Typically, when we announce a re-formulation, it’s because we’ve made significant changes to a material. In the case of Tough Resin V4, it’s a bit different. Tough V4 will be available through our North American and International stores shortly and can be purchased in the EU thereafter.
We switched suppliers for one of the components in Tough Resin and this is the reason for the re-formulation. Mechanical properties are nearly identical for both versions and the primary difference is a more blue color. This also means that V3 and V4 can safely be mixed. If you have a currently existing tank of Tough V3, you can safely insert and print with a new cartridge of V4. The ability to combine different formulation versions is a unique situation and won’t work for other materials.