In this 3DShoemaker tutorial, I’m going to show you how to 3D print foamy orthotic insoles using models from 3DShoemaker.com and filament that should work on pretty much any modern desktop 3D printer. The results are quite impressive, and the cost is similar to buying off-the-shelf insoles and far cheaper than getting anything custom done. I really think that with this approach it is now truly viable to 3D print orthotic insoles right in the clinic or even from the comfort of your own home. And if you do 3D print them yourself, it’s even easier to repeat every time you need a new pair for years to come.
Before getting started, I want to point out that much of what I do here on 3DShoemaker is highly experimental, so the following content is for information purposes only. If you chose to make use of this information and/or the 3D models sold on 3DShoemaker.com, please understand that you do so at your own risk.
I previously demonstrated how 3D orthotics models found on 3DShoemaker.com and designed in the 3DShoemaker software can be 3D printed on common desktop printers. While it was definitely viable, the quality just wasn’t as good as something you could get off the shelf or from podiatrists etc. In particular, the TPU filament, no matter the infill, just felt like hard and slippery plastic with just a bit of give. Of course you could always go with a soft durometer TPU or TPE. But common desktop FDM 3D printers, like the Bambulab X1C I use, really start to struggle and have to go extremely slow with soft filament. As people always say, it’s like trying to push a wet noodle.
Enter foaming TPU. With this bread of TPU, the filament starts off fairly hard, but then foams as it leaves the extruder, expanding and so becoming less dense and thereby softer. The degree of foaming is controlled by the temperature of the nozzle. As far as I know, the first to popularize this technology was Colorfabb with their Varioshore filament, which is what I have been using. Hardness for this filament starts at 92A and goes all the way down to 55A with maximum foaming.
Besides making it easier and faster to get more flexible TPU 3D prints, the material just feels much softer and less like plastic. It feels almost like a cross between neoprene and canvas. The resulting prints also don’t look like plastic either. They are totally matte rather than shiny and the layer lines are almost invisible. The foamy nature of the print also hides the effects of moisture absorption. As Colorfabb suggested, Filament drying so far hasn’t proved necessary for me. And you would think that this material would be finicky to print, but I haven’t had any issues at all using this profile provided by Colorfabb. And on top of all this, Varioshore has gotten multiple certifications suggesting the material is skin safe, which is important in case socks aren’t worn.
That’s the good side. There are of course some challenges. The main one is stringing. Prints have to be planned very carefully unless you don’t mind a ton of post processing. I recommend turning on the option to Avoid Crossing Walls or the equivalent in whatever slicer you are using. Also, given how flexible the filament becomes, parts can easily droop. For both of these reasons, I’ve added the Full Edge Support option as opposed to the previously introduced Partial Edge Support when ordering 3D orthotic insole models on 3DShoemaker.com. It results in more waste, but likely this material can be recycled same as regular TPU filament. The full edge support also increases print time. Perhaps some of the edge support isn’t entirely necessary and you could use some Boolean tools found in most slicers to remove some. Another con I can think of is lack of breathability given it is a closed cell foam, but some through holes in the design could improve upon that. The price is also on the high side. Right now it costs around $50 US for 700g. My size insoles used about 100g each plus half that in waste, so 300g total or $21 in filament. But I wear US men’s size 14 so it would be a lot cheaper for most people.
If you haven’t come across my earlier video explaining edge supports, where I previously referred to them as smart supports, you might be wondering why not just 3D print the orthotic in a flat position. There are a few reasons. First, a lot of 3D printers don’t have a large enough bed size for orthotic insoles for larger shoe sizes. Second, the bottom of the insole isn’t necessarily flat, so you end up needing support material which ends up being quite tricky to remove. And third, stringing is more of an issue with the flat topology and striations greatly detract from the aesthetics of the insole. An edge support solves all of this. The most recent version of the Edge Supports includes a kind of perforated edge, making it extremely easy to remove from the orthotic insole. Perhaps a small amount of sanding or grinding could be done to clean up the edge.
As I mentioned earlier, the Colorfabb Varioshore profile for the X1C was a great starting point for me. There are a few settings that could be tweaked. The most influential setting for this filament is nozzle temperature. Colorfabb suggests anywhere from 200°C to 250°C with the latter achieving maximum foaming. I found that quality and integrity greatly degraded at higher temperatures though, so I stuck with the profile default of 230°C. If you do decide to try a higher temp, remember to also adjust the flow ratio so things don’t get overcrowded. A few other things I changed were seam position to nearest in order to reduce stringing from longer travels, brim to outer and inner for better stability of the print, and infill to 10% gyroid. As far as hardware, I used the smooth PEI Engineering plate and a 0.6 nozzle, though I think a 0.4mm nozzle would be fine.
I’ve been wearing these orthotic insoles in my shoes for a few days now and they feel fabulous. I wouldn’t expect better if they had been done on a $100K SLA printer. I’m quite pleased with the results of this project. I hope you’ll give it a try to. If you want to, you can find the highly customizable Orthotic Insoles Designs from the Designs menu on 3DShoemaker.com. Make sure to choose the option for a Full Edge Support in the Edge Supports section. And of course you can also design your own orthotics, even vacuum form them to foot models, using the 3DShoemaker plugin for Rhino 3D. In future posts, I’ll get into how to design or order insoles for addressing specific issues, like leg length discrepancies. If you have any comments our questions, please leave them below, and please subscribe to the newsletter if you get a chance. Thanks for reading.
