Customizable wall ooze calibrator

thingiverse

Most 3D printers consistently undercalculate their wall widths while printing, resulting in components that are slightly too small to fit together seamlessly. This issue is why many engineering parts have a built-in tolerance gap that can be adjusted. However, printing multiple non-fitting parts just to determine the optimal tolerance value doesn't make sense. This approach aims to identify the correct value from the start or to fine-tune settings over time to minimize oozing. This print is part of a comprehensive suite of calibration test prints designed to precision-calibrate your 3D printer for accurate printing of components that fit together without post-processing requirements. Print Settings Printer: Homebrew special Rafts: Doesn't Matter Supports: No Resolution: Any Infill: Any Notes: Use the exact settings you plan to use for your engineering print. Keep in mind: The bottom layer of the slotted part is 0.8mm thick, so choose a top/bottom layer that totals more than that. The slotted part has undercuts designed for 0.2 layer height and 0.4 nozzle. Post-Printing Using and measuring the calibrator (See the images) Clean up the print and place the slotted part on a flat surface. No need for perfect cleanup. Each wedge is sized to fit into the slot next to it. Turn the wedge upside-down and slide it into the corresponding slot from right to left. Use enough force to make it wedge, but the bottom of the slotted part should not bend open to accommodate the wedge. Sliding it in with just your finger on top of the wedge provides a nice amount of force. Measure how far from the end it refuses to slide further. That measurement divided by 100 is the wall ooze factor. Repeat for the other slots to get a good average and feel how much it varies. Each slot and wedge is slightly bigger than the previous one, so it should be obvious which one fits which. However, if you average all the values, you should get the right answer regardless. Write the slicer settings you used on the back of the part, and mark the wedges so that you can match them to the slotted part later for reference. Once you print three of these, you'll truly have no clue which is which. When designing parts that should mate with each other (depending on geometry), you probably need to allow for double the wall ooze factor, since you have two walls that should be smaller than expected. For a part that should mate with a non-printed wall, you likely only need to account for one wall ooze factor. How I Designed This After two failed prints of Emmet's gear bearing, I decided to actually measure the wall ooze factor so that I can print with confidence. Trying to do this with most tools is futile, since the measurement should be taken over the whole surface to account for all kinds of inaccuracies, and the measurement is so small that it's easy to make a mistake. I designed this wedge system that amplifies the error by a factor of 100, creating a wedge with a slope of 1 in 25 (Each wedge and slot combo has four walls touching). This allows you to measure a very small error using a simple ruler. The slotted part has undercuts to minimize extra ooze at the bottom layer of the slot, and the wedges are designed to be upside-down to also minimize the effect of first-layer oozing. Custom Section I am keen to improve this, so if you have any suggestions on how to improve it, let me know. As far as I can see, this measurement accounts for most of the following problems: Overextrusion Slop/backlash in the mechanics of the printer Ghosting due to jerky movement Jitter/vibration while printing walls Infill squeezing the walls out