PCB laser welding tips

PCB laser welding tips

1. Tools/raw materials: laser welding head, tin wire, flux. There are many options on the market. Use a properly laser-controlled welding head.

2. Suitable alloy solder wire. It is recommended to use lead-free tin wire. You can choose the wire thickness based on your components. 0.8mm or 1.00mm is normal. You also need to consider whether the tin wire is a clean cotton wool or no-clean flux.

3. Get flux-cored wire if possible

Flux is an additive in solder that facilitates the soldering process by removing and preventing oxidation and improving the wetting characteristics of liquid solder. Solder wire has different types of flux cores.

4. Get PCB circuit boards and electronic components.

5. Buy a fixture to fix the components

Soldering is one of the most required skills to get involved in the field of electronics. These two go together like peas and carrots. And, while it is possible to understand and make electronics without picking up a laser head, you will soon find that a whole new world can be opened up with this simple skill. Soldering should be a skill in everyone's arsenal. In a world of ever-increasing technological environments, we think it's important that people everywhere not only understand the technologies they use on a daily basis, but are also able to build, change, and repair them. Soldering is one of many skills that will enable you to do just that.

Soldering to circuit boards can be tricky: too much heat can cause copper traces to move right off the board substrate. Use a laser rated for 15-25 watts, no more.

Start by lightly rubbing the copper with a board typewriter eraser until it's bright and shiny. As with any electrical connection, use 60-40 rosin core solder, preferably a gauge close to the size of the lead you're connecting. Insert the wire or component lead into the board from the back and bend it back just enough to prevent the component from falling out.

Lightly touch the tinned solder tip to the copper wire and the front at the same time. After a few seconds, touch the lead with the solder tip, adding enough solder to make a puddle, but not enough to make a fat blister. The solder needs to wet both the lead and the copper wire.

Quickly turn off the laser and remove the solder. After the solder cools enough to freeze, do not disturb the circuit board. If you use the appropriate amount of heat, this should only be a few seconds, and a PCB circuit board is welded.

PCB laser soldering parameter settings

Laser power: Select the appropriate laser power based on factors such as the type and thickness of the welding material and the size of the welding point. Generally speaking, the greater the power, the greater the depth and intensity of the welding, but too high a power may cause the welding part to overheat and damage the circuit board or electronic components. For welding small electronic components on PCB circuit boards, it is usually necessary to select a lower laser power, such as a few watts to tens of watts.

Pulse frequency: The laser pulse frequency affects the heat input and welding effect of welding. A higher pulse frequency can make the welding process smoother and reduce defects such as spatter and pores, but it will also increase the heat accumulation in the welding area. In actual operation, it needs to be adjusted according to the specific situation. Usually the pulse frequency is between tens of hertz and hundreds of hertz.

Welding speed: The welding speed determines the time the laser acts on the welding part. Too fast speed may result in loose welding; too slow speed may cause overheating of the welding part and even burn the circuit board. Generally speaking, for PCB laser welding, the welding speed can be controlled between a few millimeters and tens of millimeters per second.

Spot diameter: The spot diameter directly affects the size and energy distribution of the welding point. Smaller spots are suitable for welding delicate components or tiny solder joints, and can provide higher energy density, but also require higher precision in welding position; larger spots are suitable for welding larger solder joints or situations that require greater heat input. Usually, the spot diameter can be selected between 0.1 mm and 1 mm.