While surfing the net recently, I saw several commercial plastic cornets on the market. They were very nice but expensive. In fact more expensive than an entry level brass instrument. I thought that this shouldn't be the case. I worked in the plastics sector for 10+ years and I know how much does a sack of plastic (50kgs) costs. It is really dirt cheap. With that amount of plastic, one can produce 50 trumpets. Well one can talk about additional design costs etc, come on I'm also in design bussiness for years. That is not so expensive either. We should be able to give a good sounding plastic instrument to masses for free. So I immediately thought of designing a 3d printable cornet giving away the design to people. So I started to work and first developed my 3d printable cornet.
I wanted my design to be made up from many small pieces to enable it to be printed by the smallest & cheapest 3D printers. This idea of making the instrument from many pieces would also enable it to be packed into the smallest package. So I've made made many small assembly details on every part for easy assembly by any inexperienced user. All pieces are snug fit, so the user would be able to assemble the instrument like a puzzle without using glue.
Step 1: Research and First Trials
After a short research I just discovered that the subject is much deeper than I anticipated. And decided to start designing and printing some simple experimental things while continuing to do further research.
I made a mouthpiece first. It was easy. Just measured a mouthpiece at hand and tried to make one exactly identical to it. I managed to blow some sounds with it as you can see below. It gave me courage :D
Then I made a toy trumpet, with two versions, one just the bell and one with fake valves. It accepts a real trumpet mouthpiece and I thought the first version can be a real mouthpiece buzz bracticer and the second version can be a kids toy. I've printed it, it produced some sounds. Not so nice ones as you might guess. If you want to make it then STL files are here.
My second design attemt was a buggle. I didn't try to build it as it was a bit large for my printer. But the STL files are here if you intend to print or take a look. Then in the end I decided to stick to the dimensions of a known, good sounding instrument. I took the cornets I own as masters and used their dimensions as template for modeling this 3d printed cornet.
The plastic thickness needs to be greater than brass thickness to obtain a adequately strong structure so the outer dimensions of the instrument are made a bit larger than brass instruments. This resulted a more modern looking, robust cornet.
Step 2: 3D Modeling of the Printable Cornet
I've modeled the whole thing in solidworks after extensively measuring the dimensions of the instruments I have, which are;Olds Ambassador Cornet,King Master Cornet,Holton Collegiate Cornet andBach Prelude Pocket Trumpet.The air path gets wider all the way from the mouthpiece to the bell as it should in a cornet (excluding the valveblock area ).
For the mouthpiece, it is a 5B, as close as possible model of a well known cornet mouthpiece with wonderful sound. I've inspired from various instruments for the exterior form of the mouthpiece and the shank. Their practical interior dimensions are compatible with a 7c mouthpiece which is very commonly used mouthpiece type. The dimensions of the mouthpiece receiver is modeled in such a way that the instrument can also be played with any ordinary real cornet mouthpiece made of metal.
You can find the step by step process of the 3d modeling of the cornet above. I kept the plastic thickness at around 3mm throughout to obtain a sufficiently strong structure. Also added extra supporting parts & thick braces to give more strength to the areas of need. I sliced the final 3d model into smaller parts to enable it to be printed by smaller sized printers. Also added extra fixing details to those sliced parts for them to be easily joined back during assembly.
Step 3: The Complete Model
After several days of modeling, here is the resulting 3d model.
Valves are bottom sprung, they should work with stronger than normal springs and vaseline as oil. Valve routes are modeled realistically. All valve slides move in addition to bellbow and main tuning slide to tune the instrument in case it is out of tune.
the STL files for the complete model can be downloaded from Thingiverse.
Step 4: 3D Printing
I've printed the mouthpiece and a 1:12 model of the cornet and some other people had time and resources to print the entire cornet. Actually there seems like a number of copies of the instrument have already been printed and their photos have been shared online since the project files were published on my website and thingiverse.
Step 5: What Does It Look Like When Complete?
I've included the photos of the printed instrument above.
If you also print it, please please please send me photos and videos ;)
Step 6: How's the Sound, Completed Cornet.
So far I've received messages from around 3-4 people who said that they've been building or have built the cornet. Some of them were kind enough to send me photos of their prints. I did a little google search and found more prints of my design on the web. I feel great. Just now while writing the instructable, I was about to say that I didn't have a video of my cornet being played and instead of adding a video of my own instrument being played, I searched youtube to find a video, in which any plastic cornet being played to add to the instructable. And voila, I found a video of my own cornet, printed by someone I don't know, being played by a nice guy. And the result joyfully for me is to see the cornet actually producing sounds :). Not superb sounds but seems like that some valve slides are installed incorrectly and that might affect the sound of the instrument. Thats good news for me :D