JPH0218990A - Removing method for integrated circuit element - Google Patents

Abstract

PURPOSE:To complete the removal of an integrated circuit element at all times when solder begins to melt, to minimize thermal damage and to shorten the operating time of the removal by removing the integrated circuit element while solder is melted by hot air under the state in which pull-up force is applied to the element. CONSTITUTION:The nozzle 18 of hot air and a suction pipe 22 are installed to a vertically moving head 16, the suction pipe 22 is mounted so that an internal pipe 27 can be shifted to an external pipe 26, and a switch means 31 operating in response to the presence of the removal of an integrated circuit element is fitted between both pipes 26, 27. When the internal pipe 27 of the suction pipe 22 is brought into contact with the element 2 and the switch means 31 is opened, hot air, is ejected against an element lead section 3 by the nozzle 18, and the element 2 is sucked by the internal pipe 27 and pull-up force is given. Accordingly, the solder 4 of the lead section 3 is melted by hot air from the nozzle 18, the element 2 is removed, and removal operation can be promoted quickly while minimally inhibiting thermal damage.

Description

[Detailed Description of the Invention] [Summary] Plane-mounted LS soldered onto a printed circuit board
Regarding the removal method for removing integrated circuit elements such as I, the purpose is to always remove integrated circuit elements reliably while minimizing thermal damage. The suction pipe is equipped with a switch means to detect the presence or absence of removal, and in response to the signal from the switch means before removal, the suction pipe is attracted to the integrated circuit element and a pulling force is applied, and hot air is led through the nozzle. The hot air is squirted onto the solder, the hot air is stopped by a signal from the switch means at the time of removal, and the integrated circuit element is pulled up in an adsorbed state.

[Industrial Field of Application] The present invention relates to a removal method for removing an integrated circuit element such as a surface-mounted LSI soldered onto a printed circuit board.

Generally, a large number of integrated circuit elements are soldered and mounted on a printed circuit board based on the circuit design, and in recent years flat-back type elements have been mounted directly on the conductor pattern of the board in response to the demand for high-density mounting. There is a tendency. By the way, such printed boards are often subject to circuit design changes, modifications, etc. (In this case, unnecessary elements that have already been soldered are removed by melting the soldered parts.

[Prior Art] Conventionally, the above-mentioned integrated circuit element is removed as follows. That is, hot air is applied to the lead portions of the elements soldered on the substrate to melt the solder.

Then, after a set time period has elapsed that does not cause any damage to the element or substrate, the element is removed by holding and lifting the element using the suction force of the suction pipe.

[Problem to be solved by the invention]

By the way, in the above conventional example, since the removal of the element is managed by the hot air injection time, it may not be possible to remove the element within the set time due to differences in the mounting position of the element, the heat capacity of the board, etc. That is, the heat of the hot air is transmitted to the solder in the lead portion of the element and the substrate, and in this case, if the heat capacity of the substrate is large, the solder does not easily reach the melting temperature, and therefore is not removed. Therefore, in such a state, it is necessary to apply a pulling force to the element to some extent and to use means for forcibly removing it.

The present invention has been made in view of the above, and an object of the present invention is to provide a method for removing an integrated circuit element that can always and reliably remove the integrated circuit element while minimizing thermal damage. It is about providing.

[Means to solve the problem]

In order to achieve the above object, the removal method of the present invention includes: attaching a hot air nozzle and a suction pipe to a head that moves up and down; disposing the suction pipe so that the inner pipe is movable relative to the outer pipe; and installing a remover between the two pipes. The configuration includes a switch means that operates depending on the presence or absence of the switch.

Then, when the head is lowered and the inner pipe of the suction pipe comes into contact with the element and the switch means opens, the nozzle blows out hot air to the element lead, and the inner pipe attracts the element to apply a pulling force. do. After that, when the solder on the lead part melts and the element is removed and pulled up by the inner pipe, the switching means closes accordingly to stop the real air and raise the head, further releasing the pulling force and pulling the element inside. It is removed from the pipe.

(Operation) With the above method, the element itself attracts the inner pipe of the suction pipe and mechanically applies a pulling force, and the hot air from the nozzle melts the solder on the lead part and removes it. The element is removed depending on the state of solder melting due to heat capacity on the board side, etc. Also, as the solder melts due to the pulling force, it is removed at an accelerated rate.The presence or absence of such removal is detected by a switch means and the head Up, down, real gush of air,
By automatically stopping, generating a pulling force, and stopping, the removal action can proceed quickly while minimizing thermal damage.

〔Example〕

Embodiments of the removal method of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a printed circuit board, on which leads 3 of a flat pack type element 2 are mounted by directly flattening them with solder 4. As shown in FIG.

