Friday, June 26, 2015

3D Printing: Thought-to-Thing in Less Than an Hour

3D printing isn't only an interesting technology. It's a convenient technology as well.

I figured this out when I needed to design a part, and I realized the entire thought-to-part process could take under an hour. Surely enough, I had my part within the hour. It's the 21st century, and although we don't have hoverboards, creating a part from an idea in less than an hour is something that blows my mind.

Why did I create this part? What does it do?

Well, I had a problem. A minor problem, but an annoying problem. A problem that could be fixed with 3D printing. The problem had to do with coffee beans:

Pouring beans into a coffee grinder seems like something you should take for granted. And I did take it for granted. Wrongly, of course. Because a single bean would get stuck in the center of the coffee grinder. Every time.

Why would someone design a coffee grinder with a bean-sized hole in the center? That, apparently, was a secret that I would never learn.

Could I shake it out? Nope. A bean would always be stuck, which meant removing the entire lid and attempting to poke it out of the way without, um, spilling the beans.

The coffee grinder needed a minor makeover. More precisely, it needed a plug to fill a hole.

I drew a diagram of the part I wanted to create and labeled it with dimensions before creating a 3D model. To find the dimensions of the part, I grabbed my calipers and started measuring the coffee grinder.

Sometimes a measurement will be an exact fraction in terms of inches or centimeters. (For example, 0.875 in. = 7/8 in.) But these measurements were just... measurements. (14.82 mm isn't close to a fraction, in inches or millimeters.) The organic shape of the coffee grinder spiral probably caused them to not be any exact value.

I fired up OpenSCAD, a 3D modeling program, and quickly designed the part. A small cylinder would press-fit into the bean-sized hole, with a large cylinder as a cap. There would be a hole through the middle for pulling the plug out with a hex wrench, just in case. And the top edge would be chamfered (flattened) so that there wouldn't be any sharp corners.

To the 3D printer! I designed and printed the part upside-down, because the top was wider than the base.

At this point, about 20 minutes had elapsed. Now all I had to do was sit back and wait.

And soon, the part was finished. Looking good!

Only 24 minutes of printing! Pretty impressive!

It makes sense, though... the part isn't even as large as a penny.

After washing it off, it was time to test the part out in the coffee grinder.

In the image above, you can see the hole in the part for removing it with a hex wrench from the coffee grinder.

I can't complain... it worked perfectly. Not only did it fit easily, but it didn't fit too tightly (I wouldn't be able to remove it) and it didn't fit too loosely (it would fall out).

Could I get it out with a hex wrench? Oh yeah. 

Less than an hour of planning, design, printing, and testing. 3D printing is one impressive technology.