JPH1161287A - Device for separating solder in waste printed circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a device which separates solder from a waste printed circuit at high efficiency and can treat a large quantity of the printed circuits by providing a driving device for vibrating or rotating a vessel for incorporating the printed circuit into granular heat medium. SOLUTION: The vessel 4 for incorporating the printed circuits 3 unnecessitated is charged into the granular heat medium 2 fluidized by heating to the temp. having the m.p. or higher of the solder. The granular heating medium 2 is heated with a heater 8 for heating the heat medium and a heater 12 for heating the air and fluidized with a blower 13. The printed circuit 3 has excellent heat retaining property and rapidly heated with the granular heat medium 2 and the solder is made to melting or semi-melting condition. Thereat, at the time of vibrating the vessel 4 for incorporating the printed circuit with a driving device 5a for printed circuit incorporated vessel, the solder is simply separated from the printed circuit 3. Thereafter, the incorporated vessel 4 is pulled up upward to recover the printed circuit 3. The separated solder is shifted downward and stored into a solder storing part 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for separating solder from a printed circuit having a solder joint, and more particularly to an apparatus suitable for mass processing of separating and recovering solder from a waste printed circuit that is no longer needed.

[0002]

2. Description of the Related Art Electronic devices such as personal computers and word processors are equipped with printed circuits using a large number of electronic components such as LSIs and connectors.
These electronic components are joined to the printed circuit by soldering or the like.

[0003] The speed of technological innovation of these electronic devices is extremely high, and models are changed every few months. Unnecessary electronic devices are discarded after separating and collecting recyclable parts or materials. Most of the disposal is landfill. The solder is usually discarded without being collected and attached to the printed circuit board.

[0004] However, solder contains lead, which is a harmful heavy metal. Landfilling solder has a significant environmental impact. For this reason, an apparatus for separating solder from waste of soldering equipment such as a printed circuit mounted with electronic components has been studied. Known solder separation devices include the following devices (1) to (4).

(1) After preheating a printed circuit in an insulated housing, a hot jet gas at 250 to 1000 ° C. and a pressure of about 3 kg / cm ² is sprayed onto the printed circuit board to melt and blow away metal such as solder. A device for collecting after cooling. See JP-A-8-274461.

(2) The printed circuit is accommodated in a rotating cage for housing a substrate, heated to 250 ° C. to 1000 ° C. by a high-temperature gas, and then the rotating cage is rotated at 12000 to 15000 rpm to separate and collect a low-temperature molten material such as solder. apparatus. JP-A-8-274462
No. reference.

(3) An apparatus for fixing one end of a printed circuit, heating the substrate with hot jet gas, and then sweeping the surface of the substrate with a rotating metal brush to remove solder. Nikkei Mechanical 1997, 2, 17 No. See No. 500.

(4) An apparatus which separates electronic components and solder from a substrate by fixing one end of a printed circuit, heating the same to a solder melting temperature or higher in a heating furnace, and repeatedly hitting a hit head against the substrate. See JP-A-8-279677.

[0009]

Since the solder has a very good wettability to the copper foil or the copper plated portion, which is the junction of the printed circuit, the solder is not heated simply by heating the circuit to a temperature higher than the melting point of the solder. It only melts and does not separate from the circuit board. When an external force such as rotation or impact is applied to the circuit board in the molten state of the solder by applying a hot jet, the molten solder is separated to some extent from the circuit board, but the residual amount of solder on the copper foil surface is large, and the solder separation rate is at most 70. %. In the method of sweeping the circuit board surface with a metal rotating brush in the molten solder state and separating the solder, the solder on the circuit board surface that the brush can contact can be separated to some extent,
It is difficult to separate the solder in the through hole where the brush is difficult to contact. Further, the metal brush may damage the circuit board more than necessary, and may cut other valuable metals together with the solder.

[0010] Heating a printed circuit with a high-temperature gas or a heating furnace requires a long time to raise the temperature because of heating through air having poor thermal conductivity. Therefore, it cannot always be said that it is suitable for mass processing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a solder separating apparatus which separates solder from waste printed circuits with high efficiency and is suitable for mass processing.

