JPH0244184A - Electric heating furnace - Google Patents

Abstract

PURPOSE:To provide always a sufficient amount of hot air to get a superior heating characteristic by a method wherein a hot air blowing port is moved to a position corresponding to a substantial central position of a heated workpiece in cooperation with movements of one transport member and a partition wall. CONSTITUTION:In case that a base plate having a small width is to be processed, a movable wall 23 is positioned at a location indicated by a solid line and a hot air blowing port 27 is positioned at a substantial central position between a fixed wall 22 and the movable wall 23. In turn, in case of processing a base plate having a wide width, a lower rotary shaft 24 is rotated to cause the movable wall 23 to be moved in a rightward direction up to a position indicated by a dotted line. At this time, a rotation of the rotary shaft 24 is transmitted to an upper rotary shaft 29 through a chain member 32 to cause a ball screw 30 to be moved similarly in a rightward direction. Since the ball screw 30 is moved by a distance half of that of a ball screw 26, a position of the hot air blowing port 27 is placed at a substantial central part between the fixed wall 22 and the movable wall 23. Accordingly, it becomes possible to get a superior temperature characteristic when the hot air is blown whatever width of the base plate 7 mat be applied.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electric heating furnace used for soldering electronic circuit boards, electronic circuit components, and the like.

(Prior Art) As a method for surface mounting various element parts on a circuit board by soldering, a method using an electric heating furnace such as a flow type (reflow soldering) is known. This soldering is done by placing multiple radiant heating zones side by side or by conveying means such as chains or belt conveyors in a flow furnace.
In this method, an object to be heated, such as a circuit board, is passed through the furnace, and the joints are soldered using radiant heat from the heating zone as the object passes through the furnace.

FIG. 2 shows an example of the configuration of a conventional adhesive flow type. Inside the reflow oven 1, four pairs of radiant heating zones 2 to 5 made of, for example, infrared heaters are arranged above and below, and these upper and lower heating zones 2 to 5, objects to be heated, that is, substrates 7 on which various electronic components (not shown) are mounted, are placed on a conveying means 6 at predetermined intervals and are conveyed from the inlet 1a to the outlet 1b of the reflow oven 1. The joint between the electronic component and the board 7 is coated with solder. In such a flow type 1, for example, a hot air outlet 8 is formed between heating zones 4 and 5, and hot air is blown onto the substrate 7 from the hot air outlet 8, causing convection of hot air on the surface of the substrate 7. There are some devices that prevent the generation of temperature differences due to differences in heat capacity on the substrate 7.

In addition, since the substrate 7 has various sizes and shapes,
As shown in FIG. 3, the conveying means used is one whose width can be changed according to the width of the substrate 7.

That is, the conveyance means 6 is wound around a drive roller and a feed roller (not shown), and has a chain member 10.1 parallel to each other.
1 and 1 are provided with locking claws 12 and 13, respectively, and these locking claws 12 and 13 support both edges of the substrate 7. One of the chain members, for example the chain member 11, is configured to be movable in the oven width direction according to the width of the substrate 7.

(Problem to be Solved by the Invention) By the way, as shown in FIG. 3, the position of the hot air outlet 8 is usually fixed at approximately the center in the width direction inside the furnace, and the wind speed is greatest at the center of the furnace. It becomes smaller at the ends. Therefore,
In the case of a large substrate as shown by the dashed line in Fig. 3, a good temperature profile can be obtained, but in the case of a small substrate as shown in the solid line, the hot air There is a problem in that the amount of air blown is small and sufficient heating characteristics cannot be obtained.

The present invention has been made in view of such conventional problems, and it is an object of the present invention to provide an electric heating furnace that can always blow sufficient hot air and obtain excellent heating characteristics even if the width of the substrate changes. purpose.

(Means for Solving the Problems) In order to achieve the above object, according to the present invention, a plurality of heating zones are arranged in parallel, and the inside of the furnace, which is provided with a hot air outlet in at least one place, is arranged parallel to each other. and an electric heating furnace in which the object to be heated is conveyed in the longitudinal direction of the furnace by two conveying members whose distance can be changed by moving one of them in the width direction of the furnace according to the width of the object to be heated, A partition wall that moves in the oven width direction in conjunction with the one conveyance member is provided near the one conveyance member, and the hot air outlet is connected to the object to be heated in conjunction with the movement of the one conveyance member and the partition wall. The structure is such that a moving means is provided to move it to a position corresponding to the center.

(Function) One movable transport member is moved according to the width of the substrate. At this time, the partition wall also moves in conjunction with the conveyance member, and as a result, the width of the furnace becomes the width corresponding to the substrate. Furthermore,
In conjunction with the movement of the conveying member, the hot air outlet also moves to maintain a position where it can always blow air to approximately the center of the substrate.

(Example) Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings. Note that the same components as in FIGS. 2 and 3 are designated by the same reference numerals.

FIG. 1 shows the configuration of a reflow oven which is an embodiment of the electric heating furnace of the present invention.
A fixed wall 22 is disposed adjacent to a, and a movable wall 23 is disposed between the - side wall 21a and the other side wall 21b. A rail 22a extending in the longitudinal direction of the reflow oven 21 is fixed on the inner wall surface of the fixed wall 22, and a fixed-side conveying member is connected to a driving roller and a feeding roller (not shown) attached to the rail 22a. That is, the chain member IO is wound. On the wall surface of the movable wall 23 facing the fixed wall 22,
A rail 23a extending in the longitudinal direction inside the furnace is fixed in correspondence with the above-mentioned rail 22a, and a movable conveying member, that is, a chain member 11 is wound around a driving roller and a feeding roller (not shown) attached to the rail 23a. has been done.

