Warp prevention jig and solder reflow apparatus

Abstract

To provide a warp prevention jig for a substrate which can be miniaturized and easily support reflow processing of double-sided and single-sided mounting substrates.SOLUTION: A warp prevention jig which is conveyed while being supported by a pair of conveyor chains in a solder reflow apparatus, comprises a pair of mounting bodies mounted on the respective conveyor chains, and a connecting body connecting the mounting bodies. Each mounting body includes: a mounting part attached to the conveyor chain; a support part having a first support surface for supporting a substrate above the mounting part; and an extension part located one step lower than the support part when viewed from the first support surface and extending along the first support surface. The connecting body includes: a clamping part clamping side ends of the extension parts of the respective mounting bodies; and a plate-shaped portion fastened by abutting fasteners to fix and connect the mounting bodies together, and having a second support surface facing opposite to the first support surface to support the substrate. The plate-shaped portion is provided with through-holes to which support columns for supporting the substrate together with the first support surface can be attached.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a warp prevention jig and a solder reflow device that prevent warp, and more particularly to a warp prevention jig that prevents warp of a printed wiring board (hereinafter also simply referred to as a board) on which electronic components are placed to manufacture a printed circuit board during reflow processing. [Background technology]

[0002] Generally, when solder is printed on a printed wiring board, electronic components are mounted on it, and the board is heated in a reflow machine to melt the solder and assemble the components, a warp prevention jig is required to suppress "board warping" that occurs due to the balance between the weight of the board and components and the rigidity of the board.

[0003] When mounting electronic components on a board, a jig called a metal mask is set on the surface of the board, solder is printed, the components are mounted, and the board is then poured into a high-temperature reflow oven to melt the solder. When reflow assembly is performed on both sides of the board (first mounting side and second mounting side), the same process must be repeated twice for each side. The reflow oven heats the board as it is transported, and typically the two opposing sides of the product board are placed on two transport rails as it is fed.

[0004] Before heat is applied, the board is flat, but when it is heated in a reflow furnace during assembly on one side (first mounting surface), it becomes prone to warping due to the weight of the board and components, the effects of unevenness in the copper foil that is provided to ensure the performance and characteristics of the product board, the effects of via hole density, the effects of differences in the linear expansion coefficients of the board materials (glass epoxy, copper foil), and the effects of the board thickness.

[0005] In particular, when multiple product boards are mounted on a board (multi-sided mounting), the board rigidity is reduced by the external processing such as perforation and V-groove processing that are provided to make it easier to separate the board after components are mounted, making it more susceptible to warping.

[0006] Furthermore, when assembling the opposite side (second mounting side), the warpage of the board that occurred during assembly of the first mounting side affects the adhesion of the metal mask during solder printing before component mounting, making it more likely that the solder printing will be misaligned between the position of the component pad on the board and the opening position in the metal mask. This makes lightweight components more susceptible to mounting defects. Board warpage can take various forms, such as upward warping, downward warping, or twisting, but the most common type is downward warping due to the weight of the components and board.

[0007] Prior art solutions include a honeycomb plate structure in which pins are pressed against the substrate from below at the warpage position as described in Patent Document 1, a structure in which a jig is used to lift the substrate to prevent downward warping due to its own weight as described in Patent Document 2, and even the application of a dedicated jig structure according to the substrate size as described in Patent Document 3. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-040875 [Patent Document 2] Japanese Patent Application Publication No. 6-188553 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-124337 Summary of the Invention [Problem to be solved by the invention]

[0009] However, with conventional technologies, all of the jig structures were large, so it was necessary to manually attach and detach the board to the jig before and after putting it into the reflow furnace, which posed a problem as the structure had to be such that it could be used for automatic transport while the jig was still attached.

