3D Printing MouseAir V2 – Part 3 / Debugging Big 3D Prints

Introduction

Part 1 of 3D Printing MouseAir V2

Part 2 0f 3D Printing MouseAir V2 /  Learning 3D

The Mouse Air project has been around in various stages since April of 2014. The goal of the project (conceived in a bar, the Fedora in Coeur d’Alene Idaho and named by Sarah, the most excellent bartender there.  And some BlueMoon Beer.)  was to be able to detect a cat walking by and fire a mouse.  It worked!  The first

version was physically large and complex, but fun!  I had so much response (including the response from the Cat) to that article and project from a variety of sources, that I decided to do a redesign of MouseAir incorporating what I had learned from the project. I aggressively redesigned to eliminate unneeded hardware and drive down the cost and size. To the right is a picture of the 3D Printed box of MouseAir V2.  The 3D Printing of the box was a big undertaking because I had to learn the whole technology.

Part 1 of 3D Printing MouseAir V2

Part 2 0f 3D Printing MouseAir V2 /  Learning 3D

Learning the 3D Printing Process

I learned 3D printing as I designed the box. This led to many mistakes, wrong turns and out right sizing errors. My very first attempt had a huge scaling error.  I quickly ended up using millimeters for all my measurements.
I printed many different variations and learned something from most of them.

The MouseAir top takes about 7 hours to print, while the bottom takes about 8 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 that lets me only print out the section of the big print that I am interested in.

 

Debugging Large 3D Prints

When you have a complex design that takes hours to print, it can be frustrating to have to wait 8 hours to see if you put the servo motor clip in exactly the right place. This caused many extra boxes to be printed out. The revelation I had to make this process turnaround more quickly was simple. I take the whole box design and then perform a difference with a cube, leaving only the part to print that I am interested in.  Now I’m being productive!

The OpenSCAD code for this debug technique looks like this:

difference()
{

	union()
	{

		

	} // union

	// difference the debug hole
	difference()
	{
		#translate([-10,-10,-10])
		cube ([190,160, 60]);

		// print hole
		//cube ([170,140, 35]);

		#translate([85,-10,-10])
		cube([105,150,300]);
	}


} // final difference

Here is full MouseAir Bottom box design in OpenSCAD.

And now with the Debug Block turned on.

This technique saved me lots and lots of time when tweaking the size of stands, screw holes and cable guides.

This idea dramatically reduced my time for testing design changes.

Up Next:

Part 4 of this series will address more of the design and more about OpenSCAD (both limitations and strengths).