In fact, SMT has a variety of quality occasionally appear, such as empty solder, false solder, even tin, broken, missing parts, offset, etc., different quality problems have similar reasons, there are also different reasons, today we will talk to you about SMT empty solder what are the reasons and improve countermeasures.
Empty soldering means that the components, especially the components with pins are not climbing tin, called empty soldering, empty soldering has the following 8 main reasons:
1. Poor stencil opening
Because the pin spacing is very dense, so the hole is very, very small, if the hole opening precision is bad will lead to paste can not be leaked or leak printed very little, resulting in the pad no paste, soldering after the appearance of empty solder.
Solution: accurate open stencil
2. Solder paste activity is relatively weak
Solder paste itself problem activity is weak, solder paste is not easy to hot melt
Solution: Replace the active solder paste
3. Scraper pressure is high
Solder paste to leak printed coating on the pcb pads, the need to scraper back and forth scraping again, if the scraper pressure and speed, the solder paste leakage will be very little, resulting in empty solder
Solution: adjust the pressure and speed of the scraper
4. Component pins warp deformation
Some component pins are warped or deformed in transit, resulting in hot melt solder paste can not climb tin, resulting in empty solder
Solution: test before use and then use
5. Dirty or oxidized pcb copper foil
The pcb copper foil is dirty or oxidised, resulting in poor pin crawling, leading to empty soldering
Countermeasures: pcb should be used as soon as possible after opening, and should be baked and inspected before use
6. Reflow soldering machine preheat zone heating up too fast
Reflow soldering preheating zone heating up too fast, resulting in solder paste dissolved in the heating and soldering area have evaporated
Solution countermeasures: set a reasonable furnace temperature curve
7. SMT machine component placement offset
Because the pin spacing is very dense, some placement machine precision can not reach, leading to placement offset, not the pin placement to the designated pad
Solution countermeasures: purchase high precision mounter
8. Solder paste printing offset
Solder paste printing machine printing offset, may be the reason of stencil, also may be the clamp plate loose
Solution: adjust the solder paste printing machine, adjust the Table table track fixture for adjustment.
Specification of NeoDen reflow oven IN6
Smart control with high sensitivity temperature sensor, the temperature can be stabilized within + 0.2℃.
Original high-performance aluminum alloy heating plate instead of heating pipe, both energy-saving and high-efficient, and transverse temperature difference is less than 2℃.
Several working files can be stored, freely switch between Celsius and Fahrenheit, flexible and easy to understand.
Japan NSK hot-air motor bearings and Swiss heating wire, durable and stable.
The table-top design of the product makes it a perfect solution for production lines with versatile requirements. It is designed with internal automation that helps operators provide streamlined soldering.
The design implements an aluminum alloy heating plate that increases the energy-efficiency of the system. The internal smoke filtering system improves the product’s performance and reduces harmful output, too.
Working files are storable within the oven, and both Celsius and Fahrenheit formats are available to users. The oven uses a 110/220V AC power source and has a gross weight (G1) of 57kg.
Post time: Dec-29-2022