JP3084942B2 - Reflow equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflow apparatus, and more particularly, to a substrate which is deformed by the heat of a heater while the substrate is being transported in a heating chamber, and which is warped or dropped from a conveyor. The present invention relates to a reflow device which can prevent the reflow.

[0002]

2. Description of the Related Art After a chip is mounted on a substrate by a chip mounter or the like, the substrate is sent to a heating chamber of a reflow device.
After the cream solder is heated and melted, and then cooled and solidified, the chip electrode is soldered to the substrate electrode. Next, a conventional reflow apparatus will be described with reference to FIG.

FIG. 5 is a sectional view of a reflow apparatus. The substrate S on which the chip P is mounted is inserted into the heating chamber 1 through an inlet 2.
A conveyer 4 is provided for transporting the conveyer 4 to the outlet 3, and a heater 5 and a fan 6 are provided above the conveyer 4. 9 is a driving motor for the conveyor 4 and 29 is a driving motor for the fan 6. The interior of the heating chamber 1 is divided into a preheating zone T1, a soaking zone T2, and a reflow zone T3 by two partition walls 30, and a cooling chamber 10 is provided at the rear of the heating chamber 1. Conveyor 4 is shown in FIG.
As shown in the figure, the chain 7 is composed of a pair of right and left chains 7, and the chains 7 are provided with attachments 8 at regular intervals, and both end portions of the substrate S are placed on the attachments 8.

The operation of this reflow apparatus will be described. As shown in FIG. 5, a substrate S on which chips P are mounted is conveyed rightward by a conveyor 4. Meanwhile, the substrate S sequentially passes through the preheating zone T1, the soaking zone T2, and the reflow zone T3. In the zones T1, T2, and T3, the heat of the heater 5 is blown onto the upper surface of the substrate S by the fan 6 so that the substrate S
Is heated, and the solder 28 is melted. Next, the substrate S is cooled by the fan 6 in the cooling chamber 10, the solder 28 is solidified, and the chip P is soldered to the electrodes of the substrate S.

[0005]

By the way, since the temperature of the substrate S rises to about 230 ° C. due to the heat of the heater 5, the substrate S is thermally deformed during the transfer, and usually, as shown by the chain line in FIG. There is a problem that the sheet is warped downward due to its own weight and is likely to fall from the conveyer 4 due to the hot air of the fan 6. Further, there is a problem that the substrate S is permanently deformed due to the thermal deformation, and is likely to be a defective substrate.

As means for preventing the substrate S from dropping from the conveyor 4, it is conceivable to increase the length L of the attachment 8 to increase the support width of the substrate S. However, the substrate S sent to the reflow device includes not only a single-sided board having a chip P mounted on one side but also a double-sided board having a chip P mounted on an upper surface and a lower surface. In the case of a substrate, if the attachment 8 is lengthened, the attachment 8 hits the chip P on the lower surface of the substrate S, so that the length L of the attachment 8 is also limited.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a reflow apparatus capable of preventing a substrate from being deformed and warped or dropped from a conveyor due to heat of a heater while the substrate is transported in a heating chamber.

[0008]

According to the present invention, a conveyor provided in a heating chamber is provided with a pair of left and right guide rails for guiding both side edges of a substrate, and both side edges of the substrate are pressed against the guide rails from above. It comprises a pressing means and a transport means for transporting the substrate by sliding it on the guide rail.

[0009]

According to the above construction, both ends of the substrate are pressed by the guide rails by the pressing means and are conveyed in the heating chamber, so that the substrate is deformed by the heat of the heater during conveyance and warps from the conveyor. It can be prevented from falling.

[0010]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of the reflow device. Inside the heating chamber 1, a conveyor 11 for transporting a substrate S on which chips P are mounted from the inlet 2 to the outlet 3 is provided, and above the conveyor 11, a heater 5 and a fan 6 are provided. . Reference numeral 29 denotes a motor for driving the fan 6. The interior of the heating chamber 1 is divided into a preheating zone T1, a soaking zone T2, and a reflow zone T3 by two partition walls 30, and a cooling chamber 10 is provided at the rear of the heating chamber 1. A front conveyor 12A is provided on the carry-in side of the heating chamber 1, and a rear conveyor 12B is provided on the carry-out side of the heating chamber 1. Next, the structure of the conveyor 11 will be described in detail with reference to FIGS.

