The operation of machines with a wide variety of sensors, but also the evaluation of volume data and point clouds are possible with WinWerth® in a unique combination. The Werth image processing software is based on 40 years of experience and is the foundation of probably the most powerful image processing sensors for coordinate measuring machines currently available. Optical distance sensors, conventional styluses in single-point or scanning mode, the Werth Fiber Probe®, X-ray computed tomography or machines with a combination of several sensors are all supported by the uniform concept. Measurement points, 2D images or volume data can also be conveniently evaluated in terms of geometrical characteristics or with part-to-part deviation analysis. PTB-certified evaluation algorithms ensure correct measurement results. All desired information is displayed in the graphic: CAD models with PMI data, voxel volumes, measurement point clouds, color-coded deviation plots from 3D nominal-actual comparisons, video images, measurement and calculation elements as well as flags with nominal and actual values, tolerances and deviations. In order to meet the most diverse requirements, the software has a modular structure. Various machines can be operated, from simple measuring projectors to complex multi-axis coordinate measuring machines with multi-sensor systems or even X-ray tomography sensors.

Modern coordinate measuring machines cover a wide range of differently complex tasks. The qualifications of the machine operators range from employees with little training, who only occasionally determine a few sizes, to specialists who, exploiting all technically feasible options, also handle very difficult measuring tasks. The very different working methods are optimally supported by the structure of the WinWerth® software for device operation. For example, there are several access levels that are adapted to the different qualification levels of the operators. Interfaces to CAD systems for target data import and to CAQ systems for statistical evaluation enable the adapted integration of the coordinate measuring machines into company software structures.



Simple graphic user interface measurement

Image processing measures almost by itself

Simple graphic user interface measurement - Image processing measures almost by itself

In practice, a few sizes of production parts often have to be determined “quickly”. This task is also carried out by employees who do not permanently deal with the operation of coordinate measuring machines. To enable effective work in this environment, the operation is limited to the most necessary. The “intelligence” of the WinWerth® measurement software then takes over, for example, the exact determination of the object area to be captured, the selection of the geometrical element to be measured (e.g. e.g. straight line, circle, corner point) as well as the linking algorithms for determining geometrical characteristics such as distances, angles and diameters.

Measurement points are distributed automatically

Measurement points are distributed automatically

For more complicated measuring tasks, the procedure described above is no longer sufficient. The operator can therefore take over parts of the actually automatically running processes (set window, select feature) himself and gradually familiarize himself with the more detailed control of the measurement sequences. To support this, 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 travel paths. In this way, 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 dialogue. Measurement sequences specified in this way can be saved and called up as an automatic sequence in case of repetition.

Programming of complex measurement sequences

User-friendly display of the test plan in the user interface

Programming of complex measurement sequences - User-friendly display of the test plan in the user interface

The programming of the measurement sequences is supported by corresponding tools of the WinWerth® measurement software. The sensors are selected directly on the user interface of the multi-sensor coordinate measuring machine. A “feature tree” represents the test plan and thus the structure of the measuring programme in a tree-like structure. Here, the relationships between geometrical characteristics, geometrical elements and technology parameters such as sensor type, illumination setting, scanning speed, evaluation algorithm and valid alignment become visible. Parallel to the feature tree, the geometric elements and the features with the associated measurement results are also displayed in the graphical representation of the measurement sequence and in the numerical measurement log. Link operations to geometric elements (intersection, intersection line) or geometrical characteristics (distance, perpendicularity) can be programmed either in the feature tree or in the graphical view.

Simulation of the tomography process with TomoSim

Simulation of the tomography process with TomoSim

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 essential artefacts. For example, an initial sample inspection programme can be taught in parallel to the production of the first workpiece and the performance of other measurements on the machine with the WinWerth® measurement software at an offline workstation. TomoSim thus enables process acceleration and a reduction in downtime, e.g. for TomoScope® machines in multi-shift operation.

In addition to a completed programme creation and feasibility check in time for the completion of the first workpiece, the simulation of the tomography process allows the testing and optimisation of CT parameters. With the help of the simulated volume, significant artefacts, e.g. due to beam hardening or too few rotary increments, can be detected and, if necessary, an appropriate artefact correction can be selected. Also new 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.

Testing and changing made easy

Testing and changing made easy

The feature tree in the WinWerth® user interface also controls the test and change mode, in which programmes can be run step-by-step and changes can be added. A text editor, available in parallel, allows experienced operators to directly enter or change DMIS programme code while teaching in programmes. By selecting a programme section with the mouse, it can be defined as a loop for repeated processing or outsourced as a subroutine. With the aid of feature-oriented measurement, selected functionally relevant test dimensions can be determined.

