CNSMT Adjustable speed reflow oven SMT PCB SMALL reflow soldering 5 heating zone up 3 down 2

Feature

Application

By re-melting the paste solder pre-dispensed on the PCB pads, the soldering of the mechanically and electrically connected solder terminals of the surface-mount components or the leads to the PCB pads is achieved. The
1. Introduction of reflow process
Surface-mounted boards for reflow soldering process are more complex and can be divided into two types: single-sided mounting and double-sided mounting. The
A, single-sided placement: pre-painted solder paste → patch (divided into manual placement and machine automatic placement) → reflow soldering → inspection and electrical test. The
B, double-sided mounting: A surface pre-painted solder paste → patch (divided into manual placement and machine automatic placement) → reflow → B surface pre-painted solder paste → patch (divided into manual placement and machine automatic Mounting) → Reflow → Inspection and Electrical Test. The
2. Influence of PCB quality on reflow soldering process. The
3, the thickness of the pad plating is not enough, resulting in poor welding. The thickness of the plating on the pad surface of the component to be mounted is not enough. If the thickness of the tin is not enough, the tin will not be sufficiently melted under high temperature, and the component and the pad will not be welded well. For the pad surface tin thickness our experience should be >100μ. The
4, the surface of the pad is dirty, causing the tin layer does not infiltrate. Plate surface cleaning is not clean, such as the gold plate has not been cleaned, etc., will cause the pad surface impurities. Bad welding. The
5, wet film bias on the pad, causing poor welding. Deposition of the wet film on the pads of the component to be mounted also causes poor soldering. The
6, the lack of pad, causing the component can not be welded or welded firmly. The
7, BGA pad development is not clean, there is a wet film or residual impurities, causing the placement of the solder is not on the occurrence of Weld. The
8, BGA plug holes prominent, resulting in BGA components and pad contact is not enough, easy to open. The
9. The BGA has a large solder mask at the BGA, which leads to the exposed copper on the pad connection and a short circuit on the BGA patch. The
10. The spacing between the positioning hole and the pattern does not meet the requirements, resulting in offset solder paste and short circuit. The
11, IC foot between the denser IC pad broken green oil, resulting in bad solder paste and short circuit. The
12. The via plug hole protrudes next to the IC, causing the IC not to mount. The
13. The stamp hole between the units is broken and the paste cannot be printed. The
14. Drill the wrong recognition point corresponding to the fork plate. When the automatic attachment is attached, it is wrong, resulting in waste. The
15. The secondary drilling of the NPTH hole caused a large deviation of the positioning holes, resulting in partial solder paste. The
16, light spot (IC or BGA next to), need to be flat, matte, no gaps. Otherwise, the machine will not be able to recognize it and it will not be automatically attached. The
17. The mobile phone board is not allowed to sink nickel gold, otherwise the nickel thickness is not uniform. Affect the signal.