Maker Tip: Print with Dissolvable Supports

Posted: January 18, 2017 in Maker Tips
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I get a lot of questions about 3D Printing. Lots of people ask what printer I have or what materials I use. As you can see in the photo above, I have a MakerBot Replicator 2X. My printer is a few years old now, but it has a heated build platform, dual extruders, and a closed in shell. While it lakes the bells and whistles of wifi and an app, it more than meets my needs. Follow me after the break to learn how I use my printer and how to use dissolvable supports!

I think of my printer as a tool and mainly print parts for projects. I use ABS for most of my parts. One major downside to ABS is that is shrinks as it cools. This means I need to scale prints to get things to fit just right. I also do not keep my ABS sealed (unless it is new) so it absorbs water, making this a bigger problem.

Lots of people assume that I print in two colors, since I have dual extruders. If I need to color a print, I prime it and paint it. I have one extruder setup for ABS. I generally purchase whatever filament is on sale, so colors vary. Right now I have orange in my printer, but I have a blue spool ready to go when it is gone. The second extruder is setup for supports.

Many times I print against gravity. I may have large spans or holes that supports. In order to maximize quality, I use dense supports. However, it is hard to remove these supports when printing with a single material. Getting a knife into a part is not always possible. Enter High-Impact Polystyrene (HIPS).  HIPS is a material that is very similar to ABS in thermal properties (I print with nearly identical temperatures and speeds, but is chemically very different. While ABS and HIPS both dissolve in acetone, HIPS will dissolve in D-Limonene and ABS will not. This makes HIPS an ideal support and raft material for ABS prints.

D-Limonene is expensive, but a little goes a long way. I purchased a gallon over a year ago and I still have most of it left. It has a nice citrus smell. Just opening the lid of the jar for a minute or two will have my whole apartment smelling fresh for days!

As a HIPS solvent, D-Limonene is very slow. To get good results I let the print soak for a couple days. Most parts float due to the hollow structure. I often use washers to wait down a print. To speed up the chemistry I leave the jar in front of a window or out on my balcony. Living in Florida, the direct sunlight and heat works well for speeding up chemical reactions!

After a print has soaked it and I remove it from the D-Limonene solution, it needs to be washed. Like soaking the print in orange juice, D-Limonene leaves a sticky residue. Soaking in warm water for about an hour does the trick and the part is ready to use! The solution in the jar pictured on the right has worked with over a half dozen prints. I have only needed to change the solution a few times. If there is HIPS remaining on the part after a few days of soaking, I know the chemical reaction has reached an equilibrium and new solution is required. While D-Limonene is clear at first, it quickly changes color to match the color of the dissolved HIPS filament.

So where do I go next with 3D printing? I have experimented with both PLA and PETG. PLA does not shrink and prints at a much lower temperature. Another feature is that it does not require a heated build platform. However, it is more brittle and often too weak for my projects. It forces me to print with more infill to get strength.

If you have spoken to me recently about 3D printing, you have almost certainly heard me mention PETG. PETG is basically the same plastic used for plastic water bottles. It prints at a slightly warmer temperature than ABS. Unlike ABS, it does not shrink, but it maintains a similar strength and flexibility. I am moving more and more to PETG, using ABS where I can to use up my remaining stock. In printing with PETG, I am using a similar profile to ABS. I am yet to tinker with the build platform temperature. With less shrinking in the material, I would expect to have a cooler build platform. Stay tuned for more!

Lastly, I have also begun to use a 3D printer pen as a way of finishing my parts. Sometimes I need to attach two parts or fill in a gap or seal some reinforcement inside a part. Printing either ABS or PLA, the $30 pen I got off ebay works well. It requires a steady hand, and often a knife to clean up any excess. I recommend picking up one of these to add to your tool box. It comes in really handy!

Hopefully this post provided some insight into my methodology. The process is constantly evolving. Printing with dissolvable supports is really a major help when making complex parts. I suggest you give it a try if you can!

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Comments
  1. […] a followup to my previous tip, I was asked how I get my prints to stick to my build platform. My MakerBot Replicator 2X has a […]

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