Multi-sensor CMMs can choose the optimum sensing technology for the application.
Mantech Sales is the UK distributor for Werth Messtechnik’s dimensional measurement machines. Multi-sensor machines available are the Werth VideoCheck and ScopeCheck; and Werth sensors are available for integration with these machines.
The Werth VideoCheck, it’s claimed, is the world’s most precise multi sensor measuring machine. It meets demands for high accuracy in production control and the laboratory, and is designed to measure parts such as injection nozzles, turbine blade cooling holes, stents, tooling, automotive, electrical and plastic parts. Machines are used for fully automatic determination of three dimensional geometries; the high performance control system allows the use of continuous path scanning systems, providing for fast 3D scanning.
Components such as high-resolution measuring scale systems, special air bearings, low natural vibration; and design measures to reduce friction, enable measurement uncertainties below one micrometer. Aluminium is used as a structural material to improve controllability of temperature-related problems. To prevent changes in the tension of the guideway systems caused by expansion, a system is used in which prestress is produced by magnetic force and gravity. This also minimises friction, reducing backlash on reversal.
An image processing sensor mechanism featuring a Werth-Zoom lens allows CNC-capable adjustment of the magnification and the working distance between the objective and the measurement object, over a range of 20 to 200mm. One advantage of this large working distance is the ability to check very deep blind holes and large diameter turned parts without collisions.
The Werth Scopecheck range is suited to applications such as general machining, sheet metal punching, plastic injection moulding operations and printed circuit boards. It offers precise, cost effective quality control for the workshop environment. Solid design of the Z-axis, enables full 3-D capability and underpins accuracy. Using an additional integrated measurement probe, surfaces that cannot be accessed by the optics, such as undercuts, can be probed and scanned. This allows for measurement uncertainties of as little as several microns.
To ensure suitability for a workshop environment, the elements determining accuracy are made of materials with a low expansion coefficient, minimising thermal deformation. Sensitive components are covered and the use of a customised compact control in separate housing minimises heat build up.
Each of these instruments includes an innovative image processing sensor system, designed for fully automatic measurements of complicated workpieces, even with poor contrast conditions. The WinWerth measuring software allows measurement programs to be created easily, which are graphically displayed as a CAD drawing allowing for simple inspection. For complex components with theoretical references, WinWerth 3D measurement software allows certain measurement points to be calculated using design functions, as in a CAD system, and the machine travels to them automatically. These could not be measured if it were guided by hand.
These machines can be integrated with a range of sensors including image processing video sensors, laser sensors, touch trigger and dynamic scanning probes, and the patented Werth Fibre Probe and Werth Contour Probe. Effectively this means machines can be customised for different measurement applications.
The Werth Fibre Probe is used primarily for scanning material surfaces, and incorporates the world’s smallest probe size of 20 microns diameter. Traditional sensors transmit signals from the probing element through a rigid shaft to the sensor, so are only suitable for measuring small geometric features under certain conditions. The Fibre Probe avoids this by doing the measurements with an image processing sensor integrated into the system, so the deflection of the shaft is not included in the measured result. Due to its small dimensions, it can be used to measure especially contact sensitive workpieces.
The Werth Contour Probe is a tactile optical contour sensor that combines a contact probe with a laser distance sensor. This allows roughness and contour measurements to be performed with high precision in a CMM. The sensor, which is normally used for direct measurements, detects the deflection of the contact probe. This allows for fully automatic contour measurement in a large measurement volume.