I have an XYZPrinting Da Vinci 1.0 and have been working on printin an ideal Marvin with it. I initially ran into a lot of problems with the supports destroying the quality of the print, but managed to get a fully unsupported print with a new cartridge. The only problem now is that the ring doesn’t seem to completely form (as seen in the attached files). I’m printing in excellent quality with medium density (30%), slow printing speed, and default layer height for that quality. Does anyone happen to know a good way to fix this problem without using supports? Thanks!
Here’s a trick of mine that you can try if you have a CAD program. I actually haven’t used in on Marvin, but have successfully used it on other similar small parts. This should work for both stock and Repetier firmware.
Create a little cube in your CAD software that is 25.4mm (1 inch) high (the same as Marvin). Width and depth are not as important, but you can make them the same as the height if you like. Hollow it out so that the base of the cube is open. Model it so that the ceiling and walls of the cube are 5mm thick. The 5mm part is important because that is roughy the height of the “hook” on the top that melts from not having enough time to cool between layers.
Place this cube alongside Marvin when you setup your print.
What happens is that most of the layers of Marvin get a moderately increased cooling interval because the printhead is off printing the layers of the cube walls between layers.
When we come to the top 5mm (where the hook is), the printhead is spending a LOT more time on the cube because it not only has to print the walls, but it also has to print the infill. Most likely the infill on the ceiling of the cube is completely solid because of the 5mm thickness. The ceiling of the cube will be bridged, but we don’t care about that.
This gives each layer of the hook on Marvin much longer to cool between layers. It will work much better than printing multiple Marvins because it will cause the most delay between layers where it is most needed, without slowing down the job by an extreme amount.
Expect to still see some curling as the hook is printed. The are more advanced tricks to minimize the curling. One is a selectively (very briefly) applied layer cooling fan - which works good for PLA, but can be problematic for ABS. The best solution by far is a heated build chamber. Unfortunately, both of these are hardware features that the stock DaVinci doesn’t have.
Update - I did try the 1 inch cube alongside Marvin. Here is the result still on the print bed with no cleanup. The hook was nicely formed. Unfortunately, the longer delay between layers made the overhang curling issue on the bottom layers a bit worse. Perhaps a higher bed temperature would help to reduce the curling.
