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Hot air fusion welding method for circuit board disassembly to reduce chip delamination rate

A circuit board, fusion welding technology, applied in electric heating devices, printed circuits, welding equipment, etc., can solve problems such as reducing chip reusability, and achieve the effects of improving reusability, reducing delamination rate, and high economic benefits

Inactive Publication Date: 2021-05-04
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the chip is prone to delamination during the heating process of circuit board disassembly, which will reduce the reusability of the chip

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Take the temperatures of the first to fifth heating chambers as 270.0°C, 256.0°C, 238°C, 240°C, and 230.0°C in sequence. During heating, the temperature rise rate of the solder in the first heating chamber is 1.2°C / s, and in the second heating chamber The temperature rise rate of the solder is 0.9 degrees Celsius / second, the temperature rise rate of the solder in the third heating chamber is 0.4 degrees Celsius / second, the temperature rise rate of the solder in the fourth heating chamber is 0.3 degrees Celsius / second, and the temperature rise rate of the solder in the fifth heating chamber is 0.1 degrees Celsius / second, the heating time of each chamber of the heating hot air is 90s. This dismantling process was adopted in fusion welding of a vibration dismantling machine, the temperature of the heating chamber was set, and 8 similar circuit boards were disassembled. Ultrasonic scanning was used to detect the disassembled chips, and it was found that delaminated chips ac...

Embodiment 2

[0028] Take the temperatures of the first to fifth heating chambers as 300.0°C, 288°C, 230.0°C, 249.0°C, and 240.0°C in sequence. During heating, the temperature rise rate of the solder in the first heating chamber is 1.5°C / s. The temperature rise rate of the solder is 1.2 degrees Celsius / second, the temperature rise rate of the solder in the third heating chamber is 0.3 degrees Celsius / second, the temperature rise rate of the solder in the fourth heating chamber is 0.2 degrees Celsius / second, and the temperature rise rate of the solder in the fifth heating chamber is 0.1 degrees Celsius / second, the heating time of each chamber of the heating hot air is 78s. This dismantling process was adopted in fusion welding of a vibration dismantling machine, the temperature of the heating chamber was set, and 8 similar circuit boards were disassembled. The delamination rate of all the chips finally detected is about 7.5%.

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PUM

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Abstract

The invention discloses a circuit board dismantling hot air fusion welding method for reducing chip delamination rate, comprising: sequentially dismantling the circuit board in the first heating chamber, the second heating chamber, the third heating chamber, the fourth heating chamber, The heating chamber and the fifth heating chamber are welded, wherein the temperature of the first heating chamber is 270-300 degrees Celsius, the temperature of the second heating chamber is 250-290 degrees Celsius, and the temperature of the third heating chamber is 270-300 degrees Celsius. The temperature of the chamber is 230-240 degrees Celsius, the temperature of the fourth heating chamber is 240-250 degrees Celsius, and the temperature of the fifth heating chamber is 230-240 degrees Celsius. By adopting the method, the delamination rate of the chip can be significantly reduced under the premise of ensuring that the circuit board is fully welded, thereby improving the reusability of the chip and having high economic benefits.

Description

technical field [0001] The invention belongs to the field of environmental protection treatment of hazardous solid waste and resource regeneration, and in particular relates to a circuit board dismantling hot air fusion welding method for reducing chip delamination rate. Background technique [0002] Waste circuit boards are an important urban mineral. Dismantling waste circuit boards and reusing high-value components has significant environmental and economic benefits. The commonly used automatic disassembly method for component reuse is to first heat the circuit board as a whole, so that the solder between the components and the circuit board pads is fully melted, and then apply a disassembly force in a certain way to make most of the components The device is detached from the substrate. Among the various components of disassembled waste circuit boards, integrated circuit chips are a category with relatively high reuse value. However, the chip is prone to delamination du...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K1/018B23K3/04B23K101/42
Inventor 向东游孟醒王翔
Owner TSINGHUA UNIV
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