Touch probe | Touch probe
Key Words: coordinate measuring, touch trigger probe, hard probe, piezo probe, non-contact measuring, video measuring, through-the-lens laser measurement
Definition:A touch probe is a tactile sensor used to gather position / surface information about a sample
A touch probe is generally comprised of two parts; the body and a stylus with a tip that makes contact with the sample. There are a variety of touch probes capable of capturing single point data or continuous surface data on a sample. Touch information is defined by X, Y and Z co-ordinates and can be used to determine the size and position of sample features.
A hard probe may be used in conjunction with a manual coordinate measuring machine and is manually positioned to record a single point on the sample surface. Touch trigger probes are precision, touch sensitive devices generally comprised of a body and a detachable stylus with a tip that makes contact with the sample. The stylus and body are connected via a movement-sensitive coupling. Every time the stylus is deflected by contact with the sample a signal is generated and transmitted to the measuring machine. These probes can be fitted on both computer controlled and manual measuring systems. A number of stylus types may be fitted to one body, without having to recalibrate the system allowing greater flexibility in the samples to be measured. Piezo-based sensors translate the defection of the probe into a constant digital signal that eliminates effects of any bending in the stylus on contact with the sample. Other types of probe trigger the probe at a constant force irrespective of the angle of contact with the sample.
Touch scanning probes remain in contact with the sample and generate a stream of data that can be translated into surface information by computer.
There are many types of probe including uni-directional and multi-dimensional probes (usually up to 6-way). Touch probes may not be suitable for very soft or flexible materials that could be easily distorted.
Touch probes are ideal for measuring areas of a sample that are inaccessible to non-contact measuring methods such as laser or video systems. These may include overlapping areas or features within fissures or bore holes. Touch probes can be incorporated in non-contact systems to create multi-sensor capability and the versatility to measure a variety of complex samples on one instrument. Touch probes can also be incorporated in automated measurement routines.
The NEXIV VMA-2520 vision system is touch probe ready allowing touch sensor capability to be incorporated into a non-contact measuring system to create a versatile multisensor system that maximizes accuracy, speed of throughput and the ability to measure complex contours. NEXIV incorporates fully automatic features suited for industrial measuring, inspection, and QC applications, accommodates 3D work pieces and integrates image processing software.