Below the rails 22a and 23a, there is a fixed wall 22 and a movable wall 2.
3 and the other side wall 21b of the reflow oven 21, a rotating shaft 24 is disposed, and a sprocket 25 is supported on a portion of the rotating shaft 24 protruding from the side wall 21b so as to be rotatable integrally with the rotating shaft 24. ing. A ball screw 26 is attached to the intersection of the rotating shaft 24 and the movable wall 23,
As the rotating shaft 24 rotates, this ball screw 26 moves, and the rail 23a1 moves together with the ball screw 26, and the movable chain member 11
And the movable wall 23 is integrally moved left and right.

A hot air outlet 27 is formed in the upper part of the reflow oven 21, and a heater 28 is disposed in the middle of the hot air outlet 27. The minus side end surface of the heater 28 is fixed to a ball screw 30 that is inserted through a rotating shaft 29 that is also horizontally supported in the upper part of the reflow oven 21, and is configured to move integrally with the ball screw 30. A sprocket 31 is supported at the right end of the shaft 29 in the drawing so as to be rotatable integrally with the rotation shaft 29 . For example, a chain member 32 is wound between the lower sprocket 25 and the upper sprocket 31, and the rotation of the rotating shaft 24 is transmitted to the rotating shaft 29 by the chain member 32. Furthermore, the opening periphery of the hot air outlet 27, one side wall 21a of the furnace 21, and the movable wall 2
A flexible sheet member 32, such as a bellows-shaped member, is disposed between the upper ends of the reflow oven 21 to close the ceiling of the reflow oven 21 and reduce loss of hot air blown into the oven.

In the glue flow furnace 21 having such a configuration, the sprocket 3
If the number of teeth of the sprocket 25 is set to twice the number of teeth of the sprocket 25, the hot air outlet 27 will move by 1/2 of the moving distance of the movable chain member 23, that is, the movable wall 24.
Therefore, the hot air outlet 27 is always connected to both chain members l011.
1, that is, approximately the center of the object to be heated.

The action will be explained below.

When processing a substrate with a small width, the movable wall 23 is located at the position shown by the solid line in FIG.
A hot air outlet 27 is located approximately in the center of the area. On the other hand (when processing a wide substrate, rotate the lower rotating shaft 24 and move the movable wall 23 to the right in the figure from the above-mentioned position to the position indicated by the dashed line in the figure. 24
The rotation is transmitted to the upper rotating shaft 29 via the chain member 32, and similarly moves the ball screw 30 to the right.

As mentioned above, the ball screw 30 is connected to one of the ball screws 26.
Since the hot air outlet 27 moves by a distance of /2, the position of the hot air outlet 27 is always approximately at the center between the fixed wall 22 and the movable wall 23. Therefore, regardless of the width of the substrate 7, it is sometimes possible to obtain good temperature characteristics by blowing hot air.

The substrate 7 supported by the locking claws 12.13 of the chain member 10.11 is transported in the longitudinal direction inside the furnace by the movement of the chain member 10.11, and the hot air blown from the hot air outlet 27 causes the electric current on the substrate 7 to be transferred. The 4-degree child component is heated uniformly without temperature differences due to differences in heat capacity, and each joint is soldered.

(Effects of the Invention) As explained above, according to the present invention, a plurality of heating zones are arranged in parallel, and the inside of the furnace, which is provided with a hot air outlet in at least one place, is arranged parallel to each other and across the width of the object to be heated. In an electric heating furnace in which the object to be heated is transported in the longitudinal direction of the furnace by two transport members whose distance can be changed by moving one of them in the width direction of the furnace, the area near the one transport member A partition wall that moves in the oven width direction in conjunction with this is provided, and the hot air outlet is moved to a position corresponding to approximately the center of the object to be heated in conjunction with the movement of one of the conveying members and the partition wall. Because the moving means is installed, even if the width of the object to be processed, such as a substrate, changes, hot air can be constantly blown onto the center of the substrate accordingly, so hot air blowing has extremely good substrate temperature characteristics during processing. becomes.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional configuration diagram of the vicinity of the hot air outlet of a reflow oven showing an embodiment of the electric heating furnace of the present invention, Fig. 2 is a configuration diagram of a conventional reflow oven, and Fig. 3 is an arrow line in Fig. 2. I[[-III
FIG. 2-5...Radiation heating zone, 7...Substrate, 10...
- Fixed side chain member, 11... Movable side chain member, 12.13... Locking claw, 21... Reflow oven, 2
2...Fixed wall, 23...Movable wall, 24.29...
Rotating shaft, 25.31... Sprocket, 26.30.
...Ball screw, 32...Chain member, 27...
Hot air vent.

Claims (1)

[Claims] A plurality of heating zones are installed in parallel, and the interior of the furnace is equipped with a hot air outlet in at least one place, and the distance between the two is reduced by moving one of the heating zones parallel to each other in the width direction of the furnace depending on the width of the object to be heated. In an electric heating furnace in which the object to be heated is transported in the longitudinal direction of the furnace by two transport members that can change the temperature, a partition wall that moves in the width direction of the furnace in conjunction with the one transport member is provided in the vicinity of the one transport member. An electric heating furnace, further comprising a moving means for moving the hot air outlet to a position corresponding to approximately the center of the object to be heated in conjunction with the movement of the one conveying member and the partition wall.