Suggestions for reducing crosstalk.
Because they don’t support a multilevel hierarchical finished goods BoM.
The rate of MES system implementations in electronics manufacturing is not slowing. The rise of Industry 4.0 and the concept of big data have stimulated many companies to seek ways of collecting all important data in real time. If implemented properly, Industry 4.0 will eliminate the need for MES systems. Taking their place will be cyber-physical systems using machine-to-machine (M2M) communication and big data used to make intelligent decisions to run production without any human intervention.
There are still no signs, however, that we will come to terms with which M2M standard to use for Industry 4.0. Among Japanese machine vendors, an IPC-led effort, an ASM-led effort, and a Siemens-led effort, everyone else is left guessing what will happen and if an industry-wide standard will emerge at all. Until that happens, and until machine vendors implement better support for Industry 4.0, electronics manufacturers are pushing forward with MES implementations.
Is the reflow profile the problem? X-ray can help.
Looking through some recent x-ray images of what I would call “good bad” boards (at least, that is what they are for me, as they showcase “good” examples of how certain “bad” types of failure look under x-ray inspection), I came across a number of different issues that are different from “traditional” BGA/QFN problems mentioned in this space before. To wit, I noted some images showed where solder paste had not reflowed under the devices, and there was the presence of foreign object(s), such as discrete components, trapped under the package.
FIGURES 1 and 2 show how unreflowed solder paste typically looks under QFN joints in an x-ray image. In the magnified view (Figure 2), individual grains of the solder paste are seen clearly, instead of appearing as a typical single smooth continuous joint. The cause of this is probably not an insufficient reflow profile. Rather, it is more likely the board has not been reflowed at all. As it may be desired, or necessary, to x-ray inspect (representative) boards after placement but before reflow as part of a quality control process, it is worth noting this characteristic shape of the solder under the components is different from what would be expected post-reflow.
Cleanliness is next to stickiness.