Soldering wires on the printed circuit board
and inserting components must undergo lead forming processing. For axial lead components (the component leads extend in a straight line from both sides), in order to be inserted on the printed circuit board, they must be bent vertically in the same direction. The two leads must be in the same horizontal plane and the two leads must be parallel.
Doing so can not only alleviate the thermal shock when the leads are immersed in the tin, protect the components and the circuit board, but also make the installation of the components convenient and reliable, for the components with the leads in the same direction (such as transistors).
In order to increase the distance of heat conduction, increase the thermal resistance, and relieve the stress of thermal expansion and contraction caused by the temperature change when the electric soldering iron is heated during soldering, the lead forming process must be performed on it.
When forming the lead, pay attention to bending and forming at a certain distance from the root of the lead. Do not apply any stress to the root, because such components become brittle and easy to break due to heat treatment during production and processing. The followings are the specific processing steps for forming leads.
(1) The wire acts as a connecting wire in the printed circuit board and can be regarded as a plug-in, so it must be formed before the wire is welded. Cut the wire to an appropriate length according to the connection requirements. Note that the cut wire must be straight and not twisted.
After the wire is stripped and tinned, use needle-nose pliers to clamp it at a distance of 20mm from the end of the trace. Use your thumb to press the wire on the needle-nose pliers at a right angle. Do not turn the needle-nose wrong at this time. Note that holding the wire with your thumb may cause dirt on the wire, so you can use tweezers or another pair of needle-nose pliers to bend the wire together.
(2) Determine the pad hole that needs to be connected, insert one end of the bent wire into the side jack, tests the length of the two holes to be soldered, take the wire out, and exaggerate the other end of the wire to a right angle; Insert the wire into the manhole, and use the method of testing the bend vertically with the inserted part facing the jack. The other end is aligned with the hole to be welded on the other side, and the wire is directly bent to a right angle.
(3) After the wire is formed, insert the wire into the hole of the pad. When inserting the wire, the lead of the wire should be vertical. If the wire is too short or too long, it will cause the wire welding to fail.
(4) After the wire is inserted, it needs to be welded on the other side of the circuit board. If the circuit board is flipped and welded directly, the wire will fall from the pad hole. Therefore, a certain method needs to be taken. The wire can be welded after the wire is inserted. Bending treatment is to keep the wire from falling off, pay attention to keeping the needle-nose pliers parallel to the circuit board when bending, and the bent wire is 30° with the circuit board.
(5) Use the same method to bend the other side of the wire, the bending direction should be along the direction of the copper foil of the circuit board, not beyond its edge. In addition, small insulation boards can also be used.
After the connecting wire leads are inserted and installed, the insulation small boards are covered on the connection surface, and then the insulation small boards and the printed circuit board are turned over for soldering. This method has an obvious advantage.
(6) After the connection line is soldered, handle the connection line. Use diagonal pliers to cut off the excess connection. The reserved length of the connection cannot exceed the radius of the pad, and it should be as flush as possible with the top of the solder joint formed by the solder.
Only by properly handling the design of the circuit board component leads can the performance of the PCB be guaranteed. If you want to learn more about printed circuit boards after reading the above, you can get a comprehensive solution by contacting us.
As a professional PCB product
manufacturer, we have accumulated rich design and production experience in this field. We have a standardized production department and a strict quality inspection system, which can control the quality of our products in an all-round way. At the same time, we will provide thoughtful one-stop service and effective solution technology according to the actual needs of customers. If you want to buy our printed circuit boards, please contact us immediately!