[0010] The present invention has been made in consideration of the above points, and one example of an object of the present invention is to provide a warp prevention jig and a solder reflow device that can be made compact and can easily handle reflow processing of double-sided and single-sided mounted boards. [Means for solving the problem]

[0011] The warp prevention jig according to the present invention is a warp prevention jig that prevents warping of a substrate that is transported by a pair of parallel-running conveying chains in a solder reflow apparatus while both ends of the substrate are supported by each of the pair of conveying chains, and includes a pair of mounting bodies that are respectively attached to the pair of conveying chains, and a connecting body that connects the pair of mounting bodies, each of the pair of mounting bodies having an attachment portion that is attached to the conveying chain, a support portion having a first support surface that supports the substrate above the attachment portion, and an extension portion that is one step lower than the support portion and extends in a direction along the first support surface when viewed from the first support surface, the connecting body having a clamping portion that clamps the side ends of the extension portion of each of the pair of mounting bodies, and a flat portion that is fastened by an abutting fastener to fix and connect the pair of mounting bodies to each other, and has a second support surface that faces opposite the first support surface and supports the substrate, and the flat portion has a through hole that can be used to attach a support post that supports the substrate together with the first support surface.

[0012] A solder reflow apparatus according to the present invention is a solder reflow apparatus that heats a substrate on which electronic components have been temporarily fixed by reflow solder to melt the reflow solder, and includes a pair of conveyor chains that run parallel to each other to convey the substrates within the solder reflow apparatus, and a warp prevention jig that is attached to the conveyor chains and prevents warping of the substrates, the warp prevention jig having a pair of mounting bodies that are respectively attached to the pair of conveyor chains and a connecting body that connects the pair of mounting bodies, and each of the pair of mounting bodies has an attachment portion that is attached to the conveyor chains and a base portion above the attachment portion. The connecting body has a clamping portion that clamps the side ends of the extension portions of each of the pair of mounting bodies, and a flat portion that is fastened by an abutting fastener to fix and connect the pair of mounting bodies to each other, and has a second support surface that faces opposite the first support surface and supports the substrate, and the flat portion has a through hole that can be used to attach a support column that supports the substrate together with the first support surface. [Effects of the Invention]

[0013] According to the present invention, it is possible to miniaturize the warp prevention jig, and as a result of this miniaturization, it can be easily attached between the transport rails of a general-purpose reflow furnace, making it easy to handle the reflow processing of double-sided and single-sided mounted boards.In addition, since the board can be easily attached and detached from the jig, it is compatible with automatic transport, and it also has the effect of making it possible to reduce the cost of board processing. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic perspective view showing the appearance of a solder reflow apparatus having a pair of conveyor chains for conveying a substrate according to a first embodiment of the present invention. [Figure 2] 1 is a schematic perspective view showing the appearance of a solder reflow apparatus having a pair of conveyor chains for conveying a substrate according to a first embodiment. [Figure 3]1 is a schematic perspective view showing a part of a pair of conveyor chains 12 on which one warp prevention jig of the first embodiment is installed, and a substrate. FIG. [Figure 4] FIG. 4 is a schematic exploded perspective view of a right-side mounting body of the warp prevention jig shown in FIG. 3. [Figure 5] 5A is a partial cross-sectional view in the left-right direction of a portion of the mounting body and connecting body on the right side shown in FIG. 3 for explaining the relationship between the substrate, the conveying chain, and the warp prevention jig positions in the first embodiment, and FIG. 5B is a right side view of the mounting portion of the mounting body. [Figure 6] 3A to 3C are schematic cross-sectional views illustrating the first and second reflow soldering steps using the warpage prevention jig of the first embodiment. [Figure 7] FIG. 1 is a schematic exploded perspective view of a warp prevention jig according to a first embodiment. [Figure 8] 1 is a schematic perspective view showing a part of a pair of conveyor chains 12 on which one warp prevention jig of the first embodiment is installed, and a substrate. FIG. [Figure 9] FIG. 2 is a schematic exploded perspective view of a right-side mounting body of the warp prevention jig of the first embodiment. [Figure 10] FIG. 10 is a schematic exploded perspective view of a connecting body in a warp prevention jig according to a second embodiment. [Figure 11] FIG. 10 is a schematic exploded perspective view of a mounting body in a warp prevention jig according to a second embodiment. [Figure 12] FIG. 10 is a schematic exploded perspective view of a warp prevention jig according to a second embodiment. [Figure 13] FIG. 10 is a schematic exploded perspective view of a mounting body in a warp prevention jig according to a third embodiment. [Figure 14] FIG. 10 is a schematic exploded perspective view of a warp prevention jig according to a third embodiment. [Figure 15] FIG. 11 is a schematic exploded perspective view of a warp prevention jig according to a modified example of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, a warp prevention jig according to an embodiment of the present invention will be described with reference to the drawings. In the embodiments, components having substantially the same functions and configurations are designated by the same reference numerals, and redundant description will be omitted.

