How the Promega lets you have a heated chamber for long and complex prints without limiting your ability to prototype and test changes quickly
With the design choices we’ve made in the Promega, we really aimed to accommodate two broad styles of printing. In this article, we’ll go into a little of what that means, and how best to set up and run your printer, based on what you’re trying to do with it.
The first kind of printing is large quantity, small size production parts, in a material like PLA or HIPS. The top window can be removed (and ought to be removed for printing PLA anyway, which softens around 45°C) for quick bed access, and the PTFE filament feed tubes can be bypassed for faster loading. In this configuration, you can pump out dozens of copies of small parts quickly, with barely any downtime between runs. This is perfect for the hobbyist or professional who needs a lot of parts fast.
The second kind of prints are big jobs that take full advantage of the Promega’s print volume, heated bed, and heated print chamber. For large prints in ABS-R, ABS, PETG, HIPS, etc, you will want to maximize the bed temperature, especially if you are printing on glass. The fully enclosed print chamber will also be needed in order to bump ambient temperature up to 60°C, which pushes the bed into the 100-115°C range, even when using the glass print surface. In this mode, with the windows all on, the PTFE tubes will need to be used to feed filament. The extruder system, chain, etc all fit under the top window while still maximizing print volume. This is accomplished by the slight curve on the back of the sheet metal slot, which has the necessary room to accommodate the extruder system when at the highest point at the back of the printer. This printing mode is for those large prints in challenging materials, where the Promega is really the only option in its price range.
While we aim to let you use the Promega to print how and what you want, we also don't want the printer to have any chance of damaging itself or your prints. If we didn't design carefully, there would be a chance of thermal runaway, where temperatures in the print chamber exceed the rated temperature of components inside. To prevent any such issues, the back slot opening acts as a vent, and is a fail-safe to prevent overheating beyond system tolerances, even with all the windows on and the bed heated.