CN207219178U - A fixture for SMT printing - Google Patents

Abstract

A kind of SMT printings tool, including printing screen and bottom plate；Printing screen includes silk screen body, and the printing hole matched with printed circuit board is offered on silk screen body；Four corners of silk screen body are provided with positioning hole；Also the printing hole matched with printed circuit board is offered on bottom plate；The positioning hole corresponded on bottom plate on silk screen body is provided with matched fixing hole；The accommodating chamber for accommodating printed circuit board is formed between printing screen and bottom plate.The utility model reduces the energy consumption of unit output value compared with traditional handicraft, has saved cost, simplifies typography, tin cream destroyed risk when improving printing efficiency and printing quality, and avoiding production, has significant progressive.

Description

A fixture for SMT printing

technical field

The utility model belongs to the technical field of SMT (surface mount technology), and relates to a fixture for SMT printing.

Background technique

With the rapid development of the electronics industry, there are a wide variety of electronic products, and precision electronic components are widely used in various industries. At the same time, the quality and yield of precision electronic components are required to be higher. The quality of SMT of PCB directly affects the processing efficiency and yield rate of its production, and the quality of SMT is closely related to the printing stencil, so the structural design of the printing stencil is very important.

The printing stencil is a mold used to print solder paste. When printing solder paste, it is leaked onto the PCB pad through the opening of the stencil, that is, it is printed on the PCB pad through the size of the stencil opening, and then passed through the furnace. At present, the SMT tin printing double-sided process generally adopts the method of first printing, patching, and reflowing to produce one side, and then reprinting, reprinting, and reflowing to produce the other side. Two reflow processes need to add a reflow furnace equipment, thereby increasing the energy consumption per unit of output value; at the same time, when printing on both sides, the solder paste on the other side is easily damaged when printing after reprinting.

Therefore, how to solve the above problems is what those skilled in the art should study.

Contents of the invention

In order to overcome the deficiencies in the above-mentioned prior art, the purpose of the utility model is to provide a jig for SMT printing with simple structure and low production cost.

In order to achieve the above purpose and other related purposes, the utility model provides a fixture for SMT, including a printing screen and a bottom plate; the printing screen includes a screen body, and the screen body is provided with a The printing holes matching the circuit board; the four corners of the screen body are provided with positioning holes; the bottom plate is also provided with printing holes matching the printed circuit board; the bottom plate corresponds to the screen The positioning hole on the body is provided with a fixing hole matched therewith; an accommodating cavity for accommodating the printed circuit board is formed between the printing screen and the bottom plate.

In the above technical solution, the relevant content is explained as follows:

1. In the above solution, the printing screen is a magnetic steel sheet with a thickness of 0.2mm.

2. In the above solution, arc-shaped concave edges are provided on the circumference of the bottom plate.

3. In the above solution, the four corners of the bottom plate are provided with triangular fixing grooves for inserting the corners of the printed circuit board; the fixing holes are also arranged on the groove walls of the triangular fixing grooves.

Due to the use of the above technical solutions, the utility model has the following advantages compared with the prior art:

The utility model adopts the printing fixture to fix the printed circuit board, and adopts the printing process of printing-turning board-re-printing-patch-reflow welding-cleaning the printed circuit board, which saves a reflow welding step compared with the traditional process, and saves A reflow furnace equipment was installed, which reduces the energy consumption per unit output value, saves costs, simplifies the printing process, improves printing efficiency and printing quality, and avoids the risk of solder paste being damaged during production.

Description of drawings

Fig. 1 is a structural representation of the utility model;

Fig. 2 is the schematic diagram of printing screen structure in the utility model;

Fig. 3 is a schematic diagram of the process flow of the utility model.

Detailed ways

The implementation of the present utility model is illustrated by specific specific examples below, and those skilled in the art can easily understand other advantages and effects of the present utility model from the content disclosed in this specification.

