JPH0655287U - Printed board - Google Patents

Abstract

(57) [Abstract] [Purpose] When mounting a component on a printed circuit board and performing reflow soldering, a component mounting hole that does not cause solder clogging in the land of the solder mounting hole for soldering a component to be mounted later is printed. Use as a substrate. [Structure] A part 5 having no copper foil having an appropriate width is formed around the component mounting hole 1 on the substrate surface, and a notch 7 is formed outward from the part 5 having no copper foil in the flow soldering direction. And the component mounting hole 1 which is parallel to the flow soldering direction with the notch
A solder resist having an appropriate width is formed on the land 4 reaching the outer periphery of the land 4.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a printed circuit board, and more particularly to a printed circuit board that is easy to mount and solder after-components after flow soldering after components are mounted on the printed circuit board.

[0002]

[Prior art]

 Conventionally, in flow soldering when mounting components on a printed circuit board, solder adheres to the lands that are used for component mounting after flow soldering and blocks the mounting holes for post-mounted components, which makes it impossible to mount post-mounted components. In order to prevent this, the following measures were mainly taken. Block the holes for mounting the retrofit parts with a stick that will not be deformed or melted by the solder heat. Cover the mounting holes and lands for the retrofit parts with masking tape or resin coat. Provide a slit in the land.

However, these measures have some drawbacks. The above measures (1) and (2) require the use of members such as rods and resin coats and jigs, which causes the problem of incurring these costs. Therefore, there are problems such as a decrease in component mounting speed and an increase in man-hours. As another countermeasure, in the conventional printed circuit board where component mounting holes were formed by press working, there was a problem that the mounting holes in the unmounted state were blocked with solder after the flow soldering.

FIG. 2 shows a conventional component mounting hole for mounting a post-mounting component, and FIG. 2 (a) shows a component mounting hole of a printed circuit board in which the mounting hole has been processed by press working, and a portion near a land. FIG. 2B is a plan view, and FIG. 2B is a cross-sectional view taken along the line AA of FIG. The land 2 of the component mounting hole 1 has a land cutout portion 3 which is partially cut away. A part of the copper foil of the land 2 slightly penetrates into the wall of the component mounting hole 1 by pressing. This is because the copper foil is pressed into the component mounting hole 1 by the press punch. Therefore, when the flow soldering is performed, the copper foil in the wall of the component mounting hole is soldered, and the mounting hole is blocked by the solder. Also, the smaller the mounting hole diameter, the easier it is to close the hole with solder.

Therefore, conventionally, the width of the land cutout portion 3 is increased, the number thereof is increased, or the number of the land cutout portions 3 is increased so that the mounting holes of the unmounted components that have not been mounted can be reliably blocked even after the flow soldering. Measures such as increasing the hole diameter of the component mounting hole 1 are used, but this also causes a soldering failure such as insufficient amount of solder or insufficient solder leakage when soldering to later-installed components. Was becoming.

[0006]

[Problems to be solved by the device]

 The present invention improves the defect of the conventional land by preventing the component mounting holes from being clogged by these soldering, and can reduce the component mounting speed when mounting the component on the printed circuit board without compromising the component mounting. Without increasing the number of man-hours for mounting, it is possible to prevent the mounting holes for the retrofit parts from being blocked by the flow soldering of the component terminals mounted on the press-printed printed circuit board, and to mount the retrofit parts easily. The purpose is to provide.

[0007]

[Means for Solving the Problems]

 This invention devises the shape of the copper foil around the component mounting on the printed circuit board and the shape of the solder resist to prevent soldering, so that the mounting holes of the retrofit components to be mounted after the flow soldering are A feature of the printed circuit board is that it is prevented from being blocked by solder before mounting components.

That is, according to the present invention, in a printed circuit board for flow soldering, the land has an inner diameter slightly larger than the component mounting hole and the land does not reach the outer shape of the land in the front-back direction of the flow when soldering inside the land. From the notch part without the copper foil that cut out a part of the land and the opposite side of the board conductor connected to the land, from the center of the land to the outer edge of the land The printed circuit board is characterized by comprising a solder resist printed in a narrow width.

