A number of metal Additive Manufacturing processes require the part to be cut from the build plate once finished. All residual metal left on the build plate between each build requires removal and the build plate needs to be completely level and correctly textured prior to additively manufacturing the next part. In series production, this can often result in a bottleneck, explains DCM Tech Inc, a producer of rotary grinders based in Winona, Minnesota, USA.
Since the metal part is ‘welded’ to the build plate, it is typically removed with electrical discharge machining (EDM) wire or a bandsaw. However, these approaches involve removing a thin layer of the build plate surface, gradually reducing its thickness until it is no longer usable. Most of the cuts are not entirely flat or level, either.
One alternative is to cut close to the part, but this leaves material that must be removed later. With EDM and bandsaws, the process can take hours and hard materials like Inconel tend to strain-harden, further increasing the difficulty. Some shops even address the issue with a CNC milling machine, but this can also take hours and limit the availability of the equipment for actual production. Exceptionally hard AM materials like Inconel and titanium further lengthen the required milling time.
A more efficient alternative, explains DCM, utilises advanced precision rotary surface grinders to remove unwanted residual material with a large rotary grinding wheel surface. This technology has long been used in metalworking and glass grinding to create perfectly flat, parallel surfaces. The equipment is ideally suited to the AM process and quickly and accurately removes any residual metal from the build plate surface, restoring it to precise dimensions.