Oh That’s Handy – 3D Printed Prosthetic

20180114_e-Nable Prosthetic Hand

If you’ve been paying any attention to 3D printing over recent years, no doubt you’ve seen at least a few 3D printed prosthetics. From the Iron Man prosthetic arm to the prosthetics being 3D printed for our animal friends, 3D printing is ushering in a new generation of low-cost, customisable prosthetics. Perhaps you’ve even seen my build of the fully robotic InMoov hand which has been documented on this blog.

At the extremely affordable end of the spectrum for humans, Enabling the Future (also called e-NABLE) is one of the most well-known names, developing a range of  open source prosthetics since 2013, which can be freely downloaded, printed, assembled and sent off to those in need. As part of my research I have wanted to build one of the e-NABLE hands for a while now to understand more about them, particularly in comparison to the more complex InMoov robot arm. As pictured above, I’ve finally got around to printing the Phoenix v2 hand, which is wrist actuated to open/close the fingers.

When you look at all the details, it really is a clever design which is optimised for 3D printing on a desktop FDM machine, with almost no support material or waste, and tolerances that fit really well together. Anyone with a 3D printer could assemble one of these, most of the non-3D printed parts can be sourced at a local hardware store or found in your shed (screws and fishing line). The instructions are very clear, and there are loads of videos to help demonstrate the assembly process and how some of the technical aspects of the hand work. Because I printed in ABS rather than PLA plastic, the only small hurdle I had was in the thermoforming process of the gauntlet (the bent white piece that mounts to the users arm), which required me using a strip heater in the university workshop. If you find yourself in a similar situation, you can check out the details which were posted in one of my previous posts. However, I recommend using PLA if you have the choice to make this part easier, only requiring some boiling water as demonstrated in this video. In itself, this is a really cool technique that I will use in the future to create stronger parts; you can always learn a lot from 3D printing other people’s designs.

Overall the e-NABLE community really has done a great job in refining this design over the years, and I’m already working on some of my own iterations which will hopefully be fed back into the e-NABLE community in the future. If you’re looking for a project to build and learn from, or potentially getting involved in the community and building hands for people in need, Enabling the Future is definitely worth researching.

– Posted by James Novak

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3D Printed Kobayashi Fidget Cube

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One of the great opportunities presented by 3D printing is to print multiple parts as a single object, and have them move afterwards as a complete assembly. There are many great examples, and this Kobayashi Fidget Cube has been on my “to-print list” for some time now. The file is freely available on Thingiverse, and it is pretty awesome!

The photos above give some idea of how it works; a series of cubes that are linked, allowing them to rotate around through a series of positions as you fold and open sections of the object. However the video below (not my own) shows exactly how it works, and is basically a form of fidget device that is currently a popular trend.

As well as being a fun object, it is a great test of your printer’s accuracy and settings, and I must admit my Cocoon Create only had average results. The cube works, but some of the movements are much stiffer than the video. This is probably to do with my settings, I was a little impatient in printing so did not optimise as much as necessary things like layer thickness (used 0.2mm and should’ve tried 0.1mm) and printing speed (50mm/s instead of perhaps 30mm/s or less). I also had to use a knife to slice some of the bottom layers where the cubes had fused together on the print plate. Not a bad first effort, but I might try printing again soon to get a really smooth operating fidget cube.

– Posted by James Novak

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

Lucky Bamboo, Lucky 3D Printing

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My desk is loaded with 3D prints, I’m surrounded by plastic! To even things out a bit I’ve added some greenery in the form of bamboo. The great thing is that it can grow in water, no need for messy soil, and it doesn’t need much light (hopefully the glowing of my computer screen is plenty!)

However the pot I have for it came with a plastic insert (black) designed for soil. It only fits in one way, being tapered, so I couldn’t just flip it upside down and drill a hole to support the bamboo. Of course, that’s just another excuse to design something new for 3D printing!

The white part in the photos above is the simple part I designed, basically the same dimensions as the original black insert but reversed with an open bottom, and a hole to allow the bamboo to fit through, including its roots. This sits down loosely inside the plant pot, and then 2 smaller inserts slot in around the bamboo when it’s inserted to hold it nice and vertical (right image). All printed without support material on my Cocoon Create, now with the Micro Swiss upgraded hotend (which seems to be working very well).

