Printing a prototype propeller for my Lightnin lab mixer

The worn-out stainless propeller was going to cost $500 to replace. But the size and pitch of the blades was not ideal anyway. So I drew them using Fusion 360 and printed in PLA plastic, this enabled experimenting with different sizes and pitches. How about getting a tight fit on the shaft? No problem. I measured it with calipers and printed that size. It was a little tight so I printed it slightly larger. One issue: Mixing slurries with hot water bends the blades and the collar loosens.

Related Pictures

Learn to draw and print a mixer propeller

Available on the Downloads page

This picture has its own page with more detail, click here to see it.

Lilly will take you step-by-step through the 3D design process of drawing a propeller. We tried many methods of doing this to finally arrive at a simple procedure that produces a flexible parametric design. Follow the full transcript as you watch. Use the same process to create one in this or other CAD software. Our design has only nine steps yet is flexible enough to accommodate a different number of blades, changes in the blade shape, angle, thickness and size and different heights and diameters for the hub and hole.

Depending on the degree to which this can be secured to the shaft, it can be quite durable on a lab mixer, even for high speed mixing. Test, adjust the design and reprint (using PLA filament) until it is working well and then have a metal one printed at a 3D printing service provider. Or from a harder plastic.

3D printing a propeller for our lab mixer

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It has already been drawn using Fusion 360. Choosing Make -> 3D Print, then selecting the propeller and clicking OK handed the 3D geometry off to Simplify 3D, the software that actually ran the printer. Within Simplify 3D the object can be positioned and reoriented on the bed and set to print solid or with infill. A moving slider can animate how the printing will be done, layer-by-layer. I had the printer directly connected via a USB cable so it was just a matter of clicking to start the print. The process begins by preheating the bed and head, the actual printing took about 15 minutes (with printed support under each blade). This fit tightly on the shaft that lasted months of everyday use! A replacement lasted many months more. By that time I had a stainless steel one printed at a service provider.

A must-have: Laboratory variable speed propeller mixer

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If you are at all serious about testing glazes and clay bodies, you need one of these. There are other methods, but nothing else comes close to this. It is the most valuable and frequently used tool in any ceramic bodies and glazes testing lab or classroom. This is the Lightnin brand, they are expensive but high quality. This is a 1/20 hp variable speed unit, it could be $4000 new! But you can get them used on ebay.com (the industrial mixers are most common, lab mixers are jealously guarded). This one uses a 7.9mm dia (5/16") shaft. We adapted a mount (to give it vertical adjustment) from small drill press.

Links

Media	Draw a propeller in Fusion 360 for use on an overhead propeller mixer Lilly will take you step-by-step through the process of parametrically drawing a propeller for use on a lab overhead slurry mixer. A file that you can edit is also available for download.
Glossary	3D-Printing Standard 3D printing technology (not printing with clay itself) is very useful to potters and ceramic industry in making objects that assist and enable production.
Glossary	Propeller Mixer In ceramic studios, labs and classrooms, a good propeller mixer is essential for mixing glaze and body slurries.

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