Overhang Test

thingiverse

This is the beginning of a larger suite of test prints I am developing that can be used to calibrate your 3D printer affordably and quickly. Find a full write-up and other tests on my blog at http://blog.ansonbiggs.com/yet-another-test-suite/ ## Summary No one likes using supports, so it's essential to know the limitations of your printer so you can use a minimal amount of support and still get great-looking models. This model tests three different kinds of overhangs in one: concave, convex, and flat surfaces. It shows how your printer handles each one. Generally, concave overhangs print better than convex ones, making this print great for visualizing this. The idea behind this is that printing outside of parametric models usually has very weird shapes which normal flat tests don't test for. This model is fully parameterized if you have Inventor. ## Project Contents This project contains a .stl and a .ipt Inventor file. By default, the .stl is pretty small and should be printable in under 45 minutes. If you want to print it larger to make any issues more prevalent, then you can easily scale the model in your slicer without any issues. The model also has a small notch on the back at the 50-degree mark, making it easy to tell when you're at this point because most printers begin running into issues with overhangs. Preview of the file in Inventor ## Goals of This Print This print is designed to be small, fast, and easily readable, making it easy as possible for you to troubleshoot overhang issues. If you're having extreme overhang issues, I would recommend starting with my Bridge Test. Bridging and Overhangs are highly correlated, but getting beautiful overhangs takes more fine-tuning than successful bridges. This test is a profile with 2 arcs and a flat surface that's lofted up at increasing angles until you end up parallel with the ground. The reasonable expectation of any printer is that it can print perfectly until about 45 to 50 degrees before it runs into issues. The model has a small notch on the back to indicate when you go to 50 degrees, so if you have any issues before this point, then your issue isn't Overhang; it's something else that I probably have a guide on. You can see the print having worse issues as the print angle gets more aggressive ### Eliminating Overhangs It is essential to note that for most prints, the best way to fix overhangs is not to have them at all. Usually rotating a model or adding a chamfer or fillet can decrease an angle, making your print easier for your printer, while saving filament and in some cases actually making your print stronger. ### Speed Slowing your printer down means that the filament has more time to cool down where it was placed and not drag or fall. Printers can have vastly different speeds so it's essential to search online for numbers that make sense for you, then slowly change them from there. ### Temperature Overhangs print more material over thin air as the angle decreases. This means it's crucial to ensure your temperature isn't higher than its required to be and that your print head fans are running at full to ensure the filament hardens as quickly as possible once it leaves the print head. --- ## Print Settings ### Rafts This print should be just fine without a raft. If you're having problems with the print not sticking to the bed, then I would look up guides on troubleshooting that. ### Resolution Whatever you usually print at. Smaller layer height should make overhangs turn out better. ### Infill At the default size, you shouldn't need any infill; but if you scale it up, then I would recommend using your normal infill for prints just to keep as many variables the same as possible. I generally stick to around 15%. ## Download View this Project on my Thingiverse at https://www.thingiverse.com/thing:3042444 View this Project on my GitLab at http://bit.ly/OverhangTest