Middle-temperature energy-saving leadless solder paste special for tuners

Abstract

The invention aims at solving the problems of the lead-free solder paste used in the production of tuners such as rosin joint, excessive residual solder beadings after welding and easy shedding of welding spots which are likely to happen in production, and provides a medium-temperature energy-saving lead-free solder paste specially used for tuners; the medium-temperature energy-saving lead-free solder paste is composed of Sn64Bi35Ag1 alloy solder powder and soldering flux paste; the soldering flux paste contains the components with the following weight percentage: 20-30% of high-viscosity perhydrogenated rosin, 20-25% of low-viscosity perhydrogenated rosin, 4-6% of modified hydrogenated castor oil, 2-4% of acid amide thixotropic agent, 4-6% of C3-C18 fatty amine salt of C4-C10 dibasic acid, 2-3% of phenolic antioxidant, 0.5-01.0% of cyclohexylamine hydrochloride, 1-2% of non-ionic halogen compound, 8-10% of hexamethylene glycol, 3-5% of wetting agent and 23-28% of diethylene glycol solvent. The medium-temperature energy-saving lead-free solder paste can effectively prevent the shedding phenomena of solder paste, has no solder beadings in products, little and transparent residue after welding, good insulating property, no-clean property and extremely strong postwelding reliability, and can reduce the heat shock damage to components and circuit boards and lower power consumption by about 8-10% at the same time.

Description

technical field [0001] The invention relates to a welding material for assembly of electronic printed circuit boards, in particular to a medium-temperature energy-saving lead-free solder paste specially used for tuners. Background technique [0002] With the rapid development of the electronic manufacturing industry, the production of electronic tuners is becoming more and more modernized. However, due to the limitation of single-sided mixed packaging of the product itself, the assembly of electronic tuner circuit boards must be composed of surface mount (SMT) and through-hole sockets. Assembly (THT) consists of two different processes. Due to the continuous development of electronic processing towards the direction of micro-shape and high integration, the electronic components used in electronic tuners are getting smaller and smaller, and the assembly density of electronic components is getting higher and higher, especially in In the THT process, the solder paste is easy to...

AI Technical Summary

Problems solved by technology

[0002] With the rapid development of the electronic manufacturing industry, the production of electronic tuners is becoming more and more modernized. However, due to the limitation of single-sided mixed packaging of the product itself, the assembly of electronic tuner circuit boards must be composed of surface mount (SMT) and through-hole sockets. Assembly (THT) consists of two different processes. Due to the continuous development of electronic processing towards the direction of micro-shape and high integration, the electronic components used in electronic tuners are getting smaller and smaller, and the assembly density of electronic components is getting higher and higher, especially in In the THT process, the solder paste is easy to drop when the components are inserted, resulting in a more serious phenomenon of virtual soldering, so the requirements for the solder paste are getting higher and higher, especially the post-soldering reliability requirements for the solder paste are more stringent, electronic tuning The device requires that the solder joints after soldering be matte or matte. In lead-free solder, the preferred alloy composition is Sn64Bi35Ag1. The solder paste is generally composed of 35-50 mass% resin (such as modified rosin resin, dehydrated malic acid resin, etc.), 1-10% by mass of thixotropic agent (such as modified hydrogenated castor oil, fatty acid glyceride, etc.), 35-55% by mass of solvent (such as undecanol, 2-methyl-hexanediol, etc.) , 1.5-5% by mass of active agents (such as succinic acid, tetrabutylammonium hydrobromide, etc.), the existing solder paste of this type is difficult to meet the above requirements, and there are mainly the following deficiencies in the soldering of tuner packaging:

[0003] 1. The solder paste of the plug-in components is easy to fall off during the plug-in process, resulting in false soldering

[0004] 2. After using the solder paste for 1-2 hours, there will be more tin beads in the post-soldering residue, especially between the pads with small spacing, there will be a short circuit phenomenon

[0005] 3. After 1-2 hours of use, the solderability of the solder paste gradually deteriorates, resulting in a decrease in the mechanical strength of the solder joints. In the subsequent assembly and handling process, due to force or collision, the interface between the component and the pad will be damaged. fall off and scrap

[0006] 4. At the same time, due to the high reflow temperature of the original high-temperature solder paste, the thermal shock damage to components and circuit boards during soldering is large, and the power consumption is high

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