Multilayer sintering and welding process for rectifier bridge

Abstract

The invention discloses a multilayer sintering and welding process for a rectifier bridge. The process comprises the following steps: a, overturning operation is carried out; b, a lower graphite mould is taken and arranged on a platform, and a semi-finished product to be sintered is horizontally transferred from an upper graphite mould to the lower graphite mould which is taken off; c, the same lower graphite mould or a plurality of upper graphite moulds are used to repeat step a and step b, two or more than two lower graphite moulds are overlapped, and a support separating bar is arranged between two adjacent lower graphite moulds to complete overlapping operation of two layers or more than two layers; and d, the graphite moulds of two layers or more than two layers after overlapping areput into a sintering furnace, and are sintered into at least two sheets of frames of the rectifier bridge in the sintering furnace. The process does not need a correction process, has a simpler and more convenient operation, can overcome poor welding caused by irregular frame, greatly improves pass rate of the product, can form a plurality of frames of the rectifier bridge in one time, improves productivity under a condition of the same energy consumption, and not only saves energy consumption, but also reduces environmental pollution.

Description

technical field [0001] The invention relates to a rectifier bridge sintering process, in particular to a rectifier bridge multi-layer sintering and welding process, which is suitable for sintering and welding two or more layers of a rectifier bridge. Background technique [0002] Traditional rectifier bridge sintering process: install the connecting piece into the graphite mold, spray the flux formed by alcohol and rosin on the connecting piece, use a vacuum suction cup such as a sieve plate to absorb the solder piece of the corresponding specification, and put the positioning column of the suction cup into the graphite mold In the positioning hole, turn off the vacuum, let the solder piece fall on the corresponding boss of the connecting piece, spray flux on the solder piece again, use a vacuum suction pen to suck the chip onto the solder piece as required, and spray flux on the chip, Then repeatedly use the vacuum suction cup to place the corresponding specifications of th...

AI Technical Summary

Problems solved by technology

[0003] The above-mentioned traditional rectifier bridge sintering process mainly has the following disadvantages: 1. In the whole process, the soldering piece is used twice, so that the mold can only be moved gently on the console at a slow speed, otherwise it will cause a large number of dislocations between the chip and the welding piece , it is very inconvenient for the staff to operate, and the production efficiency is extremely low

2. During the assembly process, the mold must move continuously in each process. Although it moves slowly and gently, it will inevitably cause some chips and solder pads to be misaligned. After the sintering is completed, there will be more Poor welding and poor electrical properties make the formed rectifier bridge not meet the product requirements and increase the production cost

3. The traditional rectifier bridge sintering process has high requirements on the flatness of the frame. If the frame is slightly uneven, it will lead to poor welding of at least one product. Therefore, it is necessary to use a graphite upper mold with a certain weight to flatten during the welding process. The frame, which leads to a slow heat transfer rate during the entire welding process, and the welding material solder sheet requires a long time for high temperature, at least 12 minutes, so the chain belt of the sintering furnace can only run at a slow speed of 144.9cm / min, And every 2 molds need a distance of 37mm, and the maximum production capacity per hour is only 70 molds, a total of 960 pieces, to ensure the welding temperature, resulting in low equipment utilization. At the same time, nitrogen protection, electric energy and nitrogen are required throughout the sintering process. The energy consumption remains high, and the welding effect is affected after the graphite upper mold that absorbs the most heat and seriously hinders heat transfer is used in the traditional process

4. In the assembly process, the long-term use of flux not only pollutes the environment, but also makes the air quality of the assembly workshop poor, affecting the health of operators

5. In the traditional process, soldering flux needs to be sprayed at the same time as the soldering piece. The components of the flux are alcohol and rosin, resulting in a large amount of rosin remaining on the sintered frame. It must be cleaned with alcohol before compression molding in the subsequent process. It can be compressed and molded after being dried, which seriously affects the production efficiency and increases the production cost of the product and the labor intensity of the workers.

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