[0012]

SUMMARY OF THE INVENTION According to the present invention, a waste printed circuit is immersed in a particulate heat medium, and the printed circuit is melted by heat conduction from the particulate heat medium to a temperature at which electronic components do not melt. Heating and vibrating the heat medium causes the heat medium to penetrate into the solder joint, and scrapes and separates the solder with the particulate heat medium. The solder separation device according to claim 1, wherein the particulate heat medium-filled container, an air blowing device that blows air for flowing the particulate heat medium into the heat medium-filled container, A heating medium heating device that heats the particulate heating medium to a temperature at which the solder melts and the electronic components do not melt, a mesh-shaped printed circuit storage container that contains the waste printed circuit, and a container that contains the printed circuit are placed in the particulate heating medium. And a printed circuit storage container driving device that vibrates or rotates the device.

According to a second aspect of the present invention, there is provided the solder separating apparatus according to the first aspect, further comprising a solder storage portion provided at a bottom portion of the heat medium filling container, and the solder stored in the solder storage portion. A solder discharging means for discharging to the outside is provided.

According to a third aspect of the present invention, there is provided a solder separating apparatus, wherein a mesh-shaped electronic component collection container is provided so as to surround the printed circuit storage container, and the electronic component leaked out of the printed circuit storage container along with the separation of the solder. Is collected.

According to a fourth aspect of the present invention, there is provided a solder separating apparatus, wherein the printed circuit container is lifted from the particulate heat medium in the container filled with the heat medium or is moved up and down to be immersed in the heat medium. A device is provided.

According to a fifth aspect of the present invention, there is provided a solder separating apparatus which sucks air which is an atmospheric gas in a heat medium filling container, separates and recovers a particulate heat medium mixed into the air by a cyclone, and re-opens the inside of the heat medium filling container. And a cyclone-type particulate heat medium recovery and recirculation device.

According to a sixth aspect of the present invention, there is provided a solder separating apparatus including a printed circuit pre-heating device for pre-heating a waste printed circuit to be processed next time by suction from the heat medium filling container by air by the particulate heat medium recovery and reflux device and air. It is characterized by having.

It is desirable that the frequency at which the printed circuit container is vibrated is 15 Hz or more.

When the printed circuit container is rotated, the minimum rotation radius A (unit: m) and the number of rotations B of the container are required.
The relationship with (unit: min ⁻¹ ) is desirably A × B ² ≧ 90000.

The printed circuit container has a perforated structure for allowing the particulate heat medium to enter the container. The particulate heat medium that has entered the printed circuit container enters the through hole of the printed circuit with the vibration or rotation of the container and acts to peel the solder from the board or the electronic component.

In the electronic component collection container provided to surround the printed circuit container, as the solder separates from the printed circuit, the electronic component is also separated, and may leak out from the hole of the printed circuit container. Because there is
Provided to collect leaked electronic components. This electronic component collection container also has a perforated structure so that the solder and the heat medium can pass freely.

As the heating medium, ceramic particles such as silica sand or zircon sand, or stainless steel particles can be used, but the heating medium is not limited thereto, and may be a solid at the heating temperature. When these heating media are used, the solder separated from the printed circuit has a large specific gravity and settles at the bottom portion of the heating medium filling container. Therefore, a solder storage section is provided at the bottom of the heat medium filling container to store and collect the solder.

Since the air, which is the atmospheric gas in the heat medium-filled container, is heated by heating the heat medium, it is desired to use the air for preliminary heating of a printed circuit to be processed next or for hot water supply and heating. However, the scattered heat medium is mixed in the atmospheric gas. Therefore, the atmospheric gas is sucked, the particulate heat medium is recovered by the cyclone, and the heat medium is returned to the heat medium filling container again.

According to the present invention, it is possible to provide a mass processing apparatus capable of efficiently separating and collecting solder from a printed circuit in a short time.

In the solder separating apparatus according to the present invention, the waste printed circuit is placed in a printed circuit container made of a screen such as a mesh and a reinforcing skeleton, and then put into a heated and flowing heat medium. The heating and vibration may be performed after the printed circuit is turned on. The printed circuit is rapidly heated due to the excellent thermal conductivity and heat retention of the flowing heat medium, and the solder will soon become molten. When the printed circuit container is driven by vibration or rotation or a combination of both, the solder is efficiently separated from the circuit board in a short time. At that time, the solder is almost separated from the surface copper foil and through holes of the circuit board except for the reaction part with copper due to the polishing and wiping effects of the heat medium particles. Therefore, there is almost no residual solder.

