JP4147277B2 - Printed wiring board cradle and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the production of a printed wiring board in which electronic components are mounted on both sides, the present invention can be used when a component is mounted on the first surface of the printed wiring board and then cream solder is printed on the second surface of the other side. The present invention relates to a printed wiring board cradle that reliably supports a mounted first surface and a manufacturing method thereof. Furthermore, the cradle of the present invention can be used for transporting the reflow furnace as it is by appropriately selecting the constituent materials.
[0002]
[Prior art]
Double-sided mounting, in which electronic components are mounted on both sides of a printed wiring board, has been widely carried out in response to the demand for reducing the size and weight of electronic circuits, starting with mobile phones. In this double-sided mounting, first, an electronic component is mounted on the first surface of the printed wiring board, and then the electronic component is mounted on the second surface.
[0003]
To mount an electronic component on the second surface of the printed wiring board, turn the printed wiring board on which the electronic component is mounted on the first surface, and support the first surface with a receiving table or jig. Then, solder printing is performed on the back surface, that is, the second surface, and then electronic components are mounted and fixed.
[0004]
As a method of a cradle or jig for supporting the back surface of a printed wiring board, it is roughly divided into a pin standing method and a metal that selects and uses one type of pin from rod-shaped pins having a diameter of 3 mm to 5 mm. There are two types: a block made of resin, rubber, or the like, in which a concave portion for receiving an electronic component is provided and supported by the surface of a cradle or a receiving jig.
[0005]
FIG. 2 is a schematic cross-sectional view for explaining a state in which the printed wiring board 3 is supported by the pin-up type printed wiring board cradle 1. The diameters of these support pins 22 are 3 mm or more, and they are erected on the first surface of the printed wiring board 2 so as to avoid the positions of the mounted electronic components 4 to 43. It comes to support.
[0006]
FIG. 3 is a schematic view showing a state in which the concave portion 8 that receives the mounted electronic components 4 to 43 is supported by the printed wiring board cradle 1 that has been mechanically machined such as a milling machine. The cradle 1 is made of a metal or resin block such as aluminum or methallyl resin, and a recess 8 is cut into the surface of these blocks by milling or the like at a corresponding position of the mounted electronic components 4 to 43. The electronic parts 4 to 43 protruding from the printed wiring board 3 are received in the concave portions, and the printed wiring board is supported by other convex surfaces.
[0007]
In addition, as disclosed in Japanese Patent Laid-Open No. 6-338530, the first surface of the printed wiring board on which the electronic components are mounted is brought into contact with a liquid molding material made of silicone rubber and cured. A wiring board cradle is used. The cradle is intended to support the printing pressure of the printed wiring board over the entire surface of the cradle by fitting and abutting the electronic component to the recess formed by the electronic component on the first surface. The dimensional accuracy of the silicone rubber component cannot be secured and has not been put to practical use.
[0008]
In addition, as disclosed in Japanese Patent Application No. 2000-003336, in a practical example, the conductive rubber sheet is processed with a laser beam, and a thin sheet that is easy to process is laminated to improve the processing accuracy of the concave surface. The processing cost is reduced.
[0009]
In addition, in the example of Japanese Patent Application No. 2001-376075, an integrated cradle in which a portion that supports a printed wiring board is configured by a surface or a pin is proposed by photoforming using a photocurable resin composition.
[0010]
As described above, in the conventional printed wiring board pedestal method, the receiving portion that comes into contact with the substrate is mainly composed of a circular surface or a rectangular surface having a diameter of 3 mm or more. That is, in the places where electronic parts are densely packed, they are gathered to form protruding portions, and the receiving portions are arranged so as to avoid these protruding portions. Therefore, the arrangement design of the receiving portion is complicated, and there are cases where the portion that needs to be supported cannot be sufficiently supported depending on the component mounting state.
[0011]
In addition, due to the demand for smaller and lighter electronic circuits, the board is also being made smaller, thinner, and lighter. Many small parts such as 0603 are mounted on the entire surface of the board, and the parts are less than 2 mm in the dense part. There is also a demand for a cradle configured to receive a narrow gap.
Furthermore, short delivery times are essential at the prototype stage of the product. If the cradle is machined or hardened, the total production time is 2 to 3 days, making it difficult to meet short delivery times. .
[0012]
[Problems to be solved by the invention]
The object of the present invention is to always provide a mask for printing and a mounting machine even when the other surface protrudes from the electronic component when mounting a solder paste or electronic component for mounting the electronic component on the back surface of the printed wiring board. Printed wiring with the characteristic that it can be transported as it is in the reflow furnace according to the material characteristics, based on the structure that prevents the printed wiring board from bending due to the printing pressure during printing and the pressing during component mounting. It is intended to provide a plate cradle at a low cost and with a short delivery time.
