Don't knowLead-free solder pastePurpose? Don't know how to choose solder paste? Jiajin Yuan, the developer, tells you

Generally speaking, solder paste needs to be heated to cure, which requires reflow soldering. Reflow soldering is a heating furnace that can provide the heat required for solder paste to help it solidify.

The main uses of tin-lead solder: It is widely used in soft soldering in the electronics industry, wave soldering, immersion soldering and other precision soldering in various industries such as heat sinks and hardware. Special welding processes as well as spraying, electroplating, etc. Anti-oxidation solder rods produced through special tempering and refining processes,It has unique high antioxidant performance,The scum is less than that of ordinary solder,It has low loss and good fluidity.

Solder paste is a material used to connect the electrodes of components to the pads of circuit boards. This material is an alloy mainly composed of tin. After curing, it can conduct electricity between the electrodes of components andPCBThe function.

How to choose the right solder paste?
　Solder paste is divided into two major categories: lead-free and environmentally friendly solder paste and ordinary lead-containing solder paste. Among them, lead-free and environmentally friendly solder paste is classified by melting point into high-temperature and medium-temperature types. Low-temperature solder paste The melting point of lead-containing solder paste is mostly183It's about a certain temperature, similar to that of environmentally friendly medium-temperature solder paste. If you need an environmentally friendly series for export, you should choose high, medium and low-temperature solder paste, or even environmentally friendly halogen-free solder paste. Otherwise, it is recommended to use leaded solder paste, which is cheap and easy to use. The brightness is relatively better than that of the environmentally friendly series.
　　However, solder paste at each temperature has its own characteristics or advantages and disadvantages.
　　High-temperature solder paste(QL-305/0307): Contain silver3%and0.3% ,It has good solderability, good electrical conductivity and high mechanical strength, but due to its melting point217-227At this temperature, when the circuit is in operation, there are many high-temperature resistant onesPCBThe board and components are prone to damage. If the furnace temperature is not reached, the tin will not melt, causing problems such as false soldering. At the same time, due to the high silver content, the cost is relatively high. It is selected for high-precision and high-demand circuit board mounting.
　　Low-temperature solder paste(QL-4258)Because it contains bismuth/BiAlloy, with a relatively low melting point, is138Degree It generally will not damage the components andPCBplate It can reduce high-temperature impact, but has weak mechanical strength and is relatively brittle. If operated improperly or affected by external forces, it is prone to dropping parts. It is recommendedLEDIndustry selection.(LEDSoft light strips require solder paste with high mechanical strength (high-temperature and medium-temperature solder paste should be used).
Medium-temperature solder pasteQL-3503/3510): Contain silver0.3%and1% ,Melting point172The temperature, advantages and disadvantages lie between high and low temperatures, with relatively good performance and moderate price.
In addition, pay attention to the selection of solder paste and solder powder:2-7#Tin powder is generally:3#powder25-45um,4#powder20-38umThe smaller the pitch of the component pins, in most cases, it is recommended to use finer tin powder, such as4#5#Tin powder, etc., to prevent the production of defective products.
Transportation and storage of solder paste: Solder paste needs to be refrigerated (not frozen), refrigeration temperature3-10During transportation, ice packs and insulated foam boxes are usually used for packaging. Additionally, there are also solder pastes that can be stored at room temperature.3-25The degree is the best.

Nowadays, solder paste, solder bars and solder wires have been widely used inSMTCommunication equipment, computers and other electronic devices, whether it is spot welding, wave soldering, reflow soldering or printing, from large electronic equipment factories of various brands to small mobile phone repair shops, we can all see their presence. They are the most widely used welding materials in the current market. It is believed that in the future development, solder paste, solder bars and solder wires will still be applied in the soldering operations of more electronic devices.

 The above isJJYThis is the content about solder paste, solder bars and solder wires that I have introduced to you all. I hope it will be helpful to you. For more information and prices of solder paste, you can log in to the official website of JJY for consultation.