WinWerth® measurement software

For more complicated measuring tasks, the procedure described above is no longer sufficient. The operator can therefore take over parts of the processes that actually run automatically (setting windows, selecting features) and gradually familiarize himself with the more detailed control of the measurement sequences. For support, measurement points or scan lines are automatically distributed on the geometry elements to be measured, e.g. as circles, cylinder surface lines, stars or spirals, taking into account the necessary traverse paths. The complete measurement sequence, including evaluation, is first created offline using the CAD model or online with the minimum number of points for the respective geometry element. Measurement points and scan lines can be subsequently moved, deleted or added with the mouse or via a dialog. Measurement sequences specified in this way can be saved and called up as an automatic sequence in the event of repetition.

TomoSim is the first coordinate measuring software to simulate the tomography process offline using CAD data or a point cloud in STL format. The realistic simulation, taking into account the set CT parameters, enables the calculation of a volume including all significant artifacts. For example, an initial sample inspection program can be taught in at an offline workstation in parallel with the production of the first workpiece and the performance of other measurements on the machine using the WinWerth® measurement software. This enables TomoSim to speed up processes and reduce downtimes, e.g. for TomoScope® machines in multi-shift operation.

In addition to a completed program creation and feasibility check in time for the completion of the first workpiece, the simulation of the tomography process allows the testing and optimization of CT parameters. With the help of the simulated volume, significant artifacts, e.g. due to beam hardening or too few rotary increments, can be detected and, if necessary, an appropriate artifact correction can be selected. Another new feature is the complete offline programming of volume-based evaluations such as burr detection, void analysis, porosity analysis, text recognition, SurfaceScan Predefined or in volume sections.

Another benefit of the CAD module integrated in WinWerth® is that CAD information can be used to position the coordinate measuring machine. Werth was probably the first manufacturer of coordinate measuring machines to introduce this technology back in the mid-1990s under the name CAD-Online®. The entire measurement sequence can be controlled by selecting the geometric features on the CAD model. The measuring machine automatically moves to the generated measuring positions and measures with the selected sensors.
In this way, for example B. automatically capture measurement points as point clouds using probe or measure larger areas with the Werth 3D Patch or confocal sensors by automatically stitching the individual measurements together in high resolution. Technology parameters such as the illumination setting for the image processing sensor can be set directly on the measuring machine, taking into account the interaction between the illumination, measuring object and imaging system. Collisions are avoided by automatically modifying the movement sequences based on the workpiece and machine or sensor geometry.

Many CAD systems now offer the option of integrating PMI (Product and Manufacturing Information) data. In addition to the geometry description of the CAD features, the resulting CAD data sets also contain the dimensions defined by the designer. When the geometrical characteristics are selected, the WinWerth® measurement software distributes measurement points or scan lines on all geometrical elements that are to be linked to find a solution, and the measurement sequence is created at least partially automatically. Due to the increased requirements when creating the CAD model, this solution is unfortunately still not very widespread.

If the complete measurement sequence is to be generated fully automatically, all the necessary parameters must be stored in the PMI data or determined automatically by the measurement software. If these requirements are met, the complete measurement sequences for the measurement of close-tolerance metal tools for the production of injection molds for contact lenses, for example, can be created fully automatically in WinWerth®. The measurement is carried out with a multisensor coordinate measuring machine using a combination of optical distance sensors with image processing and with the aid of an automatic rotary/tilt axis for the workpiece.

In contour image processing, the image within an evaluation window is viewed as a planar whole. Contours are extracted from this image using suitable mathematical algorithms (operators). Each pixel of a contour corresponds to a measurement point. The measurement points are strung together like a string of pearls. This makes it possible to detect and filter out interfering contours caused by surface structures, breakouts and dirt during measurement (contour filters) without changing the shape of the contours. It is important for practical use that several contours can be differentiated within a capture area and the desired one can be selected. This allows reliable edge detection even with large tolerances and rigid scanning in transmitted light. In a further step, modern systems interpolate the coordinates of the measurement points within the pixel grid and thus allow higher accuracies.

With 2D contour image processing and the associated image processing filters, measurements can also be taken in any cross sections of the CT volume or point cloud. Among other things, this makes it particularly easy to measure workpieces made of several materials.