[0013]
The present invention provides a plurality of supports of different heights having different widths, each having a width of 0.1 to 5 mm, and having a width of a portion in contact with the substrate, without bending the printed wiring board surface on which electronic components are mounted on one side. A plate member, a sandwiching member having a slit-like through-opening for sandwiching and standing the support plate member, and a compression elastic modulus for standing and holding the support plate member is 5000 kg / mm 2 or more. The printed wiring board pedestal is characterized by comprising a pedestal and entirely made of a conductive material.
[0014]
The printed wiring board cradle described above, wherein the support plate member, the holding member, and the pedestal are made of a material that can withstand a temperature within 200 ° C to 330 ° C.
[0015]
The printed board according to the above-mentioned, wherein the printed wiring board is protected by covering a portion of the support plate member that comes into contact with the printed wiring board with a metal film such as plating, a lining made of conductive rubber, or a cap. Located on the wiring board cradle.
[0016]
The holding member having the slit-like through opening is processed with a laser or a router, and then fixed to the base, and then the support plate member is inserted into the opening of the holding member. The method includes the process of adjusting the height of the printed wiring board.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the printed wiring board cradle of the present invention will be described in detail with reference to FIGS. 1 (a) to 1 (c).
[0019]
Fig.1 (a) is a cross-sectional schematic diagram which shows the state which supported the printed wiring board 3 with which the electronic components 4-44 were mounted in the single side | surface by the printed wiring board stand 1 of this invention.
The printed wiring board cradle 1 of the present invention has a holding member 12 fixed in advance to a pedestal 11 that is electrically conductive and has a high compression elastic modulus, and then has a width of 0.1 mm to 5 mm and is the same height. The plate members 13 to 18 are configured to be inserted / held between the holding members 12. In particular, as shown in FIG. 1B and FIG. 1C, if there is a place in the arrangement of the electronic component 4 mounted on the printed wiring board, the upper limit width as in the support plate member 22 is obtained. There is no problem even if it is 5 mm.
[0020]
The support plate member material may be a conductive material having high hardness. Specifically, a metal material having a compressive elastic modulus of 5000 kg / mm 2 or more can be used, and among them, SUS material, nickel material, copper material and the like can be used. It can be used because it can be processed accurately. Further, in the case of a cradle made of a support plate member having a thickness greater than 0.5 mm and a width of 0.5 mm to 5 mm, the antistatic plastic having a compressive elastic modulus of 300 kg / mm 2 or more. Material can be used. For example, MC nylon (Nippon Polypenco Co., Ltd.), metal-deposited plastic material or metal-plated plastic material can be used.
[0021]
The material for the holding member preferably has a thickness of 40% or more of the height of the support plate member in order to insert and erect a support plate member having a thickness of 0.1 mm to 5 mm. Any material that can be easily processed may be used. Various plastic materials that can be processed with a laser and GFRP materials that can be processed with a router can be preferably used.
[0022]
The pedestal material having a high compression elastic modulus is preferably a conductive metal material like the support plate member material. Specifically, a metal material having a compression elastic modulus of 5000 kg / mm 2 or more can be used, and among them, a SUS material. Nickel material, copper material, aluminum material and the like are preferable because they can be processed with high accuracy.
[0023]
On the other hand, when using an insulating material such as a GFRP material as a pedestal material, be sure to use a conductive and easily processable material as a material for the holding member so that static electricity is removed from the cradle 1. There is a need to.
[0024]
FIG.1 (b) is a top view which shows typically the contact state of the printed wiring board with which the electronic components 4-44 were mounted in the single side | surface, and the support plate member of the cradle of this invention. FIG. 1A corresponds to a schematic cross-sectional view along X and X ′ in the schematic diagram. The support plate members 13 to 18 are support plate members that are perpendicular to the squeezing direction. On the other hand, the support plate members 19 to 24 are support plate members that are parallel to the squeezing direction. As shown in this schematic diagram, the thickness of each support plate member is first designed according to the space between the mounted electronic components and the material for the support plate member to be used.
[0025]
Next, since the printing pressure during squeezing is applied to the printing surface through the squeegee, the support plate member perpendicular to the squeezing direction functions sufficiently as a support member, but the support plate parallel to the squeezing direction. As shown in FIG. 1 (b), the member is designed so that the length of the support plate member is increased, and the support plate member is distributed evenly in the Y-axis direction and the printing pressure is dispersedly supported. .
