioning the workpiece-setting the zero point-executing the program step by step. Scattered work is carried out in a certain order to avoid omissions.

At the same time, for each step, how to operate and how to check are also stipulated. For example, after replacing the jaws, how to detect whether the jaws are eccentric, etc. It can be seen that the debugging standard operating procedure is the optimization of the control point operation of the debugging work, so that every employee can do things in accordance with the relevant regulations of the procedure, and there will be no big mistakes. Even if there is a mistake, it can be quickly checked through the SOP to find the problem and improve it.

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At the same time, because SOP itself is also the product of continuous summary, optimization and improvement in practical operations, the common wisdom of many people has been accumulated in this process, so it is relatively optimized, has good implementability, and can improve things. s efficiency.

2. Lean process quality control

The standardization of processes is an important part of lean quality management. The process is the basic unit of the product formation process, and the quality of the process directly determines the quality and production efficiency of the product. Process quality is affected by many factors. In summary, there are six main aspects, namely 5M1E (human, machine, material, method, environment, and measurement), which constitute the six major elements of process standardization.

The quality of the process is affected by the 5M1E factor, and the 5M1E factor is also affected by the quality of peripheral related work. Process standardization requires the standardization of 5M1E elements, which also implies the standardization of 5M1E peripheral related work. Process standardization is to ensure the quality and efficiency of PCBA process through the standardization of 5M1E elements.

The important evaluation index of process quality is the process capability index, and the intuitive results of process quality are shown as qualification rate, unit working hours and other indicators. Process quality can also be evaluated and analyzed through histograms and control charts. Process quality affected by external factors such as 5M1E can also reflect changes in external factors. The ease of evaluation of process quality can promote effective evaluation and improvement of 5M1E and peripheral work.

Process standardization is the common management requirement of lean production and ISO9000 system, and the common requirement of production management, quality management, cost management and other functional management. Process standardization is not in-depth, detailed and coordinated. Process standardization should comprehensively reflect the standardization requirements of quality, quantity, and cost.

The goal of lean quality management is to seek the comprehensive improvement of operating system quality, efficiency, and cost. The operating system does not deliberately distinguish between production functions and quality functions, nor does it distinguish between lean production projects or six sigma projects from a project perspective, and advocates a variety of tools and methods. Integrated use. Lean quality management takes process standardization as the basis, which is to promote enterprises to pay more attention to process standardization, break functional boundaries and jointly promote process standardization, and build a solid foundation for comprehensive improvement of quality, efficiency, and cost in response to rapid changes in multiple products.

Process measurement is a management requirement specially emphasized by the ISO9000 quality system. In production management, statistics are often used to express relevant production results. There is a difference between measurement and statistics. Measurement implies a comparison with the standard, and the data result is in the coordinate system. However, statistics does not emphasize comparison with standards, and often does not delve into deviations.

3. Really implement the principle of "prevention first"

It is necessary to transform the theoretical "prevention first, combining prevention and gatekeeping" into "real" prevention. This does not mean that gatekeepers are no longer gated, but the function of gatekeepers is to be further improved, that is, the content of gatekeepers. It includes two aspects: one is the check of product quality, and the next step is the check of process quality. To achieve 100% qualified products, the first important thing is not the inspection of product quality, but the strict control of the production process in advance.

Demand, customers are the only factor that determines quality;

Second, reduce anything that does not meet customer needs;

Third, maintain the consistency and stability of products, services and processes;

Fourth, the only way to provide the lowest price and make a profit is to improve quality and speed.

Improve processes, eliminate defects, and reduce fluctuations. Including the following meanings:

First, most PCBA quality problems exist in the process rather than people;

Second, the methods of improvement include documenting work procedures, checking the transfer between work steps, teaching employees the knowledge and methods that they need continuously, reducing quality fluctuations, and improving speed.

Third, you must become a person who uses process concepts to consider problems and consequences, that is, process thinkers.

All decisions are based on facts and data. It includes two meanings:

First, the obstacles to the use of data are: lack of ready-made data, lack of training in collecting and analyzing data, and people using data only to punish or reward employees instead of improving processes;

Second, the data includes result data (customer satisfaction, financial revenue and expenditure, etc.) and process data (speed, delivery period, quality, defects, etc.).

5. IIoT industrial IoT intelligent flexible control system that realizes Industry 4.0

The quality control can be achieved through the digital automated production line of the Industrial Internet of Things, but the degree of flexibility is still relatively insufficient, so it is difficult to meet the demand for rapid production line conversion during rapid process adjustment. The manufacturing method of the traditional production line needs to be upgraded, and the dynamic optimization process technology for the decoupling of the process process is proposed. The characteristic of this process is that the production process is loosely coupled, it can be dynamically reconfigured at the production line level, and the process is decomposed and rearranged.

The dynamic service programming technology for PCBA production process and the service adapter that supports online command execution can respectively solve the problem of online reconfiguration of production technology and equipment resources based on Web services and the problem of dynamic execution of equipment plug-and-play automation configuration and interoperability commands. . Realize the minute-level dynamic order cutting and production conversion in the assembly process; the PCBA product quality problem detection time reaches the second level, and the process defect traceability time reaches the minute level.