Giant 3D Printed SUP Fin

20170511_3D SUP Fin

Behind the scenes I’ve been working on a Stand Up Paddle (SUP) fin project for quite a while now, 3D printing many prototypes, and more often than not, failing! There is more to this project than meets the eye, but for now the details are under wraps. However I thought it might be interesting to share some of the 3D prints in case anyone feels inspired to give it a go themselves.

The design pictured above is the first one that worked successfully without breaking or having other technical issues. Printed in 4 pieces on my Cocoon Create due to the size, it required a bit of gluing, and as you can see from the pink highlight, a bit of gap filling with a 3Doodler Pen (if you want to know more about using a 3D printing pen as a gap filler, check out one of my previous posts all about it). As a result the fin is about 400mm long, huge compared to the fin that came with the board (which for any SUP fans out there is a Slingshot G-Whiz 9’4″)

20170511_3D SUP Fin

These images show some of the breakages I’ve had due to layer delamination – unfortunately the optimal way to print the 4 pieces in terms of minimising support material and warping is vertical, however the optimal orientation for strength is laying down on the flat sides (similar to the image on the right). A bit of an oversight on my part I’ll admit, however I was genuinely surprised how much force the flat water put on the fin. Another issue may be the minimal infill, which was also beefed up in my later prints to add internal strength. There is always a delicate balance between print orientation, layer strength and infill in 3D printing, to name just a few!

The main thing is that the fin prototype now works, and I may have a more advanced version being printed using Selective Laser Sintering (SLS) as I write this… If you keep an eye on my blog by subscribing below, you may just get to see where this project is going 🙂

– Posted by James Novak

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Repairing 3D Prints with a 3D Pen

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It’s been a while since I last played with my 3Doodler Pen to repair a broken 3D print – the results were pretty cool, although it takes some practice to get reasonable results. Check out the post and images here. Some people make pretty amazing sculptures with the pen, however I find the real value in using the pen to fill gaps created by warped 3D prints and fix other cosmetic problems.

One of my latest projects is assembled from 16 separate pieces printed on my Cocoon Create 3D printer (60 hours worth of printing!), and inevitably with such large pieces printed using desktop FDM technology, there are some gaps caused by print warping. Most of them are reasonably small, but some like the ones shown above and below are quite large. Unfortunately the 3Doodler uses 3mm filament, meaning that I couldn’t use the same 1.75mm filament used to print the parts to begin with, but given that this project doesn’t need to be cosmetically pretty (prototype only), a different shade of yellow that came in the box will do.

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The first step is of course to use the pen to extrude material into the cavity, ensuring to move slowly and use the hot nozzle to bond the new plastic with the original. It can get a bit messy and smelly (do it in a well ventilated area – I had a fan blowing to keep a lot of the fumes moving away, but there were times my eyes were stinging), and as shown in image 2 above, might look a bit rough, but that’s OK. You can go back over some of the rough patches using the side of the hot nozzle to try and smooth them out, not extruding any material but using the nozzle like a hot rolling pin. This technique is also great for blending some of the sharp edges or smaller gaps that don’t really need to be filled. The final step is to use a metal file to clean things up, giving a much smoother finish.

Admittedly this process wasn’t all smooth sailing, my 3Doodler kept getting clogged despite me taking it apart and cleaning it out – I have a feeling it might be the material quality and/or the temperature of the nozzle not being quite as hot as it needs to be, so a lot of time was wasted trying to manually push the filament through the pen and get a steady flow. I did notice that when I pushed the hot nozzle into my original print (the darker yellow plastic) it melted much quicker than the 3Doodler filament, despite them both being ABS. So material quality is likely the cause. But the final result is worth the pain, gaps are cleaned up nicely and the surface is nice and smooth. Time for some testing!

– Posted by James Novak

Drawing in 3D – First Attempt

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If you follow 3D printing at all, chances are you’ve at least heard about 3D printing pens like the 3Doodler and others, with the 3Doodler originally funded through Kickstarter and now a successful brand. While I’ve seen people make some really interesting things like the Eiffel Tower and Golden Gate Bridge, I have to admit the pens have never really interested me. I can see the fun for kids because they are so easy to pick up and begin using, much like a hot glue gun, and there are templates you literally trace over to construct your object. However the models are really only visual, it would be almost impossible to make anything accurate or functional in the same way you can with an actual 3D printer.

However I was given a 3Doodler, and have been looking for an excuse to try it out. Well, one broken 3D print off my Cocoon Create (who by the way have their own 3D Pen which was sold through Aldi for $79) and I finally had my chance! The benefit I see of such pens is the ability to repair and weld details on a regular 3D printed part – in this case a Voronoi Tealight Candle Holder available on Thingiverse. You can see the before and after photos above.

I have to admit the process wasn’t nearly as easy as I thought. The slowest speed of the pen is still quite fast, and once the plastic starts coming out of the nozzle you really need to get moving! The easiest repairs were the little ones near the bottom of the design, just a quick squirt and it was done. The larger distances were much more messy because of the speed of extrusion, but adhere well to the existing design especially if you use the nozzle to melt some of it to begin with and fuse the new material. I found that once I had roughed out the repair, I could use the hot nozzle to go back and “smooth” the outside surfaces like putty (although the result is far from smooth). This could be further improved with acetone (you can see some of my previous experiments cleaning surfaces with acetone here) but for an experiment like this, I’m happy to leave it as is.

The kit comes with both ABS and PLA filaments, with 2 temperature settings on the pen to match. However it would definitely be interesting to experiment with some different materials – I see on the 3Doodler website they also sell a Flexy Material in numerous colours. I wonder if you could put a conductive filament through to draw electronic circuits? Hmm that’s not a bad idea, perhaps there is more use to this pen than I first thought…

– Posted by James Novak