Measurement with CAD data

Simple operation with CAD-Online®

Measurement with CAD data - Simple operation with CAD-Online®

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 as early as the mid-1990s under the term 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 measurement positions and measures with the selected sensors.
In this way, measurement points can be automatically captured as point clouds with styluses, for example, or larger surfaces can be measured with the Werth 3D Patch or confocal sensors by automatically placing the individual measurements side by side in high resolution. Technology parameters such as the illumination setting for the image processing sensor can be adjusted by direct operation on the measuring machine, taking into account the interaction between illumination, measuring object and imaging system. Collisions are avoided by automatically modifying the motion sequences based on the workpiece and machine or sensor geometry.

Time-saving programming with CAD-Offline®

Time-saving programming with CAD-Offline®

The WinWerth® measurement software can also be operated without the measuring machine on a CAD-Offline® workstation. Werth was also a pioneer in this field and supplied solutions to customers as early as the beginning of the 1990s. Here, the test programmes are only created and tested on the CAD model. Especially in the case of tactile sensors, this often saves several hours of time when creating measurement sequences without positioning to measurement points and clearance positions. The device simulation for offline programming is carried out on the 3D CAD model of a workpiece. The collision analysis takes place in the background. With CAD-Offline®, expensive machine time is saved. The test plans are already completed when the first workpiece or measuring object is produced. Measuring object-related influencing factors can then be reworked in a test run in single-step operation. Online and offline work can be carried out with a consistent operating concept from one source and the “correctness” of the measurement results is ensured. This is not the case with programming workstations that are independent of the measuring device manufacturer.

PMI information makes work easier

PMI information makes work easier

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 dimensioning specified 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 the solution, and the measurement sequence is created at least partially automatically. Unfortunately, due to the increased requirements for the creation of the CAD model, this solution is still not very widespread.

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

Werth image processing

Evaluating images perfectly for optics and computer tomography scan

Werth image processing - Evaluating images perfectly for optics and computer tomography scan

The image processing algorithms used to evaluate the image contents and determine the measurement points also have a significant influence on the quality of the measurement results from image processing sensors or the evaluation of cross sections during tomography scans. Today, the evaluation is mainly realised by PC hardware and software. In a first processing step, the image can be improved with image filters (optimising contrast, smoothing surface disturbances). This enables reliable measurements even with difficult edges and rigid scanning in incident light.

Contour image processing for reliable measurement

Contour image processing for reliable measurement

In contour image processing, the image is viewed as a two-dimensional whole within an evaluation window. Contours are extracted from this image using suitable mathematical algorithms (operators). Each image point 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 mould of the contours. It is important for practical use that several contours can be distinguished within a capture range 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.

Raster scanning: resolution independent of the measuring range

Raster scanning: resolution independent of the measuring range

Contours larger than the field of view of the respective lenses can be captured as a whole by automatic contour tracking in conjunction with the CNC axes of the coordinate measuring machine (contour scanning). This scanning method is well suited for checking a few relatively large contours, e.g. on punching tools.

Another method for capturing larger areas of the workpiece is “raster scanning HD” (patent). Here, the image processing sensor captures images of the workpiece at high frequency during movement. These are resampled and superimposed to form an overall image with up to 4000 megapixels (as of 2021). In the “in the image” evaluation, 100 bores can then be measured in 3 s, for example. By measuring even large areas with high magnification and averaging over several images, which improves the signal-to-noise ratio, the accuracy is also increased. The method can be adapted to the requirements of the measurement task.

With Raster Scanning HD P, image acquisition only at areas of interest using a preset path results in a further reduction in measurement time and data volume compared to rectangular scanning of the entire workpiece with Raster Scanning HD N. On rotary axis devices, Raster Scanning HD ROTARY enables image acquisition during rotation with measurements on the “unrolled” overall image of the lateral surface of rotationally symmetrical workpieces.

Volume Section Sensor

Volume Section Sensor

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

Special measuring methods for computed tomography scans

Increasing the resolution and extending the measuring range by rastering

Special measuring methods for computed tomography scans - Increasing the resolution and extending the measuring range by rastering

In Raster Tomography, several sections of the measuring object are captured one after the other and the corresponding image stacks are stored. Scanning can be performed along the rotary axis (X-scanning), perpendicular to the rotary axis (Y-scanning) and in both orientations (XY-scanning). During the evaluation, the corresponding pixel or voxel information is merged for the entire object. This is done without stitching, using only the highly accurate coordinate axes. Capturing a small workpiece at a higher magnification with multiple grid steps increases the resolution, while capturing a large workpiece in multiple sections extends the measuring range.

