With stories of 3D printing silicone and Nutella all over the internet, we’re curious about how 3D printing food and other paste material works. To clear up some of our questions and curiosities, we brought in paste extruder company Structur3D to tell us more about 3d printable paste materials and the extra tools you need to make it happen.
What is 3D Printing with Paste?
There are many different types of 3D printing materials on the market today, and most of them are made of different kinds of plastic to give you an end product that’s solid and hard. This is great for creating custom machine parts, toys and robotics, but what about the custom parts or projects that need to be flexible? Things like flexible phone cases or even shoes that require flexible material to function properly.
As the 3D printing industry becomes more easily integrated with mainstream consumer technology, the desire for soft, flexible 3D prints will grow. We’ve already seen a lot of growth this past year in brands like New Balance and L’Oreal. Now, with special paste extrusion systems, 3D printing with paste is possible for the everyday consumer with their desktop 3D printer.
Why should I care about 3D Printing with Paste?
Paste printing helps take your desktop 3D printer to the next level. Just think about it – printing with pastes allows you to mix hard and flexible materials in a single design all with your existing 3D printer. The design possibilities are endless.
Mechanics of 3D Printing Paste
Paste extrusion systems works with most FDM desktop 3D printers. It works by dispensing any paste material through a user-filled syringe cartridge system to a special extruder tip mounted to the 3D printer head. Don’t worry, the open cartridge system ensures your printing materials never come in contact with each other so you’re free to swap between foodstuffs and non-edibles. Depending on what type of material you are using, you may or may not be able to re-use your syringe.
Is your 3D printer compatible?
Generally speaking, if it runs open source software, it should be able to print with paste. Paste extruder systems work with both direct drive systems and non-direct drive systems. Depending on your printer, you’ll need to adjust your extruder steps per millimeter based on your current gear ratio or direct drive.
Refer to our Compatibility list to see if your printer is compatible. We are always updating and refreshing this page as new printers hit the marketing, so if you don’t see yours listed, feel free to contact us to ask.
4 Flexible Materials I can Print with a Paste Extruder
This is where the fun begins – you’re really only limited by your imagination. Here at the Structur3D E3 lab (stands for Extrude, Experiment, Explore), we’ve printed with everything from polyurethane and conductive ink to Nutella and icing sugar.
You need to start by asking yourself what do you want to print, and then choose the best material to suit your design. We’ve provided some details on a few of our favorites, but this is by no means the end of the road. The world is your oyster.
Product to use:
Depending on your design, to 3d print silicone you can use anything from industrial grade silicone to a brand you buy at your local hardware store. Here at the E3 lab, we typically use 100% transparent DAP silicone from Walmart.
If you’re looking for something a little more industrial, you can try products from companies like Smooth-On. They have thousands of options, all with varying chemistry so you can closely match your print needs (like curing time, hardness, colour etc.) with your project.
As long as it flows, you can print it! We have even printed successfully with $2 caulking from Home Depot.
Typically, you won’t be using a heated bed for any printing with a paste extruder, as you don’t want to affect premature curing in the tip, so make sure it’s turned off.
You’ll want to prep the print bed so the print can be easily removed after printing. Silicone prints well on wax paper, and this allows for easy removal. We use blue tape to adhere the wax paper to the bed. If you notice any residual wax on your finished product, or have issues removing, you can use hot water to dissolve any remaining wax.
As with all 3D prints, the speed at which you print depends on your nozzle size and material’s viscosity. We suggested a starting speed between 30-70mm/s and we recommend always planning for a few test prints when getting started with a new material to ensure you get the best result.
Things to think about:
Pay attention to overhang and bridging. It’s possible to achieve a 3D shape with silicone, but the quality will be dependant on the design. You’ll have more control than if you were printing with food, but less than if you were printing with plastic. Another option could be to print separate shapes and join them together during post-processing with more silicone.
Overall, printing in paste can be somewhat forgiving as the previous layer is still ‘wet’ when depositing a new layer. If there is some inconsistency, the needle will plow through the paste without damaging/skipping/bending the nozzle tip, hopefully fixing the inconsistency for the next layer.
Silicone will not keep very long in the syringe as it starts the curing process as soon as it leaves the factory tube. If you leave the syringe for more than a few hours, you’ll need to replace with a fresh one.
If you’re interested in printing with Silicone, check out our Forum post for using off-the-shelf silicone.
Product to use:
We have used store bought and homemade icing here in the E3 lab. We recommend using the traditional recipe for Royal Frosting, as we know it will harden after a few hours making it great for cake toppers and decorative additions to any dessert.
Another thing to remember here is the shelf-life. Freshly made icing prints the best. If you store it in the syringe for more than a few hours, it just doesn’t print well.
If you need to take a break from printing, don’t store the syringes in the fridge as the icing will become too hard to print. Leftover icing should just be discarded (or eaten) – no problem right?!
Step one – turn off the heated bed. We have found aluminum foil works best for the base. Similar to silicone, we use blue tape to secure the foil to the bed.
