Tuesday, January 13, 2015

Test - 3D Printed Gears

One of my goals for the 3D Printer was fast and cheap production of gears. Buying plastic gears can be expensive and they often require modifications. This can waste a ton of time. In addition, they might not be the exact number of teeth required for a project. I decided to test the 3D printer and determine what settings and orientations were best for high quality parts.

I started off by printing some 64 pitch gears. I was curious to see if the printer was capable of making these parts. The results were pleasantly surprising! All of these close up shots were taken with my phone. I hacked together a macro lens using a thumb sized magnifier. I taped the lens over my camera and got a 10x zoom! The only down side is there is a fair amount of distortion over the images. However, it reveals details that the camera or my own eyes couldn't see alone.

This is one of my first test prints of a 64 pitch gear. There is some surface roughness that can be seen on the gear, but all of the teeth seem to have a reasonable profile. This gear was printed in the coarsest layer height (0.1mm per layer). The layers don't seem to create "steps" in the teeth.The surface roughness is still pretty good even though the layers are visible

This is a picture that just looked cool. I have no idea what happened with the focus of the camera but it added some neat effects. This gear was printed on the highest layer resolution (0.025mm per layer). Here the layers can't be seen. It just looks slightly opaque.

Here is a side by side comparison between the course and fine layer resolutions (0.1mm and 0.025mm per layer respectively). Both gears seem to have reasonable tooth profiles. It is hard to tell whether there is warpage in the teeth as the lens created considerable distortion in the picture. The lens also created a very shallow depth of field so only portions of the gear are in focus at once.

I also worked on larger gears. The majority of these gears are 32 pitch - 40 tooth gears. I wanted to see how different orientations of the gears in the printer would cause different amounts of warpage on  the overall shape. I also wanted to see how various levels of post curing reduced wear on the gears. I also printed a set of 20 pitch - 25 tooth gears. All of the gears meshed fine, however some warpage in the gears led to noticeable wobble on the shafts. I found increasing the resolution and adding more supports during the printing helped to mostly eliminate these issues. I'll have some projects coming soon that will be built off of these gears. There is also a cluster gear in this photo that contains a timing belt pulley in addition to a 32 pitch gear. This part couldn't be made through traditional machining techniques, so I'm very excited to see what unique structures I can design and build with the 3D printer.

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