[0026]
FIG.1 (c) represents another embodiment which showed typically the contact state of the printed wiring board with which the electronic components 4-44 were mounted in the single side | surface, and the support plate members 13-18 of the cradle of this invention. It is a top view. If the size and thickness of the support plate member are created based on a preset reference, for example, the support plate members 13 and 20 can be created by stacking two support plate members 14 of the same size. The support plate member 22 can also be created by stacking two support plate members 23 of the same size. Further, the support plate member 19 is set to be four times as long as the support plate member 13 so as not to be deformed when inserted and assembled into the holding member 12 because the size is too long, and is constituted by four support plate members 13. Yes. These support plate members are prepared by presetting material (hardness), dimensions, and dimensional accuracy. In particular, since the height dimensional accuracy of the support plate member is important for maintaining the flatness of the printed wiring board, the height dimensional accuracy is set within 0.01 mm.
[0027]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
[0028]
Example 1 The cradle of the present invention shown in FIGS. 1 (a) and 1 (c) was prepared. First, the support plate member was deburred by cutting an MC nylon sheet having a thickness of 0.5 mm into a reference size with an NC processing machine and performing mechanical polishing. The support plate members 13 to 16, 20, and 21 are cut to a reference size height of 20 mm × 20 mm, and the support plate members 22 to 23 are further doubled to a reference size of 20 mm × 40 mm, and further to the support plate member 17, 18, and 19 were created by cutting to 20 × 80 mm, which is four times the standard size. That is, the support plate member 14 is made of one standard size product having a thickness of 0.5 mm × height 20 mm × length 20 mm, whereas the support plate member 15 (2 mm thickness) is the reference size product 4 described above. It is composed of sheets. The support plate member 23 was 5 mm thick.
[0029]
Next, the support plate holding member 12 is a slit for inserting and holding the support plate member by irradiating a CO2 laser onto a conductive rubber (black NBR / EP sheet manufactured by Tigers Polymer Co., Ltd.) having a thickness of 3 mm. A shaped aperture was created. Since the thickness of the conductive rubber used was 3 mm, each supporting plate member was firmly held by stacking three rubber sheets that were similarly processed to have openings.
[0030]
As shown in FIG. 1 (a), an aluminum plate having a thickness of 3 mm was cut into a predetermined size with a milling machine to create a base 11. Three support plate holding materials prepared as described above were stacked on the pedestal 11 and bonded and fixed to attach a support plate holding material 12 having a thickness of 9 mm. Next, a support plate member made of MC nylon sheet having a predetermined length was inserted and held between the required number of slits in the slit-like opening, and the height of the support plate member was adjusted to prepare the cradle of the present invention.
[0031]
[Example 2] According to the procedure described in Example 1, first, each support plate member made of the material SUS304H was prepared.
[0032]
Next, the support plate holding member 12 is a slit-like opening for inserting and holding the support plate member by router processing into a glass cloth reinforced epoxy resin laminate (made by Matsushita Electric Works Co., Ltd.) having a thickness of 1.5 mm. It was created. Since the thickness of the used glass cloth reinforced epoxy resin laminate was 1.5 mm, each SUS support plate member was firmly held by stacking the six glass cloth reinforced epoxy resin laminates that had been subjected to opening processing. I did it.
[0033]
In accordance with the procedure described in the first embodiment, the support plate sandwiching material prepared as described above is stacked on the aluminum pedestal 11 having a thickness of 3 mm, and the support plate having a thickness of 9 mm is bonded and fixed. A sandwich 12 was attached. Next, a SUS support plate member having a predetermined length was inserted and held in the slit-shaped opening by a required number, and the height of the support plate member was adjusted to prepare the cradle of the present invention.
[0034]
[Example 3] According to the procedure described in Example 1, first, the support plate member was cut into a reference size by irradiating a 0.2 mm-thick nickel sheet with a YAG laser, and mechanically polished. By doing, burr and chamfering were performed. Since the compression modulus of the nickel sheet is large, the thickness of the support plate member was 0.2 mm with respect to the support plate member 14 and 0.4 mm with respect to the other support plate members. .
[0035]
In this embodiment, the support plate members 14 and 17 having a narrow width are subjected to nickel plating with a thickness of 25 μm over a length of 1 mm on the front end portion of the support plate members 14 and 17, and the cross-sectional area of the support member to which the printing pressure is applied is increased by 1.25 times. However, there was no significant difference in the stress concentration on the printed wiring board as shown in the use examples described later.
[0036]
Next, according to the procedure of Example 1, the support plate holding member 12 inserts and holds the support plate member from conductive rubber (black NBR / EP sheet manufactured by Tigers Polymer Co., Ltd.) having a thickness of 3 mm. Slit openings of 2 mm and 0.4 mm thickness were created. Since the thickness of the conductive rubber used was 3 mm, each supporting plate member was firmly held by stacking three rubber sheets that were similarly processed to have openings.
