We all used to think that 3D printing (additive manufacturing) was like magic – parts just popped out of the printer perfectly formed – like a Star Trek replicator. While 3D printing technology is very cool (and getting ever-cooler) still, the completed product, especially using metal powders, can be fairly unrefined. A solution to achieving highly accurate, quality finishes on the 3D metal part surfaces that matter most, lies in combining two advanced technologies – 3D printing with high-speed CNC machining.
Metal powder deposits are laid down layer by layer to build the desired part. This process is suitable for quick printing of large, low-fidelity parts. For high accuracy and smaller 3D components, such as those used in the medical device industry; dental implants, abutments, orthopedic screws and surgical instruments, finishing work is essential in order to achieve a quality surface, conform to tight tolerances, and retain the part’s true geometry.
Because size and consistency of metal powder particles can be relatively coarse in comparison to very small components, the process can’t always achieve the desired definition. Sharp internal pockets or corners are tough to print to a good standard. The powders may also plug up micro holes that are intended in the design and small hole threads may not be achievable by printing alone.
Numerous post-processing methods used in additive manufacturing include friction welding, heating and reworking, trimming and grinding, sanding and polishing or filling and gluing. However, these are all fairly expensive and time consuming – better suited to one-off prototyping than to high-precision, high-efficiency production runs.
High-speed machining is the ideal finishing tool for 3D printed parts. By providing maximum feed rates and taking multiple shallow passes, it enables precision fine finishing to ensure tight tolerances, burr-free holes or slots, plus a smooth and accurate surface facing with no unsightly step marks.
Colibri Spindles is well versed in this hybrid approach to additive manufacturing. The coolant-driven HSM Jet Spindle has been used extensively in the machining of 3D printed parts for applications such as slotting, chamfering, surface finishing and more; resulting in vastly improved part quality, increased productivity and ultimately, higher profits.
What's your experience with 3D Metal Printed part quality and finishing?