1. Preferred surface assembly and crimping components
Surface assembly components and crimping components, with good technology.
With the development of component packaging technology, most components can be purchased for reflow welding package categories, including plug-in components that can use through hole reflow welding. If the design can achieve full surface assembly, it will greatly improve the efficiency and quality of assembly.
Stamping components are mainly multi-pin connectors. This kind of packaging also has good manufacturability and reliability of connection, which is also the preferred category.
2. Taking PCBA assembly surface as the object, packaging scale and pin spacing are considered as a whole
Packaging scale and pin spacing are the most important factors affecting the process of the whole board. On the premise of selecting surface assembly components, a group of packages with similar technological properties or suitable for paste printing of steel mesh of a certain thickness must be selected for PCB with specific size and assembly density. For example, mobile phone board, the selected package is suitable for welding paste printing with 0.1mm thick steel mesh.
3. Shorten the process path
The shorter the process path, the higher the production efficiency and the more reliable the quality. The optimal process path design is:
Single-side reflow welding;
Double-sided reflow welding;
Double side reflow welding + wave welding;
Double side reflow welding + selective wave soldering;
Double side reflow welding + manual welding.
4. Optimize component layout
Principle Component layout design mainly refers to component layout orientation and spacing design. The layout of components must meet the requirements of the welding process. Scientific and reasonable layout can reduce the use of bad solder joints and tooling, and optimize the design of steel mesh.
5. Consider the design of solder pad, solder resistance and steel mesh window
The design of solder pad, solder resistance and steel mesh window determines the actual distribution of solder paste and the formation process of solder joint. Coordinating the design of welding pad, welding resistance and steel mesh plays a very important role in improving the through rate of welding.
6. Focus on new packaging
So-called new packaging, is not completely refers to the new market packaging, but refers to their own company has no experience in the use of those packages. For the import of new packages, small batch process validation should be performed. Others can use, does not mean that you can also use, the use of the premise must be done experiments, understand the process characteristics and problem spectrum, master the countermeasures.
7. Focus on BGA, chip capacitor and crystal oscillator
BGA, chip capacitors and crystal oscillators are typical stress-sensitive components, which should be avoided as far as possible in PCB bending deformation in welding, assembly, workshop turnover, transportation, use and other links.
8. Study cases to improve design rules
Manufacturability design rules are derived from production practice. It is of great significance to continuously optimize and perfect the design rules according to the continuous occurrence of poor assembly or failure cases to improve the manufacturability design.
Post time: Dec-01-2020