When 3D printing, the inability to print features that overhang beyond a certain angle can be really frustrating.

 

What Did We Use Before Scaffold?

Same material breakaway supports aren’t always the perfect solution because fragile models can break during removal and surface finish left behind can be poor. There are also many other restrictions including:

 

- Parts that don’t have a large area contact with the bed to hold them down while printing

- Unable to print objects within objects or printed in place mechanism

 

For quite some time, people in the 3D printing industry have recommended using PVA or to use HIPS and dissolve it in limonene, but unfortunately PVA isn’t up to the task of being a great support material, it really struggles with adhering to build materials and exceptionally high viscosity results in low flow and the need for high pressures. Also, when standard PVA is heated in the nozzle for an extended period of time the polymer chains begin crosslink and form a new, non-liquid material, with a consistency that resembles sand. Sand cannot be extruded and this kills the nozzle.

 

HIPS works well as a support material exclusively for ABS and limonene isn’t very toxic, however it’s a different case once you dissolve a polymer in this. If you get limonene with HIPS dissolved in it on your skin the limonene soaks in and leaches the polymer into your skin.

 

What is Scaffold?

Scaffold is a breakthrough in soluble and breakaway support material. Scaffold opens up great new capabilities in what is possible on open platform 3D printers. The Scaffold material is made using a blend of PVA/PVOH resins, meaning this material sticks really well to a range of materials. The experimentation stage showed good results, but there were some known issues, such as cross-linking and viscosity. SpoolWorks found an effective way to boost flow without compromising adhesion or solubility. An unexpected bonus here was that it also interrupted the cross-linking process, slowing it down considerably, and once cross-linked the material is less like sand and more of a paste like substance. This means that in most cases you can just purge out the substance and save the nozzle. 

 

Scaffold adheres well to Edge, PLA, Nylon, PET and co-polyesters and the melt flow is vastly improved compared to conventional PVA. The resistance to cross-linking is considerably increased, if cross-linked the material forms a not fully solid material that can usually still be purged, it’s recommended that long dwelling in a hot nozzle should be avoided.

 

The Scaffold Soluble Support material is less susceptible to moisture absorption, comparable to Nylon. It’s supplied in a resealable bag with desiccant for storage and use and if in doubt you should dry it on a heated bed at 45C.

 

This material provides you with a reliable and easy means of supporting complex overhangs and it’s perfect for printing mechanical parts with overhanging internal features.

 

Printing with Scaffold

Printing optimally with soluble and breakaway support requires specific strategies to get the best results. You must have solid interface layers of support material, where the final top layers of support are printed solid, not sparse. These interface layers are now available in many of the popular slicing packages out there, Slic3r, MatterControl, and Simplify3D. Simplify3D has the additional advantage of being able to manually place and remove supports, this can be extremely useful.

 

Printing with soluble support is very different to printing with same material breakaway support. When printing with soluble support, you are creating a mould into which you’re printing the build material. The surface finish and shape of that “mould” is what will define the shape and surface of the supported build material. The better you can get that supporting structure to form the shape you want of the underside of the model, the better results you get.

 

Different 3D materials behave differently with Scaffold and selecting an appropriate build material to go alongside is essential. PLA, other PETs, and co-polyesters work well with Scaffold. Nylon really sticks well to Scaffold, this can be an advantage and a disadvantage, it isn’t going to break away easily and cleanly (you can remove it with water), but it will hold the Nylon in place and makes rafts a very effective bed surface for printing nylon.

 

Material Soluble Breakaway Comments
Edge Yes Yes Optimised pairing
PLA Yes Yes Very usable and good for large parts
Nylon Yes No Extremely strong adhesion, prevents breakaway, but resists warp
TPU Flexibles Yes Yes Flexibility provides very satisfying peel-away
PET/Co-polyester Yes Yes Usable, but with reduced adhesion
ABS No No Does not adhere

 

 

SpoolWorks have developed this material so it’s more resistant to moisture, but because it’s a water-soluble material, there’s only so much they can do. They have provided Scaffold in a resealable bag with desiccant, though. SpoolWorks have also designed an in-bag spool holder than can be 3D printed and only needs some minimal hardware that you probably already have on hand. This means that you only ever need to open the bag once, to get the material onto the holder and fed through the outlet, keeping exposure to atmospheric moisture to a minimum.

 

Printing Scaffold

- Print Temperature - 215°C
- Bed Temperature - From 20°C to 55C ideally, but will cope with bed temperatures as high as 110°C
- Print Speed - ~50mm/s
- Support Infill - ~15%
- Support Angle - 45° & -45° (create a crosshatch pattern)
- Dense Solid Layers - 3
- Dense Solid Infill - 90%
- Upper & Lower Separation Layers - 0
- Support Angle - 46° and up
- Support Pillar Resolution - 1mm
- Raft - Yes

 

Removing Scaffold

- Remove the print from the Bed
- Break away as much as is possible
- Leave submerged in water to soak for ~60 minutes
- Flush out the part and clean off as much as you can
- Soak for a further 2 hours or overnight
- Clean off the remaining Scaffold with scourer pads or scrubbing brushes (for easily accessible areas) bottle brushes (for small openings)
- Dry the part - take note that there may be some water incursion into the model from soaking that can leak out over time

 

Scaffold opens up new possibilities in design freedom. Large overhangs, protruding features and complex models are now all possible thanks to Scaffold.