The requirements for metrology regarding throughput and flexibility are steadily increasing. Not only are individual measuring methods becoming faster—measuring systems should also become universally deployable. Ideally, different kinds of measurement tasks should therefore be able to be performed by one single system and in one process.
Entire Metrological Analysis
The combination of gear and 3D coordinate metrology not only allows the complete measurement of various gear, prismatic and free-form components but also the entire metrological analysis with regard to form and location. This means that complex components can be analysed in a fully function-orientated manner. This is particularly evident in the case of components where gearing and geometrical elements are combined, such as planetary gear carrier sets.
In conjunction with a change rack, it is possible to automatically switch between different probe configurations during the course of a measurement program. An intervention by the operator is not required and thus reproducible, user-independent measurement results can be achieved.
Gear and 3D measuring systems normally differ in their construction. Gear measuring systems are conceived for measuring rotationally symmetrical workpieces with three linear and one rotary axis. Gear measurements can be performed according to gearing principles with the aid of the integrated rotary table, thus enabling optimum tactile contact conditions.
On the other hand, 3D coordinate measuring systems are more universally applicable due to their rectangular measuring volume, with prismatic and free-form components being typical.
The accuracy and acceptance procedures are also based on the respective application fields. Gear measuring machines are accepted according to the VDI/VDE-Directives 2612/13 and 3D measuring machines according to the ISO 10360 series of standards. The data from the 3D coordinate systems describe the precision of single-point probing and linear measurements. These are performed on reference standards such as spherical reference standards, step gauges or ball bars.
In order to combine both metrology principles, both acceptance procedures are used on a combination machine. In favour of achieving an optimal precision, the smallest residual, structural errors are captured and compensated by CAA laser compensation. These errors are reduced to a minimum in various ways, such as structures made with mechanical precision and the application of hand-lapped granite guideways.
Measuring Against CAD Data
If a 3D coordinate measuring machine is equipped with an integrated rotary table, the basics of gear metrology can be combined with the flexibility of 3D coordinate measuring machines. This procedure provides the possibility to use gear measuring software as well as 3D measuring software on one measuring machine.
In this way, prismatic components, for example cases can be programmed and measured against the CAD data, with extensive shape and position analysis also being feasible. In particular, position tolerances can be evaluated this way both in terms of production as well as function. On request, certain machine sizes can be equipped with tailstocks for the measurement of shafts.
The optimal utilisation of the coordinate measuring machine is due to the application of the 3D and gear measuring software. A broad range of gear measuring machines offers solutions analysis of minute gears up to large ring gears and bearings with a diameter of up to 6,000 mm.