This is the third post in a series about 3D printing with Ninjaflex, which initially began using the stock standard extruder on a Wanhao Duplicator i3 (click here to start at the beginning), before a 3D printed modification was trialled (click here for post 2), and now here we are with a completely upgraded extruder specifically for printing with soft materials.
Pictured above you can see some fancy red anodised components and exposed gears – this is the Flexion HT Extruder, a relatively expensive upgrade (US$179) which is about half the cost of the entire printer itself. It replaces the entire core of a standard single extruder; all that remains from the original is the stepper motor and cooling fans. So why upgrade?
Well as the previous posts discovered, the highly flexible nature of Ninjaflex (shore hardness of 85A) meant that it was difficult for the standard extruder to force down through the hotend and out the nozzle. Imagine taking a length of soft liquorice and trying to push it through a hole that is smaller than the liquorice diameter! As a result, after a few minutes of printing, it was common for the filament to begin looping out the back of the extruder. The Flexion extruder has much tighter tolerances around the filament the entire length it travels, so there is nowhere for the filament to go except down. Also, it has adjustable pressure using the round dial you can see with the knurled detail in the photo above – this means you can apply more force on the soft filament to maintain a strong grip against the stepper motor gear. By rotating the dial, you can quickly scale the pressure back when you change to a rigid filament like PLA, with 4 levels of variation possible and a grub screw to really dial in each setting. The design is completely open, (when it was assembled I initially thought something was missing!), which means you can see the filament and gears, which is great for maintenance and adjustment. And while I haven’t tried yet, according to the Flexion website the nozzle can handle higher temperatures than a standard extruder, up to 290°C, which is great for plastics like nylon and polycarbonate.
The photo at the top right is one of the first 3D prints done to test the abilities of the extruder, taking approximately 4 hours. It looks good from a distance, although there are some small gaps where we started with too much retraction and not enough flow – at this point we are still experimenting with settings to get the best results, currently trying 107% flow, 40mm/s print speed and 1mm retraction. If you are using a Flexion for Ninjaflex and have some reliable settings, I’d love you to post a comment and share them!
This is a short little update following on from my last post attempting to 3D print with Ninjaflex filament (soft TPU):
After limited success using the stock extruder on a Wanhao Duplicator i3, I found a 3D printable Extruder Drive Block on Thingiverse to supposedly help stop the filament from finding its way out out the back rather than being forced down into the nozzle. Well, as you can see from the photos, it looks like it fits quite well, although I did have to slice and file a few areas to fit properly – most notably around the shaft of the stepper motor which was far too tight and stopped it from turning, and the wheel that pushes the filament against the stepper gear which was blocked from putting any force against the filament so did not drive it down into the nozzle. Admittedly, the file on Thingiverse was designed for the Duplicator 4, so it was a bit of a long shot to work with the i3.
So back to the drawing board I’m afraid for Ninjaflex printing – perhaps time to upgrade to a Flexion extruder, or look at some other TPU materials that might be slightly stiffer and more suitable for this basic extruder. Flexible PLA looks interesting. If you’ve had any successes 3D printing with Ninjaflex on a printer like the Duplicator i3, leave me a comment 🙂
I’m sure if you’ve been 3D printing for even a short time, you’ve heard of Ninjaflex – a brand of flexible filament for your FDM printer that has rubber-like properties, rather than the usual rigid plastic parts that are more common with ABS or PLA filaments. While I’ve known about them for many years, I’ve never risked clogging my printer after hearing some bad experiences with these softer materials. Until this week!