[0016] (First Example) 1 and 2 are schematic perspective views showing the appearance of a solder reflow device 13 having a pair of conveyor chains 12 that convey a substrate 9 of this embodiment in a reflow facility 11. For ease of explanation, the directions of the orthogonal XYZ coordinate axes shown in the figures are defined as the XYZ directions, the direction from the front passage opening 14a toward the rear passage opening 14b on the front side of the solder reflow device 13 is defined as the Z direction (i.e., front and rear), and the left and right directions (X direction) and the up and down directions (Y direction) as viewed from the front passage opening 14a are defined. Furthermore, the dimensional proportions of the components shown in the figures are approximate and are not intended to limit the present invention.

[0017] (solder reflow equipment) The solder reflow device 13 is a heating furnace having a substantially sealed internal space within an outer casing 14, with a heater (not shown) disposed above it. Long, horizontally elongated front and rear passage openings 14a, 14b are formed in the front and rear walls of the outer casing 14. A pair of parallel conveyor chains 12 on the left and right are passed through the front and rear passage openings 14a, 14b in the front-rear direction. Each of the pair of conveyor chains 12 may be a so-called roller chain.

[0018] 1 and 2 show two warp prevention jigs 18 mounted parallel to the left and right on a pair of conveyor chains 12, and a single board 9 placed on the warp prevention jigs 18. The board 9 is placed with the surface on which electronic components (not shown) to be soldered are temporarily fixed facing upward. In the solder reflow device 13, the board 9 supported by the warp prevention jigs 18 is placed above the pair of conveyor chains 12 and conveyed into the solder reflow device 13.

[0019] Therefore, the board 9 placed on the warp prevention jig 18 on the conveyor chain 12 on the front passage opening 14a side is conveyed through the inside of the solder reflow device 13 as the conveyor chain 12 runs, and is heated together with the electronic components as it passes through the solder reflow device 13, thereby melting the reflow solder. The reflowed board 9 is discharged from the rear passage opening 14b.

[0020] Figure 3 is a schematic perspective view showing a portion of a pair of conveyor chains 12 on which one warp prevention jig 18 of this embodiment is installed to support the substrate 9, and the substrate 9 on both sides of which electronic components 10a are mounted on one first mounting surface 9a and electronic components 10b are mounted on the other second mounting surface 9b.

[0021] (Substrate 9 & conveyor chain 12) The insulating substrate that forms the base of the substrate 9 is formed into a roughly rectangular shape using a known insulating material, for example, primarily composed of glass epoxy resin, and a predetermined wiring pattern (not shown) is formed on both sides of the insulating substrate, a first mounting surface 9a and a second mounting surface 9b, and electronic components 10a and 10b are mounted on each surface to form a predetermined circuit.

[0022] The electronic components 10a and 10b are mounted on the substrate 9 by temporarily fixing them with reflow solder to predetermined connection lands (not shown) of the wiring pattern of the substrate 9, which are the connection points of the electronic components, in a pre-processing step of the reflow soldering process performed by this solder reflow device 13.

[0023] After the electronic components 10a have been temporarily fixed to the first mounting surface 9a of the substrate 9, the electronic components 10a are soldered through a reflow soldering process, and then another electronic component 10b is temporarily fixed to the second mounting surface 9b on the other side, and the reflow soldering process is once again performed to subject the electronic component 10b to solder reflow processing.

[0024] The pair of conveyor chains 12 are stretched between a pair of driving sprocket wheels (not shown), extending horizontally and parallel to each other and running side by side in the front-rear direction.

[0025] Each conveyor chain 12 is made up of multiple connected combinations of outer roller link plates 15, inner roller link plates 16, and connecting pins 17 that rotatably connect these. Support pins 17a are provided at a predetermined pitch on each of the opposing inner roller link plates 16 of each conveyor chain 12, extending horizontally inward from the connecting pins 17. The support pins 17a are formed to protrude long enough to allow a warp prevention jig 18 to be attached or for the left and right edge portions of the substrate 9 to be placed on them.