It’s probably not the sort of design worth sharing on 3D file websites given it is very specific to this plant pot, but if for some reason you want this file just leave me a comment and I’ll email it to you.

– Posted by James Novak

Star Wars Death Trooper

20170415_3D Stormtrooper

Sometimes you just see a 3D print and think OMG, I NEED THIS!

Enter the Star Wars Death Trooper model by Paul Braddock, available on MyMiniFactory. Having repaired my Cocoon Create 3D printer (again!) in my previous blog post, and also upgraded my version of Cura (losing all of my print settings refined over the last year), this was a great model to iron out the kinks and get back to normality – I hate being without a working 3D printer.

From a technical standpoint my print isn’t perfect with the wall thickness far too thin, leaving some holes and messy details (eg. if you look closely at the eye socket of the skull). My new Cura settings still need some tweaks. However given all the hurdles, it’s still a pretty damn cool print that is really brought to life by the addition of a bit of black paint, and a simple coffee stain for the skull. I recommend checking out the original by Paul to see all the details of the design that aren’t captured well in my print, he’s done a brilliant job of finishing his print to give it an aged bronze look that shows every little scar and crack of the smashed Stormtrooper helmet.

If you want to make one for yourself, don’t forget to upload a photo of your 3D print to Pinshape by May 12th – there is a competition to win 1 of 40 rolls of filament (ABS or PLA) or some Resin if you use an SLA printer. You get an entry for every 3D print you upload of anything on the website!

– Posted by James Novak

Is That A Clogged Nozzle, or…

20170413_3D Nozzle Clog

No it’s just a clogged 3D printer nozzle, thanks for asking!

2017 seems to be my year for repairs on the Cocoon Create 3D printer, it was only a few months ago I wrote a big post about repairing and replacing the PTFE tube after it got seriously clogged. I did some research and found out exactly what the tube is for, and bought a roll of spare tube for future repairs (click here to read more).

Lucky I did! This seems to be the same sort of problem, however instead of the PTFE tube just getting clogged, when I opened up the nozzle the tube had become melted and broke off inside, completely stuck as you can see in the photo. I wonder if the spare PTFE tube I had installed was made from dodgy materials, allowing it to melt? Or maybe the ABS filament had just found a way around the outside of the tube and caused it to clog. Either way it’s getting a bit frustrating to have the same issue.

Luckily this wasn’t too difficult to fix (although I did jump straight on Ebay and buy a couple of spare brass nozzles – just search for RepRap MK10 0.4mm nozzle since the Cocoon Create is based on the RepRap Prusa i3). Using a drill and holding the nozzle with some pliers, I gradually worked my way up from a 2mm to 4mm diameter, clearing out the clogged material. 4mm is almost exactly the same as the internal nozzle diameter, so it cleared everything out nicely.

With some new PTFE tube installed, I’m back up and running again and the first print is coming out nicely (stay tuned to see what it is). Let’s see how long it lasts this time…

– Posted by James Novak

New Year 3D Printer Repairs

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After something like 150 hours of 3D printing leading up to Christmas it’s no wonder that my Cocoon Create decided to extend its holiday with some down time to kick off 2017. There have been 2 problems to do with extrusion that I’ve come across, and thought they might be handy to know how to fix for others with this printer, or indeed any of the many derivatives of the original RepRep Prusa i3 which this printer is based off.

The top image shows the first problem which I noticed after some jamming and issues swapping out filaments – basically a build-up of filament “powder” over time from the gear grinding it when it’s been jammed. This one’s a nice easy fix, just a cleanup and a reminder to open up the extruder occasionally to keep things clean. If you’ve never opened the extruder before it’s nothing scary, just 2 bolts on the left where the fan is mounted to the heat-sink which opens the whole thing up as shown above. You might be surprised how simple the whole mechanism is.

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After fixing this problem and doing a couple of prints, I then noticed the filament was getting jammed again and I couldn’t push filament through the nozzle no matter what I did. Opening the extruder (same process as before except now removing the small screw on the right of the metal block to release the actual nozzle) the problem was pretty clear – a clog in the PTFE tube which you can see above. A lot of people are surprised to open their extruder and find a plastic tube inside, and this is the first time I’ve really had a problem with it. This tube is made from PTFE, basically Teflon like in your non-stick frypan, and seems to serve a couple of functions from what I’ve read online:

  1. it stops heat from the nozzle climbing too high into the extruder and prematurely melting the filament, which would cause serious clogs.
  2. being non-stick, it helps the filament keep sliding smoothly down to the nozzle without sticking as it gets warm.

