Before you improve something, you should have a problem, right? Well actually, we didn’t. We just started to experiment with our whistle heads design. Our Artist Series whistle heads are printed a carbon-fill filament. It’s a PETG with 20% carbon fibers. The PET (PolyEthylene Tereftalate) material is known because you buy them as drinking bottles at the supermarket. Fully recyclable and food safe. The filament (PET modified with glycol) is extremely water repelent. Sounds ideal for a mouth piece, right? However, the filament is pretty rough to the touch, which means the object need finishing. Picture below: unfinished object and a piece of non-printed filament.
Finishing means filing and sanding with different grain sizes (up to 3000). The downside is here that we’re removing material from the mouthpiece, so we have to take this into account while designing. Especially at the blade of the mouthpiece, it is crucial we have a precise print. This needs to be done with care, since the blade determines how, when and at which distance from the windway (or ‘duct’) the air is being split. The end of the duct sometimes has a chamfer. Subsequently, all these variables have an effect on how the mouth piece ‘projects’ the sound, whether it plays easily or not, and whether sounds ‘airy’ or not. The tip of the blade has a certain angle, and the top and bottom are called the over- and undercut of the blade (if any).
So the blade is where air, generated by the musician, is cut after it leaves the windway. In the picture below, the blade clearly has a sharp edge; this is where the air is ‘broken’. This is needed as the air oscillates below and above the blade at great speed. This is why we can hear the air starting to produce a tone, even without having a body attached to the mouthpiece. The area below the blade is called the chamber and determines the ‘color’ of the tone (among other things). The chamber leads to the body. The body has a certain ‘bore’ (diameter). The bore does not only affect playability, but also sound. For every type of whistle there is an optimal bore, although we also make high whistles with a ‘big bore’. So while there is flexibility in all of these variables, we are ultimately limited by physics or ergonomics, if not pure sound.
So we have seen that part of the problem of 3D printing is the time it takes to produce and finish mouthpieces. It takes about 30 minutes to fully finish a carbon printed mouthpiece. Important is to print the mouth piece with a 100% infill, so completely solid.
A normal 3D printer takes about 7 hours to print our mouthpiece with a resolution of 0.1 mm. If you speed up the printer, you may end up with gaps in your print. Too slow and you may have blobs sticking to your object.
So, for our new design, we are looking for quicker prints and a faster finish process without loosing any of the musical characteristics (or if possible, improve them).