[0026] (Warp prevention jig 18) The warp prevention jig 18 is a device that prevents warp of the substrate 9 that is transported by the pair of transport chains 12 while both ends are supported by each of the pair of transport chains 12 in the solder reflow device 13. The warp prevention jig 18 is a device that can be used for reflow processing of both double-sided and single-sided mounted substrates.

[0027] 3 shows a warp prevention jig 18 for use in the reflow treatment of a double-sided mounted board. Essentially, the warp prevention jig 18 has a pair of mounting bodies 20 that are respectively attached to a pair of conveyor chains 12, and a connecting body 19 that connects the pair of mounting bodies 20. However, in the case of the reflow treatment of a double-sided mounted board, the warp prevention jig 18 also has a support pillar 30 that is attached to the connecting body 19 and supports the first mounting surface 9a of the board 9.

[0028] (wearing body 20) Each of the pair of mounting bodies 20 having the same shape is a bent plate-like member integrally formed with an attachment portion 21 that is attached to the conveying chain 12, a support portion 22 having a first support surface above the attachment portion 21 that supports the first mounting surface 9a of the substrate 9, a side wall 23 that protrudes downward from the inner edge of the support portion 22, and an extension portion 24 that is one step below the support portion 22 when viewed from the first support surface and extends from the inner lower edge of the side wall 23 in a direction along the first support surface.

[0029] 4, each mounting portion 21 of the mounting body 20 has a relatively large, for example rectangular, opening 21a formed therein so as to be detachably fitted onto two adjacent support pins 17a of the conveyor chain 12. Each mounting portion 21 of the mounting body 20 has a first support surface and an extension portion 24 formed in a stepped manner that are parallel to each other. The opening 21a has a height that is wider than the difference between the steps.

[0030] The mounting portion 21 of the mounting body 20 extends vertically so as to be close to or in contact with the inner roller link plate 16, and is bent horizontally at its upper edge to continue to the support portion 22 having a first support surface that supports the base plate 9. The left-right width of the support portion 22 of the mounting body 20 up to the side wall 23 is formed to be longer than the axial (left-right) length of the support pin 17a of the conveyor chain 12 fitted in the opening 21a of the mounting portion 21, and is set so that the side wall 23 does not interfere with (abut against) the support pin 17a.

[0031] As shown in Fig. 4, the extension 24 extending from the lower end of the side wall 23 of the mounting body 20 has a parallel plate shape with side edges 24a at both its front and rear edges parallel to the support part 22 having a horizontal first support surface. Fig. 4 is a schematic exploded perspective view of the right mounting body 20 shown in Fig. 3.

[0032] (Concatenated body 19) 3, connecting body 19, which serves as a base, has a flat portion 19a that includes clamping portions 19c that clamp front and rear side ends 24a of each extension portion 24 of the pair of mounting bodies 20, and a second support surface that faces the opposite side from the first support surface and supports substrate 9. Connecting body 19 is fastened to each extension portion 24 of the pair of mounting bodies 20 with abutting fasteners (connecting screws SCW such as set screws and female screw holes 19b), thereby fixing and connecting the pair of mounting bodies 20 to each other. The screws SCW are threaded through the female screw holes 19b, and the tip of the screws abuts against and presses against the extension portions 24 of the mounting bodies 20, thereby fixing connecting body 19 and the pair of mounting bodies 20 together.

[0033] The front and rear edges of the flat portion 19a of the connecting body 19 are provided with clamping portions 19c having a U-shaped cross section in the front-rear direction that clamp the front and rear edges of the extension portion 24 of the attachment body 20. The width of the groove, which faces the inner walls in the front-rear direction of the clamping portion 19c of the connecting body 19, is approximately the same as the width and thickness of the extension portion 24. Therefore, when the extension portion 24 of the attachment body 20 is inserted into the clamping portion 19c of the connecting body 19, the attachment body 20 can slide. Although not shown, the side ends 24a of the extension portion 24 of the connecting body 20 are marked with a scale (in 1 mm increments). Therefore, before the connecting body 19 and the attachment body 20 are fixed together, the length of the warp prevention jig 18 can be adjusted using the left and right ends of the connecting body 19 as scale marks.

[0034] The flat plate portion 19a of the connecting body 19 has two screw joints (connecting screws SCW, female screw holes 19b) that correspond to the mounting body 20 as abutting fasteners.