A very cheap, simple part that has a lot of responsibility. Mine must’ve gotten worn out or slightly dislodged during my last attempt at fixing the extruder. Thankfully my printer came with 1 replacement, which I cut to size (make sure both ends are nice and square so that there are no gaps for filament to get caught in) and now I’m up and printing again with no problems. Also I’ve jumped onto Ebay and ordered a 2m length of PTFE tube (inside diameter 2mm, outside diameter 4mm) from China for $2.50 – I recommend anyone who has a 3D printer with this part order some PTFE tube as backup, it’s very cheap but if you need to buy something locally in a 3D printing emergency, prices look at least 10 times higher. For a couple of dollars it might just help keep you sane.

Some good forums discussing PTFE tube issues:

I’ve previously written about another type of clog where filament breaks off inside the extrusion tube as you’re retracting it, and you can’t force a new piece in – check out the post here if this sounds like what you’re experiencing.

Happy 3D printing, happy new year.

– Posted by James Novak

Cocoon Create Goes the Distance

20161122_cocoon-create-print-summary

This week I’ve spent 48 hours printing 14 segments of my latest PhD project on my Cocoon Create 3D printer, and despite the usual hiccups like print warp and delamination of layers (they are some large pieces using ABS so it’s no surprise – stay tuned for a post on using a 3D print pen to fill gaps), the printer itself performed beautifully. With another 59 hours of printing left to go, I thought it was time to write a little update on the printer and why I think it’s probably the best value printer out there.

Firstly some clarification – the Cocoon Create is based on the open source RepRap Prusa i3, one of the most popular 3D printer designs ever. Many derivatives exist out there that all look identical, including the Wanhao Duplicator i3 Plus which I’ve seen marketed quite a lot on Ebay. The benefit of this is that there are endless supplies of spare parts and forums offering tweaks and suggestions, you just need to look further afield then the “Cocoon Create” since this is the branding for the printers sold at Aldi in Australia only as part of the promotion this year. So there’s not much of a community out there specifically for this printer. But for the general type of printer, the numbers are huge.

As you can see from the top photo, I’ve nearly printed 1km worth of filament with this printer, which I only bought in February this year during Aldi’s promotion. You can read about my first impressions here. For many years I’ve enjoyed successes with the UP range of printers (including the UP Plus 2 and UP Mini), but with the Cocoon Create proving to be just as reliable, and only 1/3 of the price of the UP Plus 2 ($499 AUD), the Cocoon Create is definitely proving to be better value for money. If you do the maths, this printer has so far cost me only $2.90 per hour of printing (+ materials and electricity of course).  In particular the positives I really enjoy are:

  • Rugged steel design means that there is no movement in the printer – I never have to adjust the level of the print bed. Just click print and it works every time.
  • Good print plate that the filament adheres to quite well – no need for glues or tape. I also really like using the Brim setting in Cura to help hold the prints onto the bed and really minimise warping on large prints. I wrote a post about that previously with photos showing with and without the brim setting.
  • Decent sized build platform, twice the size of the UP printers 🙂 (200 x 200 x 180mm)
  • Open in every way – software and hardware. Unlike many of the printers on the market, you can see and access all of the main features of the printer. Great if anything happens and you need to replace a part. Also you can use just about any software you like for slicing models and saving out G Code. I’ve just stuck with the recommended Cura so far, it has all the settings I need. The great thing about this is that you can get right into the details of the print settings, tweaking until you get your print just right – many printers come with proprietary software, which is normally good for simple plug-n-play prints, but won’t give you full access to settings.

A few things that are still a bit annoying, because hey, it’s still only a cheap printer and can’t be perfect:

  • The print plate can’t be removed from the printer (well not easily – you would need to re-level the plate each time), meaning that you need to scrape prints off in situ. I do prefer the ability to swap plates and remove a print when I can get at it easily with some tools.
  • The user interface is extremely old-fashioned, possible a relic from the 80’s – a single dial is used to scroll through menus and make selections, and it gets a bit painful.
  • Emergency stopping a print when something goes wrong requires either cycling through a few menus (see point above), or cutting power all together which is never a great solution. Perhaps a nice red emergency stop button would fit in with the 80’s styling?
  • Running back and forth between computer and printer with a SD card can be painful – with the cheap cost of WiFi chips these days, hopefully the next version can stream directly from the computer. However most printers still suffer from some sort of physical connection or SD card. Maybe it’s just because I keep my printer in a separate room to avoid the fumes…

Those are some of the main things on my mind as I reach the halfway point of this big session of printing on the Cocoon Create – keep your eyes out in 2017 for a return of the printer to Aldi, I have it on good authority that it will be making a comeback 😉 Follow my blog (bottom of the page) or twitter if you’re interested as I will definitely be posting the news as soon as I have details.

