The latest AM orthopaedic implants are typically made by SLS, SLM or EBM processes. Titanium powders in the size range of 5 to 45 micron are preferred for the SLS and SLM processes, and 45 to 90 micron for EBM. After manufacture, the implants then have the bulk of the residue powder removed from the build block with brushes and vacuums, sometimes followed with an air wash or blast process to remove any semi-adhered powder particles. However, because of the nature of the porous trabecular structures, small residues of powder are often still trapped inside the component and these must be removed.
Guyson’s Powder Flush is based on the company’s Orbit 600 rotary basket spray wash unit. The machine is made from 304 stainless steel, and is fitted with a 100-litre insulated tank and hot spray flushing capability. The latter is facilitated through a high flow rate and pressure pump featuring Viton seals. Powder Flush offers directed jets for component flushing followed by compressed-air wash. A PLC/HMI control panel to the left of the machine provides data monitoring and timed pre-heat function, ensuring accurate and repeatable process operation. LED interior lighting and a double-glazed viewing window, in the lid, facilitates visual checks on parts in-process.
During operation, the implants are individually or batch loaded on non-contaminating fixtures that present the workpiece to the directed flushing jets in close proximity to the trabecular surface, thus ensuring thorough powder removal. Timed electronic interlocks prevent the door opening during operation, while the machine is also equipped with process alarm signals offering audible and visual cues via an Andon beacon to show the end of the process. Completing the system is fluid level sensing and filtration, fitted to the rear of the unit.
Guyson’s managing director Mark Viner says: “The Powder Flush unit adds to the portfolio of Guyson products provided for the 3D print/AM market. This includes our Euroblast Ex range of ATEX-certified blast cabinets for surface finishing exotic metal AM parts, often used in the aerospace and medical markets. We also offer the Guyson PRS [Powder Recovery System], which is an automated post-processing system specifically for EBM builds that uses robotic blasting to reveal components and manage the resultant powder in a contained blast system. In addition, we can provide our Kerry branded range of ultrasonic baths and tanks for 3D-printed FDM support removal.”