Term for a type of working spindle used in 5-axis CNC machining.
At prism heads the working spindle is suspended from one side. Therefore, they are a special kind of robot heads. The c-axis is exactly one rotational axis around Z, while the second rotational axis does not lie within the X/Z or Y/Z plane, but is inclined to it (according to the prism in Geometry).
Compared to forkshaped heads/cardan heads, prism heads have a greater dynamics and are more space saving. Due to the system, this solution is less stiff.
Because of the inclined plane, a greater working range can be covered having to have a smaller angular motion. On the other hand, the calculation of the movements is more expensive than the calculation of a standard robot head with rectangular rotational axes.
The term prism is a registered trademark of the SCM-group for their 5-axis prism heads.
Increasingly, one can find the technically seen wrong term cardan head for prism or robot heads, and in contrast, the actual gimbaled 5-axis heads named Gabelkopf. Presumably, this goes back to the wrong translation from the Italian "freely movable in space". Since up to the beginning of 2011 the linguistic use of the terms was not standardized, there is no common rule.