![]() There are two major issues to avoid to prevent wave solder shadowing: component spacing and rotation. Wave shadow soldering can lead to incomplete solder joint formation and other manufacturing errors. This design consideration is known as the wave soldering shadow–essentially, the amount a component blocks the flow of solder to components behind it parallel to the direction of the wave solder. When the wave washes over a pin and solderable surface, it momentarily leaves an absence of solder behind this section of the wave. Imagine the wave passing over components as the board travels through the machine. Placement and layout will influence the effectiveness of the wave solder process. How Placement Can Affect the Effectiveness of Wave Soldering In its place, alloy compositions such as SAC (tin, silver, copper) have risen to prominence as excellent lead-free solder that is not as susceptible to whiskering as some other alloys. While a health issue, leaded solders have the excellent ability to prevent the formation of whiskers (extrusions of metal from the surface thought to arise to relieve intermetallic strain), which can lead to shorting of electronics and a reduction in the board’s lifetime reliability. While lead-tin solder was the gold standard in soldering for years, RoHS compliance has eliminated it in consumer electronics. However, boards should not be exposed to elevated temperatures any longer than necessary to prevent damage to the board and heat-sensitive components. The slower quenching rate is to prevent warpage to the board and allow time for the solder to set. This keeps the thermal exposure of the boards in the wave soldering process to an absolute minimum.Ĭooling - Converse to the preheating phase, the board is slowly returned to ambient temperature in a heated environment. Wave solder - Boards pass through the molten solder wave with careful temperature controls to reach the eutectic point of the soldering material. Preheating - The boards are brought up to temperature to engage the applied flux and prevent thermal shock due to the high temperatures of the molten solder. Excess flux residue may or may not need to be cleaned. The entire process of soldering involves some additional steps beyond submitting the boards to the wave:įlux application - To ensure the cleanliness of the soldering site, flux is used to remove oxides, prevent the formation of new oxide layers, and assist the wetting of the solder to the soldering surface, which assists with joint formation and structure. As the board is propelled through the machine, the liquid solder can make contact between the pin and the surrounding pad, quickly making a conductive solder joint. In this process, a board is passed through a wave solder machine that controls the height of the standing wave as well as the amount of time each board spends in contact with it. Wave soldering is a technique that is essential for bulk PCB production containing through-hole components. Wave soldering is the older of the two mass soldering processes, but this is not a case of technological obsolescence there are advantages of wave soldering that persist to this day. ![]() ![]() This is especially true when producing lots of appreciable volumes–simply, time is money. When dealing with hundreds (or even thousands) of components in a design, including those that can be barely visible without some magnification, automated services need to be employed. ![]() Soldering, however, has progressed far beyond the handheld iron of hobbyists and simple boards. ![]() Components need to be placed and securely bonded to the board to meet their intended functionality. Wave soldering is a much faster and more economic method of mass soldering than solder reflow.Ī molten solder pool provides the soldering material for through-hole componentsįollowing layout design and fabrication, the final step before verifying the completeness of a board is the assembly. Placement can inhibit the effectiveness of the wave soldering process in tight designs. Wave soldering is an assembly process by which a molten wave of solder passes on the underside of the board, forming a solder joint between pin and pad. ![]()
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