Supports
Difficulty: Advanced
Objective: Learn how to add supports and by which method.
What are Supports?
When I was in China I worked on site of constructing a manufacturing facility. In the picture above you can see the scaffling that we used to build it. (It was really scary as the thin bamboo would bend as you walked on it!) Scaffling is similar to supports, both are removed after the construction is complete, and necessary to construct it.
For those of you who do not have PVA filament capability on your printer, this is an essential blog for you. Supports are extra plastic that are printed for stabilizing and for areas where the printer would otherwise print on air. After printing the supports are broken off. This sounds easy enough but it is the hardest aspect of 3D printing. And unfortunately I have not yet come across a software that has a user interface that makes it easy to add supports and adds good supports.
How do I Add Supports?
(Methods of Adding Supports from best to worst)
1) Just don't. If you can design your model so that no supports are needed, then this is ideal. But this is often not possible. Therefore see if you can orient your object in a way that uses the least amount of supports.
2) Custom supports added as part of the model. Sounds easy, but requires the user to know where supports need to be added, how to add them, and how to make the supports. Overall it is an advanced method. But is the method I use and recommend.
3) Autodesk Meshmixer. Is for people who are willing to put the effort in one step ahead of using the printers settings for supports but not enough effort to make the supports themself. It is a way to add supports automatically much better than your printer will.
4) Default automatic supports on the printer's settings. Easiest method as you simply click yes to supports, but expect to spend the rest of your day trying to get those supports off. You'll break your model in half, slice your finger open trying to cut the support off. It aint fun.
There are usually advanced settings where you can adjust the settings of the automatic supports, but by this point you might as well use any of the methods above this.
Why are Supports So Difficult
1.) You have to know where to add supports and how dense to add them
2.) If you rescale your model size for printing it will also rescale the supports making them too small or large. Causing them to be too thin to print properly or too big to break off.
3.) When the model is sliced supports often confuse the slicer making strange codes for the printer.
4.) When breaking off supports you can easy break the part of the model off along with the support. Especially with small details.
5.) Since you are breaking off the support it will be noticeable. It will take after maching such as sanding to hide the rough spot where the support was broken.
6.) If you have a really complex model, the time need to add and take off supports can be a long time.
Feasible Designs of Supports
There are a few designs listed below that I have found useful. Lets say we want to print this cute little dragon:
The Beam
You can use a circle, square, triangle, I-beam, or whatever cross section. (I will mention that 3d printer that I use at work slightly struggles with circles so I like square cross sections).
The Thin Plane
Theses are easy and work well as long as they don't exceed a certain height. Once they become too tall they wobble too much and are not stable. However you can always taper the plane so that only the tip is thin.
The Ring
This is a mix of the beam and thin plane. This design is great because when you squeeze the cylinder it pops right off. I used it to print a goblet and it worked beautifully. The cylinders are not solid, they are thin as if you took the thin plan above and rolled the ends together.
The Tree
This is what Autodesk Meshmixer uses and is good because it doesn't waste as much material. Like the beam method except that it branches out both towards the object and the bed plate. This can be combined with any of the above, for example making a thin plane with holes in it, like a bridge truss. Perhaps this is the best method by optimization, but can be yer most time intensive.
When do you not need supports?
First of all anything that is horizontal will not need supports. I have seen printers bridge 6 inch gaps with just a little error. However to be on the safe side I would bridge no longer than an inch. Under such a bridge no supports would be needed. Please note that the bottom layer of the bridge must be horizontal and not slanted or arched.
Please leave a comment.
And as always, thanks for visiting.
3D Printing Ninja
3DNinjaneer@gmail.com
Category: 3D Printing Preparation, Advanced, Basics, Design, Settings, Supports, Trouble Shooting
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