#3D-Printed Parametric Cat Food Dispensing Toy
##Note
This GitHub project holds the source files for the Food-Dispensing Cat Toy. For the printable final renders, please visit the Thingiverse project page at http://www.thingiverse.com/thing:40425.
##Overview
This project is an exploration into designing and manufacturing a cat toy that rolls around and occasionally dispenses a cat treat. It consists of a cylinder with small perforations so that the food contained within can be seen, heard, and smelled. It also contains one large hole that acts as the dispensing mechanism. The hole diameter (in relation to the size of the treats inside) and the overall length of the tube dictate how easily a piece of food will drop out.
##Parameters
This 3D model is parametric, meaning you can alter a number of things about it. Look at the top of each OpenSCAD file for the all-uppercase constants. Each model shares some common ones (all in millimeters):
- CYLINDER_DIAMETER :: the outside diameter of the cylinder
- CYLINDER_THICKNESS :: the thickness of the cylinder
- CYLINDER_LENGTH :: the length of the cylinder
- CYLINDER_EDGE :: the margin at the top, bottom, and around the dispenser hole that has no cutouts
- DISPENSER_HOLE_DIAMETER :: the diameter of the dispenser hole
Each model then has some shape-specific hole parameters, be they OVAL, SQUARE, or DIAMOND (technically, triangles):
- OVAL_HOLE_WIDTH :: the width of the hole
- OVAL_HOLE_HEIGHT :: the height of the hole
- OVAL_HOLE_ANGLE :: rotationally, the angle between each column of holes
- OVAL_HOLE_DISTANCE :: linearly, the distance between holes within a column
##Render Notes
Note that the sheer number of boolean subtracts makes this a difficult final render to an STL-exportable object in OpenSCAD, even on a powerful modern machine. This is compounded by the length of the cylinder. I've seen it easily take 10 minutes.
##Design Notes
Triangle variant :: I was unable to get this to print correctly as-is on the MakerBot Replicator. I suppose I could have made the cylinder thicker and/or the inter-triangle braces thicker, but I moved on to other, more interesting designs.
Oval variant (thin) :: Visually, this one printed much nicer, but did not seem structurally strong enough for use. It was far too brittle.
Oval variant (thick) :: Ovals, spaced further apart than the "thin" variant and with a thicker wall.
Square variant :: This version is the strongest, but is absolutely the least interesting visually.
Endcap (flat) :: An end-cap design that friction-fits into the ends of the tube. It is flat on the end, making it easy to print. It is a really tight friction fit, but it works for me. If your printer is not as detailed as the Replicator, you might want to adjust the TOLERANCE constant at the top of the file to loosen it up a bit.
##TODO
- I'd like to design an endcap with a partial sphere so that the tube cannot flip up on one end get stuck in that position. That sort of design will either be in two pieces (the flat endcap plus a partial sphere to glue on to it) or will require support.
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