![]() ![]() For example, BGA (ball grid array) package contains lots of solder balls that will be melted during reflow soldering. Too low a temperature stops solder paste from sufficiently reflowing while too high a temperature may cause damage on SMT components or boards. Temperature control plays a crucial role in reflow soldering process. Peak temperature leads solder paste to be melted and reflowed. ![]() This phase witnesses the advent of peak temperature during the whole process. Otherwise, flux fails to play its active role in soldering process. Accordingly, temperature has to climb to the extent that flux can be activated. Similar with wave soldering, reflow soldering also depends on flux that has been contained in solder paste. Otherwise, soldering quality will possibly be compromised. Second, it is responsible for pushing volatile solvents contained in solder paste to expel. First, it allows boards to be assembled to consistently reach required temperature fully compatible with thermal profiling. Pre-heating features two purposes during reflow soldering. ![]() To achieve well-baked bread, oven should be preheated in advance. It's not a tough job to understand the significance of pre-heating when comparing reflow solder oven with toaster or baking oven. Real reflow soldering won't start until those preparations have been fully made. Then, components are placed on pads by pick and place machine. First, solder paste is accurately placed on each pad through a solder paste stencil. ![]() This process primarily contains two steps. For example, PCBCart (a China-based full turnkey PCB Assembly service supplier) engineers take advantage of fixture to fix THT components prior to wave soldering so that all parts can be accurately mounted on boards with soldering defects dramatically decreased.Īs its definition goes, electrical components are temporarily attached to contact pads prior to real soldering through solder paste. Generally speaking, even though the same wave soldering equipment is applied, different Assemblers possibly feature different manufacturing efficiency due to different operation methods and extent of understanding on soldering machine. should be taken into considerations and calculation. Furthermore, other factors such as speed of band carrier, wave contact time etc. In addition, alloy won't be generated by flux and metal if temperature is not sufficiently high. If temperature is set to be too low, flux won't be melted so that it won't maintain activity, reaction capability and capabilities to dissolve oxide and dirt on the surface of metal. As far as time and temperature are concerned, a professional wave soldering machine is of much necessity while PCB Assembler's expertise and experience are seldom easy to obtain since they depend on years' accumulation, application of up-to-date technologies and business focus. After being cooled to room temperature, board will be successfully assembled.Īs circuit boards are placed on pallet ready to go through wave soldering, time and temperature are closely associated with soldering performance. As temperature reaches the peak in wave soldering stage, its reduction comes, which is called a cooling zone. Wave soldering profile conforms to a temperature curve. As temperature constantly rises, solder paste becomes liquid with a wave formed from whose edge boards will travel above and components can be solidly bonded on boards. In a pallet along a chain similar to conveyor belt, PCBs travel through a heat tunnel to carry out pre-heating and activate flux. Leading functions of solder flux include:ġ) To eliminate oxide from metal surface of boards and components' pins Ģ) To stop circuit boards from secondary oxidation during thermal process ģ) To reduce surface tension of solder paste Solder flux plays a crucial role in smooth implementation of soldering. Cleanliness of metal surface is the basic element ensuring soldering performance, depending on functions of solder flux. Wave soldering process is composed by four steps: flux spraying, pre-heating, wave soldering and cooling. ![]()
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