[0009]

[Action]

 Make the inner diameter of the land larger than the circle diameter of the component mounting hole, form the part without the copper foil on the substrate surface of the component mounting hole of the board and the inner diameter of the land, and make the copper foil in the solder flow direction during soldering. When the solder is used for flow soldering, the structure is such that the land cutout is formed by cutting out the inner diameter of the land more than the non-existing part, and the solder resist reaching the outer peripheral surface of the land through the cutout from the component mounting hole is applied to an appropriate width. Since the solder resist surface has no affinity with the solder, the solder is repelled, and the solder resist portion of the solder on the land does not get over when the solder is applied. Since there is no copper foil larger than the component mounting hole diameter, the solder resist reaching the outside diameter of the land from the component mounting hole divides the solder on the land into two parts, and the surface of the component mounting hole is covered with solder. Is no longer a.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a shape of a land for mounting a post-installed component of a printed circuit board and a component mounting hole 1 according to the present invention, and FIG. 1 (a) is a plan view of the component mounting hole 1 portion of the printed circuit board of the present invention. 1B shows a cross-sectional view taken along the line BB of the component mounting hole 1 portion of the printed circuit board of FIG. The inner diameter of the copper foil shape of the land 4 of the retrofit component of the present invention is hollowed out slightly larger than the hole diameter of the component mounting hole 1. Therefore, the land 4 connected to the board conductor is provided with the copper foil-free portion 5 having a width outside the center of the component mounting hole 1, and the portion 5 without the copper foil is subjected to the flow soldering. In the case where the printed circuit board travels in the direction opposite to the traveling direction, inside the land 4 with the component mounting hole 1 as the center, outside the center of the component mounting hole 1 and notch that does not reach the outer periphery of the land 4. 7 is formed, and a solder resist 6 having an appropriate width is printed on the land surface reaching the outer periphery of the land 4 from the center of the component mounting hole 1 to the opposite side of the board conductor 10 of the printed circuit board.

With this configuration, when flow soldering is performed on the print substrate without mounting the component in the component mounting hole 1, the land 4 is first soldered in the solder bath. Then, when the printed circuit board comes out from the solder bath while moving in the traveling direction, the solder adheres to the copper foil of the land 4 except for the solder resist 6 portion and the copper foil-free portion 5. The component mounting hole 1 has a portion 5 with no copper foil between it and the land 4, and the solder on the land 4 is divided into two parts by the solder resist 6 that reaches the outer periphery of the land 4 from the component mounting hole 1. The component mounting hole is not blocked.

As an embodiment of the present invention, the hole diameter of the component mounting hole 1 is 0.8 mm, and the dimension of the portion 5 without the copper foil inside the mounting hole and the land 4 is 0. In the printed board printed with the width of 5 mm, the width of solder resist 6 without soldering layer is narrower than the width of part 5 without copper foil and is 0.3 mm, with the notch entering 0.5 mm in the land. When flow soldering was applied without mounting the components in the mounting holes, the solder did not block the component mounting holes. In addition, when the post-installed parts were soldered by inserting them into the unmounted holes that were once passed through the solder bath, problems such as insufficient solder did not occur. The solder resist 6 may be any one that does not have solder on the lands 4, and the solder resist according to the present invention may be a resin material of a commercially available solder resist, or may be silk-printed.

[0013] The width from the outside of the hole of the part without copper foil around the component mounting hole into which the post-installed component is inserted at the time of flow soldering and the width of the solder resist are increased as the width is increased. Although it has a great effect of preventing the mounting holes from being blocked, it weakens the mounting strength of the components when mounting the components to be retrofitted. Therefore, the dimensions are appropriately selected according to the diameter of the mounting holes of the components.

[0014]

[Effect of device]

 As described above, according to the present invention, a copper foil land is formed around a component mounting hole of a post-installed component of a printed circuit board, and a copper foil-free portion is formed around the component mounting hole. The solder resist that reaches the outer circumference of the component mounting hole and the land is printed across the parts, so that even when soldering without inserting the component into the component mounting hole, the hole is not blocked by the solder and the product Without reducing production speed, increasing man-hours, and without using jigs, it is possible to prevent solder from blocking the mounting holes for non-components on the printed circuit board after flow soldering. became.

[Brief description of drawings]

1A and 1B are views showing an embodiment of a printed circuit board according to the present invention, in which FIG. 1A is a plan view and FIG. 1B is a sectional view taken along line BB of FIG.

FIG. 2 is a diagram showing an example of a conventional printed circuit board, FIG. 2 (a) is a plan view, and FIG. 2 (b) is AA of FIG. 2 (a).
FIG.

[Explanation of symbols]

 1 Component mounting hole 2 Land 3 Land cutout part 4 Land 5 Copper foil free part 6 Solder resist 7 Cutout part 10 Board conductor

Claims (1)

[Scope of utility model registration request] 1. In a printed circuit board on which flow soldering is performed, a land having an inner diameter slightly larger than a component mounting hole and a part of the land that does not reach the outer shape of the land in the front-back direction of the flow at the time of soldering inside the land are provided. On the opposite side of the board conductor connecting to the land and the notch without the notched copper foil,
A printed board comprising a solder resist printed from a center of the land to a peripheral edge of the land and having a width narrower than a width of the notch without the copper foil.