Turnkey pcb manufacturing process to achieve zero bad products，we should pay attention to the details

In the turnkey pcb manufacturing assembly process, the control and management of each link has a great impact on quality assurance. In the assembly process, technical means can be effectively utilized to standardize the management of related results; at the same time, the usage of management means to achieve product quality and reduce costs, which is the purpose of many users to find a turnkey pcb manufacturing processing plant. These factories have different management methods in terms of introduction of new products, selection of materials, SMT and assembly in manufacturing. After every detail is done to the extreme, you can implement the goal of zero-bad work in pcba mounting processing, which can be managed from the following aspects:

(1) product design is the source.

The manufacturability of PCBA pre-processing product design directly affects the quality of the product. This is also the source of improving product quality. The purpose of designing a new model is to find relevant design content, manufacturing conditions, parameters, etc. that are suitable for production. To provide effective design improvement recommendations during the new product design step, DFM can be used to explore and improve design manufacturability issues after receiving gerber data and PCB manufacturing requirements. Such as PCB size and panel design, positioning of L and MARK points, rationality of pad design, matching of pads and electronic components, solderability of materials, automation of equipment, solder joints for wave soldering design, etc. After in-depth analysis, we will provide improved suggestions to our customers, which will effectively improve the quality of our products. In order to standardize management design issues, the  problems arising from the PCB design can be classified as DFM audit forms. Before the test, according to the list on the DFM, the organization technicians can confirm each time, which can better prevent the omission of design problems and affect the quality after mass production.

(2) Reasonable material selection is protection

The materials used for PCBA processing are mainly divided into main materials, auxiliary materials, and other solvents used for cleaning the plates. The main materials mainly refer to electronic components and PCB boards. The basic requirement for selection is to first ensure the weldability of the weldable end of the part, and then perform reliability and reliability tests to meet the quality requirement, etc., which is closely related to the coating treatment and processing of the surface layer of the part. The gold-plated layer has good solderability but high cost and is suitable for high-performance electronic products. Others are usually tin plated.

In addition, it is the external dimensions of the components and the matching and assemblability of the part feet to the PCB holes and copper foil. Automate production of equipment to ensure high quality and productivity goals. The secondary material refers to solder paste, red glue, tin wire, tin bar, tin water etc. These materials are primarily core materials used to solder PCBs and components. When selecting, it is necessary to understand the compositional match between the solderable end of the material and the auxiliary material. At present, industrially used more auxiliary material combined with SAC305. In order to reduce production costs, more and more companies are shifting to low-yield and non-silver, especially for DIP.

The control of the defect rate is also basically stable, but it is unstable in terms of poor soldering during solder paste soldering. However, regardless of the conversion situation, in the selection and change of auxiliary materials in pcba mounting processing, it is necessary to understand the melting point and design moderate temperature curve conditions. Through the correlation experiment of welding effect, the welding reliability was evaluated, and the project implementation management was evaluated.

(3)Technological design

The good technological flow and craft window design in turnkey pcb manufacturing is generally in the early stage of product trial, and organizes relevant technicians and managers to conduct DFMEA analysis on the product. Identify potential failure problems and develop appropriate precautions. In the process of programming and design, these issues are planned to be operational standards for critical control. Effectively prevent unprepared problems from occurring. In addition, you can directly quote past failed cases and experiences to get better quality assurance. In the craft design, the undesired links of possible losses and abnormalities must be monitored to achieve automated production and reduce product turnover.

(4) Reasonable craft parameters

To achieve full lead-free, the process window is greatly reduced during PCBA processing. In order to test the craft conditions and parameters, it is recommended to use the DOE test method to optimize the craft parameters. Such as speed, pressure, wiping frequency, demolding speed, reflow soldering temperature setting and other printing related parameters. Standardized control management using DOE test methods. It is possible to reduce the quality instability caused by changes in other factors.

(5) Application and design of anti-loose working device

In the SMT production process, the impact on quality is the open mode and design of the steel mesh. Therefore, the choice of steel plate thickness, opening method and size during PCBA processing, especially the control of tin beads, has always been a headache problem for the industry. However, there is an anti-tin bead treatment method in the design of the steel plate opening, which can effectively reduce the occurrence of undesirable problems. Also it can also play the same role for special and abnormal components and PCB pad designs.

(6)Therefore, the mold designer needs to design according to the nature of the product, the actual condition of the part, and the shape of the pad. At the same time, summarize the design experience, form standardized technical data or refer to the IPC-7525 mold design principle to improve the welding straight-through rate. In addition, the immersion immersion tin plate is also the root cause of the direct impact on the quality of wave soldering. The choice of material, the size of the shape, the shape and size of the opening, and the thickness all affect the effect of immersion in tin. Typically, the designer will use the assembled product.

(7) Quality Control System Monitoring Management System

Turnkey pcb manufacturing processing electronics assembly and OEM, ODM companies have basically established relevant quality control and management systems, such as IS09000, IATF16949 and other quality systems. These systems form a management and control system from the whole to the local, but require detailed and in-depth analysis and improvement of other improvements and control methods. At present, there are 5S management, QCC, 6e, product pass rate and so on. These tools and improved methods can solve difficult quality problems more effectively, especially for applications of 68, and enable more scientific analysis of quality data and problems.

In the analysis of the idea of adopting the "DMAIC" process, the improvement ideas will be more convincing. Thereby effectively achieving product traceability. Prior to the processing and assembly of the PCBA, serial number and bar code management were introduced to facilitate traceability of abnormal quality. At present, the better traceability method is to print 4x4QR code on the product, read the data through the scanner, understand the product production and LOT related information, and systematically and completely realize the abnormal traceability and investigation.

In order to realize the quality control of each part of PCBA processing, combined with the continuous development of quality control system, the control methods and means of each link are especially studied, especially the relevant parameters of the equipment and the optimized craft flow. It can better use the technical power to switch to the management level, effectively manage the precipitation of pcba chip processing technology, and achieve on-site control standardization. In addition, the improvement of product quality is endless. In order to achieve a high-quality SMT processing plant, the “zero bad” awareness is the key to decision and determination. It is the belief that the SMT processing plant will continue to improve by making everything 100% correct. Only a high-quality manufacturing site can achieve true zero defects.