While printed molds are fast to produce, they are slow to process with cycle times between 2-3 minutes versus the 30-45 seconds for a traditional metal mold. This is acceptable when you’re doing low-volume work, but it can add up quickly the more shots you’re looking to achieve. Although our DT resin is the toughest on the market, it has low thermal conductivity. This makes it difficult to quickly remove heat and be ready for the next shot.
To counteract this, we implemented a two-phased (passive and active) cooling approach where we passively cool the part with the mold blocks while the mold is still closed. Once the part has solidified, we open the mold blocks and use compressed air to do the active cooling. This step which accounts for the majority of our heat transfer cools both the part and the mold blocks
This approach has worked well enough for us but innovation doesn’t stop at “well enough”. We know that our molds have a low thermal conductivity so using the same cooling channels that metal molds use will yield significantly worse results. A quick look at the heat transfer equation for conduction tells us that in order to reduce the cooling time we need to either increase the surface area of our cooling channels or reduce the distance between the cooling channels and the part … or both.