Research on Three - phase Induction Pump for Wave Soldering Machine
Abstract: An automatic single / dual wave soldering machine with a three-phase asynchronous induction pump as a crest generator is developed to replace the mechanical pump wave soldering machine. It has no rotating parts, no wear, no maintenance and improves the reliability of the whole machine .
Key words: three-phase asynchronous induction pump wave soldering machine maintenance no moving parts
First, the situation at home and abroad
Dual wave printed board mounting technology (SMT) on the surface of welding single wave soldering process (SMC) and a surface of the circuit board member, the required application of liquid solder wave soldering techniques and equipment.
At present, the domestic peak pick-up technology are mechanical pump wave soldering machines, only one developed a single-phase induction electromagnetic pump wave soldering machine. Abroad, the wave soldering machine is also based on mechanical pump wave soldering machine, in the late 1980s, Switzerland, the United States produced a conductive electromagnetic pump wave soldering machine (patent US-3.797.724) due to unstable performance and discontinued.
China in the 90's developed the first generation of single-phase induction electromagnetic pump wave soldering machine (patent CN91058162A.CN.93246899.3.), From the beginning, China's wave soldering technology walk in the forefront of the world, followed by military technology The second generation of electromagnetic guns electromagnetic induction pump - three-phase asynchronous induction pump have been successfully developed (patent CN96236223.9). Single / dual-wave automatic welders using a three-phase asynchronous induction pump as a crest generator have also been in mass production.
Second, the development of three-phase induction pump the necessity
At present, most of the wave soldering machines for electronic assembly are mechanical pump wave soldering machines. Since the mechanical pump blades rotate at high temperatures (about 250 ° C) and rapidly wear out, on the one hand they are contaminated with solder and on the other hand, they are regularly serviced , Replacement of worn blades and wear parts, inconvenience to the user, and again, due to mechanical pump rotation movement, resulting in tin surface disturbance, making oxidation increased, the formation of large amounts of tin slag.
To solve the above problems, developed a conductive electromagnetic pump wave soldering machine, canceled the mechanical pump, without any rotating parts, no wear, maintenance-free, reduced production of tin oxide slag, partially solved the problem of mechanical pump wave soldering , But the conductive electromagnetic pump because of its inherent structural instability, the problem of fluctuating peaks and downs and can not meet the production process requirements.
In 1990s, domestic relevant units developed single-phase induction electromagnetic pump wave soldering machine to solve the above problems and solved the problem of wave instability without any rotating parts and maintenance-free, basically solving the problems of mechanical pump wave soldering machine. However, The machine in the production of wide-wave peak (300mm ~ 400mm peak width) and ultra-high peak (40mm height), appears to be insufficient strength.
In view of the above problems, the three-phase asynchronous induction pump based on the theory of electromagnetic gun has been developed successively in our country with no rotating parts, no wear, no maintenance, smooth and smooth wave crest, tin surface smooth, Oxidized slag formation decreased significantly, due to high efficiency, can be prepared wide wave crest (400mm) and ultra-high peak (40mm) of the wave soldering machines, wave soldering machines basically meet the needs.
Third, technical principles
1, mechanical pump wave soldering machine principle
Mechanical pump schematic
As shown in the figure, the mechanical pump pumped liquid tin material has a rotating component, resulting in wave instability, must be added several times the pressure steady flow can be used, and due to the rotation caused by tin surface instability formation of a large number of tin oxide slag Welding costs rise, rotating at high temperatures, resulting in blade and seal wear failure, must be discontinued and repaired regularly.
2, the principle of conductive electromagnetic pump
Conducted electromagnetic pump principle
As shown, the principle of conductive electromagnetic pump is: the conductors in the magnetic field, through the current, the conductor will be the thrust of the magnetic field, the three directions perpendicular to each other, the size of the thrust F = I × B.
Conductive electromagnetic pump without any rotating parts to solve the mechanical pump wear problems, the formation of maintenance-free welder. However, due to the liquid metal contact with the large current electrode to the liquid metal conduction current process, due to the oxide residue on the electrode attachment and shielding, resulting in wave instability, and even ups and downs, can not be stable, the domestic imports of Switzerland such models Nearly 50 basic have been disabled.
3, induction electromagnetic pump principle
It uses the principle of single-phase C-type opening electromagnet, due to the difference between the inner and outer ring magnetic field generated within the outer and outer phase difference, and thus form the forward magnetic field component, that is from the leading phase to the lagging phase of the forward magnetic field component. The liquid metal brazing filler metal in the forward magnetic field component cuts the flux lines and is therefore subjected to a forward force to pump the liquid metal brazing material.
