One of the biggest limitations of 3D printing is the fact that everything you print is in distinct layers. This means that any surfaces that are curved in the Z-axis suffer from a stair-stepping effect because of the layer lines. You can minimise this by using the smallest layer heights possible. This in turn, however, slows down your print time dramatically. There is another way to deal with this issue though, it’s called non-planar 3D printing.
What is non-planar 3D printing?
Non-planar 3D printing is a technique that configures the G-code of a print to instruct the printer to move in the Z-axis at the same time as it moves in the X- and Y- Axes. This means that the printer is then capable of making true 3D prints rather than 2.5D prints where the print head only moves in the Z-axis between layers.
Being able to move in the Z-axis while printing means that parts can have a smoothly curved top surface rather than having a stair-stepped curve. This not only looks cool and unique, but it also offers actual mechanical advantages. For example, non-planar prints are actually stronger vertically than traditional 3D prints. Furthermore, the smooth surface makes non-planar printed parts more aerodynamic which is great for printing wings for model aircraft and other airflow sensitive models.
It’s not so easy
Unfortunately, the software support is minimal at best with one somewhat maintained GitHub fork of Slic3r that requires Linux to run being the only available option. Most slicer software suites don’t support non-planar slicing. This is partly because it’s more complex, and partly because there’s minimal call to support it.
Another issue is that you need to have a print head that has an elongated nozzle and minimal material to the side of the print head. This is because of the angles of the prints. Normal prints lay down lower layers first and never dip back down below the current layer. In non-planar printing, however, this isn’t quite as simple. For example, if you tried to print a model skate-park, the ramps can reach quite high. If there’s not enough clearance between the nozzle, print, and things like the heatsink fan then the hot end could end up impacting the print.
Non-planar 3D printing is a cool option to have. Unfortunately, it’s unlikely to become a mainstream option. To do so, a novel application needs to come along that catches public opinion to drive further innovation. Have you made any non-planar 3D printables? Let us know what you made and how it went, down below.