What is it?
Print orientation is one of those key skills that should be learnt at the beginning of your 3D printing journey. It can have a significant affect on the quality and properties of your part. Once understood, it becomes second nature and is integrated into your design processes without even realising, this is a good example of design for manufacture.
How to use it to your advantage
The orientation of your part on the build plate plays a big factor in your parts strength as the layer lines are a weak point. Layer lines are the stacked layers of plastic extruded from the nozzle of a 3D printer horizontally along the Z-axis. Because each layer is placed separately, they do not bond to each other as much as if they were one solid part. Therefore, to gain maximum strength from your part, it should be printed with the layer lines perpendicular to the direction of force. Using this method will spread the load evenly across each layer rather than a single point of weakness.
How does orientation affect quality? As mentioned earlier, an FDM 3D printer operates by stacking multiple thin 2D layers of polymer vertically. Because of this, there can be a ‘stepping’ effect caused on curves along the Z-axis between each layer. This can be minimised by adjusting the layer height but will never be eliminated. To achieve the highest possible surface quality, it is best practice to orient small or critical features along the X or Y axis rather than the Z axis. In this orientation, features are formed primarily within individual layers instead of across multiple stacked layers, significantly reducing the visible stepping effect.
3D printers are also limited by overhangs. These are walls or features that extend away from the part without anything underneath to support it as it is being printed. A typical FDM 3D printer can handle overhangs of up to 45 degrees. Past this supports are required. Supports do exactly what they are called, they are sacrificial parts that are printed to support the features of your part that can’t support themselves. They will also be needed if your part has any features that will be printed ‘floating’ to begin with and then connect up with the main part.
Bed adhesion describes how well your part is ‘stuck’ to the build plate of a 3D printer. It is important as if it is low you run the risk of your part coming loose and your print failing. Ideally your part has a large flat contact area between it and the print bed. To increase this area a brim can be used.
Finally, print orientation will affect the dimensional accuracy and tolerances. For example, holes printed horizontally may have dropping at the top where the sharpest overhangs occur. These tolerances will be different depending on the orientation of the part which is why this is important to consider.
WRITTEN BY OLIVER ROTHNER
Award-winning product designer and engineer.
Currently working as Project Manager at Pro2Pro whilst obtaining further qualifications.