Positioning jig for fixing longer FPC (Flexible Printed Circuit) in SMT (Surface Mount Technology)

Abstract

The utility model discloses a positioning jig for fixing a longer FPC (Flexible Printed Circuit) in SMT (Surface Mount Technology), which comprises a jig body, a plurality of convex hulls are arranged at the upper end part of the jig body, and a positioning pin is arranged on each convex hull. According to the utility model, through the arrangement of the convex hulls and the positioning pins, each bonding pad on the FPC can be fixed on the convex hulls, thereby counteracting the position change of the bonding pads caused by the expansion and contraction of the FPC in production, ensuring that the positions of the bonding pads on the same FPC produced in the same batch or different batches are kept fixed relative to the positioning jig, and improving the production efficiency. Therefore, it is ensured that the same screen or the screen of the same structure can be always suitable for production of the FPC, stable and consistent SMT quality can be kept, design and production of the screen and first-batch production of the FPC can be carried out at the same time, production timeliness is improved, waiting time of subsequent procedures is avoided or shortened, and production efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of FPC production, and particularly relates to a positioning fixture for fixing a longer FPC in the SMT process. Background Art

[0002] In the production of FPC, the positions of the pads on it are fixed after the design is completed, and a stencil is designed and manufactured accordingly to apply solder paste through the stencil onto the pads in the SMT process.

[0003] At present, the base film of FPC is generally made of polyimide, that is, PI film. During the production process of FPC, the PI film will expand or contract to a certain extent, resulting in a deviation between the pad positions on the formed FPC and the initial design positions. The longer the FPC, the more obvious the position deviation of the pads, resulting in poor solder paste brushing in the SMT process. To solve this problem, the common practice in production is to first produce the FPC, then measure its actual length, and then generate a stencil design drawing and produce it after adjusting the design dimensions of the FPC accordingly. This method has the following disadvantages: 1. The design and production of the stencil can only start after the production of the first batch or the first piece of FPC is completed, with poor timeliness, causing delays in subsequent processes such as SMT and affecting production efficiency; 2. The FPCs in the same batch will also have fluctuations in size expansion and contraction, and there will still be a situation where the stencil cannot fully match the FPC, which will further affect the yield rate of SMT. Summary of the Utility Model

[0004] In view of the problems existing in the above-mentioned prior art, the utility model provides a positioning fixture for fixing a longer FPC in the SMT process, which can fix each pad on the FPC on the convex bumps, offset the change in the pad position caused by the expansion and contraction of the FPC itself during production, ensure that the positions of the pads on the same model of FPC produced in the same batch or different batches are fixed relative to the positioning fixture, so as to ensure that the same stencil or stencils with the same structure can always be applicable to the production of this type of FPC and maintain stable and consistent SMT quality, and the design and production of the stencil can be carried out simultaneously with the first batch production of the FPC, improving production timeliness, avoiding or reducing the waiting time of subsequent processes, and enhancing production efficiency.

[0005] To solve the above technical problems, a technical solution adopted by the utility model is as follows:

[0006] A positioning fixture for fixing a longer FPC in the SMT process includes a fixture body, and a positioning part for clamping the FPC is provided at the upper end of the fixture body. A plurality of convex bumps are provided on the positioning part, and a positioning pin is provided on each convex bump; each positioning pin can fix the FPC on one of the convex bumps to fix a pad on the FPC on one of the convex bumps.

[0007] As a further elaboration of the above technical solution:

[0008] In the above technical solution, the length of the positioning portion is less than the length of the FPC.

[0009] In the above technical solution, the height of each convex hull is 1.5 mm.

[0010] In the above technical solution, each convex hull is integrally formed with or detachably fixedly connected to the jig body.

[0011] In the above technical solution, the contour edges of each convex hull are preferably arranged outside the contour edges of each pad.

[0012] Compared with the prior art, the beneficial effects of the present utility model are as follows: By providing convex hulls and positioning pins, each pad on the FPC can be fixed on the convex hulls, offsetting the change in the position of the pads caused by the self-expansion and contraction of the FPC during production, ensuring that the positions of the pads on the same type of FPC produced in the same batch or different batches remain fixed relative to the positioning jig, thereby ensuring that the same stencil or stencils of the same structure can always be applicable to the production of this type of FPC and maintaining stable and consistent SMT quality. Moreover, the design and production of the stencil can be carried out simultaneously with the first batch production of the FPC, improving production timeliness, avoiding or reducing the waiting time in subsequent processes, and enhancing production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of the operation structure of the current SMT process;

[0014] Figure 2 is a schematic diagram of the structure of the jig, FPC and stencil in the SMT process of this embodiment;

[0015] Figure 3 is Figure 2 an enlarged schematic diagram of part A in

[0016] In the figure: 1. Jig body; 2. Convex hull; 3. Positioning pin. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The present utility model will be further described in detail below with reference to the accompanying drawings.