After the solder is separated from the container containing the printed circuit, it is immediately transferred to a subsequent process by a transfer mechanism or manually, and another waste printed circuit preheated in the preheating chamber is transferred to the heating medium. come. The solder is then separated again. By repeating this process, a large amount of waste printed circuits can be processed.

With the separation of the solder, most of the electronic components are separated from the circuit. The detached electronic component can be collected by pulling up the printed circuit container or the electronic component collection container from the heat medium.

The solder separated from the printed circuit settles due to a difference in specific gravity from the heat medium and is stored in the solder storage section.
After a certain amount of solder is stored, the solder is recovered by extracting the solder from a discharge port provided near the solder storage part.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments, but the present invention is not limited to these embodiments.

FIG. 1 shows a solder separating apparatus using a vibration driving method according to an embodiment of the present invention.

The configuration of the solder separating apparatus shown in FIG. 1 is composed of a heating medium filling container 1, a particulate heating medium 2, a printed circuit 3, a printed circuit storage container 4, a printed circuit storage container driving device 5a, and an electronic component collection container 6. , Air 7, heating medium heater 8, separated solder 9, separated solder discharge cock 10,
Air distribution plate 11, air heater 12, blower 13, heat medium discharge cock 14, support column 15, cyclone 16, heat medium storage tank 17, heat medium recirculation pump 18, print circuit preheating chamber 19, preheated printed circuit 20, mesh screen 21, heat exchanger 22, heat medium filled bottom plate 2
3, an air injection nozzle 24 and a solder reservoir 25.

In FIG. 1, a printed circuit 3 which is no longer needed is put into a printed circuit container 4. After the printed circuit 3 is loaded into the printed circuit container 4, the container 4 is loaded into the flowing particulate heat medium 2 heated to a temperature equal to or higher than the melting point of the solder. The heating is performed by the heating medium heating medium heater 8 and the air heating heater 12, but only one of them may be used. Although a sheath heater or the like is used as the heater, a heat exchanger using another heat source may be used. Although the blower 13 is used for flowing the heat medium, another blower such as a bebicon may be used. The printed circuit 3 is excellent in heat retention and is rapidly heated by the flowing heat medium 2, so that the solder is in a molten state or a semi-molten state. Here, if the printed circuit container 4 is driven by the printed circuit container driving device 5a, the solder is
Easily separated from surface leads and through holes. Here, the frequency of driving the printed circuit container 4 by the driving device 5a may be 15 Hz or more,
It is even better if z or more. When the solder separation process is completed, the printed circuit container 4 is lifted up, the printed circuit is collected, and the printed circuit 20 preheated in the printed circuit preheating chamber 19 is newly put into the printed circuit container 4 and again. Perform solder separation processing. A printed circuit for performing the next process is newly introduced into the preheating chamber. The separated electronic components may be collected by lifting the electronic component collection container 6. The solder separated in this process moves downward due to a difference in specific gravity with the heat medium, and is stored in the solder storage section 25. The bottom plate 23 is preferably tapered to facilitate the storage of solder. After a certain amount of solder is stored, the separated solder discharge cock 10 is opened, and the separated solder 9 is discharged and collected. At this time, a suction device may be provided at the tip of the discharge cock 10 to suck the separated solder 9. When the heat medium flows, a part of the heat medium may be scattered together with the air. The particles are captured by the cyclone 16 and stored in the heat medium storage tank 17. What is necessary is just to reflux in a heat medium storage container. In this case, the capture of the scattered heat medium is not limited to the cyclone, but may be another dust collecting device such as a bag filter. Further, the heat medium recirculation pump 18 may be another blowing device such as a blower. The exhaust heat from the preheating chamber 19 can be used for hot water supply or heating by the heat exchanger 22.

In the present invention, the heating medium heating device comprises a blower 13 and an air injection nozzle 24. The solder discharging means includes a pipe for leading the solder in the solder storage part to the outside of the heat medium collecting container, and a solder discharging cock 10 provided in the pipe. The printed-circuit-housing container lifting / lowering device includes a support 15 for supporting the printed-circuit housing 4 and a device for vertically moving the printed-circuit housing along the support. The cyclone-type particulate heat medium recovery device includes a cyclone 16, a heat medium storage tank 17, a heat medium recirculation pump 18, and piping connected between the heat medium filling container and the cyclone and between other devices. The printed circuit preheating device includes a printed circuit preheating chamber 19, a mesh screen 21, and a heater (not shown).

