PCB welding we first do what to prepare, what skills?
PCB welding we first do what to prepare, what skills?
A: The correct use of electric iron
1, electric soldering iron before use on the tin, the specific method is: the electric soldering iron heat until just to melt the solder, coated with flux (rosin), and then evenly coated with solder on the tip, the tip uniform Eat a layer of tin (shiny thin can be).
2, during the ordinary welding (such as universal board soldered in-line components), one hand soldering iron, one hand solder wire, near the root, two gently touch, a solder joint formed. The ideal shape of the solder joint is the kind of shit.
3, in the universal board welding components, the pin as far as possible to plug in the end.
4, welding time should not be too long, or easy to scorch the components, if necessary, clamp the pins with tweezers to help heat dissipation.
5, the welding is completed, to use alcohol to clean residual flux on the circuit board to prevent carbonized flux affect the normal work of the circuit.
4, electric iron should be placed on the iron rack.
Second: the order of component welding
The first difficult after the first low after the high, the first chip after the cartridge.
Mission: easy welding, save time.
First welding difficult, which is mainly pin-intensive chip integrated chip. If you put these hard on the final welding, welding failure once the failure of the pad, it will come to naught.
First low after high, the first chip after the cartridge. This is easy to weld. Welding high components first may hinder the soldering of other components, especially when large, large components are dense. If you first solder the inserted components, the circuit board will be put on the welding station uneven, affecting the welding mood.
Three: manual welding chip components method experience
First, clean the pad coated with a layer of flux, and then use a clean thermostat soldering iron to the pad a thin layer of solder (usually when the circuit board is made of good tin, but sometimes the tin is still very hand-made Necessary), the components are placed on the alignment, fixed on the tin diagonal, and then pick one side with a vertical iron pin out of the ice in the direction of the slow slip over, while a little hard under the pressure on the side of the component; and then the same method of welding Edge; then on the other two sides. Final inspection, bad welding again. Soldering iron temperature to be moderate, generally about 400 degrees as well.
Inspection methods: first visual inspection, and then use the tedious thing to check each pin is loose, and finally available multimeter measurement.
If the short circuit between the two pins can be coated with some flux, take advantage of the occasion of the alcohol has not yet been hot and then take a soldering iron to get a (tip must get clean).
Welding is a very important technical issue in electronic production activities. The quality of the welding has a direct impact on the quality of the production. Electronic beginners tend to ignore this problem, below I talk to you about the basic knowledge of welding.
1 electric iron choice
The main tool for soldering is electric soldering iron. In addition to commonly used in addition to internal heat and external thermal iron, there are suction tin electric soldering iron and constant temperature soldering iron. At present, most of the commercially available electric soldering iron, commonly used specifications are 20W, 40W, 70W several. Which kind of soldering iron to choose, it depends on the specific welding object to decide. If you make a semiconductor radio or other small electronic components, then you should choose 20W soldering iron, because it has a fever, power consumption, small size and light weight and so on. If you are installing a television set or repairing a larger appliance, use a 40W electric soldering iron with a higher power rating. Power soldering iron must be sure to choose the right over the General Assembly bad transistors or other heat-sensitive components, too small tend to be not strong components welded on the surface to see the weld is firmly pulled, in fact, is prone to false welding or Weld phenomenon.
Iron soldering iron head is generally made of copper, commonly used tip has straight and curved two. The new electric iron or just put on the tip of the iron surface has a layer of oxide layer, so the tin can not be used, the first use of sandpaper to burnish the surface of the tip iron oxide layer, and then to the electric iron after heating for some time , In a clean place coated with a layer of rosin, then coated with a layer of tin, this process is called tin. Good soldering iron tin can be used normally. In the future use of the process, the tip of the tip oxidation occurs on the tin can not, this phenomenon is called burn, you must also use the above method to re-tin treatment.
2 solder selection
Soldering commonly used solder is solder, the most suitable is the market supply of a solder wire solder called, its low melting point, good conductivity, coexist a certain intensity, the internal pre-filled with rosin, it is very easy to weld, the most convenient Suitable for electronic circuit production.
3 flux selection
Flux in the welding to prevent surface oxidation of the role of flux. Common flux is rosin, it is neutral, will not corrode the circuit components and tip. There is also a flux is welding oil, also known as solder paste, flux better than rosin, but she brought a little corrosive, the general welding components wipe the welding oil clean.
4 Preparation before welding
First of all, the surface of the printed circuit board is treated with a fine sandpaper on the printed circuit board polished copper surface, washed with water, coated with a layer of rosin alcohol solution can be carried out. Rosin alcohol ratio of 1: 2. After the surface treatment of the printed circuit board can guarantee the welding quality, but also improve the welding speed.
5, welding methods
First prepared components into the printed circuit board provides a good location, the components and the printed circuit board copper foil connection point, coated with a small amount of flux to be heated iron soldering iron tip with the right amount of solder on the edge, How much depends on the size of solder joints to decide. Welding, the tip of the tip to contact the solder joints and component leads, according to the shape of the solder joint to make some movement, so that the flow of solder covered solder joints and infiltration into the gap was welded, the contact time is about 3-5 Seconds or so, then take away the electric iron. Remove the electric iron time, direction and speed, determine the quality and appearance of the welding the correct way is to leave the solder joints, the iron quickly back to take a look, and quickly leave the solder joint, so welding out The solder joints are bright, smooth, and no glitches.
In welding, the welding time should not be too long, so that the components are not bad, but also not too short, resulting in fake welding or Weld. After the welding is completed, use the column to clamp the soldered components and pull them with appropriate force to check if the components are soldered. If you find loose, you must re-welding.