JPH0347340Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device for fixing electronic components to a printed circuit board.

[Conventional technology and problems]

As electronic components become more and more chipped, mounting of printed circuit boards has shifted to single-sided or double-sided surface mounting, and soldering has become a problem. In other words, when surface-mounted printed circuit boards are soldered using conventional flow soldering methods, there are many problems regarding the reliability of soldering, such as decreased solderability, bridging, and poor soldering. Therefore, in place of the flow soldering method, reflow soldering methods have come to be widely adopted. In order to carry out this reflow soldering method, an adhesive curing device, a reflow soldering device, and a reflow soldering device are used to perform the pre-process of the so-called reflow soldering method, in which electronic components are temporarily fixed to a printed circuit board. Currently, devices for soldering are being developed.

However, in the reflow temperature profile of a reflow soldering machine that uses a far-infrared heater in the preheating section and a halogen lamp in the reflow section, as shown in Figure 5, the chip temperature on the top surface of the printed circuit board is as shown by curve a. However, as shown by curve b, the chip temperature on the bottom surface of the printed circuit board is 100°C to 150°C for about 1 minute. As shown in FIG. 6, this has a problem in that it has an adverse effect on electronic components such as electrolytic capacitors, which have poor heat resistance and whose limit temperature is about 80° C., resulting in a decrease in their functionality.

In addition, as shown in Figure 7, the temperature profile of a typical adhesive curing device that uses an ultraviolet lamp in the preheating section and a far infrared heater in the thermosetting section shows that the temperature of the adhesive application surface is curve a. As shown, the temperature of electronic components such as electrolytic capacitors attached to the back of the printed circuit board with lead wires becomes like curve B, rising to 100 to 120 degrees Celsius for about 30 seconds, which is favorable as described above. isn't it.

[Purpose of invention]

The present invention was devised in view of these circumstances, and uses simple and rational means to solve the problems of the conventional technology.
By supplying outside air to the underside of the printed circuit board or releasing hot air from the underside of the printed circuit board to the outside of the aircraft, the temperature at the back of the printed circuit board can be lowered, preventing deterioration of electronic components with poor heat resistance, and ,
The present invention aims to provide a device that can reasonably prevent the reflowed lower electronic component from shifting or falling during reflow of double-sided patterns.

[Structure of the idea]

The structure of the present invention that solves the problems of the conventional technology is as follows:
A device for fixing electronic components to a printed circuit board carried by a conveyor such as a chain conveyor mounted inside the machine, the printed circuit board loading side of the machine along the carrier;
Further, a vent having a fan is provided on both sides, and the other end of a duct, one end of which is connected to the vent, is opened and exposed below the forward path of the conveying body.

〔Example〕

The details of the embodiments will be explained with reference to the drawings.

Fig. 1 is a perspective view showing the outline of the reflow soldering device, Fig. 2 is a longitudinal sectional front view of the same, Fig. 3 is a longitudinal sectional side view of the main parts, and Fig. 4 is a temperature profile diagram for curing adhesive. .

Reference numeral 1 denotes a machine body, and inside the machine body 1, a conveyor 3 such as a chain conveyor is installed which conveys a printed circuit board 2 from an upper side to a lower side at a predetermined speed. Further, an ultraviolet lamp 4 is disposed at the upper part of the upper side of the body 1, that is, at the upper part of the upper side of the forward path side of the transport body 3, and the ultraviolet lamp 4 is disposed at the lower side of this lamp. A plurality of sets of far-infrared heaters 5 are arranged so that the far-infrared heaters 5 are separated from each other, and a reflow zone consisting of a plurality of sets of far-infrared heaters 6 sandwiching the forward side of the carrier 3 is arranged on the downstream side of the far-infrared heaters 5. There is. In the figure, 7 is a cooling fan.

In such an apparatus, the present invention provides ventilation holes 8 at appropriate intervals on both sides of the machine body 1 along the conveyance body 3, and provides fans 9 in each of these holes. This vent 8 and the lower part of the forward path side of the carrier 3 are connected by a duct 10, and outside air is supplied to the lower part of the printed circuit board 2 by the fan 9, and the temperature of the back surface and the top surface of the printed circuit board 2 is increased. Either the temperature difference between the top and bottom surfaces of the printed circuit board 2 can be increased by sucking and removing the hot air from the bottom of the printed circuit board 2 to the outside of the machine using the fan 9. be.

In addition, the present invention includes a long blower structure having an axis perpendicular to the transport direction of the transport body 3 at the lower part of the printed circuit board loading side of the machine body 1, and a ventilation hole 12 provided on the bottom surface of the machine body 1. A facing fan 11 is provided, and outside air sucked by the fan 11 is supplied through a duct 13 toward the downstream side of the conveyance.

〔effect〕

As described above, according to the configuration of the present invention, the following effects can be obtained.

(a) As shown in Figure 4, for example, in the case of adhesive curing, the surface temperature of the printed circuit board is maintained appropriately as shown by curve a, and the electronic components (such as heat-resistant The temperature of electrolytic capacitors with poor performance is controlled to below 100°C as shown in the b curve, and electronic components do not deteriorate.

(b) When performing double-sided reflow soldering, one side with completed reflow soldering should be on the back side.
The reflow soldered parts will not be remelted by high temperatures and will not shift from the pattern or fall, unlike in the past, and temporary fixing with adhesive, which was an essential requirement in the prior art, can be omitted.

[Brief explanation of the drawing]

Fig. 1 is a partially omitted perspective view showing an example of the device of the present invention, Fig. 2 is a longitudinal sectional front view of the same, Fig. 3 is a longitudinal sectional side view of the main part, and Fig. 4 is a temperature profile for curing adhesive. Fig. 5 is a reflow temperature profile diagram of a conventional device, Fig. 6 is a cross-sectional view of a portion of a printed circuit board with electronic components attached to the back side, and Fig. 7 is an adhesive curing temperature profile diagram of a conventional device. This is an isle diagram. 1... Airframe, 2... Printed circuit board, 3... Carrier, 4... Ultraviolet lamp, 5... Far infrared heater, 6... Far infrared heater, 7... Cooling fan,
8...Vent, 9...Fan, 10...Duct,
11...fan, 12...vent, 13...duct.

Claims (1)

[Scope of Claim for Utility Model Registration] [Paragraph 1] (a) A device for fixing electronic components to a printed circuit board that is carried by a conveyor such as a chain conveyor mounted inside an aircraft; , (b) Provide a vent with a fan on the printed circuit board loading side of the machine along with the transport body and on both sides, and connect the other end of the duct with one end connected to the ventilation port to A device for fixing electronic components to a printed circuit board, characterized in that an opening is provided on the lower side of the outgoing path of the body. [Claim 2] The device for fixing electronic components to a printed circuit board according to claim 1, wherein the device is an adhesive curing device for temporarily fixing electronic components to a printed circuit board. [Section 3] The device for fixing electronic components to a printed circuit board according to claim 1, wherein the device is a reflow soldering device for fixing electronic components to the pattern of the printed circuit board with cream solder or the like.