Metal 3D printing can unlock a whole range of new types of parts, and while some may work right out of the furnace, others may need some post-machining before use. Below are some of the post-processing techniques you can use on metal 3D printed parts.
Green State Sanding
You can wet-sand green parts under warm water with 240-320 grit sandpaper or Scotch-Brite to get a smooth finish once sintered. Green parts are fragile, and you cannot access supported surfaces, so be cautious as any modifications may affect precision or sintering performance. Sand over a receptacle or filter to prevent sink clogging, and use proper PPE.
Machining Metal 3D Printed Parts
You can machine metal 3D printed parts after sintering to clean up surfaces and dial in precision on specific features. Offset the faces you wish to machine in your design so that when material is removed you can meet your tolerances. Be careful about how much material you take away, however, because you run the risk of exposing infill if you machine too much material away.
The Metal X can print print threads or tap threads on your metal 3D printer. Tapped threads will be tighter tolerance than printed threads because the cut from a tap is cleaner than the extrusion of a printer. If tapping your printed threads, you should use 50% thread engagement for your tapped hole size in steels and other hard metals. The Metal X can print threads down to an M3, below which they must be tapped. Printed threads may need to be chased with a tap or need lapping compound to clean up the surfaces, and you'll want to print larger threads so you don't cut all the way through the walls of your part with a tap.
Metal X customers can access the full Metal X design guide on the Markforged support page.