Factors affecting the quality of placement
发布时间：2014-05-21 16:22:51 浏览次数：1055
Mount the three elements of quality are: the right components, location accuracy, pressure (patch height) right.
1. Element correctly - require the type of component assembly bit number, type, nominal value and the polarity mark to meet the product characteristics such as the assembly diagram and schedule requirements, can not paste the wrong position.
2. Location accuracy - or pin the ends of components and the pads are 3-inch graphics as far as possible homogeneous, middle.
Placement positions of components to meet the technical requirements. Chip component because the two ends from the larger role of the orientation effect, mount the two directions when the device length as long as the ride ends on receipt of the corresponding pad, the width direction of the 1 / 2 lap in the pad, the reflow Time to self-positioning, but if one side does not take receipt of the first pad, the reflow will result when the shift or suspension bridge. For the SOP, SOJ, QFP, PLCC and other components of the self-positioning effect is relatively small, can not mount reflow offset is corrected; therefore, must ensure the pin mounting width of 3 / 4 at the pad, the pin the toe and heel should be in the pad. If the mount beyond the allowable deviation of position, you must manually dial is then welded into the reflow oven; otherwise, must be repaired after reflow will result in hours of work, material waste, and even affect product reliability. Placement positions found in the production process beyond the tolerance range are mounted coordinates should be timely.
Hand placement positions of placement accuracy when required, pin and pad alignment, center, do not put stickers are not allowed in the solder paste on the drag look is so graphics paste adhesion, causing the bridge.
3. Pressure (patch height) right.
Patch pressure (high) to properly fit, welding ends or pin component is not less than 1 / 2 thickness to be immersed in solder paste. When the general components of the paste extrusion patch volume (length) should be less than 0.2mm, SMD components for the narrow space between the solder paste during extrusion volume (length) should be less than 0.1mm. Patch pressure is too small, welding ends or pin floating components in the paste surface, solder paste viscosity not live components, the delivery and reflow prone position when moving; patch excessive pressure, excessive amount of paste extrusion more likely to cause solder paste adhesion, reflow time prone to bridging, serious damage to components will be.
1. Element correctly - require the type of component assembly bit number, type, nominal value and the polarity mark to meet the product characteristics such as the assembly diagram and schedule requirements, can not paste the wrong position.
2. Location accuracy - or pin the ends of components and the pads are 3-inch graphics as far as possible homogeneous, middle.
Placement positions of components to meet the technical requirements. Chip component because the two ends from the larger role of the orientation effect, mount the two directions when the device length as long as the ride ends on receipt of the corresponding pad, the width direction of the 1 / 2 lap in the pad, the reflow Time to self-positioning, but if one side does not take receipt of the first pad, the reflow will result when the shift or suspension bridge. For the SOP, SOJ, QFP, PLCC and other components of the self-positioning effect is relatively small, can not mount reflow offset is corrected; therefore, must ensure the pin mounting width of 3 / 4 at the pad, the pin the toe and heel should be in the pad. If the mount beyond the allowable deviation of position, you must manually dial is then welded into the reflow oven; otherwise, must be repaired after reflow will result in hours of work, material waste, and even affect product reliability. Placement positions found in the production process beyond the tolerance range are mounted coordinates should be timely.
Hand placement positions of placement accuracy when required, pin and pad alignment, center, do not put stickers are not allowed in the solder paste on the drag look is so graphics paste adhesion, causing the bridge.
3. Pressure (patch height) right.
Patch pressure (high) to properly fit, welding ends or pin component is not less than 1 / 2 thickness to be immersed in solder paste. When the general components of the paste extrusion patch volume (length) should be less than 0.2mm, SMD components for the narrow space between the solder paste during extrusion volume (length) should be less than 0.1mm. Patch pressure is too small, welding ends or pin floating components in the paste surface, solder paste viscosity not live components, the delivery and reflow prone position when moving; patch excessive pressure, excessive amount of paste extrusion more likely to cause solder paste adhesion, reflow time prone to bridging, serious damage to components will be.
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