Eccentric sections can be scanned tomographically with high resolution and linked metrologically with Multi-ROI CT

Eccentric sections can be scanned tomographically with high resolution and linked metrologically with Multi-ROI CT

Eccentric Tomography scan allows the workpiece to be placed anywhere on the rotary table (patent). This eliminates the need for costly and time-consuming alignment of the workpiece and increases ease of use. With the help of section tomography or ROI tomography (ROI: Region of Interest), parts of the measuring object are measured with high resolution without having to capture the entire measuring object, e.g. , completely with high resolution using Raster Tomography, which is time-consuming and requires a lot of memory. Multi-ROI tomography offers a combination of the benefits of eccentric and sectional tomography scans. Multiple parts with high resolution can also be selected at any position in the measuring object.

Measuring multi-material workpieces with Dual-Spectra Tomography scan

Measuring multi-material workpieces with Dual-Spectra Tomography scan

 In X-ray tomography measurements of metal-plastic components such as feeding connectors, for example, the metal pins often cause artefacts due to beam hardening and scattered radiation, which make measurements on the plastic housing difficult. In Dual-Spectra Tomography scan, the measurement software combines two CT measurements at different cathode voltages into one volume. The radiation spectra are matched to the two materials. The corresponding reduction of artefacts in the volume reduces the measurement uncertainty when determining sizes between the different materials. For this purpose, the WinWerth® MultiMaterialScan enables the automatic calculation of separate STL point clouds per material from the CT volume data, even for several different metal components, with the aid of the patented subvoxeling procedure.

Reduction of measurement time through continuous rotation of the device axis with OnTheFly-CT

Reduction of measurement time through continuous rotation of the device axis with OnTheFly-CT

With tomography scan in conventional start-stop operation, the rotary motion is interrupted for the acquisition of each radiographic image to avoid motion blur during exposure. OnTheFly Tomography scan makes it possible to save dead time for positioning the workpiece by continuous rotation. With this method, on the one hand the measuring time can be greatly reduced with the same data quality, on the other hand the data quality and thus the measuring uncertainty can be improved with the same measuring time.

Increasing automation

Automatic measurement of workpieces

Regardless of the type of programming, the measuring machine can execute the measurement sequence automatically or semi-automatically (on manually operated machines). This means that the machine can also be used by users who do not know the inspection process in detail. Operation is reduced to inserting the parts, determining their position by measuring a coordinate system on the workpiece (pre-alignment) and starting the programme. The pre-alignment can be automated or even omitted by using fixtures. Such fixtures can also hold several workpieces simultaneously (pallets). This allows set-up times to be reduced. The WinWerth® software then automatically repeats the measurement sequence at the various locations on the pallet.

Integrated into the production process

Integrated into the production process

For users untrained in the operation of measuring devices, WinWerth® offers the possibility of simply selecting the part number and starting an automatic programme sequence with it. Alternatively, this can be done by scanning a barcode on the production order. An automatic fault handling function helps, for example, if the parts are not inserted correctly.

Alternatively, a workpiece changing system can be integrated into the housing of the TomoScope® coordinate measuring machines without further precautions for radiation protection. With several ready-loaded pallets, measurements are possible overnight and at weekends.

Automatic feeding by means of feeding devices can also be integrated. For this purpose, the measuring programmes can be prepared remotely at offline workstations. The workpieces are fed into the robot’s safety area via an airlock. In this way, the geometrical characteristics of workpieces such as valve blocks, housings and castings are determined almost every half minute, a nominal-actual comparison is carried out with the measuring point cloud of a master part and the workpieces are tested for defects such as burrs. The measurement results can be determined with the help of parallel evaluation computers and merged in a common protocol, also with the measurement results of interlinked multi-sensor devices.

Specific access to measurement results in production with WinWerth® Scout

Specific access to measurement results in production with WinWerth® Scout

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 listed. There, next to the identification number of the job, is the current status, such as “Job started”, “Tomography”, “Tactile measurement” or “Evaluation”. Completed jobs are automatically moved to another list and color-designated according to their status: green for “in tolerance”, yellow for “intervention 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 finished measurements, another window opens with a list of all measured workpiece groups or workpieces whose status is also color-coded.

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

Nominal-actual comparison of part-to-part deviation analysis

Deviations of the workpiece from the nominal state are displayed in color-coded form

Nominal-actual comparison of part-to-part deviation analysis - Deviations of the workpiece from the nominal state are displayed in colour-coded form

In order to illustrate the deviation of the workpiece geometry from the nominal values, a comparison to the CAD model with a color-coded display of the deviations in WinWerth® is suitable. This procedure is absolutely necessary for the inspection of free-form surfaces. For measurement, the areas of interest of the object are scanned or captured as a point cloud. WinWerth® then compares the measured values with the CAD model. The result is documented in each case by vectorial or color-coded representation of the deviations to the CAD model. This evaluation can be carried out as part of the measurement sequence on the machine or in offline mode at a separate evaluation station. The colors of the measurement points illustrate the deviation between target and actual. To include the part tolerances in the display, a subdivision into four basic classes is made:

  • positive within tolerance
  • negative within tolerance
  • positive outside tolerance
  • negative outside tolerance

The amount of deviation is represented by color coding. Alternatively, the user can configure color coding according to his wishes.

