TRISKELION ULTRA-PRECISION TOUCH PROBE
IBS Precision Engineering has developed an new ultra-precision touch probe system, the Triskelion probe. This probe system is suitable for point measurements as well as scanning. Its excellent measuring uncertainty and full 3D measurement capabilities make this probe suitable for ultra-precision 3D metrology. Possible applications include 3D ultra-precision (micro-/nano-) CMMs as well as on-machine metrology on machine tools.
Probe concept & design
A schematic representation of the probe concept is shown in below. The stylus is elastically suspended by means of flexures. The stylus is a attached to these flexures via a rigid body; this body contains target discs which serve as measurement targets for the capacitance sensors. During deflection of the probe tip, the capacitance sensors measure the displacements of these target discs; the displacement of the probe tip can thus be determined.
The image above shows the working principle of the probe system for deflection of the probe tip in vertical and sideways direction. Note that this is a 2D simplification, the actual design features three flexures and three capacitance sensors, allowing deflection in full 3D, while the deflection of the tip is also measured in x-, y- and z-direction.
The suspension of the stylus is realized by means of a monolithic metal suspension foil. This foil contains both the flexures and the three-legged body which connects the flexures to the stylus. The thickness of the flexures is reduced to achieve the desired (low) stiffness of the suspension and to ensure that elastic deformation takes place in the flexures and not in the three-legged body or in the stylus. At the end of each flexure, circular target discs serve as the targets for the three capacitance sensors.
The image below shows a model of the realized probe-system. For this design, a stylus length of 8.5 mm is applied, with a Ø 0.5 mm spherical ruby probe tip. The following section will discuss the most important design features of the realized probe system.
Advantages / design features
- Low contact force
- 3D scanning up to 90 degrees
- Large measurement range
- Probe tip size / Flexibility
- Low replacement costs
- Robust design
For more details and specifications, please open / download our brochure below: