Embedding Electronics in 3D Printed Objects
Additive manufacturing can be an incredibly useful tool for prototyping and low volume production. Due its robust nature, one can create a single, complex, homogeneous parts that may not be possible to create through other manufacturing techniques. Therefore, it can be incredibly fast and efficient to go straight from a CAD drawing to a final part without very many intermediate steps. But, when the desired prototype consists of other non printed parts such as mounting hardware or even electronics, the user can find themselves in the arduous process of having to modify the original CAD drawing, sectioning it into various parts, printing these multiple parts, and joining them with various post processing techniques. For examples, imagine a simple mounting plate that requires mounting hardware, such as nuts, in the middle of the design. To incorporate the metal hardware into the design, the engineer would have to section the plate in half within the CAD file, print two separate parts, insert the hardware, and then glue the halves together. This adds unwanted steps to the process, and creates a new point of failure for the original design. A more efficient way of handling this problem can be solved through three main steps: Pausing the print at a specific point, inserting the hardware, and then resuming the print.
Pausing the print: In order to embed a desired, non-3D printed object into a single 3D print, the user must determine when in the print the "chamber" that the object would fit into is only partially printed, and then pause the print at that point in time. If the print is one that lasts many hours, the user would not want to sit and watch the print, and missing the small window by even a few seconds can render the technique useless. Therefore, the user should look at the CAD file within the slicing software to determine when the perfect window is. It is important to keep in mind that slicing software uses an estimate when calculating print time and one should therefore error on the early side.
Placing the object: Once the print is paused at the desired location, the user is then ready to insert the foreign object. When doing so, a few considerations must be taken into account. First, the object cannot extend higher than any current printed layer. If this is not the case, the hotend may come in contact with the object and either damage it, or cause the print to fail. A way to avoid this is to allow the print to continue as long as possible before pausing it to ensure that there is indeed a "chamber" or slot for the part to fit into. It does not really matter what is being inserted but once the part is put into the print and the print is resumed, it more than likely will no longer be accessible once the print is complete. Therefore, if necessary, measures should be preemptively taken to reduce movement of the object that is embedded in the print. Hot glue, velcro, or simply a press-fit can be used to mitigate the objects movement in the finished part.
Resuming the print: Once the object is placed into the part and clearance is guaranteed, the print can be resumed. Special care should be taken in making sure that the printer or print are not bumped during the insertion process. Doing so could result in a shift in the printed part or hot end and ultimately a useless print. Once the print has been resumed, it can continue normally until completion.
Applications of embedding objects into homogeneous 3D printed parts: While the possibilities of this technique are quite extensive it can be used to encase electronics, mounting hardware, or even weights into the parts.