PCBA circuit board processing electrIC welding
There are many places in the design where PCB processing and testing requires manual welding with electric soldering iron
The difference between manual soldering with electric soldering iron and machine soldering such as wave soldering and reflow soldering is that manual soldering with soldering iron is greatly affected by human factors. Unlike machine welding, once the process parameters are adjusted, the production is very stable. Manual welding also has the problem of welding temperature and welding time. First of all, the manual lead-free welding process of the electric iron, the welding process window and the heat transfer from the electric iron to the bonding pad are introduced. We must deeply understand the meaning of welding principle, welding temperature and welding time, and through theoretical guidance and diligent practice, we can become a qualified technician.
1. Preparation before welding
1. When we just use a new electric soldering iron, we should first have a preliminary understanding of the characteristics of the soldering iron itself, such as operating voltage, electric power, heat recovery rate, size and type of soldering head
2. It should be known whether the type of solder is lead-free solder and the thickness of its melting point tin wire
3. Understand the type of components, such as components or patch components, and thermal keys
4. Learn about PCB information, pad electroplating type, such as whether it is tin based, gold plated, OSP and parameters. In general, the temperature of the gold-plated plate used for welding the osp should be appropriately higher than the heat absorption capacity of the tin substrate and multilayer plate, which should be greater than that of the double-layer plate and single-layer plate;
5. Be familiar with the size of welding spot and heat dissipation rate of welding surface;
6. Antistatic efficiency of electric soldering iron, whether the workbench has an anti-static grounding port, and generally, when the electric soldering iron is connected to the power supply, the anti-static channel should also be connected.
In short, it is very useful to be familiar with the efficiency of the tool and the basic parameters of the welding object for adjusting the temperature and model of the tip of the soldering iron Of course, when conditions are met, welding process parameters can pass PCB temperature test and test welding
2. How to operate the soldering iron
Operators who use electric soldering iron for manual welding for the first time shall be strict with themselves, develop good operating habits, achieve correct welding posture, and master the basic welding steps and the basic essentials of manual welding.
1. Correct welding posture
In the manual welding of electronic products, sitting welding is usually used. The height of the workbench and seat shall be appropriate. The relative position between the operator's head and the soldering iron should be 30-50cm, with one hand holding the soldering iron and the other holding the tin wire. Observe the welding spot visually.
2. Method for welding operators to hold electric soldering iron
Generally, according to the size of the soldering iron, there are three different operation methods: reverse clamping, forward clamping and pen clamping. The reverse grip is suitable for large welding points of large soldering iron with power greater than 75W; The holding method is applicable to the operation of medium power electric soldering iron and electric soldering iron with elbow. The pen holding method is applicable to the welding of components on printed circuit board by low power electric soldering iron, mainly used for manual welding of electronic products.
Manual welding technology of electric soldering iron processing and assembly of pcb
3. The direction in which the soldering iron contacts the solder joint
When using the pen grip method to weld electronic products, the electric soldering iron should contact the solder joint at 45 degrees, which is conducive to the operation and observation of the formation of the solder joint.
4. How to Clamp Tin Wire
There are usually two methods to fix the welding wire, one is suitable for continuous welding and the other is suitable for intermittent welding (welding is usually large in the welding spot). In actual welding operation, gloves shall be worn when handling welding wire. Especially lead containing tin wire, which can prevent the skin from frequently contacting with lead.
The above is the explanation given by the editor of pcb circuit board company.
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