Easy Funnels with Openscad

thingiverse

This is an activity to start using OpenScad as a fast and easy 3D Design tool. We will design using just a few concepts, so it's really simple. Print Settings Printer Brand: RepRap Printer: PowerCode Rafts: No Supports: No How I Designed This Very first steps with Openscad I actually needed a small funnel, so I thought that it is a fairly simple object that I could create using #OpenScad, and at the same time get familiar with it. At the end, what is a funnel? Just a concatenation of cylinders and cones, well actually a concatenation of conical and cylindrical surfaces, so think I should be able to do it fairly quick. I suggest that you watch this short video from Thingiversity, and that will help you find the next part very easy to follow. Project: Easily designing a Funnel with OpenScad Objectives • Become familiar with OpenScad Designing (very first steps): simple commands as well as variables setting. • Become familiar with how we must start by sketching on paper, and planning our work. • Generate 3D files: .scad and .stl that you can print Audiences • Any kid studying anything in relation with 3D printing or designing student (beginners level) • Anyone who needs a funnel fast! Preparation • Students will need access to computers and ideally a 3D Printer in the classroom • Computers will be equipped with the necessary 3D printing software and OpenScad. • It is helpful to have students form into working groups of two or three so that they can collaborate on the design process. Having students work in groups is also helpful if you have a limited number of computers and/or limited 3D printer access, plus you will end up with several designs. Part 1: Sketch the Funnel How does a funnel look like to you? Sketch it on a piece of paper. Note also the important data, like size and radius of each section of the funnel. The following is what I think a funnel should be like. if you want to print OK, make sure there are no overhangs greater than 45º You intend to print this funnel, so think how are you going to place, the big section in the top or in the bottom. For each section you should note its radius at the bottom and at the top (they could be the same) and its height. Part 2: Start designing (Start programming) Launch OpenScad. We are going to use three commands: cylinder which can create cylinders and cones, translate, to move them, and difference to create surfaces rather than volumes (we want the funnel to be functional, not a solid part) Begin defining the dimensions: H1=10, R1=20, H2=…… Besides the radiuses and the heights you will want to define the sides of your surfaces. Why? Because otherwise instead of cylinders you might end up with prisms. Define also the thickness of your funnel. 3: Let’s create the first section, use this code, and then hit F5 to preview what you made: cylinder (h=H1, r1=R1, r2=R2, $fn=Sides); 4: Let’s make it hollow, for that we will create another one slightly smaller (radius same as before minus the thickness), and subtract it from the first one: difference() { cylinder (h=H1, r1=R1, r2=R2, $fn=Sides); cylinder (h=H1, r1=R1-thick, r2=R2-thick, $fn=Sides); } 5: Repeat previous steps for making the next section. Note that you might not see it if it is inside the first section, so can type % at the just before difference(), and it will become transparent, remove the percent sign to see it again solid. Then you will have to push it up so that 2nd section start at the end of the first one, for that you will use translate before the previous object (difference): translate ([0,0,H0+H1]) difference() { cylinder (h=H2, r1=R2, r2=R3, $fn=Sides); cylinder (h=H2, r1=R2-thick, r2=R3-thick, $fn=Sides); } // 6: Repeat for as many sections as you want your funnel to have. Openscad screen Part 3: Export STL and print Hit F6 to render, and then export to STL, in order to have a file with STL extension that you can print. Results: At the end of this project, each group of students should have: • 3D printed funnels objects • Basic familiarity with OpenScad, and programming