CN / EN
PCB surface finishing methods comparison
Date:2020-03-29View:372
With the continuous development of the electronics industry, the demand for pcb boards has also increased. Common surface technologies for pcb boards are HASL, immersion gold, gold plating, OSP, etc. In fact, HASL is divided into HASL with lead and HASL lead free.

Today, we will introduce the difference between these two surface finishing methods.

1. From the surface of tin, HASL with lead is relatively bright, and lead-free HASL is relatively dim. Besides, HASL lead-free is a little worse than leaded.
2. HASL with lead is harmful to human body, but lead-free is not. HASL eutectic temperatures are lower than lead-free. The specific content depends on the composition of the lead-free alloy. For example, the eutectic of SNAGCU is 217 degrees, and the soldering temperature is the eutectic temperature plus 30-50 degrees. It depends on the actual adjustment. The eutectic with lead is 183 degrees. The mechanical strength and brightness are better with lead than without lead.
3. The lead content of lead-free tin does not exceed 0.5, and the lead content reaches 37.
4. Lead will increase the activity of the tin wire during the soldering process. Leaded tin wire is better than lead-free tin wire, but lead is toxic and long-term use is not good for the human body. And lead-free tin will have a higher melting point than leaded tin. This makes the solder joints much stronger.
5. Lead will increase the activity of tin in the soldering process. There are lead-tin wires, which are better when compared with lead-free tin wires, and lead-free tin spray has a higher melting point than lead-plated tin, and the solder joints will be much stronger.
6, pcb board proofing HASL lead-free and lead-plated tin price is the same, there is no difference.

What is the difference between HASL with lead and HASL lead free on PCB? What are the temperatures?

1.PCB HASL lead-free belongs to the environmental protection category and does not contain harmful substances "lead", with a melting point of about 218 degrees; the temperature of the tin spray tin furnace needs to be controlled at 280-300 degrees; the peak wave temperature needs to be controlled at about 260 degrees; The temperature is 260-270 degrees.
2. The PCB board has HASL with lead which does not belong to the environmental protection category containing lead and has a melting point of about 183 degrees; the temperature of the tin spray tin furnace needs to be controlled at 245-260 degrees; the peak wave temperature needs to be controlled at about 250 degrees; The temperature is 245-255 degrees.
Mold opening in industrial design refers to the tool set that forms the product design, including mechanical equipment and molds. Does the PCB proofing need to be opened? With this doubt Xiaojie brother takes everyone to understand.
First of all, we have to figure out what it means to open the mold body. In fact, the mold opening usually refers to the mold used for punching when making the shape. Some factories also refer to the test stand. Everyone has a different understanding. You can understand whether the PCB board is proofed or not. In fact, the samples are only used for testing and debugging. There is no need to open the mold, including the test stand. It is not necessary to open.
What to do if the structure drawing is not correct when the mold is opened, and the data needs to be modified, so it is not necessary to open the mold, and it can be made directly by CNC. For testing, choose flying probe test, which will reduce many risks. At least don't worry about reopening the mold. If it is mass production, it is recommended to open the mold and make the goods faster, it will be a bit cheaper, depending on the positioning of your own products, some do not accept the mold punch.
Regarding the cost of pcb proofing and v-cutting, normal pcb proofing and v-cutting are free of money. If the amount of a SET is large, such as more than 50PCS, V-cutting costs will be charged separately, mainly for small boards. If there are many models cut together and V cut, an appropriate fee will also be charged when quoting.