To make a door stopper…
Preface
I want to prevent my door from opening. Why you ask? Let’s skip the details for now. Anyways, to make this a reality, I explored several ideas such as using screws to attach to the wall, 3D printed velcro, and compliant mechanisms. Here’s how I explored these topics.
Quick Intro
Additive manufacturing, aka 3-D printing, is a way of manufacturing something by laying layers upon layers of plastic on top of each other. The most common machine for this form of manufacturing is the FDM(Fused Deposition Modeling) printer, which is the machine I’ll be using for my prints. I’m also using Ultimaker Cura as my slicing software, and 0.4mm PLA as my printing material.
First Design
As you can see above, my designs are very rudimentary, and looking back, I added a lot of unnecessary components. However, in my defense, I have never taken any design classes, and my understanding of torsion, tension, and all those scientific terms is minimal. I did learn how to create and print screws and bolt efficiently, I should have known before printing out this giant screw.
If you are using Ultimaker Cura as your slicing software, in your experiment tab, you’ll find middle, exclusive, and inclusive. When you print something out, your printer slices your print as if every layer is .2mm, while in real life, your prints might expand in size. Because of this, carefully cut holes you made with very precise measurements while being worthless. However, if you turn the settings to exclusive, the slicer will exclude a certain length of your printed walls to account for the increase in size. There will be times when inclusive is the better choice, so don’t stick to exclusive as the new normal.
First attempt
As you can see here, my print is absolutely useless because I do not have the right sanding tool to reach the inner wall where my supports were placed. However, the screw fits perfectly. As I reflect back on my mistakes, I realize I didn’t need the twisty part at all, it was basically for aesthetic purposes. But, this design didn’t work, so let’s move on.
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For my 3D printed velcro design, I referenced a youtube video by Teaching Tech, go check it out, where he demonstrates the use of 3D printed velcro. Printing out the velcro was much harder than I expected due to unforeseen circumstances such as my filament breaking. The final result worked fine though, as expected.
In Teaching Techs video, he demonstrated the strength of the velcro, and I can confirm its strength. The problem is, it was hard to implicate the velcro to my 3D design, and it was so useless that I just stopped. 3D printed velcro is fun and all, but I’m not yet experienced enough to make use of it. It deserves an honourable mention.
What Else?
And lastly, I decided to fall back on a style of designing that uses one fully connected piece that can bend and shift, aka compliant mechanisms. This idea struck me when I remembered a video I watched a while back on compliant mechanisms on youtube by youtuber Veritasium called Why Machines That Bend Are Better.
My first design used straight beams, which failed immediately after print.
My second design used a rigged snake like pattern that is able to introduce thinner elements along the beam to spread out the force. But it broke as well.
My third and final design used much thicker walls and I included notches along the main beam because that’s where it broke first in my second design. Though it isn’t broken yet, it is showing signs of damage where the bendy part connects to the main body. Unfortunately, I’m running out of patiences so I’ll just leave it at that. My current printed version is too big for the door stopper, but once my actual prototype is done, I’ll go apply it.
Guess what, it didn’t work. However, I refined my model and came up with this design, which I name V4.
I know, not pretty. All that matters is that it works. Which I don’t yet know if it does. We’ll know in a couple hours or so. Please hold.
It also didn’t work. Now, introducing V4.1.
It fits, but still does not work. V4.2?
Not even close.
This is my final design.
Did it work? Not at all. I give up. You win door.
Unfortunately, I was not able to create a door stopper that can work. I have learned many lessons along this journey, and accidentally created a wrist gripper. It’s as the saying goes, shoot for the moon, and if you miss, you’ll land in the stars.
What’s the lesson to learn here? Don’t mess with doors. (And get proper education before taking on a challenge you know you can’t do.)
Here’s a video of my test: https://youtu.be/m-tpIqhciv4
