Knowing how to orient your model for 3D printing correctly is one of the biggest challenges in getting effective parts. Stratasys systems use soluble support material, which means almost any orientation can work to 3d print a model. However, orienting a print to not fail is only the tip of the iceberg. Depending on the geometry of a part, you may want a certain face or feature to look perfect, the part to be strongest in one direction, or to minimize the amount of support material used to reduce print time and cost.
I have created three example models that emulate common 3D printing situations, and will walk through how I would orient these models, prioritizing surface finish, strength, and minimal support material use. These parts provide hypothetical situations where you might use the part to give insight for different applications.
Before we dive in, it is important to note that this guide assumes that you have a basic knowledge of FDM 3D printing, and are familiar with the 3D printer you are using.
Example Model 1: End Use Part
Sliding parts are very common, and if they do not use ball bearings, chances are they use bushings made of plastic. For example, some furniture drawers and cabinets use nylon contact surfaces for sliding. Here I’ve modeled a half-circle slider with holes for mounting. How should I orient this model for printing?
This is how I would orient the part, based on our application of using this model as an end use part. This orientation will give us the best possible surface finish on the rounded surface that will be the sliding contact surface. This orientation will minimize the amount of support material and cleanup necessary as well. By positioning the model in this way, we hit the sweet spot of getting the best surface finish where we want it, appropriate strength for the application, and minimizing support material. But what if you had different intentions for this part?
If you want the indicated face of the model to have the smoothest surface finish possible, we would want to orient it as shown – maybe this part of the model is visible to the end user when moving the drawer. However, this would cause the layer lines of the print to conflict with the path of motion for the slider.
In addition, when looking at the orange support material area, this orientation requires more support material in order to get accurate dimensions on the mounting holes.
What if you want the flat face to have the best possible surface finish? We would want to orient it facing upwards, but this would cause a rougher surface on the rounded portion.
Looking at the support material, it becomes apparent that this orientation would cause more cleanup than the first (ideal) orientation.
Example Model 2: Prototype Part
As an example of a prototype part, I’ve modeled a simple airfoil. An airfoil can be a complicated shape to manufacture, and a challenge to position even for 3D printing. Because a complex shape like this can be hard to manufacture, it’s even more critical to be able to create a functional prototype before investing in tooling.
For the simple airfoil prototype, there are a couple ways we could orient it to get a balance of surface finish, strength, and minimizing support material.
This orientation is how I would position the part, in order to get the smoothest surfaces possible, and minimize support material. The smooth surfaces of this theoretical airfoil would be an important feature.
This orientation may give the strongest part for a wing application. However, gently sloped surfaces like that on the top of our airfoil can often appear rough when created with FDM 3D printing. This is caused by breaking down a precise smooth surface into a “stepped surface”, where the layers are stacked one on top of another. However, this orientation is best for handling the forces that our airfoil may experience, by aligning the direction of the layers at 90° to the lift it would experience.
Example Model 3: Tooling Jig
Our final example is a tooling jig, intended to drill a hole in the end of a cylindrical object. I imagine this fixture would be clamped a drill press, so that a pipe could be placed in it to have to a hole drilled through the end.
For our tooling jig, strength is the biggest priority. As such, I would orient the part this way, even though it means using a little more support material. This orientation will give us a nice surface finish on the top surface, but more importantly, it will position the layers at 90° to the forces our clamps will exert on the part.
Another possible orientation would minimize the support material used. This orientation will decrease the amount of cleanup and print time, if the tool is needed as soon as possible, however it will not be quite as strong in the desired direction.
This orientation is possible, but one that does not accomplish any of our priorities for strength or minimizing the amount of support necessary. Unless your application really needs a nice surface on the top one indicated, this orientation is not ideal.
Orienting a model can sometimes be both an art and a science. However, knowing the priorities for your part in terms of strength, surface finish, and minimizing support material can help hone in on the best possible way to print your model. Hopefully, these example models give some insight into the orientation options you have to get your desired results.