JPH0644200U - Substrate fixing jig - Google Patents

Abstract

(57) [Abstract] [Purpose] In the solder reflow step of surface-mounting electronic components on a printed circuit board, warp of the board is prevented, and soldering failure caused by insufficient heating of the mounting surface is eliminated. [Structure] The heat capacity of the jig is reduced by using a metal plate with a thickness of 1 mm or less, and one side is 8 to 1 in comparison with the outer shape of the substrate.
A 5 mm short area is punched out along with one side of the metal plate to form a U-shape, and a holding member 3 is attached to the opening side 2 so as to be openable and closable around one end side of the opening side and is received at the other end side. The frame 4 having the window 1 is formed by providing the portion 4, and the ribs 5 and 5'folded in the direction perpendicular to the plate surface are provided on the inner periphery of the window.
A substrate retainer 6 is provided on the surface opposite to the rib.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a board fixing jig used in a solder reflow process when surface-mounting an electronic component on a printed circuit board.

[0002]

[Prior art]

 As a method for soldering and mounting various electronic components on the printed circuit board, holes are made in the substrate, the leads of electronic components with leads are inserted and soldered, and the electrode section is provided on the surface of the substrate. , And the surface mounting method in which the electrode parts of leadless electronic parts, in which the electrodes are attached to the parts body, are connected by soldering.

On the other hand, in the step of the surface mounting method, a solder paste in which solder powder is made into a paste with a solvent or the like is applied or printed on a substrate pad (electrode portion), and a surface mounting electronic component is formed thereon. The solder reflow method is used to mount the device, pass it through a high-temperature atmosphere to fully evaporate the solvent, and after the solder has melted sufficiently, return it to a normal-temperature atmosphere to solidify the solder and solder the board and electronic components Mainly performed.

In this method, there is no problem when the printed circuit board is thick, but in the printed circuit board having a thickness of 1 mm or less, the board is warped due to the high temperature heat during the solder reflow process. When the board is warped, the electronic components placed on the board are shifted from a predetermined position and soldered. Misalignment may occur. Therefore, in order to prevent the substrate from warping as much as possible, a jig for preventing substrate warpage is used.

Conventionally, as a jig of this type, a heat-resistant double-sided tape is attached to a metal plate having a thickness of 1 mm or more, and a substrate is attached thereon to fix the jig. However, in this method, since the metal plate is thicker than 1 mm, the heat capacity is large, so that the heat may not reach the board side, in other words, the component mounting surface sufficiently, and some parts may not be soldered locally. Also, when the components are mounted on both sides, it was not possible to fix the substrate and the metal plate when mounting the back side, because there were components mounted on the front side. Further, as a measure for the above-mentioned heat capacity problem and mounting on the back surface, a method of hollowing out the central portion of the metal plate is also used, but in this case, the strength of the metal plate becomes weak.

[0006]

[Problems to be solved by the device]

 The present invention is intended to solve such a problem of the surface mounting method by solder reflow, and its purpose is to prevent warpage of a printed circuit board during solder reflow and to prevent misalignment of electronic components. The point is to eliminate defects.

[0007]

[Means for Solving the Problems]

 That is, the present invention is a jig for preventing the warp of the board during solder reflow for surface mounting electronic parts on the printed circuit board, and one side is 10 to 25 mm larger than the outer shape of the printed circuit board. A square metal plate with a thickness of 1 mm or less is punched out along with one side of the square in a region where one side is 8 to 15 mm shorter than the outer shape of the substrate, and a protruding portion is formed in the U shape or the U shape. A holding member is attached to the U-shaped opening side so as to be openable and closable around one end side of the opening side, and a receiving part is provided on the other end side to form a frame body having a window. At the same time, the inner circumference of the window should be bent to a width of 2.5 to 6 mm in a direction perpendicular to the metal plate surface to form a rib, and a board retainer should be provided around the window on the side opposite to the rib. Is a board fixing jig.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a view showing a base plate fixing jig which is an embodiment of the present invention, and FIGS. 2 and 3 are views showing other embodiments.

First, prepare a rectangular or square metal plate whose one side is about 10 to 25 mm larger than the outer shape of the printed circuit board to be fixed, and one side of the center portion of the printed circuit board has the outer shape. A shorter area of about 8 to 15 mm is punched out together with the opening side (2) to form a U-shape as shown in FIG. At this time, the width of each side of the U-shape is 9 to 20 mm. Of this, the part of the inner circumference width of 2.5 to 6 mm is bent in the direction perpendicular to the metal plate surface, and as shown in FIG. Form ribs (5) for reinforcement as shown in c). The width of each side of the U-shape and the width of the rib (5) may be determined according to the strength required by the size of the printed circuit board.