See Figures 1 through 3. It should be noted that the structures, proportions, sizes, etc. shown in the drawings attached to this specification are only used to match the content disclosed in the specification, for those who are familiar with this technology to understand and read, and are not used to limit the implementation of the utility model Therefore, it has no technical substantive meaning. Any modification of structure, change of proportional relationship or adjustment of size shall still fall within the scope of The technical content disclosed by the utility model must be within the scope covered. At the same time, terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit this specification. The practicable range of the utility model, and the change or adjustment of its relative relationship, without any substantial change in the technical content, shall also be regarded as the practicable scope of the utility model.

As shown in Fig. 1 and Fig. 2, a kind of SMT printing process uses printing jig, comprises printing screen and base plate 1; Described printing screen comprises screen body 2, is provided with described screen body 2 The printing hole 3 that printed circuit board 5 matches; The four corners of described screen body 2 are provided with positioning hole 4; Also offer the printing hole that matches with described printed circuit board on the described base plate 1 (in the figure not shown); the bottom plate 1 is provided with a fixed hole 6 corresponding to the positioning hole 4 on the screen body 2; the printing screen and the bottom plate 1 are formed for accommodating the An accommodating cavity for the printed circuit board 5 .

The printing screen is a magnetic steel sheet with a thickness of 0.2mm.

An arc-shaped concave edge 11 is provided on the circumference of the bottom plate 1 . The concave bottom of the concave edge 11 is located inside the edge of the printed circuit board 5 , which is convenient for taking and placing the printed circuit board 5 .

The four corners of the bottom plate 1 are provided with triangular fixing slots 7 for inserting the corners of the printed circuit board 5 ; the fixing holes 6 are also provided on the walls of the triangular fixing slots 7 .

As shown in Figure 3, the SMT printing process using the printing fixture; includes the following steps:

Making printing fixtures: According to the position of SMT components on the printed circuit board and the shape of the pads, make printing fixtures for missing solder paste;

Screen solder paste printing: fix the printed circuit board in the printing fixture, and evenly print the solder paste on the electrode pads of the components;

Flip board: Flip the jig and print the solder paste evenly on the electrode pads of the components on the other side of the printed circuit board;

Mount SMT components: mount SMT components on the printed circuit board so that the electrodes are accurately positioned on their respective pads;

Reflow soldering: soldering by reflow soldering method;

Clean the printed circuit board and complete the printing.

in the step During the soldering process, the solder paste is melted and reflowed to fully infiltrate the components and the pads of the printed circuit board.

in the step In the cleaning process, the printed circuit board after reflow soldering is soaked in an inorganic solution and cleaned by ultrasonic shock.

The utility model adopts the printing fixture to fix the printed circuit board, and adopts the printing process of printing-turning board-re-printing-patch-reflow welding-cleaning the printed circuit board, which saves a reflow welding step compared with the traditional process, and saves A reflow furnace equipment has been installed, which reduces the energy consumption per unit output value, saves costs, simplifies the printing process, improves printing efficiency and printing quality, and avoids the risk of solder paste being damaged during production, which is a significant improvement.

The above-mentioned embodiments only illustrate the principles and effects of the present utility model, but are not intended to limit the present utility model. Anyone familiar with this technology can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the utility model should still be covered by the claims of the utility model.

Claims (4)

1. A kind of 1. SMT printings tool, it is characterised in that：Including printing screen and bottom plate；The printing screen includes silk screen sheet Body, the printing hole matched with printed circuit board is offered on the silk screen body；Four corners of the silk screen body are provided with fixed Position hole；Also the printing hole matched with printed circuit board is offered on the bottom plate；Corresponded on the bottom plate on the silk screen body Positioning hole be provided with matched fixing hole；Formed between the printing screen and the bottom plate for housing the printed circuit The accommodating chamber of plate.
2. 2. SMT printings tool according to claim 1, it is characterised in that：The printing screen is that thickness is 0.2mm's Magnetic steel disc.
3. 3. SMT printings tool according to claim 1, it is characterised in that：It is recessed that the circumference of the bottom plate is provided with arc Side.
4. 4. SMT printings tool according to claim 1, it is characterised in that：Four angles of the bottom plate are provided with and supply institute State the triangle fixing groove of the corner insertion of printed circuit board；The fixing hole is also provided in the cell wall in the triangle fixing groove On.