Tips on how to solder by hand with a soldering iron in circuit board processing and assembly

PCBA circuit board design, processing, testing there are many places need to use the soldering iron manual welding, today's electronic senior line manual welding master will tell you the manual welding skills.

Electric soldering iron manual welding and machine welding such as wave soldering reflow soldering difference is that soldering iron manual welding more human factors influence. Unlike machine welding, once the process parameters are adjusted to produce a very stable, manual welding also exists welding temperature and welding time problems, we first introduce the manual lead-free soldering process of soldering iron, welding process window, and the principle of heat conduction of the soldering iron to the pad, to deeply understand, the meaning of the welding temperature welding time, through the guidance of theory, coupled with diligent practice, in order to become qualified skilled workers.

1. Do the preparation work before welding

① we just use a new soldering iron, the first to the iron's own characteristics, such as working voltage, electrical power, back to the heat reheat rate, the size and variety of the iron head has a preliminary understanding

②The variety of solder should be lead-free solder, as well as their melting point wire thickness to understand

③Knowledge of component types, e.g., plug-in or SMD components, thermally sensitive keys

④ on the material of the printed board, pad plating type, such as whether tin-based, gold-plated, osp and parameters to understand, usually solder osp, gold-plated board temperature should be appropriately higher than the tin substrate, multilayer board to absorb more heat than the double-layer board and single-layer board.

⑤ Familiarity with the size of the solder joint and the speed of heat dissipation from the solder surface.

(6) the anti-static performance of the soldering iron, whether the bench has an anti-static grounding port, usually when the soldering iron is connected to the power supply, should also be connected to the anti-static channel.

In short, familiar with the performance of the tool, as well as the basic parameters of the object to be soldered, to adjust the temperature and model soldering iron tip is very useful, of course, when available, through the pcb temperature test and test welding to further confirm the parameters of the welding process.

2. How to operate the electric soldering iron

The first time the use of soldering iron engaged in manual welding operators should be strict with themselves, to develop good operating habits, to achieve the correct posture of welding, skilled in the basic steps of welding and the basic elements of manual welding.

①Correct welding posture

In the manual welding of electronic products, generally take a sitting welding, workbench and seat height to be appropriate, the relative position between the operator's head and the soldering iron should be maintained 30 ~ 50cm, one hand to hold the soldering iron and one hand to hold the wire, and eyeball the soldering point./span>

②The method of holding the soldering iron by the soldering operator
Usually according to the size of the soldering iron, there are three different methods of operation: reverse grip method, positive grip method, pen grip method, which is suitable for larger power soldering iron greater than 75 watts soldering large solder joints; positive grip method is suitable for medium power soldering iron and the operation of the iron with elbow, and pen grip method is suitable for small power soldering iron soldering components on the printed circuit board, which is mainly used for manual welding of electronic products.

③ Direction of soldering iron contacting solder joints
When using the pen grip method to solder electronic products, the soldering iron should be 45 degrees in the direction of contact with the solder joint, it is conducive to the operation and observation of the formation of the solder joint.

④Tin wire holding method
Solder wire holding method, there are usually also two methods, one suitable for continuous welding, the other suitable for intermittent (welding is usually larger solder joints), the actual welding operation process, take the solder wire to wear good gloves, especially leaded wire, to prevent the skin often in contact with lead.

⑤ Basic operation of manual welding

The manual welding process can be subdivided into five steps and required to be completed within a time frame of 3 to 5 seconds, they are:

a. Prepare the soldering iron tip and tin wire close to the pad

b.Heating, first the tip of the soldering iron against the pad, is the pad first preheat

c.Put the tin wire against the contact part of the soldering iron head and the pad to make it melt quickly

d.After the solder joint is formed, first remove the solder wire

e.Remove the soldering iron and the solder joint is cooled and formed

In the case of small solder joints, welding can also be completed using the three-step method, and the five-step method in which step bc is combined into one and step de is combined into one.