Form rolling is different from older methods that cut away the unwanted material in order to shape the part. For one thing, with form rolling, the outer diameter of the blank work piece is actually smaller than the outer diameter of the finished product. This means material is not wasted. You use less metal to start with, and there are no metal scraps to throw away. Another difference is that the tools are in contact with the work piece for a very short time. This means your tools last longer. No wasted material and long lasting tools yield high production efficiency.
Dies are matched to the desired shape of the finished product. The results are reliable, accurate and stable. This quality lends itself to medium and high volume parts production.
cutting process cross section
form rolling process cross section
fig. A cut cross section (above) and form rolled cross section (below)
First of all, form rolling is a quiet process. Second, because the parts are rolled and not cut, the lubrication oil stays clean. Not only are there no metal scraps to throw away, there is also little waste oil to dispose of. Form rolling is an environmentally friendly means of production.
The dies and the work piece come together in a small, localized area. Also, form rolling is done by repeated applications of pressure only on the area to be shaped. Compared to other processing methods such as those involving heat and annealing, the amount of power applied to the part is small.
Because the surface that has been worked on was pushed, not cut, the finished surface is of notably higher quality.
The drawing on the right is about fiber flow. In a major difference between cut parts and rolled parts, the basic structure of the metal (fiber flow) is not the least bit damaged or mutilated. Because the shape transformation is about plasticity, the internal metallic structure of the finished product's surface is actually enhanced. Form