Use This Clever Technique to Bond Your PLA 3D Prints to Acrylic

3D printing is incredibly versatile, which is why it has become so popular. But it isn’t perfect for every situation and you may find yourself in need of qualities that you can only get from other fabrication methods and materials. Fortunately, Julius Curt came up with one way to get the best of both worlds using this technique to 3D-print PLA directly onto acrylic.

This is a way to effectively bond 3D-printed PLA and laser-cut acrylic parts together. With laser-cut acrylic, you can get parts that are very smooth, flat, and transparent. With 3D-printed PLA, you can get parts with complex three-dimensional geometry. Put the two together and you can get a part that has all of those properties — at least in some areas.

The obvious way to do something like this would be to glue the two parts together. But adhesives are material-specific and it can be difficult to find one that bonds well with both PLA and acrylic. It can also be difficult to glue the two parts together with any kind of precision. Curt’s technique solves both of those problems and also eliminates the cost of glue. This seems to create a really tough bond that should be stronger than either part, similar to a good weld.

The idea here is super easy to understand: you’re just printing onto the acrylic sheet instead of onto the printer’s bed. But Curt has some great tips on the practical aspects of the operation.

The most important part is positioning. Like when flipping a workpiece on a CNC mill, you have to ensure the acrylic piece is exactly where the printer thinks it is — otherwise you won’t bond the PLA in the right place.

Curt’s process starts with laser-cutting the acrylic part. Then an outline of the acrylic part is used to 3D-print a “fence” on the printer’s bed slightly shorter than the thickness of the acrylic. One portion of that fence should be level with the acrylic to give the printer a place to wipe the nozzle. The fence holds the acrylic part in place in exactly the right spot on the bed, so the printer can then begin extruding PLA onto its top surface. From there, it can print as it normally does.

It is even possible to get fancy with this technique by placing the acrylic part on top of printed PLA, then printing more PLA on top of that. However, that won’t create a bond on the bottom surface of the acrylic, because the PLA underneath will already be cool.