FIG. 2 shows a printed circuit solder separating apparatus using a rotary drive system according to an embodiment of the present invention.

The configuration of the solder separating device shown in FIG. 2 is almost the same as that of FIG. 1 except that the printed circuit container driving device 5b is of a rotary drive type.

In FIG. 2, the printed circuit collecting container 4 is driven to rotate by a rotary driving device 5b,
Separate the solder from the printed circuit. At this time, the relationship between the minimum turning radius A (unit: m) and the number of rotations B (unit: min ⁻¹ ) should satisfy A × B ² ≧ 90000, and A × B ² ≧ 120,000 It is good. That is, the shorter the radius of rotation, the higher the number of rotations is required. However, in FIG. 2, the printed circuit collecting container 4 has a donut shape and prevents the movement of the circuit in the direction of the rotation center where a high number of rotations is required. It is possible to set a low rotation speed. For example, considering an example of a donut-shaped printed circuit collecting container capable of processing a plurality of substrates of A size, the diameter to the inner surface of the donut-shaped printed circuit collecting container needs to be about 0.2 m and the outer diameter is about 0.4 m. it is conceivable that. Therefore, the minimum turning radius is 0.2 m
Therefore, the minimum rotation speed can be calculated as 670.8 min ^-1 by the above equation. In this point, the apparatus is greatly different from the apparatus described in Japanese Patent Application Laid-Open No. 8-274462 which requires a high speed rotation of 12000 to 15000 rpm. Note that the rotational drive direction does not need to be constant, and may be reversely rotated from the middle or alternately rotated forward and backward.

Hereinafter, experimental examples will be described.

(Experimental Example 1) A printed circuit having a size of 10 cm square, for which the amount of solder to be deposited is known in advance, was used as a test piece, placed in a printed circuit storage container, and a heating medium heated to 220 ° C. flowed. The printed circuit container was driven by a vibration method for 30 seconds to determine the solder separation rate of the test piece. FIG. 3 shows how the solder separation rate changes with changes in the frequency and stroke.

When the vibration frequency is 15 Hz or less, the smaller the vibration stroke is, the lower the solder separation rate is. However, when the vibration frequency is 15 Hz or more, the solder separation rate is 95% or more at any vibration stroke, and when the vibration frequency is 25 Hz or more, the solder separation rate is 98% or more. It was confirmed that a solder separation rate was obtained. When the printed circuit was heated in an electric furnace without using a fluidized bed and was similarly driven to vibrate, the solder separation ratio was about 70% even at a vibration frequency of 35 Hz and a vibration stroke of 30 mm. Inspection of this test piece revealed that the amount of solder attached to the copper foil surface was large and that the solder was not completely separated.

(Experimental example 2) A printed circuit having a size of 10 cm square, for which the amount of solder to be deposited is known in advance, was used as a test piece, placed in a printed circuit storage container, and a heating medium heated to 220 ° C. flowed. Then, the printed circuit container was driven for 30 seconds by a rotation method, and the solder separation ratio of the test piece was obtained in the same manner as in Experimental Example 1. The relationship between the distance from the center of rotation of the test piece at each rotation speed and the solder separation rate is determined, and the radius of rotation x (number of rotations) ² (unit: m · (min ^-1 ))
² ) and examined how the solder separation rate changes with the change of this parameter, and shown in FIG.

When the radius of gyration × (number of revolutions) ² is 80000 or less, the solder separation rate is 50% or less, but when it is 90000 or more, the solder separation rate is 95% or more, and it was confirmed that a high solder separation rate was obtained. When the printed circuit was heated in an electric furnace without using a fluidized bed and rotated similarly, the solder separation rate was about 70% as in Experimental Example 1.

(Experimental Example 3) Next, the relationship between the heating time of the printed circuit and the attained temperature was examined for each heating method. A thermocouple was adhered to the surface using a printed circuit having a size of 100 mm square as described above, and the outside of the adhered portion was covered with a heat insulating material. The heating method is as follows: (a) put in an electric furnace adjusted to 200 ° C .; (b) inject hot air adjusted to 200 ° C. into the circuit; (c) heat medium whose temperature is adjusted to 200 ° C. is flowing. The circuit was heated by each of the three methods of placing in a fluidized bed, and the relationship between the heating time and the substrate temperature was determined, and is shown in FIG.

