Flexible Build Platforms Work For FDM, How About SLA?

Flexible steel sheets as the foundation for build platforms are used to great advantage in FDM 3D printers. These coated sheets are held flat by magnets during printing, and after printing is done the sheet (with print attached) can be removed and flexed to pop the prints free. This got [Jan Mrázek] thinking. He was pretty sure the concept could extend to the build platform on his Elegoo Mars resin printer. With a flexible build platform, troublesome prints could be more easily removed, so he non-destructively modified his printer to have a similar system. [Jan] is clear that this is only a proof of concept, but the test results were good! He printed several jobs that were known to be trouble, and they were all a piece of cake to remove.

[Jan]’s mod consists of a 3D printed, two-piece unit that encapsulates the normal build platform and contains a few strong magnets. A thin sheet of steel sticks flat to this new piece, held in place by the magnets within, and becomes the new build platform. After a print is done, the sheet is removed and [Jan] reports that its flexibility is a big help in removing otherwise troublesome prints, such as the 3D printed solder stencil we covered recently.

[Jan] provides his CAD model but doesn’t really recommend using it for anything other than development work. Results were promising, but there are a number of drawbacks to the prototype. For one thing, it makes the build platform thicker and the Z-axis limit switch needs to be physically lowered in order to zero the unit. Also, the thicker build platform means the volume of resin the build tank can hold is reduced. Still, the idea clearly has merit and shows there absolutely is value in hardware having a hackable design.

3D Printing Flexible Surfaces Out Of Non-Flexible Material

Here’s some interesting work shared by [Ben Kromhout] and [Lukas Lambrichts] on making flexible 3D prints, but not by using flexible filament. After seeing a project where a sheet of plywood was rendered pliable by cutting a pattern out of it – essentially turning the material into a giant kerf bend – they got interested in whether one could 3D print such a thing directly.

Inspiration for the project was this laser-cut plywood.

The original project used plywood and a laser cutter and went through many iterations before settling on a rectangular spiral pattern. The results were striking, but the details regarding why the chosen pattern was best were unclear. [Ben] and [Lukas] were interested not just in whether a 3D printer could be used to get a similar result, but also wanted to find out what factors separated success from failure when doing so.

After converting the original project’s rectangular spiral pattern into a 3D model, a quick proof-of-concept showed that three things influenced the flexibility of the end result: the scale of the pattern, the size of the open spaces, and the thickness of the print itself. Early results indicated that the size of the open spaces between the solid elements of the pattern was one of the most important factors; the larger the spacing the better the flexibility. A smaller and denser pattern also helps flexibility, but when 3D printing there is a limit to how small features can be made. If the scale of the pattern is reduced too much, open spaces tend to bridge which is counter-productive.

Kerf bending with laser-cut materials gets some clever results, and it’s interesting to see evidence that the method could cross over to 3D printing, at least in concept.