[0035] The flat portion 19a has a through hole 19d in its center to which a support column 30 can be attached, which supports the substrate 9 together with the first support surface (if the lower end of the support column 30 is male threaded, a female threaded hole for the support column or the lower end of the support column 30 can be a bolt and nut).

[0036] In this embodiment, the connector 19 and the mounting member 20 are made of a heat-resistant metal material. That is, the components of the warp prevention jig 18 are made of a material that undergoes sufficiently little dimensional change when heated to 240°C in a reflow furnace.

[0037] (Support column 30) 3, the support pillar 30 of the warp prevention jig 18 may be a square pillar, but is, for example, cylindrical, with a rounded upper end 30a and a male threaded portion 30b at its lower end, which may be a cup screw or a truss screw.

[0038] The support pillar 30 is attached to the flat portion 19a of the connecting body 19 so as to protrude perpendicularly from the upper surface thereof by screwing its male screw portion 30b into a predetermined female screw hole 19b in the flat portion 19a of the connecting body 19.

[0039] Furthermore, the length of the support pillar 30 is formed so that when the warp prevention jig 18 is attached to the substrate 9, the upper end 30a of the support pillar 30 lightly contacts the lower surface (first mounting surface 9a) of the substrate 9 (at a position equal to the first support surface of the support portion 22 from the flat portion 19a).

[0040] (Example) Figure 5 is a partial cross-sectional view (Figure 5A) of the right-side mounting body 20 and part of the connecting body 19 shown in Figure 3 in the left-right direction, and a right-side view (Figure 5B) of the mounting portion 21 of the mounting body 20, to explain the relationship between the positions of the substrate 9, the conveying chain 12, and the warp prevention jig 18.

[0041] With reference to FIG. 5, the following (1) to (6) show the preferable conditions for the relationship between the substrate 9, the conveyor chain 12, and the warp prevention jig 18 (the connecting body 19 and the mounting body 20) in this embodiment. (1) The dimension of the front-to-rear width 21aW of the opening 21a of the attachment portion 21 of the attachment body 20 is the same as the chain inner width E, which is the distance in the front-to-rear direction between the two support pins 17a that fit into the opening 21a. (2) The vertical width 21aH of the opening 21a of the attachment portion 21 is the same as the height B within the chain, which is the vertical diameter of the two support pins 17a that fit into the opening 21a. (3) The dimension of the front-to-rear outer width 21W of the mounting portion 21 is equal to or less than the chain outer width E', which is the span of the inner roller link plate 16 in the front-to-rear direction between the two support pins 17a that fit into the openings 21a. (4) The vertical height 21H of the mounting portion 21 is equal to or less than the conveyor chain outer height B', which is the vertical span of the inner roller link plate 16 between the two support pins 17a fitted in the openings 21a. (5) The height 22H from the upper surface of the clamping portion 19c of the connecting body 19 to which the mounting body 20 is attached to the first support surface of the support portion 22 is equal to or greater than the height dimension of the electronic component 10a already mounted on the first mounting surface 9a of the substrate 9. (6) The thicknesses of the opening 21a and the flat portion 19a are set so that the lower surface (second support surface) of the flat portion 19a of the connecting body 19 to which the attachment body 20 is attached is flush with the lower edge of the opening 21a of the mounting portion 21. In other words, the thicknesses of the opening 21a and the flat portion 19a are set so that the support pin 17a and the second support surface of the flat portion 19a of the connecting body 19 support the second mounting surface 9b of the board 9.

[0042] (Explanation of operation) In the first embodiment, we will first explain the case where the warp prevention jig 18 is used to prevent downward warping of one side (first mounting surface 9a) in the first reflow soldering process, and then the warp prevention jig 18 is used to prevent downward warping of the remaining side (second mounting surface 9b) in the second reflow soldering process.

[0043] As shown in FIG. 6(A), electronic component 10a is temporarily fixed to first mounting surface 9a of substrate 9 in advance, and warpage prevention jig 18 is assembled and then mounted between conveyor chains 12.

