Metal 3D printing is a fantastic tool but the idea that you can now print “anything” is a myth. You need to design for this process just as you do for any other serious fabrication process. For metal Additive Manufacturing, the key concern during design is your support strategy.
What happens if you can’t access the supports to remove? In many cases, you can develop custom build parameters to address it. Most service bureaus use a standard set of print parameters that are optimized for a generic case that yields high density and good surface finish for a variety of parts. However, with thousands of possible parameter combinations, you can optimize on other criteria depending on your objective.
QRP recently worked on a project for the University of Texas-Dallas to print a radiation sensor for a space application. They needed to have a lattice sphere surrounding a solid sphere that is electrically isolated from each other as shown below. We designed the inner “sphere” with a tear-drop shape so that no supports would be needed on the underside as it grew. The space in-between is impossible to reach to remove supports so we needed it to close up on its own.
We conducted many tests on just the critical dome section and investigated the tiny, 125-micron, features where they needed to close up on each other. The result was an optimized set of parameters for this case alone.
For the final part we printed it with 3 different parameter sets each optimized for 3 different bodies with unique needs. We also plated it with 10 to 20 microns of electroless nickel and ended up with a beautiful shiny part. The final result is shown below. This was a great project to work on with possible future iterations that will replace the solid inner sphere with a lattice as well.