This is the 3rd and final Volume of a 3 part blog series regarding part orientations when 3D Printing in FDM. If you missed my last posts please start with 3D Printing Orientations Guide Volume 1. In Volume 1 we covered Build Speed and Surface Quality. In Volume 2 we covered Airflow and Support Removal. This Volume we will focus on Strength and Support Structures.
Recall from the introduction in Volume 1, I mentioned building our parts in layers causes the finished part to be Non-Isotropic, that is, the parts strength will be different depending on direction of testing. This is somewhat comparable to wood grain. It is easier to break a board going with the grain than going against it. Consider our L Bracket again (pictured below).
Using two orientations we can see different directions in the “Grain”. Figure 2 would be the best choice for part orientation considering the force as shown (also assume the fixture point is the bottom face).
In Volume 1 I mentioned support removal as a consideration of part orientation. Another one related to support is the actual structure itself. As our parts are building, any overhang needs a support structure. Think about one cross section of the combined model and support structure. The printer lays down a layer of support (when needed) and a layer of model.
Every other layer, the printer needs to “toggle” the head in order to accomplish the transition between model and support material. Each machine has a different way of performing this and it does add time to the build for every head “toggle”. If we reduce the amount of support structure, we can reduce the build time.
See image below. Both orientations have the same Z-Height, orientation 2 would build faster as we are removing the “toggle” and reducing the cost by reducing the support material.
What if your part geometry requires the support? There could be instances you could section your model and bond them together after printing. In the Fortus line we have another trick up our sleeve. On the Fortus machines we have the ability to print our support structure from model material. It still leaves a few layers of soluble support in between but greatly reduces the time it takes for toggling.
Still have questions or have any ideas for future 3D Printing related blog posts? Ask them in the comments section below!