[0044] To assemble the warp prevention jig 18, as shown in FIG. 7, two attachment bodies 20 and a connecting body 19 are prepared, and the extension portions 24 of each attachment body 20 are inserted into the clamping portions 19c at both ends of the connecting body 19. The attachment bodies 20 are inserted into the connecting body 19 and become slidable, so the length of the warp prevention jig 18 (between the mounting portions 21 at both ends) is set to the dimension between the pair of conveyor chains 12 using the scale on the attachment body 20, and the warp prevention jig 18 is assembled by fixing it with the screws SCW and the female screw holes 19b. The pair of conveyor chains 12 in the specified position are pushed apart to the left and right, and the warp prevention jig 18 is pressed against and clamped between the conveyor chains 12. This clamping and fixing of the warp prevention jig 18 ensures that the warp prevention jig 18 will not fall off even if the conveyor chain 12 is turned upside down during its rotation.

[0045] When the first reflow soldering process is performed, the board 9 is placed on the warp prevention jig 18 (second support surface) and the transport chain 12 (support pins 17a) with the first mounting surface 9a facing upward, as shown in Figures 6(B) and 8. The placed board 9 is oriented so that the surface on which the electronic components 10a to be soldered are temporarily fixed faces upward, with both left and right side edges of the board 9 placed on the support pins 17a of the transport chain 12, and the center of the board 9 supported by the connecting members 19 of the warp prevention jig 18.

[0046] After the first reflow soldering step is completed, as shown in FIG. 6(C), the substrate 9 is removed from the warp prevention jig 18 (second support surface) and the conveyor chain 12 (support pins 17a).

[0047] When electronic component 10b is temporarily fixed to second mounting surface 9b of substrate 9 and a second reflow soldering process is performed, warp prevention jig 18 is attached to conveyor chain 12 upside down (upside down) as shown in Fig. 6(D) (see Fig. 3), which is different from the method of using warp prevention jig 18 in the first reflow soldering process. Note that, in the case of mounting on second mounting surface 9b, components have already been mounted on first mounting surface 9a, so a gap is provided between the surfaces of substrate 9 so as not to interfere with the components, and a support pillar 30 is inserted from below through female screw hole 19b in the center of connecting body 19 and fixed upright to hold substrate 9 (see Fig. 9).

[0048] As shown in Figure 6(E) and Figure 3, the substrate 9 is placed on the support part 22 (second support surface) of the mounting body 20 of the warp prevention jig 18 with its second mounting surface 9b facing upward (electronic components 10a have already been mounted on the first mounting surface 9a), and the center of the substrate 9 is supported by the support pillar 30 of the connecting body 19 of the warp prevention jig 18.

[0049] In a solder reflow device, the substrate 9 must be attached and held parallel to the conveying chain 12 of the conveying rail, so multiple (at least 3 to 5) warp prevention jigs 18 are attached at predetermined intervals along the longitudinal dimension (front-to-back direction) of the product substrate 9 to hold the substrate 9 in place.

[0050] When mounting components on the second mounting surface 9b, the components are already mounted on the first mounting surface 9a, so in the case of the same type of multi-sided board 9, the support pillars 30 are set to be positioned on the dummy sections (waste board sections) provided between the products, and are made to contact the surface of the board 9, making it possible to hold the components in place.

[0051] If the position of the support pillars 30 is changed for each warp prevention jig 18 and the holding position relative to the board 9 is limited, it would be necessary to read the heights of the first and second mounting surfaces of the warp prevention jig 18 with a sensor and transport the board 9 at that timing. For example, as shown in Figures 6(B) and 6(E), the height position of the board 9 relative to the transport chain 12 differs between the first and second reflow soldering processes, so a board transport conveyor (not shown) that supplies the board 9 to the transport chain 12 provided upstream of the solder reflow device adjusts the height position of the board 9 according to the read heights of the first and second mounting surfaces, and then feeds the board 9 onto the transport chain 12.

[0052] (Explanation of effect) As described above, by applying the first embodiment to the conveyor chain 12 of a general-purpose conveyor rail, the following effects can be obtained. (1) Warping of the substrate 9 during mounting on the first mounting surface 9a and the second mounting surface 9b of the substrate 9 is suppressed, component mounting problems are reduced, and stable component mounting can be achieved. (2) In addition, it can be attached to a general-purpose conveyor chain 12, and by pressing it against the conveyor rails and clamping it to fix it, the warp prevention jig 18 is held in a structure that prevents it from falling off even if it is inverted (upside down) due to rotational movement, and automatic conveyance can be performed with the warp prevention jig 18 attached. (3) Since manual attachment and detachment of the substrate 9 is no longer necessary, the cost of processing the substrate 9 can be kept low.