As shown in FIG. 5, in the method of FIG.
The time to reach 0 ° C. was less than one minute, and it was found that the temperature was raised at a rate three times or more that of the other methods.

(Experimental Example 4) Next, the recovery of the solder was examined. Into a fluidized bed in which 30 liters of a heat medium is flowing at 200 ° C., 3 liters of solder particles having a size of 1 mm or less were introduced and allowed to flow for 10 minutes. After cooling, the stored material in the solder storing part was recovered, and the concentration of the solder in the recovered material was determined by chemical analysis. As a result, it was found that the solder concentration was 95% or more, and the solder could be recovered with high efficiency by the fluidized bed method.

[0045]

As described above, according to the present invention, it is possible to provide a solder separating apparatus capable of separating solder from a waste printed circuit with high efficiency and capable of mass processing.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a solder separating apparatus using a vibration driving method according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a solder separating apparatus using a rotary drive system according to one embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a change in a frequency and a stroke and a solder separation rate in a solder separating apparatus using a vibration driving method.

FIG. 4 is a diagram showing a relationship between a change in a parameter of a radius of rotation × (number of rotations) ² and a solder separation rate in a solder separating apparatus based on a rotational driving method.

FIG. 5 is a diagram showing a relationship between a printing circuit heating time and a circuit reaching temperature in each heating method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Heat medium filling container, 2 ... Particulate heat medium, 3 ... Printed circuit, 4 ... Printed circuit storage container, 5a ... Printed circuit storage container drive device, 6 ... Electronic component collection container, 8 ... Heat medium heater, 9 ... Separated solder, 13 ... Blower, 1
5 ... pillar, 16 ... cyclone, 17 ... heat medium storage tank, 1
8: Heat medium recirculation pump, 19: Print circuit preheating chamber, 24: Air injection nozzle, 25: Solder reservoir.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Isao Okochi, Inventor 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi Research Laboratory, Hitachi, Ltd. No. 1 Hitachi, Ltd. Hitachi Research Laboratory (72) Inventor Ryo Yamada 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi Research Laboratory Hitachi Research Laboratory (72) Inventor Tomohiko Miyamoto Ibaraki Prefecture 7-1-1, Omikamachi, Hitachi City Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Takeyu Komuro 7-1-1, Omikamachi, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd.

Claims (6)

[Claims] An apparatus for separating solder from a waste printed circuit, comprising: a heating medium-filled container filled with a particulate heating medium; and blowing air from a bottom into the heating medium-filled container to form the particles. Air blowing device for flowing the heat medium, a heat medium heating device for heating the particulate heat medium to a temperature at which the solder in the printed circuit is melted and the electronic components are not melted, and a mesh-shaped device for containing the printed circuit. A solder separating apparatus for a waste printed circuit, comprising: a printed circuit container; and a printed circuit container driving device for vibrating or rotating the printed circuit container in the particulate heat medium. 2. A solder separating apparatus according to claim 1, further comprising: a solder storage portion for storing the separated solder at a bottom portion of the heat medium filling container, wherein the solder stored in the solder storage portion is transferred to the heat medium. A solder separating device for a waste printed circuit, comprising a solder discharging means for discharging the solder to the outside of the filling container. 3. The solder separating apparatus according to claim 1, further comprising a mesh-shaped electronic component collecting container surrounding the printed circuit container, and leaking out of the printed circuit container as the solder is separated. A solder separation device for a waste printed circuit, wherein electronic devices that have come out are collected. 4. The solder separating apparatus according to claim 1, wherein the printed circuit container is lifted up or down to be pulled up from the particulate heat medium in the heat medium filling container or to be immersed in the heat medium. A solder separation device for a waste printed circuit, comprising a circuit container elevating device. 5. The solder separating apparatus according to claim 1, wherein air which is an atmospheric gas in the heat medium filling container is sucked, and a particulate heat medium mixed in the air is separated and recovered by a cyclone, and the air is separated again. A solder separation device for a waste printed circuit, comprising a cyclone-type particulate heat medium recovery / recirculation device for returning the heat medium into a heat medium filling container. 6. A pre-heating circuit for a waste printing circuit according to claim 5, wherein a pre-heating of the waste printing circuit is preheated by the air sucked from the inside of the heating medium filling container by the cyclone type particulate heating medium recovery and reflux device. A device for separating solder from waste printed circuits, characterized in that the device is provided.