I'm still in awe that with an entry level consumer 3D printer I have the ability to turn around a functional design in just a few days. It's now at the point where I'm actively looking for opportunities to use this capability because I've realised the key to maximising the use of this technology is my mindset. It's how you think about solving problems with product solutions. I no longer have to go out and research endlessly for a great off the shelf solution, nor do I have to settle for a cheap and convenient off the shelf solution that's only 'close enough'. Now I can design my own custom solution to suit my needs at my discretion - and all I need is a printer, calipers, and some CAD skills.
My sister recently moved into a new apartment. As with any apartment, the effective use of space is critical. Initially, her TV was set up on top of a set of drawers in her living room, but told me she wanted to put the TV on the window sill so she could rearrange her furniture and create more space. I had an idea immediately - rather than extend the window sill or mount a shelf, I could 3D print her some smaller feet for her TV!
As pictured above, the feet attached to the bottom of the TV are too long for it to be placed on the window sill without it falling off. It occurred to me that I could design and make new feet for the TV that would enable it to sit on the sill.
Designing A Solution
To design new feet, I had to remove the existing ones and measure the critical features with my trusty calipers. I first determined the length I had to shorten them to, and the hole diameter and interface for mounting them to the TV with screws. The next step was designing a part that could provide the required features and be 3D printed efficiently.
The foot itself was kept fairly simple and geometric so it was quick to design, and easy to modify later. As it's a component that's largely out of sight, fancy aesthetics weren't really a requirement.
Designing for 3D printing has it's own limitations and requirements like every other manufacturing process. In the case of using a fused deposition modeling (FDM) printer, gravity is the main limitation. With that in mind, the part had to be designed for it would be printed resulting in lots of vertical surfaces connected by circular arcs. Typically anything with overhangs or shallow angles requires printing support material, which means unsightly surfaces and more work finishing the part in post-production. Something that I always try to minimise through the design process.
As you can see above, I kept the top and bottom surfaces flat for good print bed adhesion, however in order to support the top surface I created a pill shaped internal cavity.
The Finished Foot
The final design was printed after two prior iterations to fine tune the locating surface and screw hole placement. The feet were printed in a black ABS for strength and to match the colour of the TV. The first iterations I printed in PLA of an earlier design were actually so strong that all 90kg of me could stand on them!
You might have noticed a line on the top surface of the rear foot. This is a split in the printed layers where the ABS plastic has contracted as it cooled. The split was due to a lack of a printing enclosure which is normally used to maintain a warmer ambient temperature to prevent cooling. Using an acetone and ABS solution, I was able to make a sort of putty or glue to fuse the split rather than print again.
Looking from the top you can see the huge reduction in size that was needed so the TV could fit on the window sill. My design didn't require the locator pins of the original since it's symmetrical.
As you can see above, the new feet offered a huge improvement with the TV now on the window sill, freeing up my sister to move her drawer unit elsewhere.
There was even a few millimeters to spare!