[0053] The warp prevention jig 18 of this embodiment can suppress "warping of the board 9" that occurs when solder is printed on a printed wiring board, electronic components are mounted thereon, and the board is heated in reflow equipment to assemble the components by melting the solder, due to the balance between the weight of the board 9 and components and the rigidity of the board 9. Furthermore, the miniaturization of the warp prevention jig 18 allows it to be easily attached between the conveyor rails of a general-purpose reflow furnace, so that manual attachment and detachment of the board 9 to and from the warp prevention jig 18 is not necessary, allowing for automatic conveyance, and reducing the cost of processing the board 9.

[0054] (Second Example) This embodiment is the same as the first embodiment except that the first embodiment has a plurality of through holes 19d (female threaded holes for the support columns) arranged in a row along the extension direction of the flat portion of the connecting body 19, and further, each extension portion 24 of the pair of mounting bodies 20 has a slit SLT that extends along the row of the plurality of through holes 19d and allows the support column 30 to pass through.

[0055] If it is desired to provide flexibility and change the holding position when mounting the second mounting surface 9b, this can be achieved by providing a row of multiple (e.g., nine) female screw holes 19d for board support columns at equal intervals, as shown in Fig. 10, and by providing a sliding portion with a slit structure, such as a slotted elongated hole (slit SLT) provided in the extension portion 24 along the row of the multiple through holes 19d, as shown in Fig. 11. Here, the female screw holes 19b for connecting the abutment fasteners (screws SCW) for fixing the connecting body 19 and the pair of mounting bodies 20 are positioned off-center rather than on the row of the multiple through holes 19d of the connecting body 19. This allows the tip of the screw SCW of the abutment fastener to abut against the side of the slit SLT of each extension portion 24 of the mounting body 20, allowing the connecting body 19 and the pair of mounting bodies 20 to slide relative to each other.

[0056] (Explanation of effect) As described above, according to the second embodiment, in addition to the effects of the first embodiment, it is possible to improve the degree of freedom in the placement position of the support pillars 30 that support and hold the substrate 9 when mounting the second mounting surface 9b (as shown in FIG. 12, the placement position of the support pillars 30 can be selected from eight positions in addition to the center).

[0057] (Third Example) This embodiment is the same as the second embodiment except that, while in the first and second embodiments, both left and right side edges of the substrate 9 are placed on the support pins 17a of the conveying chain 12 when the first mounting surface 9a is mounted, in this embodiment, both left and right side edges of the substrate 9 do not come into contact with the support pins 17a of the conveying chain 12 when the first mounting surface 9a is mounted, and the warp prevention jig 18 itself supports the substrate 9.

[0058] 13, each of the pair of mounting bodies 20 has a support eaves portion 21b above the opening 21a of the mounting portion 21 to support both left and right edges of the substrate 9. Each support eaves portion 21b protrudes horizontally from above the mounting portion 21 toward the inside.

[0059] In this embodiment, as shown in FIG. 14, the warp prevention jig 18, which is composed of a connecting body 19 connected to the mounting body 20 shown in FIG. 13, supports both the left and right side edges of the substrate 9 with the support eaves 21b when mounting the first mounting surface 9a, and supports the substrate 9 together with the second support surface of the connecting body 19.

[0060] (Explanation of effect) As described above, according to the third embodiment, in addition to the effects of the second embodiment, the support canopy portion 21b can prevent contact between the support pins 17a of the conveying chain 12 and both left and right side edges of the substrate 9, and even if the conveying chain 12 is inverted (turned upside down) in response to the rotational movement of the conveying chain 12, the warp prevention jig 18 can be further prevented from falling off.

[0061] (Description of Modifications) In the warp prevention jig 18 of the third embodiment, the pair of mounting bodies 20 are identical and formed symmetrically, and each has one abutting fastener (a connecting screw SCW such as a setscrew and a female screw hole 19b). However, the warp prevention jig 18 of this modified example is the same as the third embodiment except that the flat portion 19a of the connecting body 19 has at least one set of abutting fasteners (a connecting screw SCW such as a setscrew and a female screw hole 19b), one of the pair of mounting bodies 20 is integrated with the connecting body 19, and the extension portion 24 is formed asymmetrically in the pair of mounting bodies 20.

