3D Printed Flexible Lens Cover

IMG_20200113_3D Print Lens Cover

I’ve said it countless times before, and I’ll say it again – some of my favourite 3D printing projects are the ones which are quick, easy, and either add value to an existing product (e.g. see my 3D printed webcam mount or lucky bamboo holder), replace something broken or lost (e.g. my SUP paddle lock),  or in this case, something missing.

I recently bought an old pair of binoculars (or is it just a binocular?) from an antique store. They came in a pretty beaten up case, and were missing two of the protective lens covers, but overall worked nicely with lenses that weren’t scratched. The lens covers that did come with the binocular were cracking and didn’t really stay in place any more, so it was 3D printing to the rescue.

Planning to use some PolyFlex TPU95 filament from Polymaker to create a soft, rubber-like lens cover, I ended up designing the lens covers to be just slightly smaller than the measured diameter of each lens, 0.25mm smaller to be specific, with the intent of creating a secure friction fit, but not so tight they had to be stretched over the lenses. The design is very simple, a couple of extrudes in Fusion 360, before adding the circular pattern detail around the outside (which was not part of the original lens caps!) to add a personal touch. Now that they’re printed they remind me of beer bottle caps, but the intent was just something a bit rugged and easy to grip without spending a long time trying to be too clever in CAD.

These were 3D printed on a Wanaho Duplicator i3 Plus with an upgraded Flexion Extruder. What’s a Flexion Extruder? Well, you can read my whole series documenting early experiments trying to 3D print flexible materials here, but long story short, a Flexion Extruder is the ultimate upgrade for cheap desktop FDM machines that allows you to successfully and reliably 3D print with soft TPU materials. If you don’t have a Flexion, or a good quality system like the Prusa MK3S which has been designed to print a whole range of materials including TPU, chances are you will end up with a tangled mess of filament coming out the side of your extruder, or worse! They’re just too soft to be forced down into the hotend and come out of a tiny nozzle.

The other trick is getting the right settings to print with – you will find loads of different theories and recommendations online, 3D printing TPU is a bit of a dark art and there are many different types of flexible TPU that require different settings. So getting things right will take some time. This is a good general guide to follow, and I’d reiterate that you MUST print extremely slow – I used 20mm/s for the lens caps. Also, follow the recommendations from your filament supplier, this material from Polymaker was printed at 220°C with the build plate at 50°C. Seemed to be about perfect.

IMG_20200113_3D print flexible TPU

Above you can see just how flexible the end result is, the lens caps easily bend and squash without permanent deformation. If you’ve got any settings you’ve found are reliable, or just general tips and tricks for 3D printing TPU, please comment below to build up some resources for others to find.

Happy 3D printing.

– Posted by James Novak

Using Every Last Drop

IMG_20180917_Webcam 3D Print Mount

Perhaps it’s the result of spending 10 years as a poor uni student, but I really like to use every last drop of liquids: sauce, toothpaste, shampoo and yes, deodorant. Many of the roll-on style deodorants, such as those from Nivea, have a domed lid, meaning it’s impossible to tip them upside down as liquid is running low and store them so gravity can do its thing. In my mind, this is a design flaw in the packaging (although from Nivea’s point of view, this is a great way to keep people buying more products more often).

I had originally planned to create my own design to solve this problem, however, after a quick search on Thingiverse I was pleasantly surprised to see many people had already beat me to it! There are plenty of designs to choose from, and I decided on this helix design for its interesting form. Click here to download the file for yourself from Thingiverse.

The print took just over an hour to complete, and as you can see from the pictures, it does exactly what it promises. I also streamed the 3D print on my YouTube channel, so if you like watching the grass grow, here is an hour of entertainment just for you! Make sure you subscribe if you want to be alerted of the next live 3D print 🙂

– Posted by James Novak

Ninjaflex Part 3 – Flexion Extruder Upgrade

20180515_Flexion Wanhao

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

Ninjaflex Extruder Mod – Fail

20180409_Ninjaflex Mod

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

3D Printed Ninjaflex – First Test

20180406_Ninjaflex Wanhao

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