Tech Tuesdays: Part Orientation
Figure 1: Model containing critical features relying on part orientation for strength and function
Part Orientation For Model Strength
By orienting a part properly, part strength can be improved; small features can become stronger by simply rotating the part, and functional parts have more functionality when oriented properly. For example, the hinges and a latch on the part shown in Figure 1 would have had limited strength if not orientated properly.
The orientation in Figure 2 has limited strength in the current position. By slicing the part in this position, we can see that the areas around the latch and hinge become small surfaces (Figure 3) and will not provide enough strength. Furthermore, the slicing of the model is in the direction of the flex point of the latch and hinge, creating a weak point in the model that may fail when function is tested.
By rotating the model 90 degrees (Figure 4), we achieve an orientation that provides much better part strength. When the model is sliced there is more surface area around the latch and hinge areas. There will not be any flexing in the direction of the slicing, thus a stronger, more functional model.
The hinge and latch will also have more surface area, as seen in Figure 5, and are now part of a larger slice. Furthermore, the hinge and latch is not flexing in the slice direction; this build orientation will provide a stronger, more functional model.
Part Orientation For Build Speed
Part Orientation can affect support usage and build speed of the part. Rotating a part to a different orientation can decrease support usage and the build time of a part.
Step 1: Rotate the part in the x-axis, with the bosses down, and process the part, as seen in Figure 6.
Step 2: The part has been sliced, supports added, and toolpaths created (Figure 7). The estimated build time for this part is 5 hours and 32 minutes, using 2.58 cubic inches of support material.
Step 1: Rotate the part in the x-axis, with the bosses up, and re-process the part, as seen in Figure 8.
Step 2: The part has been sliced, supports added, and toolpaths created (Figure 9). The estimated build time for this part is 3 hours and 53 minutes, using 1.10 cubic inches of support material.
As we can see, build time and support usage can be greatly affected by the build orientation. In this instance, changing the orientation on the part, has decreased the build time by 1 hour 26 minutes, and support usage decreased by 1.48 cubic inches.
Part Orientation For Smooth Surface Finish
When orientating a part, consideration must be given to surface finish. This is due to the process of slicing the part in increments. Better surface finishes will be achieved by building the surface in the xy plane. Any surface built in the z-axis will be stepped. If the part was built as orientated in Figure 10, there would be a poor surface finish along the angled surface.
Step 1: Slice the part. As seen in Figure 11, stepping is visible along the topmost, angled surface in this orientation. If printed, this portion of the part would have a rough surface.
Step 2: Rotate the part around the X-Axis (Figure 12)
Step 3: Process the file again; notice that the angled surface is now being in the x-y plane. Since the contours of the part can be followed by the print head, this will produce a smooth surface finish.
As part size and complexity increases, orientation becomes more and more important; whether the goal is too attain fastest possible print time, the strongest features, or the smoothest possible surface finishes, selecting the correct build orientation is critical for meeting these goals. However, certain orientations will prove more useful than others, and many times a certain orientation will provide the best possible surface finish, whilst also creating a part that is durable and fast to print. Utilizing the correct build orientation is one way to gain immediate improvements in part quality, letting you take advantage of all that additive manufacturing has to offer. For more, visit us at www.cimetrixsolutions.com
- Cimetrix Staff