xy spinning vs oscillating

Spin Forming - General info
Spinforming is a hot forming process that rotates a metal tube around its central axis (similar to a lathe), softens the material by adding adequate heat, and then forms the material to its final shape using a forming roller. Our spinforming process begins with an extruded tube and is an unsupported process that does not use a mandrel, sometimes referred to as “free air” spinning. There are many other applications of conventional spinforming where a flat sheet of material is formed against a mandrel. Those techniques differ from free air spinning, but all rely on similar principles.
Spinforming - Oscillating vs x-y
A simple version of free air spinforming is referred to as x-y spinning. This technique pushes the roller into the blunt cut edge of the tube, forcing the tube material to reduce in diameter as the roller is advanced. Steels and stainless steels do not respond well to x-y spinning, but the approach can be useful for our aluminum liners. During x-y spinning there is not much opportunity to increase wall thickness, other than the thickness increase brought about by the reduction in diameter of the starting material. That is where oscillating motion comes in…
Most of Steelhead’s domed vessels are formed through oscillating roller motions. In this approach, the roller contacts the tube some distance into the tube, away from the cut edge, then rotates downwards along a defined path, drawing outwards towards the cut edge. This motion deforms the tube into a dome shape with a defined neck diameter. The advantage of the oscillating approach is that more material can be built up through the dome and in the neck due to the drawing effect of this motion. This process is suitable for almost all ductile metals, including carbon and stainless steels.