[0018] The embodiments described with reference to the accompanying drawings are exemplary and are intended to explain the present application, and should not be construed as limiting the present application. In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present application. In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, the meaning of "a number of" and "a plurality of" is two or more, unless otherwise specifically and clearly defined. In the present application, unless otherwise clearly specified and limited, the terms such as "mounted", "connected", "connected to", "fixed" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application may be understood according to specific circumstances. In the present application, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "under" the second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than that of the second feature.

[0019] For ease of understanding, Figure 1 The schematic diagram of the operation structure of the positioning fixture, FPC and stencil in the currently commonly used SMT solder paste brushing process is shown. It can be seen that when the FPC is relatively long, due to the expansion and contraction of the PI film, the positions of the pads on it and the solder paste brushing holes on the stencil cannot always be perfectly matched; moreover, the upper end of the positioning fixture needs to clamp the FPC, and its upper end needs to be at least as long as the FPC.

[0020] As Figures 2-3As shown in the figure, this embodiment is a positioning fixture for fixing a longer FPC in the SMT process, including a fixture body 1, with a positioning part for clamping the FPC provided at its upper end. A number of convex bumps 2 are provided on the positioning part, and a positioning pin 3 is provided on each convex bump; each positioning pin 3 can fix the FPC on a convex bump 2, so as to fix a pad on the FPC on a convex bump 2.

[0021] It includes a fixture body 1, with a positioning part for clamping the FPC provided at its upper end. A number of convex bumps 2 are provided on the positioning part, and each convex bump 2 can lift a pad on the FPC; a positioning pin 3 is provided on each convex bump 2, and each positioning pin 3 can fix the FPC on the convex bump 2.

[0022] During application, the FPC is fixed on the convex bump 2 with the positioning pin 3, so that each pad on the FPC is located on the convex bump 2. When the actually produced FPC is slightly longer than the designed length, using the flexibility of the FPC, it is bent and abutted against the side of the convex bump 2 on the positioning part. When the FPC is slightly shorter, the positioning pin 3 can still pull the FPC to make the position of its pads within the set tolerance range, ensuring that the positions of the pads on the same model of FPC produced in the same batch or different batches remain fixed relative to the positioning fixture, so as to ensure that the same stencil or stencils of the same structure can always be applicable to the production of this model of FPC and maintain stable and consistent SMT quality. Moreover, the design and production of the stencil can be carried out simultaneously with the first batch production of the FPC, improving production timeliness, avoiding or reducing the waiting time in subsequent processes, and enhancing production efficiency.

[0023] In a further design, the length of the positioning part is less than the length of the FPC. The contour edges of each convex bump 2 are preferably provided outside the contour edges of each pad. Each of the convex bumps is integrally formed with or detachably fixed to the fixture body.

[0024] It can be understood that due to the buffering of the convex bump 2, the actually available length of the positioning part on the positioning fixture will be longer than the length of the positioning fixture. Therefore, the length of the positioning fixture can be reduced to reduce the consumption of its raw materials and the production cost of the positioning fixture; when the FPC is too long, in order to further reduce the processing difficulty and material loss of the positioning fixture, the convex bump 2 can also be formed separately and then assembled onto the fixture body 1.

[0025] In this embodiment, the positioning fixture is made of bakelite, and the height of each convex bump 2 is 1.5 mm.

[0026] The above does not impose any limitation on the technical scope of the present invention. Any modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solutions of the present invention.

Claims

1. A positioning fixture for fixing a longer FPC in the SMT process, characterized in that, It includes a fixture body, and a positioning part for clamping the FPC is provided at the upper end thereof. A number of convex bumps are provided on the positioning part, and a positioning pin is provided on each convex bump; each positioning pin can fix the FPC on one of the convex bumps so as to fix a pad on the FPC on one of the convex bumps.

2. The positioning fixture for fixing a longer FPC in the SMT process according to claim 1, wherein, The length of the positioning part is less than the length of the FPC.

3. The positioning fixture for fixing a longer FPC in the SMT process according to claim 1, wherein The height of each convex bump is 1.5 mm.

4. The positioning fixture for fixing a longer FPC in the SMT process according to claim 1, characterized in that, Each convex bump is integrally formed with the fixture body or detachably and fixedly connected thereto.

5. The positioning fixture for fixing a longer FPC in the SMT process according to any one of claims 1-4, characterized in that, The contour edges of each convex bump are conveniently arranged outside the contour edges of each pad.

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