I. The correct components
Requirements for the assembly of the type, model, nominal value and polarity of the components of the bit number and other characteristics of the mark should be in line with the product’s assembly drawings and detailed list of requirements, can not paste the wrong location.
II. The position is accurate
Components of the end or pins and pad graphics should be aligned as far as possible, centered, but also to ensure that the component welding end contact solder paste graphics. Components mounting position to meet the process requirements. Two ends of the Chip components, wing-shaped pin and J-shaped pin device, ball-shaped pin device placement position requirements are as follows:
1. The two ends of the Chip components: two ends of the Chip components of the self-localizing effect of the role of the larger, mounting components in the width direction of more than 1/2 lap in the pad, length direction of the two ends as long as the lap to the corresponding pad and contact the solder paste graphic, reflow can be self-locating, but if one of the end did not lap to the pad or did not contact the solder paste graphic, reflow soldering will be Shift or bridge.
2. Wing-shaped pin and J-shaped pin devices: for SOP, SOJ, QFP, PLCC and other devices, the role of self-localization is relatively small, the mounting offset can not be corrected by reflow soldering. If the mounting position exceeds the allowable deviation range, it must be manually corrected before entering the reflow soldering furnace. Otherwise, the reflow soldering must be reworked, which will result in a waste of man-hours and materials, and even affect the reliability of the product. During the production process, when the mounting position is found to be out of the allowable deviation range, the mounting coordinates should be corrected in time.
Manual mounting or manual dialing requires accurate mounting position, pin and pad alignment, centering, do not put inaccurate, dragging on the solder paste to find the right, so as to avoid solder paste graphic adhesion, resulting in bridging.
3. Spherical pin device: As BGA, CSP and other spherical pin device pad area relative to the area of the component body is relatively large, self-localizing effect is very good, so as long as to meet the two points can be, one is the BGA solder ball and the corresponding pad corresponds to one by one; the second is the center of the solder ball and the center of the pad of the maximum offset is less than 1/2 the diameter of the solder ball.
III. The pressure (patch height) appropriate.
Patch pressure (Z-axis height) to be appropriate. Patch pressure is too small, component welding end or pin floating in the solder paste surface, solder paste can not stick to the component, in the transfer and reflow soldering is easy to produce the position of movement, in addition, because the Z-axis height is too high, the patch components thrown down from a high place, it will result in the position of the patch offset.
Patch pressure is too large, the amount of solder paste extrusion is too much, easy to cause solder paste adhesion, reflow soldering is easy to produce bridging, but also due to the sliding caused by the patch position shift, and in serious cases, it will also damage the components.
Zhejiang NeoDen Technology Co., LTD., founded in 2010, is a professional manufacturer specialized in SMT pick and place machine, reflow oven, stencil printing machine, SMT production line and other SMT Products. We have our own R & D team and own factory, taking advantage of our own rich experienced R&D, well trained production, won great reputation from the world wide customers.
In this decade, we independently developed NeoDen4, NeoDen IN6, NeoDen K1830, NeoDen FP2636 and other SMT products, which sold well all over the world. So far, we have sold more than 10,000pcs machines and exported them to over 130 countries around the world, establishing a good reputation in the market. In our global Ecosystem, we collaborate with our best partner to deliver a more closing sales service, high professional and efficient technical support.
Post time: Dec-08-2023