The thickness of the metal plate is 1 mm or less in order to reduce the heat capacity as described above, but the lower limit is about 0.3 to 0.4 mm depending on the size of the printed circuit board. As an example, when fixing a 50 mm × 75 mm circuit board, it is suitable to use a steel plate having a thickness of 0.5 mm.

Next, a holding member (3) made of a metal plate made of the same material and having a width approximately the same as each side of the U-shape is attached to the U-shaped opening side (2), and the window (1 ) Is formed. A rib (5) as shown in FIG. 1 (e) is provided on the inner side of the window of the holding member (3), and one end of the rib (5) is attached so as to be rotatable around the one end side of the opening side (2) as an axis. , The U-shaped opening can be opened and closed. A receiving portion (4) for the holding member (3) is provided on the other end side of the opening side (2) so that the holding member (3) with the opening closed can be fixed. Further, a board retainer (6) for fixing the printed circuit board is provided on the surface of each side of the frame surrounding the window (1) opposite to the ribs (5, 5 '). The distance between the surface of the frame and the top of the board holder is preferably about 0.1 mm larger than the thickness of the circuit board.

The shape of the printed circuit board is not limited to a rectangle or a square, and various shapes such as a shape obtained by cutting out a part of a rectangle as shown in FIG. Is used. Therefore, it is necessary to make the shape of the substrate fixing jig suitable for these. As an example, for a circuit board having a shape as shown in FIG. 2C, it is punched into a shape in which a protruding portion (8) is provided in a U-shape as shown in FIG. Similarly, a holding member (3) is attached to the opening side, and a rib (5) is provided on each side surrounding the window (1).

Similarly, a board retainer for fixing the printed circuit board is attached, but it does not have to be a long member extending over the entire length of each side as shown in FIG. 2A, as shown in FIG. 2A. In addition, the substrate retainer (7) may be provided in a dot shape at a fixed position on each side. The sectional shape of the substrate retainer may be a U-shaped one as shown in FIG. 2B, or may be a single protrusion-like substrate retainer (7 ') for the retainer member (3) on the opening side.

In the example of FIG. 2, if there is concern about the strength of the protruding portion (8), as shown in FIG. 3, the protruding portion (8) is bridged across two opposite sides of the frame by crossing the window (1) and protruding. A reinforcing rib (9) is provided for fixing the tip of the part (8). The reinforcing ribs (9) are made of the same material as the frame body, and have a rib structure like the inner circumference of the window (1). Since a gap is provided between the reinforcing ribs (9) and the printed circuit board as needed, Are attached via spacers.

Next, a method of using the substrate fixing jig according to the present invention will be described. First, as shown in FIG. 4, open the holding member (3), insert the printed circuit board (10) from the opening side into the gap between the board holding member (6) and the frame body, and then insert the whole. The circuit board is fixed by closing the holding member (3) and sandwiching it by the receiving portion.

[0016]

[Effect of device]

 When the board fixing jig of the present invention is used, it is easy to set the board on the jig, the warpage of the printed circuit board can be surely suppressed, and the heat capacity of the metal plate is small. Sufficient heat is spread to the circuit board, and the solder on the board can also be melted sufficiently, making good soldering possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a substrate fixing jig according to an embodiment of the present invention, in which (c) to (e) are AA ′ and B in FIG.
FIG. 7B is a sectional view taken along line B-C 'and C-C'.

FIG. 2 is a view showing another embodiment of the present invention, and FIG. 2B is a sectional view taken along the line DD ′ of FIG.

FIG. 3 is a view showing another embodiment of the present invention, and FIG. 3B is a sectional view taken along line EE ′ of FIG.

FIG. 4 is a view showing a method of using the substrate fixing jig of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Window 2 Opening side 3 Holding member 4 Receiving part 5, 5'rib 6, 7, 7'Board pressing 8 Projecting part 9 Reinforcing rib 10 Printed circuit board

Claims (2)

[Scope of utility model registration request] 1. A jig for preventing warpage of a board during solder reflow for surface-mounting electronic components on a printed circuit board, one side being 10 to 25 mm larger than the outer shape of the printed circuit board. A rectangular metal plate having a thickness of 1 mm or less is punched out along with one side of the square in a region where one side is 8 to 15 mm shorter than the outer shape of the substrate, and a protruding portion is formed in a U shape or a U shape. A holding member is attached to the U-shaped opening side so as to be openable and closable around one end side of the opening side, and a receiving portion is provided on the other end side to form a frame body having a window. The inner circumference of the window is bent to a width of 2.5 to 6 mm in a direction perpendicular to the metal plate surface to form a rib, and a substrate retainer is provided around the window on the side opposite to the rib. A board fixing jig. 2. The substrate fixing jig according to claim 1, further comprising: a reinforcing rib for bridging two opposite sides of the frame body across the window and fixing a tip of the protruding portion. Ingredient