Eccentric Tomography allows the workpiece to be positioned anywhere on the rotary table (patented). This eliminates the need for complex and time-consuming alignment of the workpiece and increases ease of use. Sectional tomography or ROI tomography (ROI: Region of Interest) is used to measure parts of the measuring object with high resolution without having to capture the entire measuring object, e.g. with Raster Tomography, which is time-consuming and memory-intensive.  Multi-ROI tomography offers a combination of the benefits of eccentric and sectional tomography. Several high-resolution parts can also be selected at any position in the measuring object.

When scanning tomographically in conventional start-stop operation, the rotary motion is interrupted for the acquisition of each radiographic image so that no motion blur occurs during the exposure. OnTheFly Tomography makes it possible to save dead time for positioning the workpiece through continuous rotation. On the one hand, this method can greatly reduce the measurement time while maintaining the same data quality, and on the other hand, it can improve the data quality and thus the measurement uncertainty while maintaining the same measurement time.

The WinWerth® Scout user interface enables quick and easy access to all measuring processes in the company. Measurement orders that are still being processed are shown in a list. The current status, such as "Job started", "Tactile measurement" or "Evaluation", is displayed next to the job identification number. Completed orders are automatically moved to another list and color-coded according to their status: green for "in tolerance", yellow for "action limit" and red for "out of tolerance".

If several workpieces are measured at the same time, one or more workpiece groups are created. If you click on a measurement job in the list of completed measurements, another window opens with a list of all measured workpiece groups or workpieces, the status of which is also color-coded.

Clicking on the group or workpiece in the list view opens the WinWerth® 3D viewer. In the case of workpiece groups, an overview of the workpiece elements appears. The workpiece elements are displayed as spheres whose color indicates the status of the workpieces. Right-clicking on the workpiece element of interest opens a selection list with the result displays for the respective workpiece.

Depending on the task, the measurement results are either calculated or displayed in a reference coordinate system that has been measured beforehand (e.g. vehicle coordinates in automotive engineering) or in a coordinate system that has been generated by optimally fitting selected surface areas relative to the CAD model.

The two fitting strategies WinWerth® BestFit and ToleranceFit® can be well illustrated using the example of a 2D cross section. In the first case, the position of the measured points is optimized by minimizing the distances to the target points. As tolerances of different object areas are not taken into account during fitting, tolerance overruns may be detected, although the tolerance could be maintained by shifting the coordinate system. This method is therefore only suitable for quality control to a limited extent.

The optimization criterion for WinWerth® ToleranceFit® is to keep the distance between the measurement point and the tolerance limit as large as possible or, if the measurement point is outside the tolerance limit, to keep the tolerance overrun as small as possible. Objects recognized as faulty according to the BestFit method (red areas present), but not actually faulty, can be classified as functional according to the ToleranceFit® method. The contour is checked as with a gauge.

One of Werth's special features is the automatic detection and measurement of burrs or chips during the measurement sequence. The result is a color-coded deviation plot of the burr and the maximum burr length. In the deviation display, only the points at which the burr length exceeds the tolerance limits are shown. The burr length along the entire burr can also be displayed numerically using analysis markers. For example, a flag is set every 0.5 mm to indicate the maximum local burr length.

WinWerth® also provides a selection of software tools for material analysis of the volume data. The display of the volume data is integrated into the 3D module of the WinWerth® measurement software. The volume is visualized in the form of grey values representing the density of the material. In general, the volume becomes lighter as the density increases. Three different views can be used in parallel and displayed or hidden individually. It is possible to display the entire volume, i.e. all voxels with their respective gray value. In the "ISO surface" view, only voxels with the selected gray value are displayed. 2D cross sections can also be displayed according to the selection of the cross section plane. All variants are displayed three-dimensionally rotatable and can therefore be analyzed from all sides. CAD model, voxel volume and measurement point cloud are imaged superimposed in the same coordinate system.

The display can be clipped using any definable planes (clipping planes). The model and measured data are hidden beyond the planes. The entire workpiece can be removed plane by plane and visually inspected for voids, for example. Clipping planes can be used to test material, internal geometries and individual components of multi-material workpieces. Both the clipping planes and cutting edges for displaying and inspecting 2D cross sections can be moved and rotated in three dimensions directly in the 3D graphics using the mouse. Mouse clicks on the voxel volume now generate 3D surface points for alignment, which is thus also possible without prior calculation of the measurement point cloud.

The histogram function can be used to vary the transparency for selected grey scale ranges and image the grey values on a color scale. By varying the transfer curve in any sub-intervals, grey value or color ranges can be spread to increase contrast. The transfer curve can now be defined once for a sample part and then saved for series measurement of similar workpieces. This ensures the optimum representation of each voxel volume for fast inspection.