In FIG. 2, the conveyor 11 is mainly composed of a pair of left and right fixed guide rails 13 and movable guide rails 14 which serve as a transport path for the substrate S. Fixed guide rail 1
3 and the movable guide rail 14 have an L-shaped cross section, and a heat insulating material 31 serving as a sliding surface of the substrate S is provided on the lower upper surface. The heat insulating material 31 is made of a heat-resistant synthetic resin having a small friction coefficient so that the substrate S can slide smoothly. The reason why the heat insulating material 31 is provided on the guide rails 13 and 14 is that the guide rails 13 and 14 are formed of a metal having a small specific heat such as stainless steel or aluminum in order to secure their strength. The rails 13 and 14 absorb the heat of the heater 5 and become extremely hot, and the heat of the guide rails 13 and 14 is excessively increased by the substrate S.
In order to prevent excessive heat from being locally transmitted to the both end portions.

On the upper surfaces of the fixed guide rails 13 and the movable guide rails 14, leaf springs 15 as pressing means for pressing both end portions of the substrate S against the guide rails 13 and 14 from above.
Is installed. The leaf spring 15 presses the both ends of the substrate S with guide rails 13 and
14, and has a shape in which the lower end is curved downward in the unloading direction of the substrate S. The leaf spring 15 is fixed to the position where the guide rails 13 and 14 face each other by screws 16 at regular intervals.

In FIG. 1 and FIG. 2, a substrate S is provided between a fixed guide rail 13 and a movable guide rail 14.
A conveyor belt 17 is provided as conveying means for conveying the sheet along the guide rails 13 and 14. The belt conveyor 17 includes a driving timing pulley 18 provided outside the inlet 2 of the heating chamber 1 and an outlet 3 of the heating chamber 1.
The timing belt 20 is tuned to a driven timing pulley 19 provided outside. The timing belt 20 is a belt made of a heat-resistant material.
A feed pin 21 that pushes the sheet is protruded. Motor 22
When the timing belt 20 is rotated by the drive of, the feed pin 21 comes into contact with the rear portion of the substrate S placed on the guide rails 13 and 14, and pushes the substrate S rightward. next,
The means for adjusting the distance between the guide rails 13 and 14 will be described with reference to FIG.

FIG. 3 is a sectional view of the heating chamber 1. The movable guide rail 14 is attached to the upper end of an inverted L-shaped bracket 32, and a slider 33 is provided below the bracket 32. The slider 33 is connected to the heating chamber 1
Is fitted on a Y-direction rail 34 provided on the lower surface of
A ball screw 36 is bridged through bearings 35 provided on both side surfaces of the heating chamber 1, and a nut 37 mounted on the bracket 32 is screwed to the ball screw 36.
When the motor 38 is driven to rotate the ball screw 36,
The bracket 32 moves along the Y-direction rail 34 and the movable guide rail 14 slides in the horizontal direction, and the distance between the fixed guide rail 13 and the movable guide rail 14 is adjusted according to the horizontal width of the substrate S.

Next, the operation of the present reflow apparatus will be described.
In FIG. 1, the substrate S on which the chips P are mounted is carried into the conveyor 11 in the heating chamber 1 from the front conveyor 12A, and the substrate S is transported rightward in the heating chamber 1 by the feed pins 21. Meanwhile, the substrate S has a preheating zone T1 and a soaking zone T.
2. After passing through the reflow zone T3, hot air is blown by the fan 6 in these zones T1, T2 and T3.
The substrate S is heated by being sprayed on the upper surface of the substrate, and the solder 28 is melted.

