JPH0230146Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention instantaneously heats the leads of integrated circuits, etc. at the connection parts of printed wiring boards, etc., which have been pre-coated with solder by surface treatment such as plating. This invention relates to seals for soldering.

(Prior art) Conventionally, in order to solder a large number of leads of an integrated circuit, etc., at once to the connection parts of a printed wiring board, etc., which have been pre-coated with solder by surface treatment such as plating, it is difficult to solder them at once. A resistance welding machine with output control is used, and a special heating element (pulse heat tool) is attached to the tip of the electrode.The heating element also heats the leads of integrated circuits, etc., and welds printed wiring boards, etc. The connections are soldered (so-called reflow soldering).

The details of this conventional device will be explained with reference to the drawings. FIG. 3 is a perspective view of the pulse heat tool, and FIG. 4 is a front view of the pulse heat tool in use.

In FIG. 3, reference numeral 1 is a heating element formed into a rectangular box frame shape using molybdenum, tungsten, etc. that does not wet with solder. Current supply legs 4 and 5 for supplying pulsed current to the body 1 are each integrally provided. As shown in FIG. 4, a spindle (not shown) installed in a spot resistance welding machine or the like, which can be freely raised and lowered, is connected through the mounting holes 8 and 9 drilled in the upper parts of the current-carrying legs 4 and 5. Fixed power feeders 11 and 12
and screw them on with screws 13 and 14. In FIG. 4, 15 is a work table, 16 is a printed wiring board with pre-coated solder on the connection parts, and 17 is a work table.
is a flat pack placed with each lead 18 positioned at the connection part of the printed wiring board 16.
It is an IC. When the tool 20 is lowered onto the work table 15 and the pressing surface 10 of the heating element 1 comes into contact with the lead 18 of the IC 17 to reach a predetermined pressing force, a power supply (not shown) is applied to the tool 20 via the electrodes 11 and 12. A pulsed current is applied instantaneously to generate heat due to Joule heat. The solder on the printed wiring board 16 is instantly melted by this heat, and the connection part of the printed wiring board 16 and the lead 18 of the IC 17 are soldered. However, after the pulse current is cut off, the temperature of the tool 20 with a small heat capacity decreases. Because of the rapid descent, the solder solidifies sufficiently, and even if the tool 20 is subsequently raised, the leads 18 will not come up.

When soldering is performed using such equipment, the amount of heat required for soldering can be supplied in a short time, making it possible to easily join multiple points simultaneously with almost no thermal effect on integrated circuits, etc., increasing work efficiency. This contributes to the improvement of technology and the promotion of automation.

(Problems to be solved by the invention) However, such conventional pulse heat tools have energizing legs on each of the two opposing walls of the heating element formed in the shape of a rectangular box frame. The heat generated in the heating element is transferred to the power supply with good thermal conductivity through these current-carrying legs, and the temperature of the heating element near the current-carrying legs becomes lower than that of other parts, and the temperature on all sides The drawback was that the solder could not be heated uniformly, and uniform soldering could not be achieved.

(Means for solving the problems) In order to solve these problems, the present invention
A pair of energizing legs are integrally provided at any diagonally located corners of the heating element formed in the shape of a rectangular box frame, and a pair of energizing legs are provided at each corner of the heating element where there is no energizing leg. A heat dissipating portion is provided to protrude from the heating element.

(Function) Since the legs for energization are provided at the corners of the heating element formed in the shape of a rectangular box frame, the parts to be joined such as flat pack ICs are not heated by the low temperature part of the heating element.
All four sides can be heated to a uniform temperature.

In addition, if a pair of heat radiating parts are provided at the corners of a heating element that does not have current-carrying legs, and the heat at the corners is dissipated to the same extent as the heat loss due to heat conduction from the current-carrying legs, each of the heating elements The temperature distribution on the sides is made uniform.

(Example) Hereinafter, details of the present invention will be explained with reference to the drawings. FIG. 1 is a perspective view showing one embodiment of the pulse heat tool according to the present invention, and FIG. 2 is a perspective view showing another embodiment. In the figure, the same or corresponding parts as in FIG. 1 are given the same reference numerals.

The pulse heat tool 30 of the present invention is the third
The difference from the conventional one shown in the figure is that the current-carrying legs 4 and 5 are provided at corners 31 and 32 located on arbitrary diagonals of the heating element 1 formed in the shape of a rectangular box frame. . When the tool 30 is configured in this way, the energizing legs 4 and 5 and the heating element 1
When the cross-sectional areas of 31 and 32 have a low temperature, and the corners 33 and 34, which are relatively difficult to cool down, have a high temperature compared to the corners 31 and 32.

Usually flat package IC17 (Figure 4)
The leads 18 are connected to two sides or four sides of the package 17.
It is provided on the side and not on the diagonal of the package 17. Therefore, each corner 31 to 34 of the tool 30 of the present invention is connected to the lead 1 of the package 17.
If the lead 18 is located at a corner where there is no 8, it is possible to avoid the low temperature parts 31 and 32 and the high temperature parts 33 and 34 of the heating element 1, and press and heat the lead 18 at the four sides where the temperature is relatively even. can.

Next, another embodiment of the present invention will be described with reference to FIG. The pulse heat tool 40 shown in FIG. 2 differs from the one shown in FIG. 1 in that heat dissipation parts 35 and 36 are provided at the corners 33 and 34 where the current-carrying legs 4 and 5 are not provided. . The amount of heat radiated from the heat radiating parts 35 and 36 to the atmosphere is
If the size of the heat radiating parts 35 and 36 is determined to be equal to the amount of heat loss due to heat conduction of the current-carrying legs 4 and 5, the corners 31 to 34 of the heating element 1 will be at the same temperature, and the heating element Since the temperature distribution on each side of the heating element 1 is made uniform, the temperature on each side of the heating element 1 becomes more uniform than that in FIG. Therefore, if the lead 18 of the flat package IC 17 is pressed and heated in the same manner as described above using the tool 40 formed in this manner, the low temperature portions 31, 32, 3 of the heating element 1 will be heated.
3 and 34, all of the leads 18 can be heated to a more uniform temperature.

(Effects) The pulse heat tool of the present invention has a heating element formed in the shape of a rectangular box frame, with a pair of energizing legs integrally provided at arbitrary diagonal angles. Furthermore, since a pair of heat dissipating parts are provided at the corners of the heating element that do not have current-carrying legs and protrude from the heating element, each corner of the tool of the present invention can be connected to the leads of the flat package IC. If used in a corner where there is no corner, the leads can be pressed and heated with the four sides of the tool, which generates a uniform amount of heat, and the leads of a flat package IC can be soldered uniformly on all sides.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the pulse heat tool according to the present invention, FIG. 2 is a perspective view showing another embodiment of the pulse heat tool according to the present invention,
FIG. 3 is a perspective view showing a conventional pulse heat tool, and FIG. 4 is a schematic diagram showing an example of how the pulse heat tool shown in FIG. 3 is used. 1... Heating element, 4, 5... Legs for electricity supply, 10...
...Press surface, 31-34... Corner, 35, 36...
heat dissipation section.

Claims (1)

[Claims for Utility Model Registration] (1) A pulse that is characterized in that a pair of energizing legs are integrally provided at corners located on arbitrary diagonals of a heating element formed in the shape of a rectangular box frame. heat tools. (2) A pair of energizing legs are integrally provided at one diagonal corner of the heating element formed in the shape of a rectangular box frame, and a pair of heat dissipating legs are provided at the other diagonal corner. A pulse heat tool characterized in that parts are integrally provided so as to protrude from the heating element.