NOTE Measurements of circular movements can be carried out by different methods as described in Clause 6.6 of ISO 230-1:1996. These methods consist of using a rotating one-dimensional probe and a test mandrel, a circular masterpiece and a two-dimensional probe, or a telescoping ball bar. Other test methods may be applied if the accuracy of the equipment is the same as (or better than) the accuracy of the methods described. Influences of typical machine deviations on circular paths are shown in Annex B of ISO 230-4:1996.
The concept of checks by circular tests described in this part of ISO 13041 is to verify the circular movement- — only in one position per coordinate plane of the machine,
- — at only one feed rate, and
- — to repeat the test once in the opposite contouring direction.
NOTE ISO 13041-5, which deals with the accuracy of feeds, speeds and interpolations, also includes as test K4 a circular test. There the aim is to check the mutual behaviour of two linear axes (generally X and Y) at two defined feed rates for one defined diameter. This is more or less a diagnostic test with respect to the circular interpolation, whereas the circular tests of this part of ISO 13041 give information on the overall contouring performance of the machine.
