A rotary device

Some embodiments relate to an apparatus for holding a workpiece under tension while one or more operations are performed on the workpiece, the apparatus comprising: a frame; a first spindle rotatably coupled to the frame; a first coupler configured to couple the first spindle to a first end of the workpiece; a second spindle rotatably coupled to the frame; and a second coupler configured to couple the second spindle to a second end of the workpiece; wherein a distance between the first and second couplers is adjustable to hold the workpiece under tension between the couplers while the one or more operations are performed, and wherein the workpiece can be rotated with the couplers relative to the frame about a common axis of rotation extending between the couplers. Some embodiments relate to a system comprising a controller for controlling rotation of the workpiece. Embodiments also relate to processes comprising holding a workpiece under tension while performing one or more operations on the workpiece. Some of the processes, systems and apparatuses described may be particularly useful for cold spraying delicate workpieces such as 3D printed static mixers.