[0062] In this modified warp prevention jig 18, as shown in Figure 15, the left-side mounting body 20 is integrated with the connecting body 19, and the extension portion 24 of the pair of mounting bodies 20 is extremely short (essentially non-existent) in the left-side mounting body 20, while the extension portion 24 of the right-side mounting body 20 is long, forming an asymmetrical structure.

[0063] According to the warp prevention jig 18 of this modification, in addition to the effects of the third embodiment, the number of components can be roughly reduced, and the warp prevention jig 18 can be easily assembled.

[0064] The present invention also includes any combination of the above-described embodiments and modifications. [Explanation of symbols]

[0065] 12 Conveyor chain 18 Warp prevention jig 19 Connector 19a Flat part 19b female screw hole 19c Clamping part 19d through hole 20 Wearable body 21 Mounting part 22 Support part 23 Side wall 24 Extension part 30 Support pillar SCW connecting screws

Claims

1. A warp prevention jig for preventing warpage of a substrate transported by a pair of parallel-running conveyor chains in a solder reflow apparatus while both ends of the substrate are supported by the pair of parallel-running conveyor chains, the jig comprising: a pair of attachment bodies attached to the pair of conveyor chains, respectively; a connecting body that connects the pair of mounting bodies, each of the pair of mounting bodies includes a mounting portion attached to the transport chain, a support portion having a first support surface that supports a substrate above the mounting portion, and an extension portion that is one step lower than the support portion when viewed from the first support surface and extends in a direction along the first support surface; the connecting body has a flat portion including a clamping portion that clamps a side end of the extension portion of each of the pair of mounting bodies, and a second support surface that is fastened by an abutting fastener to fix and connect the pair of mounting bodies to each other, faces the opposite side to the first support surface, and supports a substrate; The flat plate portion has a through hole to which a support post can be attached, which supports a substrate together with the first support surface. A warpage prevention jig characterized by:

2. The mounting portion of each of the pair of mounting bodies is formed with a step between the first support surface and the extension portion in parallel, and has an opening wider than the difference in the step.

2. The warp prevention jig according to claim 1.

3. Each of the pair of conveyor chains includes support pins at a predetermined pitch that extend horizontally toward the inner side of each of the opposite conveyor chains, The openings of the attachment portion are formed to be detachably fitted onto two adjacent ones of the support pins.

3. The warp prevention jig according to claim 2.

4. The flat portion of the connecting body has at least one threaded joint as the abutting fastener.

2. The warp prevention jig according to claim 1.

5. One of the pair of mounting bodies is integrated with the connecting body, and the extension portion is asymmetrically formed on the pair of mounting bodies.

5. The warp prevention jig according to claim 4.

6. The flat plate-like portion has a plurality of through holes arranged in a row along the extension direction thereof, and the extension portion of each of the pair of mounting bodies has a slit extending along the row of the plurality of through holes along the extension direction and allowing the support post to pass through.

2. The warp prevention jig according to claim 1.

7. Each of the pair of mounting bodies includes a support eaves portion on the mounting portion that supports the substrate together with the second support surface.

2. The warp prevention jig according to claim 1.

8. A solder reflow device that heats a substrate on which electronic components are temporarily fixed by reflow solder to melt the reflow solder, a pair of conveyor chains running parallel to one another to convey a substrate within the solder reflow device; and a warpage prevention jig attached to the conveyor chains to prevent warpage of the substrate, the warp prevention jig includes a pair of attachment bodies attached to the pair of conveyor chains, respectively, and a connecting body connecting the pair of attachment bodies, each of the pair of mounting bodies includes a mounting portion attached to the transport chain, a support portion having a first support surface that supports a substrate above the mounting portion, and an extension portion that is one step lower than the support portion when viewed from the first support surface and extends in a direction along the first support surface; the connecting body has a clamping portion that clamps the side ends of the extension portions of each of the pair of mounting bodies, and a flat portion that is fastened by an abutting fastener to fix and connect the pair of mounting bodies to each other, and that has a second support surface that faces the opposite side to the first support surface and supports a substrate; The flat plate portion has a through hole to which a support post can be attached, which supports a substrate together with the first support surface. A solder reflow device characterized by:

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