Vocabulary Learning Pendulum Mechanism Made From Cnc Cut Wood and 3d Printed Parts

Hello, my name is Ansgar, and I am currently enrolled in a german school form called „Berufliches Gymnasium Technik“, which is an alternative tech orientated way to attain the privilege to enroll a university. To be more specific I am a student of the “Berufsbildende Schulen Walsrode ”.

I have recently built a CNC-machine, found an interest in 3d printing gears as well as springs and had some problems finding a motivation for learning the needed Spanish vocabulary for school. So, I decided to combine these things into a project that costs me nothing, makes me more familiar with my machines and with luck gives me a motivation to learn for Spanish.

An additional inspiration for this project was a new antique pendulum clock my father bought for our living room as well as various YouTube videos themed around 3d printing.

The idea is to power flipcharts with the vocabulary written in one language on one side and in the other language on the other side. These flip charts are now powered by a spring which is slowed down via a pendulum, so that the charts flip in the rhythm of the pendulum to make it easier to concentrate on it.

Unfortunately, did I not manage to get it perfect but instead made a “prove of concept” that works more or less.

If you want to do something similar or want to perfect my work, here is a instructable for you which explains the general procedure and what I did wrong so you can learn from it.

• Fusion 360
• A 3d-printer + Filament
• Optionally a CNC-machine (makes prototyping a lot cheaper and faster) + thin plywood (I used the backplate of an old wall unit we had lying around)
• Bearings (I used 608 2RS bearings I had left over from my CNC build) or slightly oversized holes 
• Time
• And in the optimal case having more CAD skill than I do, as well as being more familiar with your machines than I am

Every machine is different, especially in the hobby sector. Each 3d-printer needs its own calibration, with each change on the machine come new troubles. I had to learn that during this project the “hard” way. More that once did the capabilities of my machines change drastically through the smallest change, usually to the worse, releveling the bed of my printer and parts that were beforehand easily achievable are now impossible, changing the cutter of my CNC and suddenly increases the accuracy from being +1 mm off to being ± 0.05 mm off but loosing steps while cutting.

To know the capabilities of your machine and having them documented bevor starting a project in which you need some sort of accuracy is important and saves you lots of time, material and nerves as well as improves your project cancellation rate quite a bit.

If you are reading this instruction, you are probably planning on doing a similar project, thus you already have a rough idea. Now you have various options to start designing.

1.      You make a 2D sketch on paper or already in fusion and work the details in your imagination out

2.      You only use your imagination to work the model out

3.      You 3D sketch your model with simple shapes

Another thing you should keep in mind in this step is that, although you might have lots of different ideas that you would like to integrate into your design, you should think about how much time you would like to invest into the project and how much skill you actually have in CAD. To “Keep it simple” should always be the goal, or at least if you are a beginner like me.

The right organisation is very important in such kinds of projects. It is advisable to think of some kind of organisation bevor starting, especially if you know that you are going to have many documents. Outside of Fusion did I organise my documents (gcode for the 3d printer, gcode for the CNC and pictures for this instructable) by saving them all with a fitting name as well as a version number in one project folder. In Fusion I named all important sketches as well as all bodies which were organised as components.

Naming is especially important in the “manufacture” part of fusion or else it can happen that one drives the CNC into something by using the wrong code …

I recommend starting your design with the most important parts which in this case are the big gear, pendulum, and spring. I started with these and tested them out bevor designing further parts and details. If you really want to get it right the first time, is it recommendable to move the parts in Fusion like they would in real life. Do not forget to add a pocket or something similar onto the pendulum to adjust the weight. The heavier the pendulum the slower it swings. I forgot, so I just glued some on.

The Spring can easily be designed with a feature of Fusion 360, under “solid” and there under “create” is an option called “coil” which you can set, after sketching the inner diameter of the spring onto a plane, under the option “Type” to “Spiral” and under the option “Section” to “Square”.  The strength of the spring is determined by its “section size” and must be tested out. For the slicing is important that you print it instead of normal infill with so many walls that it is 100% filled. Otherwise acts the infill against its springiness.

The big gear as well as its stopper must be designed manually, I managed that by looking at some old clocks and guessing what could work.

Now after your main parts are all designed and work, you can start designing details and the remaining parts to complete your project. The remaining parts I needed were gears, a backplate with legs to mount the components, as well as a flip chart mechanism I tried to model after some calendars. If you are also using gears, then I recommend using the in Fusion integrated script under “utilities” under “add-ins” called “SpurGear” or to install an add-in from the “Fusion 360 App Store” which can also be found under “add-ins”. I used to “GF Gear Generator”, but I had, after I installed it, some problems with Fusion only starting 1 out of 10 times. I don´t know whether it was caused by the add-in, but it could have been. Furthermore, does the adding of gears generate a bunch of sketches. So, name the ones you made beforehand to keep track of them.

Don´t forget that the modules of gears that mash must be the same and to distance the gears a little bit from each other if you are 3d printing them.

I did not calculate anything else regarding the gears besides the diameter, but various calculators can be found on the internet.

For me most troubling part due to my machines working against me and me being quite a noob compared to someone not self-taught.

I made my parts while redesigning them “on the fly“, that escalated into having many versions of each part (up to 8) and my project folder overflowing with gcodes. The main problems in my current design is the flipchart shaft, due to being too thin and high, and the big gear, because it does not really attach to the gear shaft of the power transmitting gear.

In addition to that does the gear ratio not fit to its application and the spring does not have the perfect strength. But both of these problems have to be fixt by calculations or testing it out and that I am not capable of and not willing to.

Everything else has everyone to figured out by themselves, due to every machine being different.

While the printer is doing its job you can already assembled the Parts and figure possible problems that may occur out. This way you can already see of things are oversized or undersized and redesign parts if needed, without wasting too much time.

This is my first Instructable and first project with the CNC, so I had lots of complications which made the journey to this lacking product quite unpleasant. I hope this instructable was helpful or at least entertaining.