Associated Press Writer CAIROâEgypt displayed on Monday newly discovered tombs more than 4,000 years old and said they belonged to people who worked on the Great Pyramids of Giza, presenting the discovery as more evidence that slaves did not build the ancient monuments.
Wave soldering is used for both through-hole printed circuit assemblies, and surface mount.In the latter case, the components are glued onto the surface of a printed circuit board (PCB) by placement equipment, before being run through the molten solder wave.lux in the wave soldering process has a primary and a secondary objective. The primary objective is to clean the components that are to be soldered, principally any oxide layers that may have formed. There are two types of flux, corrosive and noncorrosive.
Reflow soldering is a process in which a solder paste (a sticky mixture of powdered solder and flux) is used to temporarily attach one or several electrical components to their contact pads, after which the entire assembly is subjected to controlled heat, which melts the solder, permanently connecting the joint.he rampâup rate is usually somewhere between 1.0 Â°C and 3.0 Â°C per second, often falling between 2.0 Â°C and 3.0 Â°C (4 Â°F to 5 Â°F) per second. If the rate exceeds the maximum slope, damage to components from thermal shock or cracking can occur.