How a part is designed can affect how easily, quickly and successfully it might print.
In this example a hypothetical bracket is required where the important criteria are the 45° angle, the mounting hole positions and the overall size. This page looks at the design and how it can be improved for printing.
The part can be printed as designed, but it will have an inherent weakness at the corner. Sharp corners like this cause stress concentrations which can lead to failure.
Simply by adding a radius at the corner we can gain a strength advantage, the stress concentrations will be more dispersed.
A further increase in strength can be had by added a rib as shown. The rib cannot extend to the top because of the single hole but it would still give a strength and rigidity benefit.
As before, adding blends will remove stress concentrations and help the part look more "molded" and professional.
The slicer software can be used to visualise the path of the printer and the layers. It confirms the sloped face can be printed without support and print time is given as 4.5 hours, using 22m of plastic filament.
Looking at the layer details, the wall thickness and 15% infill are visible. The wall thickness doesn't leave any room to drill out the holes or to add any threads. This can be changed by upping the wall count to 6.
With the wall count at 6, there is more plastic on all sides creating a stronger part and the flexibility to machine edges/holes if needed. Print time is now 5 hours.
For more strength the infill can be increased. Here it has been changed to 50% density with a consequent increase in print time to 9 hours. Plastic demand has also increased to 29m.
One thing we haven't resolved is the print direction. The print will most likely fail along the "grain" of the part which occurs between the layers in the Z-axis. We can rotate the part to overcome this, but there will then be support material needed for the rib.
If an asymmetric bracket is acceptable, then this design would be almost as strong and would remove the need for any support structure in the print. Radii on the top two corners could help soften the appearance.
Finally there is this design. This has a symmetrical appearance but the ribs have a draft angle on the inside face of 45°. Because the printer can print 45° slopes unsupported, the upper rib can be printed without support.
The final design looks like this. It has two ribs to gain rigidity and strength. The ribs are "drafted" on the inside face to enable the part to be printed sideways without supports. This will reduce risk of failure along the grain of the part.
Radii have been added to all internal corners to reduce stress concentrations and external corners have been softened with Radii as well.
Whether this design is acceptable will depend what is needed in terms of appearance and what screwhead size is expected around the holes; but the changes illustrate how a part intended for 3D printing can be modified, to get the best from a 3D print.
AI Website Maker