All options are open when choosing the datum system

All options are open when choosing the datum system

According to the task, the measurement results are either calculated or displayed in a reference coordinate system that has been measured beforehand (e.g. 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 easily 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 nominal points. Since 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 to a limited extent for quality control.

The optimization criterion with 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 detected as faulty according to the BestFit method (red areas present), but which are actually not faulty, can be classified as functional according to the ToleranceFit® method. The contour is checked as with a gauge.

Measurement results are fed back into production

Measurement results are fed back into production

In order to incorporate the measured or calculated deviations into the production process, the default data can be largely modified automatically with WinWerth® FormCorrect. For this purpose, the deviations between the original CAD model and the measured data of a sample workpiece are determined and mirrored on the model. From this, the measurement software generates a corrected CAD model with which systematic manufacturing deviations of the plastic injection molding process and 3D printing can be compensated. In contrast to the usual reverse engineering, the application is considerably simplified. Due to the high precision, often only one correction loop is required, so that the costs of the development process can be significantly reduced. For high-resolution corrections and for the modification of even internal surfaces, the use of coordinate measuring machines with X-ray computed tomography is recommended. A similar procedure is possible with the 2D BestFit software. The mould correction can be used both during the running-in of new cutting tools (profile grinding, form milling) and during wire erosion to correct positioning deviations.

Automatic burr detection

Automatic burr detection

A special feature of Werth is the automatic detection and measurement of burrs or chips during the measurement sequence. The result is a colour-coded deviation plot of the burr and the maximum burr length. The deviation display optionally shows only those points where the burr length exceeds the tolerance limits. The burr length along the entire burr can also be displayed numerically via analysis markers. For example, every 0.5 mm a flag is set that contains the maximum local burr length.

Evaluate point clouds

Easily evaluate point clouds from optical sensors or computer tomography scans

Evaluate point clouds - Easily evaluate point clouds from optical sensors or computer tomography scans

If no CAD data is available, the operator can select the measurement points interactively. In WinWerth®, both direct selection with the mouse and automatic decomposition into rule geometry elements are possible. For this purpose, starting from a starting point, further points are automatically added all around until the form error of the selected feature (e.g. cylinder) increases noticeably. This signals that the limits of the feature have been reached and the process is completed.

It is more effective to define the measurement sequences using 3D CAD data. By simply selecting CAD features, the necessary measurement points (patent) are automatically selected. Starting from the selection of CAD patches, all measurement points of the measured object that can be geometrically assigned to this patch are selected, taking into account predefined edge distances. This results in a complete capture of the mold of the corresponding feature with the maximum number of points.

In practice, it is common to define drawing dimensions in 2D views and cutting edges. This must also be taken into account when evaluating tomographically generated measured data. For this purpose, planes can be defined in the workpiece coordinate system and intersected with both the CAD nominal data and the actual point cloud. WinWerth® automatically extracts contours representing the nominal data and the actual contours. The same software functions that are available for evaluating contours scanned with image processing or a stylus are used to evaluate the 2D sizes in cutting contours created in this way.

Evaluate volume data

Testing the material structure and analysis of mounted assemblies

Evaluate volume data - Testing the material structure and analysis of mounted assemblies

WinWerth® also provides a selection of software tools for material analysis on the volume data. The visualization of the volume data is integrated into the 3D module of the WinWerth® measurement software. The volume is visualized in the mold of grey values representing the density of the material. In general, the volume is displayed brighter with increasing density. Three different views can be used in parallel and individually faded in or out. It is possible to display the entire volume, i.e. all voxels with their respective grey value. In the “ISO surface” view, only voxels with the selected grey value are displayed. 2D-cross sections can also be displayed according to the selection of the cutting edge. All variants are displayed rotatable in three dimensions and can thus be analyzed from all sides. CAD model, voxel volume and measurement point cloud are imaged superimposed in the same coordinate system.

The representation can be clipped over any number of definable planes (clipping planes). Model and measured data are hidden beyond the planes. The entire workpiece can be removed plane by plane and visually checked for flatness, for example. The clipping planes can be used to test material, internal geometries and individual components of multi-material workpieces. Both the clipping planes and cutting planes for displaying and inspecting 2D cross sections can be moved and rotated in three dimensions directly in the 3D graphic 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.

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

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