Some notes from printing the fan speed selector cap in ABS.
ABS printing involves higher temperatures (extruder 220°C, print bed 100–105°C). For tall and thin prints, this means that the lower layers might not have enough time to cool before the next layer is printed. Over a number of layers, this means that the extruder may end up printing on top of slush.
If you look carefully, you may see the lower layers wobbling as the extruder head is printing on top of it. This is a clear indicator of slush-printing. You may need to pause the print for a short while (30 seconds) to let the layers cool before resuming the print.
This can also be minimised by lowering the print speed. The first fan speed selector cap was printed at 60 mm/s, the second one at 30 mm/s. (Print times were ~30 min and ~1 hr respectively.)
ABS tends to curl at the edges, especially on the first layer. Minimise this by raising the platform temperature, and lowering the print speed.
The first few times I attempted to start the print, I noticed that the extruder head seemed to stop at a certain temperature. It turns out that the Flashprint first attempts to heat up the print platform, and only when the platform reaches its target temperature will the extruder head start to heat up. This may cause the initial heating time to be frustratingly long.
While you are still tweaking the design, you may want to get the Flashforge Dreamer to preheat first. A good start is the have the extruder preheat to 180°C, and the print platform to 90°C.
Be careful not to set the extruder preheat temperature too close to the print temperature (220°C), otherwise it may start oozing before the print!
While printing, be aware that the print platform is heated, and can burn those who are not careful! If you are supervising viewers, I suggest you keep the print door closed, and do not remove the print until the print platform has cooled down to below 50°C.