At this time, the substrate S tends to warp downward due to its own weight due to the heat. However, since both end portions of the substrate S are pressed from above by the leaf springs 15 onto the upper surface of the heat insulating material 31, the deformation of the substrate S is suppressed. Will be blocked. That is, with the thermal deformation of the substrate S, both end portions of the substrate S tend to float above the upper surface of the heat insulating material 31, but this lifting is restricted by the pressing force of the leaf spring 15 and the deformation of the substrate S is prevented, Therefore, warpage of the substrate S during transfer can be prevented. Further, by pressing both end portions of the substrate S against the heat insulating material 31 by the leaf springs 15, it is possible to prevent the substrate S from falling by the hot air of the fan 6 from the conveyor 4. Next, the substrate S is cooled by the fan 6 in the cooling chamber 10, the solder 28 is solidified, and the chip P is soldered to the electrodes of the substrate S.

In the case where the width of the substrate S changes with the change of the type of the substrate S, the ball screw 36 is rotated by driving the motor 38 in FIG. 3 and the movable guide rail 14 is moved in the horizontal direction and fixed. The distance between the guide rail 13 and the movable guide rail 14 is adjusted.

The present invention is not limited to the above embodiment. For example, as shown in FIG.
A leaf spring 42 extending laterally by a screw 41 at the upper end of the plate 4
, And an attachment 43 is fixed to the tip of the leaf spring 42, and a pressing roller 44 is axially mounted on the attachment 43, and the pressing roller 44 is pressed against both side ends of the substrate S by the spring force of the leaf spring 42. You may make it. In FIG. 3, when the movable guide rail 14 is slid to adjust the distance between the guide rails 13 and 14,
The timing belt 20 may be slid by a half of the stroke of the movable guide rail 14 in conjunction with the sliding of the movable guide rail 14. Center can be pushed. As the sliding means of the timing belt 20, the same sliding means as that of the movable guide rail 14 can be applied. Furthermore, although the above embodiment has been described by taking an air reflow apparatus as an example, in order to prevent oxidation of a metal portion such as a circuit pattern of a substrate, an inert gas atmosphere is supplied while supplying nitrogen gas, which is an inert gas, to the heating chamber. It can also be applied to a Chisso reflow device that heats the solder inside.

[0019]

According to the present invention, there are provided a conveyor for transporting a substrate in a heating chamber, a pair of left and right guide rails for guiding both side ends of the substrate, and pressing means for pressing both side ends of the substrate from above to the guide rails. And the transport means for transporting the substrate by sliding it on the guide rail, so that while the substrate is being transported in the heating chamber, the substrate is thermally deformed by the heat of the heater and becomes a defective substrate, The substrate can be prevented from warping and dropping from the conveyor.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a reflow apparatus according to one embodiment of the present invention.

FIG. 2 is a perspective view of a main part in a heating chamber of the reflow device according to one embodiment of the present invention.

FIG. 3 is a sectional view of a heating chamber of the reflow device according to one embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a heating chamber of a reflow device according to another embodiment of the present invention.

FIG. 5 is a sectional view of a reflow device according to a conventional means.

FIG. 6 is a sectional view of a conveyor of a reflow device according to a conventional means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating chamber 5 Heater 6 Fan 11 Conveyor 13, 14 Guide rail 15, 42 Pressing means (leaf spring) 17 Transport means 43 Pressing means (attachment) 44 Pressing means (pressing roller) S Substrate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-65891 (JP, A) JP-A-59-155796 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05K 3/34 B23K 1/008

Claims (2)

(57) [Claims] 1. A reflow apparatus comprising a heating chamber, a heater and a fan provided in the heating chamber, and a conveyor provided in the heating chamber and transporting a substrate from an inlet to an outlet of the heating chamber. Conveyor, a pair of left and right guide rails for guiding both side edges of the board, and pressing means for pressing both side edges of the board against this guide rail from above,
And a transport means for transporting the substrate by sliding the substrate on the guide rail. 2. The reflow apparatus according to claim 1, wherein said pressing means is a spring material and is mounted on said guide rail.