I’m currently working with fashion postdoctoral researcher Mark Liu, who purchased a Wanhao Duplicator i3 v2.1 for some of our research – not coincidentally, it’s identical to my home Cocoon Create 3D printer. We decided to give the Ninjaflex a go to see if it would print, and if so, what sort of quality we could get since the printer and replacement parts are cheap if we really screwed up! Photographed above is one of our first successful prints, although the truth is we had quite a few failed attempts getting to this point as we experimented with settings and carefully watched each print. The primary settings we are using for these first tests (based off the recommended settings for Ninjaflex which are available in the Printing Guidelines) are:
Extruder Temperature: 230°C
Build Plate Temperature: 40°C
Print Speed: 15mm/s
Layer height: 0.2mm
Retraction: 5mm (I think this is too much and we will try 0mm or 1mm)
These may not be perfect yet, and I’m keen for anyone’s feedback on what’s led to more successful prints with these soft filaments. The main thing we’ve noticed is that the soft filament is challenging for the extruder to push down into the nozzle and force out the tip – it is quite common for the nozzle to clog and filament to keep feeding through until it comes out the back of the extruder. Luckily nothing has jammed up yet, you can pull the filament back up out of the extruder and try again. With a bit of a search online, it seems that some 3D printable parts may solve this problem, in particular this modified Extruder Drive Block available on Thingiverse which closes the opening where the filament likes to escape, and will hopefully better force it down through the nozzle. The video below from Wanhao USA helps highlight the problem, and how this 3D printed part can fix it.
It’s early days with this filament, and I know the stock extruder of the Duplicator i3 is really not optimised for this type of material. But it can be done, and I’m sure with some tweaking can be made more reliable. Stay tuned as I am currently printing the new block to install on the Duplicator in the coming days, and will report back with results.
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.
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!
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…
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.
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:
it stops heat from the nozzle climbing too high into the extruder and prematurely melting the filament, which would cause serious clogs.
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.
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.
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.
Now that I have my Cocoon Create 3D printer I can’t help but find new things to print for my bike! Since the bike is from 2007 the licence plate is a little bit shabby, so it seemed like a good chance to print a surround to tidy the edges up and also tie in with the other 3D prints I’ve done using this green PET+ material from MadeSolid. As you can see above, I chose to split the surround into 2 halves for printing, making it both easier to print (less chance for warping) and also easier to install. If you look at the Sketchfab 3D model below, you can see I designed a few hooks and details to secure around the licence plate, so being able to install it in 2 pieces made sense. There are 2 bolts used to secure the surround in place using existing holes on the licence plate, and the bottom split area was glued after being fitted for a seamless look.
While the final design works well, this one wasn’t all smooth sailing. The first print on the left in the image below didn’t quite fit onto the licence plate, so a few details needed to be changed in the Solidworks CAD model. The second partial print I tried printing vertically, rather than lying down, with the hope that it would require less support material. Unfortunately I had to stop this print as the surface details seemed to be getting worse as it printed, probably because of the height and inherent flexibility of the thin part the higher it got (a bit like a skyscraper swaying in the wind).
The third part pictured is the final successful part, printed lying down and using support material automatically generated in Cura (my slicing tool to generate the G-code for the printer) for the overhangs. While the visible surfaces look great, the detail picture on the right shows the messy underside surfaces which I’m not too happy about. This must be a setting in Cura that I’m missing and haven’t noticed in my previous prints on the Cocoon Create which have rarely required much, if any, support material. I’ll have to have a close look next time I print something requiring a lot of support like this – anyone have any ideas?
It sure is, and while the definitions are quite complex, the best way to understand a mesostructure is to look at some images of them. The top left photo is actually a nice 3D print of one you can download free from Thingiverse, and if you’re after something to show people the interesting things that can be 3D printed, this is a great example. I’ve printed them in ABS plastic, but the structure itself is both rigid and flexible. 3D modeling them can be a good little challenge – hopefully whatever CAD program you’re using has some great patterning and mirroring tools! I used Solidworks and really made the most of the parametric functions to allow quick and easy changes in the future. By changing the density of the structure, or simply increasing the thickness of them, you can really play around with the flexibility of the structure.
The other 2 images are actually my first little attempt and having a functional use for a mesostructure. I’m trying to isolate some small vibration motors, and this was one of the ideas building upon a previous round of prototypes that I’ve posted. It’s just like building in some springs between each motor. Nice and flexible and only 25 minutes to 3D print on my Cocoon Create, which is great when you’re trying to test and iterate multiple ideas quickly. Below is the 3D model for you to spin around.