Hi agjones85,
First of all, the technology integrated in Fusion here is based on what exist in the Autodesk Moldflow products, and we do have explicit overmolding capabilities in Autodesk Moldflow Insight. This is on the list of things to bring into Fusion as well but it is going to take a little bit of time to get there.
Furthermore there are two types of overmolding to distinguish and I would like your input on which of the two you are actually asking for:
1) Insert overmolding. This is a process where parts (this could be metal bushings, or a different plastic piece) are placed (inserted) inside the mold, and the molding process will embed these inserts in the full part.
2) 2-shot overmolding (this could also be 3 or more shot overmolding, and this also goes by 2k molding in some parts of the world) where in one mold a first part is created, and where through some mechanism (there are different ways to do this) the more space is created around the first part, where a second molding shot injected into. The materials for the first and second shot are typically two different material, and the molding is done with two individually controlled injection units (connected to one mold).
Both insert- and 2 shot overmolding processes are fairly common, but they are currently not explicitly supported by Injection Molding in Fusion 360.
But I can provide a bit of guidance.
1) if you are looking for a 2 shot overmolding capability, you can try run a simulation on the first and second shot individually and establish whether the parts are individually moldable. The analysis of the first shot would be representative for if the first shot in reality. For the second shot, the simulation would represent a 'worst case' situation in the sense that the simulation would take place assuming the plastic everywhere in contact with mold steel --> cooling down quickly and making it harder to fill. In reality, the second shot will actually be in contact with plastic (= a thermal insulator) in certain places and will not cool down as fast and will be a little easier to fill.
If you are doing this, the ability to fill would probably be OK, but the results would be less reliable for establishing over all cycle time (as the simulation of the second shot would probably give a shorter cycle time than you would get in reality as the part will cool down faster in the simulation), the position of defects may not be very accurate (particularly with respect to sink mark visibility of the firs shot THROUGH a second shot), and warpage would only be done on the individual components rather than the combined product.
For insert overmolding of metal inserts, the filling result should be fairly representative under typical conditions if not including the insert (like in Fusion Injection Molding simulation today). If there are filling issues/warnings around the area where you want to place the metal inserts. I would not trust deformation/warpage/shrinkage as metal inserts can have a huge influence on the deformation of the plastic part; the metal inserts are likely very stiff but the plastic will want to shrink --> creates deformation.
Lastly with overmolding of plastic inserts (not super common but ...), like with two shot overmolding, leaving the plastic insert out of the simulation will be a conservative approach (if it fills well with the assumption not having a plastic insert, having the plastic inserts in the mold will make the part easier to Mold. But again ... don't rely on the cycle time or the warpage analysis as they may not be representative.
Again, ... we have the technology to do this, and have this on the list of thing we would like to add to Fusion as well, but it is not there explicitly today.
Hanno van Raalte,
Product Manager - Injection Molding & Moldflow products
