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Method for disassembling and modifying printed circuit board based on high temperature steam

A technology of high-temperature steam and waste circuit boards, which is applied in the removal of solid waste, recycling of electronic waste, and manufacturing tools, etc., can solve the problems of complex structure, difficult operation, and difficulty in adapting to the disassembly of circuit boards of different types and sizes. low cost effect

Inactive Publication Date: 2011-06-29
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Automated mechanical devices and their supporting facilities are generally complex in composition, difficult to operate, and difficult to adapt to the disassembly of different types and sizes of circuit boards
At the same time, there is no research precedent for mechanical modification of circuit board substrate materials by using high-temperature steam.

Method used

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  • Method for disassembling and modifying printed circuit board based on high temperature steam
  • Method for disassembling and modifying printed circuit board based on high temperature steam

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Computer memory chip disassembly

[0031] The first step is to take a piece of used computer memory. There are no non-solder connection components and electrolytic capacitors on it. All chips are packaged in dual surface mount (SOP). It is judged that the solder used is the 63Pb37Sn solder that is most commonly used in current computer originals, and its melting point is 183°C. Therefore, the final heating temperature is set to 190°C, the rotation speed is set to 300 rpm, and the rotation time is set to 30s.

[0032] The second step is to fix the waste memory on the rotating stirring device in the reactor, and adjust the length of the stirring device to 6.5 cm so that the waste circuit board is 1 cm away from the inner wall of the reactor.

[0033] In the third step, a closed high-temperature steam generator is used to generate high-temperature steam into the reactor, and the waste memory in the reactor is heated to 190°C. Turn on the rotating device to rotate at the set spe...

Embodiment 2

[0037] Dismantling of circuit boards based on plug-in resistors

[0038] The first step is to take a piece of the circuit board, the resistors on it are all in-line plug-in packages, and the leads are straight. It is judged that the solder used is 63Pb37Sn solder which is most commonly used currently. Set the final heating temperature to 200°C, and set the rotation speed to 700 rpm and the rotation time to 3 minutes.

[0039] In the second step, the circuit board is fixed on the rotating stirring device in the reactor, and the length of the stirring device is adjusted to 6.5 cm, so that the waste circuit board is 1 cm away from the inner wall of the reactor.

[0040] In the third step, a closed high-temperature steam generator is used to generate high-temperature steam into the reactor, and the circuit board in the reactor is heated to 200°C. Turn on the rotating device to rotate at the set speed for 3 minutes, use the combined effect of centrifugal force and gravity to remove the ...

Embodiment 3

[0044] Disassembly of circuit boards mainly based on BGA packaged chips

[0045] Ball grid array (BGA) packaging is one of the typical surface-mounting forms, and the south and north bridge chips of computer motherboards all adopt this packaging form.

[0046] The first step is to take a piece of this kind of circuit board, and the chip on it is a BGA package. It is judged that the solder used is 63Pb37Sn solder which is most commonly used currently. Set the final heating temperature to 200°C, and set the rotation speed to 650rpm and the rotation time to 25s.

[0047] In the second step, the circuit board is fixed on the rotating stirring device in the reactor, and the length of the stirring device is adjusted to 6.5 cm, so that the waste circuit board is 1 cm away from the inner wall of the reactor.

[0048] In the third step, a closed high-temperature steam generator is used to generate high-temperature steam into the reactor, and the circuit board in the reactor is heated to 200°C...

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Abstract

The invention discloses a method for disassembling and modifying a printed circuit board based on high temperature steam, which is implemented by using a reaction kettle with a rotary agitator through the followings steps: 1, setting the heating temperature according to the substrate materials of the circuit board and the tin-soldering component used in the circuit board, and setting the rotating speed and rotating time of the rotary agitator; 2, imbedding the circuit board into the reaction kettle, and fixing the circuit board at the rotary agitator; 3, heating the circuit board in the reaction kettle by using high temperature steam produced by a closed high temperature steam generator, and starting the rotary agitator; and 4, when the rotary agitator stops, stopping heating, then cooling the circuit board. In the method disclosed by the invention, the heating is performed by using steam in a closed environment, and the disassembling of components is implemented through applying mechanical forces which are easy to realize and wide in applicability; meanwhile, the substrate materials of the circuit board are subjected to heat treatment and modification so as to reduce the mechanical strength of the substrate material and destroy the structure of the substrate material, thereby facilitating the subsequent separation and recycling of the circuit board. The method disclosed by the invention has the characteristic of quick disassembling speed and is easy in implementation.

Description

Technical field [0001] The invention belongs to the technical field of electronic waste resource treatment and relates to a method for dismantling and modifying waste circuit boards based on high-temperature steam. Background technique [0002] Printed Circuit Boards (PCBs) are an important part of electronic waste, loaded with capacitors, resistors, diodes, transistors, inductors and integrated circuits (chips) and other components. Waste circuit boards contain a variety of toxic and hazardous substances, such as organic flame retardants and heavy metals such as lead, cadmium, nickel, and chromium. Improper dismantling and treatment will have a serious impact on the ecological environment and human health. On the other hand, because waste circuit boards are reproduced with various components and contain a large amount of valuable components such as metals, resins and plastics, their resource value is high. The use of effective technical methods to dispose of waste circuit board...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K1/018B09B3/00
CPCY02W30/82
Inventor 李金惠陈瑶段华波
Owner TSINGHUA UNIV
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