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!
– Posted by James Novak
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 🙂
– Posted by James Novak
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.
– Posted by James Novak
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
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.
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
I’ve had 3D printers at home for about 7 months now, pretty much since my first blog post designing the 3D printed kite-board fin. Inevitably there have been plenty of failed prints, and of course piles of support material. However rather than just throw it all away I’ve actually been keeping all the waste material in a bucket I keep next to whichever printer I’m using. The image above is the result of these 7 months of 3D printing; approximately 1kg of pure ABS plastic!
I’m certainly not the most environmental person, but I just can’t throw away this much perfectly usable plastic, so have put the call-out within my circles for someone with a filament extruder like the Filastruder to take it off my hands for free. Unfortunately an extruder is not part of my ‘toy’ collection (yet) or I’d be busy shredding this bag of plastic and extruding my own home brand of multi-coloured filament!
I’m not sure if anyone else has been doing a similar thing – if you own a 3D printer I’d love to know what you do with all this waste, and if you have any sort of filament extruder to recycle as much as possible. Please leave a comment with your suggestions, and I’ll post an update if I get this pile recycled by someone. Perhaps I’ll also keep an eye out for the next Kickstarter filament project!
– Posted by James Novak
UPDATE 26/6/15: I have since found a student with an extruder to take this off my hands – hopefully a small good deed for the environment.
It’s really no surprise that a new day printing with my new Solidoodle Press 3D printer has thrown up new challenges. Half way during a print I noticed that plastic had stopped coming out of the nozzle, and applying pressure to the filament from the top didn’t seem to help. Now one thing that is quite nice about the Press (as opposed to the many issues which I’ve found earlier) is that much of the nozzle can be opened with simple thumb screws. Finally, some forward thinking in terms of design! The first image above shows the cover removed, along with the front of the main body (no tools required).
I had already retracted the filament, and found that indeed my guess was correct – a blockage in the nozzle (image 2). This was a nice easy fix, removed with tweezers when the nozzle was cool. What I didn’t expect was to find the extruder gear drive completely loose (the toothed part that feeds the filament down), to the point that I could pull it off the motor with the tweezers. Obviously this is the cause of my problems. After some searching on the always useful SoliForum, I found many people experiencing the same symptoms of filament not extruding, and a nice walk-through fix from Solidoodle Support. Basically the issue (which I’m sure will be a recurring one) is that the gear is held onto the motor shaft using an extremely small screw. When this becomes loose, the motor will freely turn without engaging the gear, thus not moving the filament.
Unfortunately you need an extremely small Allen key in order to securely tighten the gear in place, threading through a 1.5mm vent on the side of the housing – which I don’t have (and doesn’t sound overly safe with all the wires there!). However by taking the gear out, I could wedge a small screw driver into the hole and pre-tighten the screw, then push it onto the D-shaped shaft of the motor in the correct orientation. It’s the best I can do for now, time will tell how long it lasts before needing to be re-tightened. Hopefully the link to the Solidoodle Support page for this fix will help anyone who comes into this issues.
– Posted by James Novak