Due to the use of magnetic phase difference generated phase difference, the formation of the forward magnetic field component, the forward magnetic field component is very limited, most of the pulsation magnetic field does not produce forward thrust to produce as shown in Figure broad-wave peak (300mm ~ 400mm peak width) and Very high peak (40mm height) is very difficult.
4, three-phase asynchronous induction pump principle
This is another patented technology obtained by China in wave soldering machines. It not only solves the problem of wave crests caused by oxide shading, but also does not have any rotating parts and no current flow in the conduction current electrodes of the conduction type electromagnetic pump of the conduction type electromagnetic pump Converters, maintenance-free, wear-free, and high efficiency, can obtain high and powerful peaks and wide peaks.
Three-phase asynchronous induction pump principle is the use of three-phase power 120 ° phase difference between each other in space, forming their own magnetic field, the magnetic field synthesis is a forward magnetic field cutting magnetic lines, the induction current, the formation of forward electromagnetic force.
As the direct use of the three-phase power of the inherent phase difference, and thus the basic synthesis of magnetic pulse-free magnetic field components, are the forward force of the resultant magnetic field, and electromagnetic guns completely the same principle, and therefore high efficiency, up to 70% from the three Wave induction welder with phase asynchronous induction pump in addition to all the advantages of inductive electromagnetic pump, such as audio perturbation vibration wave superimposed to enhance the ability to weld and crawl capacity, without any rotating parts, no wear and tear, maintenance-free, Simple structure, etc., but also has a high and powerful wave peak, available 40mm high peak and wide peak width of 300 ~ 400mm.
Since the asynchronous induction pump produces a linear thrust, the liquid metal solder does not rotate and the tin bath is calm. As a result, a large amount of oxidized slag is produced, and the single shift of the oxidized slag is reduced by about 4KG. Only one year's worth of solder can be recovered with an investment of nearly 10% Million.
Fourth, the application effect comparison
The use of three-phase asynchronous induction pump developed single / double-peak automatic welding machine, the use of comparison, we get the following results:
Due to its unique perturbation vibration wave superposition, it can effectively get rid of SMT solder joints due to thermal decomposition of flux and adhesive produced brazing zone gas, eliminating the jump welding and SMC, SMD shadow area, to SMT soldering requirements, at the same time, due to the superimposition of perturbation waves did not make wave soldering ability to significantly enhance the ability to climb to improve the welding reliability and yield.
Smooth wave crestless rotation component, as a result of three-phase asynchronous induction electromagnetic pump produces a linear thrust instead of the mechanical pump blade rotation thrust, and thus crest smooth, tin bath surface disturbance is small, slight oxidation.
Peak smooth, due to induction pump technology, combined with the voltage regulator principle, can reach the grid voltage fluctuations of 10%, the induction pump voltage fluctuations of nearly 3%, and thus the peak stability.
efficient. Due to the absence of pulsating magnetic field components, the efficiency of the three-phase asynchronous induction electromagnetic pump is greatly improved. According to the developed prototype, the peak width is 400mm and the peak height is 40mm. The magnetizing current of the three-phase induction pump is only about 5A, so that the working conditions ensure that the three-phase asynchronous induction pump works in a state of low thermal load and low current load, ensuring the long-term reliability of life.
No rotating parts, no wear, truly maintenance-free, eliminating the need for regular maintenance links.
From the above principles and the use of prototype comparison we concluded that: wave soldering machine with three-phase asynchronous induction pump to solve the current process to solve most of the problems, to achieve maintenance-free, saving solder, reducing the amount of oxide slag, convenient With the application of depth, wave soldering machine with three-phase asynchronous induction electromagnetic pump is the future trend of development, it will be in the development of electronic packaging technology, play a role in promoting The role, especially in the SMT mixed technology, the formation of a good international and domestic application prospects.
Fifth, conclusion:
   From the above principles and the use of prototype comparison we concluded that: wave soldering machine with three-phase asynchronous induction pump to solve the current process to solve most of the problems, to achieve maintenance-free, saving solder, reducing the amount of oxide slag, convenient With the application of depth, wave soldering machine with three-phase asynchronous induction electromagnetic pump is the future trend of development, it will be in the development of electronic packaging technology, play a role in promoting The role, especially in the SMT mixed technology, the formation of a good international and domestic application prospects.
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