Reference numeral 10 is a removal device, 11 is the main body of the device,
A screw rod 12 is vertically attached to this main body 11 by an arm 13, and the screw rod 12 is connected to a servo motor 1 by a gear 14.
5, and a head 16 is attached to the threaded rod 12 so as to move up and down as the head 16 rotates. A nozzle 18 is provided below the piping block 17 of the head 16 to protrude between the arrangement of the leads 3 and the passageway.
It communicates with the pressurizing pump 21 side through the 0 etc., and blows out hot air. Further, a suction pipe 22 is attached to the approximate center of the nozzle 18, and this pipe 22 is communicated with the suction pump 24 side through a pipe 23 etc.
It is designed to provide a pulling force. The circuit is configured such that the control unit 25 operates the motor 15 and each pump 21.24.

In the second part, the suction pipe 22 will be described. First, the inner pipe 27 is connected to the outer pipe 26 on the fixed side.
is movably inserted, the pipe tip 27a is bent into an L-shape, and an insulating pad 28 is attached underneath. An insulating ring 29 is attached to the inner surface of the pipe 26, and a stop 30 on the outer surface of the pipe 27 comes into contact with this ring 29.
The descent of the pipe 27 is restricted. Also, pipe 26.
Reference numeral 27 constitutes an electric circuit, and constitutes a switch 31 that is opened when the ends 26a and 27a themselves are not removed, and closed when the pipe 27 is pulled up when removed. In this case, the gap d between the tips 26a and 27a is an optimum value (for example, 0.3
mm), and the nozzle 18 and lead solder 4
The gap between the
Collision with the nozzle 18 is prevented.

Therefore, the operation of the removal device 10 having such a configuration is explained in the third section.
This will be explained using the flowchart shown in the figure and the operation state diagram shown in FIG.

First, the head 1 is placed above the element 2 to be removed on the board 1.
Nozzle 18 and suction pipe 22 of No. 6 are positioned and centrifuged. The start signal drives the motor 15 to rotate the threaded rod 12 and lower the head 16, thereby also lowering the suction pipe 22 and the like. At this time,
The pad 28 of the inner pipe 27 that protrudes from the outer pipe 26 of the suction pipe 22 hits the element 2 and is lifted, and as shown in FIG. 4(a), both tips 26a and 27a come into contact and the switch 31 is closed. Therefore, the motor 15 is stopped and reversed by this switch signal, so that the head 16 is raised by a predetermined gap d.

As a result, as shown in FIG. 4(b), the pipe 27 side of the suction pipe 22 is in contact with the element 2, the pipe 26 is positioned above it, and the switch 31 is opened. At this time, the nozzle 18 is in contact with the element 2. It is located close to and opposite to part 4.

After that, the suction pump 2
4 is activated and its negative pressure acts on the pipe 27,
The element 2 is attracted to the pipe 27 via the pad 28, and a predetermined pulling force is applied thereto. Further, the pressure pump 21 is activated and hot air from the heater 20 is ejected onto the lead solder 4 through the nozzle 18, thus starting the removal action. When the solder 4 begins to melt, the leads 3 are peeled off by the pulling force, and when the element 2 is removed and lifted as shown in FIG. 4(C), the tips 26a and 27a are brought into contact again. The switch 31 then closes. Therefore, this switch signal causes the air to stop and no longer dissolves, and the head 16 rises while attracting the element 2 by driving the motor 15, as shown in FIG. 4(d). Then, when the pump 24 is stopped and the suction is released by the footswitch signal, the element 2 comes off the pad 28 of the pipe 27 due to its own weight, and the pipe 27 protrudes from the pipe 26 to return to its original state.

Note that the switch 31 is connected to the two pipes 26 of the suction pipe 22.
．． Although the tips 26a and 27a of 27 are used, the present invention is not limited thereto.

〔Effect of the invention〕

As described above, according to the present invention, since the removal is performed while melting the solder with hot air while applying a pulling force to the element, removal always ends at the point when the solder starts melting, and thermal damage is prevented. As a result, removal work time is shortened.

By using solder melting and mechanical pulling force in combination, removal can be performed reliably, especially in situations where removal is difficult.

Since the removal action is controlled by a switch, various operations can be performed quickly and smoothly, and work can be ensured, especially when it is difficult to remove, such as solder.

The use of insulating pads can strengthen adsorption and prevent electrical damage.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an embodiment of the integrated circuit device removal method of the present invention, Fig. 2 is an enlarged sectional view of the main part, Fig. 3 is a flowchart of the operation, and Figs. 4 (a) to d. ) is a diagram showing the operating state. In the figure, 2 is an integrated circuit element, 3 is a lead, 4 is solder, 16 is a head, 18 is a hot air nozzle, 22 is a suction pipe, and 31 is a switch.

Claims (1)

[Claims] A suction pipe (22) and a hot air nozzle (18) are attached to a head (16) that moves up and down, and a switch means (31) for detecting the presence or absence of removal is provided on the suction pipe (22). , In response to a signal from the switch means (31) before removal, the suction pipe (22) is adsorbed to the integrated circuit element (2) to apply a pulling force, and hot air is applied to the lead solder (4) through the nozzle (18). Switch means for ejecting and removing (3
The hot air is stopped by the signal of 1), and the integrated circuit element (2)
A method for removing an integrated circuit device, characterized by pulling it up in a suction state.