wettable nozzle for selective soldering machine

A few pin in print circuit board if use wave soldering to do soldering that will be spend more money which concern solder consumtion , flux consumption
Today have a machine can be done soldering by using a small nozzle that call"wettable nozzle"
Meaning of wettable nozzle is liquid solder is cover around nozzle surface that it can be focus arrea to do soldering without solder splash.

Solder Hairline short between PTH component

Many PCBA that have a very narrow pin less than 20 mils pitch (pad to pad)is be faced
hairline (very small dross) short problem that difficult to visual inspection after post wave.
The way for solving this problem
1.Good perform to do maintainance (cleanning flowduct by monthly)will be decreased this problem 90%
2.Addition camera for inspection