– Posted by James Novak

3D Printed Action Camera Floaty

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Most people when they get an action camera head straight out and start filming crazy things – not me!

I’ve just bought a Garmin Virb X action camera, choosing to avoid the popular GoPro’s for a number of reasons (I’ll spare you the details!) – suffice to say that the Garmin not only records great video, but has a range of built-in sensors allowing you to overlay data on top of video. If you’re curious to see what I mean, check out their promo video.

Since many of my interests are on the water (Kitesurfing and Stand Up Paddling) I needed to add the floaty  – I lost a GoPro a few years ago in Hawaii by not having one, expensive mistake! Sure I could fork out the $27 for the Garmin floaty, but I already had a GoPro floaty as part of a kit, so why not make my own attachment?

The design of the Garmin Virb X has a range of great little details to snap on to, which is how the USB clips onto the side for charging and data transfer. So I’ve simply used these to create a 3D printed bracket, to which the GoPro floaty can stick. As you can see from the images above, 2 prongs hook around one side, while the snap comes around to the front and secures the bracket around the camera. And gee it makes a good snap sound when is attached! Very secure.

Print orientation is really important for this one, the bracket is printed standing up much like the pictures (you can see the layers in the left image). This means that when force is applied to flex and snap around the camera, the whole thing doesn’t break apart. Also a bit of filing or sanding is needed on the back face to give the floaty sticker a good surface area to stick on to. Otherwise it’s good to go straight off the printer, which took about 100 minutes to print on my Cocoon Create 3D printer. Solid infill, 0.2mm layer height, brim adhere to the platform and a small amount of support material.

If you need this part, it’s all yours for free – just download from your favourite site Thingiverse, Pinshape, 3D File Market or Cults.  Be sure to post a picture when you’re done, I hope it helps you get those awesome videos on or in the water.

– Posted by James Novak

When Layer Orientation Matters

20160819_Meshmixer Plane Cut

Often when you are 3D printing the main thing you think about is how much support material your print will have, and you orient your print to minimise this – reducing material waste, print time and any manual post-processing to clean up the print. However sometimes the best print orientation for these reasons is not the best for mechanical strength, and I’ve just discovered this with one of the parts for the InMoov robotic arm I’m currently building (see the first collection of 3D prints in my previous post).

The “RobServoBedV6” part is where the 5 servo’s connect that control the individual finger movements, using screws to fix them in place. However some of the stands are splitting as I screw into them as shown in the photo above due to the layer orientation. Yes I could use super glue to fix them, but the split will just happen  somewhere else. So I’m going to completely cut the stands away from the part, and re-print just these stands in a different orientation to improve their strength. This is where the free program Meshmixer comes in very handy, and I’ve previously published a few examples of how to use it for my friends at Pinshape – just click here to find out more.

In the top right image you can see the first step of using Meshmixer to edit the STL file. I have used the Plane Cut tool to slice away the bottom plate, and then repeat the process to remove the other 2 segments which seem to be strong enough for the screws at the moment. This leaves me with the 2 stands that I’m having issues with. These can now be exported as STL’s ready to 3D print (orientation is not important here, this will be set in my 3D print software).

Cura from Meshmixer

I’m printing these parts as we speak on my Cocoon Create 3D printer, and have used Cura to prepare the parts and get the G-code. As you can see to the left, I have oriented the parts so that the layers are perpendicular to the original orientation, meaning that when I screw into them, the force from the screw will not pull the layers apart. Super glue will hold these replacements onto the original part really well as they are printed in ABS.

If you are designing your own parts from scratch in CAD and intend to screw directly into them, keep this issue in mind. However if you’re downloading a STL where modification isn’t as easy, knowing this simple trick in Meshmixer can really help you repair and improve a part rather than trying to re-print it from scratch and potentially use a lot of support material in a different orientation.

– Posted by James Novak