That injection molding machines are not in the simulation is a problem we have to keep in mind. So there is the pressure loss in the nozzle. Some people create the nozzle in CAD to get this in the simulation. But what is with the quality of the injection molding machine. Old or new. Is the return valve working? Compression of the melt in the cylinder is not considered of simulation.
Comparing reality with simulation requires sensor in the mold to get precise information. At least pressure. But temp also would be good. Also check the hydraulic pressure curve of the injection molding machine, the curve of the ramp and especially the injection velocity curve. If the injection profile in simulation does not fit reality…well. So many things to take care of.
I got information at the last moldflow user meeting in Germany that moldflow is a bit changing. In the past the focus was most on midplane, cause many OEM use moldflow and the automotive exterior parts are big. No good idea to simulate with 3D. Takes to long. But Moldflow wants to change a bit to concentrate more on injection mold designers. So there will come a tool to simulate ejection and a tool to simulate mold deflection and lifetime for cores. That will be great.