"Not being familiar with this, I'm curious where the humans are still required in the process of doing a dozen or hundred of each board."
Some components have large amounts of mass and need to be manually placed because the PNP doesn't have the vertical space for pickup and movement to the pad or do not have feeders which can successfully hold onto the part.
And some times it's just faster to have the human place the part because they're faster than the machine due to physical limitations (like needing to move slowly so as to not drop the component or throw it at the end of travel.) Many board shops will have the PNP places the ICs/Caps/Resistors/diodes and then the placement of connectors (especially zierich) or inductors gets done manually. That is how it worked where I worked. This also provided an opportunity mid-process to do quality checks instead of just letting things go from the PNP straight into the oven.
Some components have large amounts of mass and need to be manually placed because the PNP doesn't have the vertical space for pickup and movement to the pad or do not have feeders which can successfully hold onto the part.
And some times it's just faster to have the human place the part because they're faster than the machine due to physical limitations (like needing to move slowly so as to not drop the component or throw it at the end of travel.) Many board shops will have the PNP places the ICs/Caps/Resistors/diodes and then the placement of connectors (especially zierich) or inductors gets done manually. That is how it worked where I worked. This also provided an opportunity mid-process to do quality checks instead of just letting things go from the PNP straight into the oven.