As we mentioned in our post about how we use our 3d printers, we’ve discovered recently some tweaks that allows us to 3D print watertight parts. Typically, 3D printed parts are easily permeated by liquid and we advise customers to avoid it for those kinds of applications. A printed cup, for example, would leak all of its contents in just a few minutes. But with just a few settings, we’ve been able to print parts that hold water and even stand up to low pressure. Like we said in our last post, our 3D printed nozzles have been running for three months without issue.
All About the Toolpaths
Above are the toolpaths for two adjacent layers of a part prepared with this method. 3D printed parts are made up of boundaries and infill, which respectively form the exterior and interior geometry of the part. Where a boundary starts and stops is the most vulnerable point for liquid to enter the part. And once inside, the geometry of the infill determines how much of the part it can permeate.
- Varying the number of boundaries from one layer to the next. Layer 1 has one boundary while Layer 2 has two. This helps by sealing off the holes created where boundaries start and stop.
- Making the boundaries on each layer one contiguous path. On Layer 2, the outer and inner boundaries are connected by a diagonal line. This creates a kind of maze that traps water, preventing it from reaching the part’s interior.
- Varying where boundaries start on each layer. On Layer one, the boundary starts in a different corner (not pictured) than it does in Layer 2. If they were to start in the same location, it would create an open seam in that corner of the part. Instead we have a series of tiny holes.
- Offsetting the infill pattern between layers. Staggering the infill paths fills any gaps that might occur between passes on a single layer.
While parts made this way are not perfectly watertight, they are far less susceptible to ingress than 3D printed parts typically are. If you have parts that need to be water-resistant, we can help you figure out of if 3D printing is a viable option. Contact us today or give us a call at (855) 385-8296