To finish 2015 I have finally had a chance to 3D print another part for my motorcycle – a key guard. In a previous post I showed some 3D printed rear peg plugs and mirror plugs using this same bright orange ABS colour which perfectly matches my bike. With this being a second hand bike from 2007, the paint around the ignition has many scratches, with previous owners obviously having a key-ring and letting the extra keys bounce around to cause a mess. Nothing major, but something I see every time I get on the bike. I personally keep my bike key separate so this doesn’t happen, but something to cover the scratches seems like a nice addition, and another custom feature for the bike.
With a new tank pad, I’ve used a matching pattern for this part to create some consistency in design. As usual the design was created using some digital calipers to take measurements, and Solidworks CAD software for the 3D modelling. Another quick job less than an hour to design (my favourite)!
The challenge with it is definitely in the 3D printing – it’s quite a fragile piece, and I have broken a number of previous attempts just trying to remove support material. You can see in the top left photo that this working part was printed standing up on an Up! Plus 2, ensuring the layers run in the optimal direction for strength when flexing it over the bike handlebars (it uses a snap detail to hold in place). The downside with this orientation is that support material was added to each of the openings, requiring a slow and painful process to remove it all. A couple of minor fractures had to be super-glued along the way, but at least it’s held together OK. I will try this part again in the future (hopefully on my new Tiko when it arrives!), possibly thickening it a fraction to give it a little more strength.
I also did try using acetone to cleanup the surfaces and stress marks where support was removed, which I’ve had success with on previous prints, but found that a white residue was left on the material – apparently this can happen with some colours of ABS plastic. So instead I tried ‘brushing’ the surfaces through a hot flame, with moderate success. This removed the white residue and cleaned things up a bit, but in one area did cause a bubble to form and slight blackening of the surface. Luckily these aren’t really noticeable unless you get up really close. So all in all, another great bit of custom 3D printing for my bike!
That’s it for 2015, have a fantastic Christmas and New Year, and thanks for reading my blog and following all of my trials and errors with this great technology. See you all for another big year of 3D printing in 2016.
– Posted by James Novak
I’ve written a few times now about my experiments using acetone to smooth rough surfaces (see this post about my first test of brushing acetone directly onto a surface).
This 3D print is the leaf for the center of my Mario Kart Trophy. The side pictured is the bottom side of the print, i.e. the side the support raft was fixed to. As you can see in the first photo it’s quite rough, particularly around the perimeter where the raft stopped and the overhang resulted in some loose layers. I really thought I’d have to print this again, thinking no amount of sand paper or anything else could smooth these surfaces as the loose hairy strands would simply fall off, leaving big gaps in the surface.
Enter acetone, hero of the day! Within about 1-2 minutes of brushing acetone directly onto the problem areas, the layers have dissolved and smoothed themselves out into an almost perfect surface. By using a stiff bristled brush you can actually feel the surface go tacky, and control the outcome. I’ve used acetone across this whole back side to fix up a lot of the problems – it’s really like a magic wand or blur tool in Photoshop! A must have for any 3D printers’ kit.
– Posted by James Novak
Firstly, capturing these fine details on my phone camera is a real challenge!
What I’ve done is brush acetone directly onto 1 side of an old 3D print to see how well it cleans up the layers. Having done some reading (Makezine, Airwolf3D, Solidoodle) I was expecting the surface to melt very quickly, maybe even go a bit soft and squishy – Nope! I’ve brushed on about 15 coats of acetone onto the model (leaving a few minutes drying time between coats) and at no time did the model do anything exciting. However there is a clear result, with the layers clearly blurring together and remaining glossy. It’s certainly not perfectly smooth, but running my fingernail along the surface there is a noticeable difference to the back-side which remains original.
A few thoughts from this: 1. the ABS plastic we use at uni is premium quality, so no crappy other materials mixed in to potentially cause issues. 2. By just brushing on acetone it appears to evaporate very quickly and limits any effects, which in some ways is a good thing to control how far you want to go. 3. The 3D print itself has a thick 3mm wall, so there isn’t a high risk of the acetone seeping through to the inside and causing the entire wall section to soften.
In terms of the kiteboard fins, this seems like a worthwhile outcome to smooth them off and potentially strengthen the outside surface. Cool.
If you have your own experiences smoothing out 3D prints using acetone, I’d love to hear them, this is new for me. Please leave a comment or link.
– Posted by James Novak