Moldflow Plastic Insight (MPI) is a computer simulation of injection molding that “helps us begin to understand what is going on inside the mold,”

according to Rick Millette, D-M-E field service representative.
Simulating the way a material will actually flow through a mold before it’s ever built ends up saving time and money in the long run. It’s particularly valuable for any product with varying wall thicknesses, surfaces or challenging part geometry.

“Any time I have a product that has some difficult geometry, I always want to make sure I pick the right place for the gate, core and flow,” notes Giansanti.

This accuracy becomes even more important when competing with low-cost overseas moldmakers. Plas-Pak doesn’t find itself in that position at the moment, but it’s an increasing concern for moldmakers across North America. Even though a complete mold flow analysis costs between $1,000 and $2,000 and takes a few extra days, the practice can pay off quickly, in both time and money.

Without mold flow analysis, the whole process is more about trial and error. Moldmakers have to start with small gates to fill their mold and keep increasing the size little by little until the mold gate is the correct size. Besides wasting time and money, that also creates more backpressure in the mold, which creates core shift. It’s an expensive, inefficient way to determine the appropriate gate size: you have to take the mold out of the machine each time, modify the gate and put it back in. In the process, you also create more scrap and bad parts.