Werth is a leading player in multi-sensor CMM technology. Based in Giessen, Germany, it has built a reputation for high quality precision measurement technology. The products range from classic profile and measurement projectors, with standard solutions for optical 2D and 3D co-ordinate measurement technology, to advanced multi-sensor technology, such as the Werth ScopeCheck and VideoCheck.
The company has been behind a number of patented products and sensors, including the Werth Fibre Probe and the Werth Contour Probe, and was the first company to integrate computer tomography into a CMM, with the Werth Tomoscope (see also here
LARGE VOLUME MEASUREMENT
The ScopeCheck series is designed for quality control of large volume, heavy components in the production environment, such as machining, sheet metal punching, plastics injections moulding operations and printed circuit boards.
Image: Werth's ScopeCheck series is designed for quality control of large volume, heavy components in the production environment
The ScopeCheck is very much about ease of use in such environments, with software functions such as automatic part feature recognition. The elements determining accuracy are made of materials such as steel, minimising thermal deformation. Sensitive components are covered and the use of a control in separate housing minimises heat build-up.
Due to the solid design of the Z-axis, the ScopeCheck has full 3D capability and accuracy. The basic version of the machine is equipped with an image processing sensor featuring zoom optics and basic modes of illumination. It can be further equipped with other sensors and probes, for example for measuring surfaces such as undercuts that cannot be accessed by optics. This allows measurement uncertainties down to several micrometers.
The VideoCheck series is designed for high accuracy production control in the laboratory. Applications include measurement of injection nozzles, turbine blade cooling holes, stents, tooling, automotive, electrical and plastics parts.
Unique 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. This unique design makes the VideoCheck the world's most precise benchtop measuring machine, it is claimed.
Aluminium is used as a structural material to improve controllability of temperature problems. To prevent changes in tension of the guideway systems caused by expansion, a system is used in which prestress is produced by magnetic force and gravity. This minimises friction, reducing backlash on reversal. The high performance control system allows the use of continuous path scanning systems, providing for fast fully automatic determination of three dimensional geometries.
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 200 mm. 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 Tomoscope is the world's first integration of Computer Tomography (CT) with a multisensor co-ordinate measuring machine. This allows quick, complete and non-destructive measurement of many features with CT, combined with the exact measurements of functional dimensions with tactile or optical sensors.
Image: The Werth Tomoscope is the world's first integration of Computer Tomography (CT) with a multisensor co-ordinate measuring machine - see video above
The Tomoscope measures sizes, angles and diameters of the structures inside of a part. Calibration points are measured with CMM sensors in the same measurement run. This produces a 3D reconstruction of the measuring points, which depicts the entire workpiece geometry, ensuring precision and traceability of the results.
The image processing system allows for reliable and automatic measurement of all regular and free-form geometries of a workpiece, or internal geometries and inaccessible characteristics, even when there is low contrast and object characteristics fluctuate. This makes the Tomoscope a leading piece of measurement technology for the workshop and the laboratory.
All these systems can integrate multiple probing systems, as well as laser sensors, with the primary optical sensor system. Many machines in the range allow for the integration of sensors, including image processing video sensors, laser sensors, touch trigger and dynamic scanning probes, as well as the patented Werth Fiber Probe and the Werth Contour Probe.
The Werth Fiber Probe is used primarily for scanning material surfaces. It boasts the world's smallest probe size – 20 micron diameter.
Traditional sensors transmit signals from the probing element through a rigid shaft to the sensor and are only suitable for measuring small geometric features under certain conditions. The fibre probe avoids this by taking the actual 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 particularly 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.
Each Werth instrument includes an image processing sensor system, designed for automatic measurement of complicated workpieces, even with poor contrast conditions, in transmitted and incident light.
The illumination of the workpieces is CNC controlled for all models. For highly accurate measurements, the transmitted light and the incident light that is integrated in the image beam path are primarily used.
For example, for the measurement of plastic and stamped metal parts, a flexible darkfield illumination is of great importance. A multi-segmented ringlight is ideal for these applications. The ringlight provides uniform illumination. However, when required, individual segments can be illuminated separately to enhance the image of specific features.
Special gray scale image processing filter methods reduce the influence of dirt particles, for example, upon the measuring result.
WinWerth measuring software allows efficient and easy operation of machines and for easy creation of measurement programs. Measured geometric elements are graphically displayed as a CAD drawing. With simple mouse clicks, they can be connected for measurements and constructions, making measurement as easy as the reading of a drawing.
Image: WinWerth measuring software supports the hardware
In CAD-Online mode, operation is reduced to the absolute minimum. An operator has only to select the geometric elements to be measured on the presented CAD drawing via mouse clicks. These elements are then measured automatically.
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, which would not be possible, if guided by hand.