The Switch Doc rebuilds his cat toy launcher with 3D printing

3D printing of MouseAir V2

I learned 3D printing as I designed the box. This led to many mistakes, wrong turns, and outright sizing errors. My very first attempt had a huge scaling error (Figure 9).

Figure 9: First 3D print attempt with scaling error.

I printed many different variations and learned something from most of them (Figure 10). The MouseAir top takes about seven hours to print, and the bottom takes about eight hours to print. This made fixing small problems very difficult and time consuming. I thought about it and came up with a good idea that lets me print only the section of the big print in which I am interested.

Figure 10: The 3D printer learning pile.

Debugging 3D Prints

When you have a complex design that takes hours to print, it can be frustrating to have to wait eight hours to see if you put the servomotor clip in exactly the right place. This caused me to have to print many extra boxes. The revelation that made this process turn around more quickly was simple: I take the whole box design (Figure 11) and then perform a difference with a cube, leaving only the part to print in which I am interested (Figure  12). The OpenSCAD code for this debug technique is shown in Listing 1.

Figure 11: Full MouseAir V2 bottom box design.
Figure 12: Bottom of the MouseAir V2 box with debug box applied.

Listing 1

Making a Difference

01 difference()
02 {
04         union()
05         {
07                 <your design>
09         } // union
11         // difference the debug hole
12         difference()
13         {
14                 #translate([-10,-10,-10])
15                 cube ([190,160, 60]);
17                 // print hole
18                 //cube ([170,140, 35]);
20                 #translate([85,-10,-10])
21                 cube([105,150,300]);
22         }
25 } // final difference

This idea dramatically reduced my time for testing design changes.

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