Flatness detecting method and detecting instrument thereby

Abstract

The method includes the following steps: a transparent base board is provided, electronic component is placed on transparent base board as a side having weld part of electronic component is faced to abovesaid transparent base board; distance of weld part bottom surface of electronic component to transparent base board surface is checked by a measuring device; and whether product is qualified or not can be judged by comparing maximum distance between weld part bottom surface of electronic component and transparent base board with theoretical calculation value which ensures all weld parts of electronic components to be weldable with circuit board.

Description

【Technical field】 [0001] The invention relates to a flatness detection method and a detection device using the method, in particular to a detection method for detecting the flatness of a soldered part of an electronic component and a circuit board and a detection device using the method. 【Background technique】 [0002] Among electronic components, the most common soldering method between electrical connectors and circuit boards has gone through three stages: DIP (In-line), SMT (Surface Mount) and BGA (Ball Grid Array). If the DIP method is used, the circuit board needs to be provided with corresponding through holes, so that the multi-layer lines in the circuit board need to avoid the aperture and make the lines unable to be dense, so that the volume of the circuit board and electrical connectors cannot be reduced. As for the use of SMT And the BGA method, which requires that the lower surface of the electrical connector solder feet or solder balls must maintain a fairly hig...

AI Technical Summary

Problems solved by technology

If the DIP method is used, the circuit board needs to be provided with corresponding through holes, so that the multi-layer lines in the circuit board need to avoid the aperture and make the lines unable to be dense, so that the volume of the circuit board and electrical connectors cannot be reduced. As for the use of SMT And the BGA method, which requires that the lower surface of the electrical connector solder feet or solder balls must maintain a fairly high coplanarity, otherwise it will cause a virtual soldering between some solder legs or solder balls and the circuit board, resulting in the electrical connector and the circuit board. The telecommunication connection line between them is interrupted and the predetermined function cannot be realized. Therefore, it is very important to detect the flatness of the above-mentioned solder feet or solder balls in the production process. At present, the detection method used in the industry is mainly by detecting the relative The height of the lower surface 15 of the electrical connector 10, and then compare all the measured values ​​to get the difference between the highest value and the lowest value, and then compare the difference with the theoretical calculation to ensure that all soldering pins and circuit boards can be welded Theoretical difference is compared to judge whether the welding pin meets the coplanarity requirements, but the problems that may arise in this method are: 1) If figure 1 As shown, when the lower surface 15 of the electrical connector 10 connected to the highest soldering point is partially bent upwards and deformed, the measured height of the soldering leg arranged there is A+B+C (the bottom surface bent upwards of the lower surface 15 to The height of the top of the soldering pin), and the height of the most soldering pin is B, so the height difference between the highest point and the lowest point is A+C, which may exceed the theoretical calculation to ensure that all soldering pins and the circuit board 20 can be welded. The difference leads to the judgment that the product is unqualified, but based on the lower surface of the electrical connector connected to the lowest soldering point, the height difference between the two is C, which may be within the range of theoretical values ​​to ensure that all soldering points can be contact with the circuit board

Another situation such as figure 2 As shown, when the lower surface 15 of the electrical connector 10 at the lowest soldering point is locally bent and deformed, the height of the lowest soldering point is A'+B', and the height of the highest soldering point is B'+C', assuming that A" and The length of A' is the same, and the difference between the measured values ​​of the two is C", which may be smaller than the theoretical difference to judge that the product is qualified, but based on the lower surface of the electrical connector connected to the highest soldering point, the height difference between the two is A "+C", which may be greater than the theoretical difference and make the lowest soldering pin unable to contact the circuit board

2) if image 3 As shown, assuming that the lower surface 15 of the electrical connector 10 has no bending deformation, when the height difference between the highest soldering leg and the lowest soldering leg is used to measure, the height difference between the highest soldering leg and the lowest soldering leg is E, which may not exceed The theoretical value that guarantees that all soldering feet and the circuit board can be welded by theoretical calculation will judge the product to be qualified

But when the electrical connector 10 is installed on the circuit board 20 (such as Figure 4 As shown), due to the supporting effect of the highest soldering pin, the electrical connector 10 will have a certain angle of inclination, so the height difference between the lowest soldering pin and the highest soldering pin will be F, which may be greater than the theoretical difference and make the The lowest solder pin cannot make contact with the board

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