As an automation equipment manufacturer, Chuang Times is specialized in the production of lead-free soldering stations and automatic soldering machines. Welcome to order. Currently, there is already a lot of information on lead-free soldering materials and lead-free soldering processes. It is necessary to develop lead-free soldering processes. It is very important for the factory to choose the right information and combine it organically. To develop a robust, high-throughput lead-free soldering line, careful planning is required, as well as efforts to implement the plan and rigorous process monitoring to ensure product quality and process control. These controls are related to many changes, such as materials, equipment, compatibility issues, pollution issues, statistical process control (SPC) procedures, and so on.

The use of lead-free solder materials can have a serious impact on the soldering process. Therefore, in the development of lead-free soldering processes, all relevant aspects of the soldering process must be optimized. Georze Westby's five-step approach to developing a lead-free soldering process helps lead-free solder process development and process optimization.

1 Select the appropriate materials and methods

In the lead-free soldering process, the selection of soldering materials is the most challenging. Because for the lead-free soldering process, the selection of materials such as lead-free solder, solder paste, and flux is the most critical and most difficult. The selection of these materials also takes into account the type of soldered components, the type of circuit board, and their surface coating conditions. The selected materials should be proved in their own research, or recommended by authorities or literature, or have already used experience. These materials are listed as a table ready for testing in process tests to conduct an in-depth study of them to understand their impact on various aspects of the process.

For the welding method, choose according to your actual situation, such as the type of component: surface mounting component, through-hole insertion component, circuit board condition, number of components on the board, and distribution. For soldering of surface mount components, reflow soldering methods are used; for through hole plug components, wave soldering, dip soldering or spray welding may be selected for soldering depending on the situation. Wave soldering is more suitable for the welding of through-hole insertion components on the whole board (large size); the dip soldering is more suitable for welding on the whole board (small size) or the local area through-hole insertion components on the board; the local spray flux is more suitable Welding of individual components on the board or a small number of through-hole mounting components. In addition, it should be noted that the whole process of lead-free soldering is longer than that of lead-containing solders, and the required soldering temperature is higher, because lead-free solders have a higher melting point than lead-containing solders, and its infiltration The reason is that sex is worse.

After the welding method is selected, the type of welding process is determined. At this time, it is necessary to select equipment and related process control and process inspection equipment according to welding process requirements, or to upgrade. The choice of welding equipment and related equipment is just as crucial as the selection of welding materials.

2 determine the process route and process conditions

After the first step is completed, the welding process test can be performed on the selected welding material. Through the experiment to determine the process route and process conditions. In the test, it is necessary to conduct sufficient tests on the solder materials selected in the list in order to understand its characteristics and influence on the process. The purpose of this step is to develop lead-free solder samples.

3 Develop sound welding process

This step is the continuation of the second step. It analyzes the test data collected in the second step in the process test, and then improves the materials, equipment, or changes in process to obtain a sound process under laboratory conditions. In this step, it is also necessary to understand the potential contamination of the lead-free alloy welding process, know how to prevent, determine the process capability (CPK) values of various welding characteristics, and compare with the original tin/lead process. Through these studies, the inspection and testing procedures for the welding process can be developed, and at the same time, some processes that are out of control can be identified.

4. It is also necessary to conduct reliability tests on welding samples to determine whether the quality of the products meets the requirements. If you do not meet the requirements, you must find out the reasons and solve them until you meet the requirements. Once the reliability of the welding product has been met, the development of a lead-free soldering process has been successful. This process is ready for operation with scale ready for production and can now be transformed from sample production to industrial production. At this point, the process still needs to be monitored to keep the process under control.

5 Control and Improvement Process

The lead-free soldering process is a stage of dynamic change. Factories must be wary of possible problems to avoid process out of control, but also need to constantly improve the process to

Make the product quality and qualified crystal rate continue to increase. For any lead-free soldering process, improving the soldering materials and updating equipment can improve the soldering performance of the product.