JPS61142789A - Heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a heating device for melting solder for soldering electronic components on a printed circuit board.

BACKGROUND OF THE INVENTION In recent years, the process of mounting electronic components on both sides of a printed circuit board using an automatic mounting device and then heating and soldering them using a heating device has been automated. Incidentally, in the heating device for mounting on both sides of a board, it has recently been required to solder to a position of about 0.51 from the end surface of the board.

Problems to be Solved by the Invention However, in the past, conveyance devices used chain conveyors, and heat was absorbed by the chain conveyor from the contact surface with the board, which caused the temperature at both ends of the board to drop, and the temperature at both ends of the board to There is a problem in that the temperature distribution in the center is not uniform and the solder at the edges of the board does not melt, resulting in defective products. One way to counter this is to make the guide longer to prevent heat from escaping, but this makes the guide unstable and increases the diameter of the pulley, so when transferring the board to the reflow machine, it will be difficult to use the guide when it is being transported by the transport claws. It got caught in the guide, causing damage such as cracking.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a heating device that can uniformize the temperature distribution of a substrate.

Means for Solving the Problems In order to achieve the above objects, the present invention provides a conveyance member for conveying a printed circuit board on which electronic components are attached, and a width adjustment device capable of adjusting the width of the conveyance member with respect to the printed circuit board. and a heating device that heats the printed circuit board and the conveyance member from above and below, and the conveyance member is made of a material having low thermal conductivity at a surface in contact with the substrate.

In this case, since the conveying member is made of a material with low thermal conductivity at the contact surface with the substrate, it is possible to prevent the heat held by the substrate from being absorbed into the conveying member, and as a result, the substrate It is possible to make the temperature distribution uniform between the ends and the center.

Embodiment FIG. 1 shows a front cross-sectional view of the heating device @1, and each Ir
! A plurality of block heater-shaped upper heaters 2 and lower heaters 3 are provided to perform the Xw4 node.

Electronic components 5 are mounted on both sides of the printed circuit board 4. 6a and 6b are conveyance members made of glass III, Teflon-coated belts, etc., and guides 7.8 are provided on the left and right sides thereof. Conveying member 6a.

An end portion of the substrate 4 is placed on the upper surface of the substrate 6b.

The conveyance member 6a and the guide 8 are movable in the width direction, and a width adjustment device 9 is provided that can adjust the width according to the width of the substrate 4.
It consists of

FIG. 2 shows a temperature distribution graph of the substrate 4, and the horizontal axis is the temperature distribution graph of the substrate 4.
The position in the width direction and the vertical axis indicate the temperature.

The temperature distribution on the upper surface of the substrate 4 within the heating device 1 is curve 10.
The temperature distribution on the lower surface of the substrate 4 is also controlled in the same way.

FIG. 3 shows a side view of the belt conveyor 11 from the heating device 1 and the electronic component mounting device, in which the substrate 4 is fed by a conveying claw 12, a conveying member 6a driven by a pulley 13,
Transfer to the top surface of 6b. Since the conveying claw 12 is faster than the traveling speed of the conveying members 6a and 6b in the heating device M1, the substrate 4
is conveyed while being cleaned on the conveying members 5a and 5b, and then taken out from the heating device 1. The unloaded substrate 4 is transported to the next cooling process. The substrate 4 sent into the heating device 1 is heated by a plurality of upper heaters 2 and lower heaters 3.
Conveying member 6a guided by guides 7.8.

6b. Since the transfer members 6a and 6b have very low thermal conductivity, it is difficult for heat to escape from the contact surface with the heated substrate 4, and the temperature distribution on the surface of the substrate 4 shown in FIG. Therefore, the soldering is ensured on the entire surface, and the number of defective products can be reduced.

Effects of the Invention As described above, according to the present invention, the conveying member of the heating device is made of a material with low thermal conductivity, thereby reducing heat absorption by the conveying member at the edge of the substrate and reducing the temperature drop caused by the conveying member. Since it is possible to prevent this, it is possible to eliminate soldering mistakes.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a front sectional view of a heating device, Fig. 2 is a temperature distribution state diagram of a substrate, and Fig. 3 is a state in which a substrate is transferred from an external conveyor to a heating device. FIG.

Claims (1)

[Claims] 1. A conveyance member that conveys a printed circuit board on which electronic components are mounted, a width adjustment device that can adjust the width of the conveyance member with respect to the printed circuit board, and a heating device that heats the printed circuit board and the conveyance member from above and below. A heating device comprising: the conveying member made of a material having low thermal conductivity at a surface in contact with the substrate.