Pro tip: The foil works best when the surface is a little sticky for the first layer. We mix a little bit of icing with water to create a sugar water and just brush it on the foil before printing.
Given the viscosity, we suggest using a thicker nozzle (1.54mm) which will allow for bigger and faster prints. You’ll want your head speed to be between 20-30mm/s.
Things to think about:
First and foremost, make sure your icing is mixed well to avoid any separation when force is applied during extrusion. Extra beating is key!
After printing, we keep the print on the foil, and put in the refrigerator for 24-48 hours. This will dry out the print and make it easier to be handled. The denser the print is, the longer it will take to dry out, optimized according to the size of the print. Best not to rush this step.
Product to use:
Ahhh Nutella, the product everyone loves reading about. This product choice is really quite simple – it must be name brand – Nutella isn’t Nutella if it isn’t Nutella!
Nutella reacts very similarly to icing in that fresh Nutella prints better with a fresh syringe. We’ve noticed anything left out under a week will work well as long as you have capped the syringe and/or tubing. After that, you may want to get a new syringe hooked up.
As always, we suggest turning the bed off as step one. For the print surface, both aluminum foil and wax paper work well with Nutella so the choice is yours.
As Nutella prints very similar to icing, similar nozzles can be used, but it’s always best to make a test depending on your print. Keep the speed between speed 30-40mm/s to optimize most print geometries.
Things to think about:
Even more so than silicone, you’re going to have less bridging and overhang capabilities. Nutella is great for logos and other 2.5D images. We’ve had success with designs that are up to 3-5cm in height.
Most notably, Nutella doesn’t harden the way silicone and icing does, so your print surface becomes very important. Over time, it will harden to an almost putty-like consistency, but removing it from the wax paper or foil will be challenging, if at all possible. One option could be to print directly onto your food. Here’s an example where we printed Christmas trees directly onto pancakes. You’ll need to adjust the bed height during set up to account for the food you’re printing to.
Product to use:
Clay is a material we are still experimenting with in the lab. Our Kickstarter backers kicked things off right out of the gate with great success. They’ve been using basic natural clay slurry.
First thing you’ll need to think about is will you be firing your print? If so, you’ll need to ensure your print can be moved, or can be fired directly on your print surface.
One backer provided us details in the Forums about how best to optimize slurry for 3D printing:
“The slurry has to be very well mixed and watery enough to still be extruded, but stiff enough to stay together once printed. I used the larger nozzles with pretty thick layer heights just because the clay would jam smaller nozzles a lot. You’ll get a feeling for the slurry, just mix down and test fill the syringe and push it out.”
Things to think about:
Good thing about working with clay is that you can add water to adjust the viscosity to help get you the print you’re after. The trade off could be some porosity in the final product.
Speed and nozzle plays a very big role in printing with clay. As it’s a thicker mixture, you should be able to get a good overhang and bridging, but you’ll have to print more slowly – maybe 20mm/s.
One Kickstarter backer noticed that the tubing can swell under the pressure of a thicker mixture. You’ll want to keep an eye out for stress in the tubing and syringe. If you notice too much pressure, you can try to slow the print speed and/or increase the nozzle tip.
Top 4 Tips for Printing with Paste Materials
- Choose your design carefully. Printing with paste is a cold extrusion process so the curing time is longer than with typical 3D printing. This means overhangs and support structures may not be possible depending on the material you use. Viscosity and curing time are very important things to consider when choosing your design.
- Keep curing time in mind. For a material like silicone, you’re working against time as it begins to cure as soon as it leaves the manufactured tube. Because of this, you will need to fill your syringe and begin printing pretty much right away. It also means that if you take a break from printing for a period of time, you’ll likely need to replace at least the tubing if not the full syringe. On the other end of the spectrum, printing with something like Nutella, you can leave in the tubing for a few days without too much curing.
- Choose speed and nozzle size for your material. Depending on the material’s viscosity, you’ll want to be sure the tip sizes you’re using allows for a steady extrusion. Also, if it’s too viscos, you may see pressure on the syringe. If this happens, you’ll want to thin out the material, if possible, and/or increase the nozzle size.
- Only extrude materials, do not retract. Due to the pressure that’s built up during extrusion, any attempt to manually retract will cause stress to the extrusion unit. That said, small, incremental retraction may be necessary to remove and change syringes. Ensure you always keep it to a minimum and watch for stressing.
Ready to 3D Print with Paste?
This is what you’ll need:
- FDM 3D printer!
- A paste extruder
- Approximately 2’ of tubing – Food Safe grade if you plan to print with food (the length will be dependant on which printer you have)
- Cartridge packs or syringe
- Various nozzles and connectors
- At least 60cc of paste material you’d like to print with
- An amazing design
The Discov3ry comes complete with the extruder, 6 cartridges, enough tubing for at least 6 prints, nozzles and connectors, and can be purchased from MakerShed, Amazon.com or of course the Structur3D store. Check out our FAQs and Forum, or of course reach out with any questions.
If you’ve got questions or want to know more about paste extrusion, leave us a comment!
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