History of the Wave Solder Machine
In 1955, in a foundry at Fly Metals in the UK, Allan Barnes and Ralph Strauss introduced a solder nozzle to replace floating boards on the surface of a solder bath. They developed a fountain – not unlike a water fountain, but pumping molten liquid solder through a nozzle to form a wall of raising metal, that fell back into the reservoir (the pot) to be pumped back through. Two rails to hold the printed circuit board and some forward motion – the wave solder machine was born.
The heater was gas fired the motor from a boat. Plessey, (an early radio maker) bought this first monstrosity for just under 200 pounds (Not bad for a used boat motor and gas burner. A patent was applied for in 1956 and granted in 1958.
Selective soldering machine
Wave soldering is the only way to process large numbers of through hole components in printed circuit boards. It was the best way to assemble electronics through the 1980s, when a new assembly method started to gain wide acceptance – Surface mount Technology (SMT). Even today, through hole assemblies are widely used in military, high power and other niches when the SMT assemblies still fall short.
Wave soldering is also used in surface mount where passive components (resistors and capacitors) and glued on using Surface Mount Adhesive or SMA. The SMA can be printed or dispensed. The only function of the SMA is to hold the components on through the molten wave.
Large components (networks and semiconductors) require a lot of leads and package shapes that can be made with pins, but must be inserted on the top of a PCB. Multilayer boards and the layout restrictions make SMT assembly more efficient and cheaper for these types of boards. The “sweet spot” for through hole and wave solder is in power supplies, TVs, Tuners, and in other robust assemblies (industrial and military). In these applications, it is hard to beat through hole, even today.
Wave Soldering Machine Concept of Operation
Normally there are the following components – A solder reservoir, a “wave”, and often 2 waves with different characterizes, a preheated to warm the flux and the boards, often these heating elements are hefty, Conveyerized rail or chain system they moves Printed circuit boards, A fluxer –that can be just in front of the wave solder machine or incorporated inside it. Often there is a Nitrogen system to eliminate the air (Oxygen) in the heating and soldering zones.