SMD will have a variety of quality defects occur, for example, the component side of the warped empty solder, the industry called this phenomenon for the monument.
One end of the component warped thus causing the monument empty solder, is a variety of reasons for the formation of. Today, we will explain the causes of the phenomenon and some improvement measures.
1.Solder paste printer is not flat, one end of the pad more tin, one end less tin
This is the front end of the patch triggered, due to uneven solder paste printing, solder paste printing at both ends of the pad is not the same amount, resulting in the back of the welding dissolution time is not the same, resulting in tension is not the same, and thus one end was warped to form empty solder.
The best way to improve this is to add an SPI behind the solder paste printing machine, try to detect the printing bad, avoid the flow to the welding and then the problem, so that the reworking time consuming and cost is higher.
2.Pick and place machine mount both ends are not flush or offset
After the SMD machine absorbs the component placement, may cause the suction nozzle to absorb the deviation or the camera reads the bit number placement accuracy to deviate due to the feed of the flyer, thus leading to the placement offset, the pad end is posted more, one end is posted less to reveal to the pad outside, thus leading to the time of reflow welding when the hot melt time is different, climbing tin time is different, leading to different tension, causing warping.
The method to improve this problem, on the one hand is to maintain the mounter’s flyer and camera regularly, avoid absorbing and placing deviation. on the other hand, there is a budget to get a SMT AOI machine, detect the quality of placing.
3.Reflow soldering machine furnace temperature curve setting problem
Reflow soldering itself has four temperature zones, different temperature zone role is different, in preheating and constant temperature stage, some components may be located next to the higher components, thus causing one side to be heated badly, in entering the heating welding stage, the temperature is different leading to the solder paste heat melting time is different, appearing standing monument empty welding.
The above three reasons are the common causes of components warped standing tablet empty solder, if in the production process, this phenomenon can be from these aspects of the troubleshooting.
Post time: Aug-10-2022