[0037]
[Usage Example 1] The cradle of the present invention prepared in Example 1 was set in a printing machine, and cream solder printing was performed by a conventional method on a printed wiring board on which an electronic component was already mounted on one side. At the time of mounting the component, there was about 0.20mm deflection on the diagonal line due to heat during reflow, but when this board was placed on the cradle of the present invention and printed, no printing misalignment or bleeding was observed, Printing was successful.
[0038]
[Use Example 2] Using the electronic component mounting machine in which the cradle of the present invention created in Example 2 was set, electronic components were mounted on the second surface of the printed wiring board. Next, a printed wiring board having electronic components mounted on the cradle of the present invention was passed through a reflow furnace, and the electronic components were bonded and fixed. This cradle had the characteristics to withstand the high temperature of the reflow furnace.
[0039]
[Usage Example 3] When the cradle of the present invention prepared in Example 3 was set in a printing machine and printed on a printed wiring board having electronic components already mounted on one side, cream solder printing was performed by a conventional method. No blur was observed and proper printing was possible. In addition, nickel plating with a thickness of 25 μm was performed over the 1 mm length of the tip portion where the narrow support plate members 14 and 17 contact the printed wiring board, and the support member cross-sectional area to which the printing pressure was applied was increased 1.25 times. There was no significant difference in the stress concentration on the printed wiring board.
[0040]
【The invention's effect】
The printed wiring board cradle of the present invention is equipped with a cellular phone at the top, and also has a fine part called 0603 mounted on one side in the manufacture of a double-sided mounting printed wiring board that pursues smaller, thinner and higher density. It is possible to hold the substrate flat without damaging the electronic components already mounted on the second surface of the printed wiring board on which the electronic components are mounted during cream solder printing or component mounting. The cradle of the present invention can securely hold a gap between narrow electronic components of 0.5 to 2 mm, which could not be supported conventionally, and is a substrate that is an important point at the time of mounting. It became possible to maintain flatness at 0.03 mm or less.
Further, the cradle of the present invention uses a heat-resistant material such as a glass cloth reinforced epoxy resin laminated plate as the supporting plate sandwiching member 12 as a constituent member thereof, thereby allowing the electronic component mounting machine and the reflow furnace to pass through, Components can also be mounted.
[0041]
In terms of delivery, standardizing the support plate member size to achieve a short delivery time of several hours from order receipt to completion, and SUS, conductive rubber, antistatic plastic materials, aluminum plates, etc. Therefore, the cradle of the present invention can be provided at an economical price compared with the conventional product.
Furthermore, even when the cradle of the present invention becomes unnecessary due to a model change or the like, the support plate member can be recycled and used, so that resources can be effectively utilized.
[Brief description of the drawings]
FIG. 1A is a schematic cross-sectional view for explaining a state in which a printed wiring board having an electronic component mounted on one side is supported on a cradle of the present invention.
(B) is a top view for demonstrating the contact surface of the support board member of the cradle of this invention, and the printed wiring board with which the electronic component was mounted in the single side | surface.
(C) is a top view for demonstrating the contact surface of the support board member of the cradle of another embodiment of this invention, and the printed wiring board with which the electronic component was mounted in the single side | surface.
FIG. 2 is a schematic cross-sectional view for explaining a state in which a printed wiring board having electronic components mounted on one side is supported by a conventional pin support type cradle.
FIG. 3 is a schematic cross-sectional view for explaining a state in which a printed wiring board having an electronic component mounted on one side is supported by a conventional shaving-type cradle.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Printed wiring board stand 11 Base 12 Holding member 13-24 support board member Support board member 3 Printed wiring board 4-46 Electronic component 6 Squeegee 61 Cream solder 7 Metal mask 8 Recessed part

Claims (4)

Without bending the printed wiring board surface on which the electronic component is mounted on one side, the width of the portion that comes into contact with the board is 0.1 to 5 mm, the widths are different, and a plurality of support plate members having the same height, A holding member having a slit-like through-opening for holding and standing the support plate member, and a pedestal having a compression elastic modulus of 5000 kg / mm2 or more for standing and holding the support plate member, A printed wiring board cradle characterized by comprising a conductive material as a whole. The printed wiring board cradle according to claim 1, wherein the support plate member, the holding member, and the pedestal are made of a material that can withstand a temperature within 200 ° C. to 330 ° C. 2. The wiring board is protected by covering a portion of the support plate member that comes into contact with the printed wiring board with a metal film such as plating, a lining made of conductive rubber, or a cap. 2. A printed wiring board cradle according to 2. The holding member having the slit-like through opening is processed with a laser or a router, and then fixed to the base, and then the support plate member is inserted into the opening of the holding member. The method for manufacturing a printed wiring board cradle according to claim 1, comprising a process of adjusting the height of the printed wiring board.

Images