Technical upgrading and multi-function of the hott

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Technical upgrading and multi-function of coordinate measuring machine

technical upgrading and multi-function of coordinate measuring machine: coordinate measuring machine (CMM) enables the processing workshop to detect the increasingly strict part tolerances required by users. However, the time and energy consumed in precise measurement with CMM (depending on the service life and complexity of CMM) may often become a bottleneck in the production process. By selectively upgrading CMM and adopting multi-functional CMM technology, it is helpful to improve the measurement speed and detection flexibility of CMM

cmm upgrading: when upgrading CMM, the first problem that must be considered is the mechanical performance of CMM. Therefore, it is necessary to check the use status of CMM. If the mechanical part is in good condition and can be calibrated and maintain accuracy, it is suitable to upgrade it. If the mechanical system has been damaged and lost accuracy, there is no need to upgrade it. If a CMM has good mechanical performance, the more economical way to upgrade is to update its measurement software. Software upgrading is the focus of CMM transformation. A typical example is the upgrading of a CMM that has been used for 15 years, and the hardware is in good condition, but the software operation platform is still DOS operating system. After updating and upgrading it with new measurement software based on Windows operating system (such as Calypso software package of Zeiss company), it can input CAD files, select measurement range, and automatically create measurement program. This operator oriented software allows offline programming and programming preparation for detecting new parts without interrupting measurement. If there are multiple CMM of different brands in a processing workshop, they can be upgraded to the same measurement software package, so that operators can easily rotate operations between multiple CMM. The standardization of software is also conducive to the new purchase of CMM equipment, because the measurement software can be directly transplanted to the new CMM. After the software upgrade is completed, the next step is to upgrade and update the CMM controller. By replacing the new controller, the speed and accuracy of data acquisition can be significantly improved, and information acquisition, random diagnosis and other functions and pre inspection and repair procedures can be provided for CMM. After upgrading the software and controller, updating the probe technology can also significantly improve the performance of CMM. The standard probe of CMM is a trigger probe. Once its probe contacts the workpiece to be measured, it activates the once sending switch to record a data point. At present, the performance of many trigger probes is constantly improved and improved. For example, the contact scanning probe can keep in contact with the workpiece at the touch point and provide analog feedback, so as to record a large number of data points continuously and quickly. The combination of new measurement software, controller and probe technology can greatly improve the detection speed of CMM. For example, the vast navigator Suite equipped by Zeiss for the new high-performance CMM model includes advanced logic controller, special probe and measurement software, which can quickly scan and collect data from the tested workpiece. In the past, a comprehensive inspection of the cylinder block of V6 engine took 22 minutes, but the use of navigator Kit (even without any adaptation of the measurement program) can improve the inspection speed by 30%

improvement of sensor technology: the further development of sensor technology includes the ability to collect dimensional data without contacting the workpiece. If the laser probe is used for detection, a beam of coherent light is projected onto the surface of the workpiece to be measured. Through the analysis of the reflected light signal, the single point or multi-point dimension data can be recorded (as when the contact scanning probe is used). The video sensor system adopts a camera and a set of lighting system, which can record a large number of data points at the same time, can accurately measure the edge of the workpiece, and can also record the tiny morphology that is difficult to detect by the contact probe. Non contact sensors are most suitable for measuring the morphology of soft materials with ductility and small-size workpieces. Using non-contact laser scanning probe can quickly complete large-scale and medium precision detection work (such as the detection of the installation size of the outer instrument panel of the automobile). While using contact scanning probe to detect thin-walled metal workpiece may damage the workpiece due to excessive measuring force, and the accuracy requirements for detecting such workpiece may be higher than the typical accuracy requirements for detecting engine cylinder block (<2 μ m) 10 ~ 20 times lower. The new scanning probe can make up for the shortcomings of the traditional probe. The traditional trigger probe can only be used to measure the size/position of a single point, while the scanning probe has the function of multi-point rapid measurement. Taking another sample for rework is the first choice for workpiece morphology measurement. For example, the scanning speed of the scanning probe newly developed by RENISHOW company is significantly higher than that of the traditional probe, while retaining the rapid measurement function of a single data point that triggers the probe. It is of great significance to improve the scanning speed of the scanning probe. But in the past, when trying to improve the scanning speed, the momentum and inertia of the measuring machine will reduce the measurement accuracy. When the measuring machine drives the probe to quickly sweep the workpiece and change the direction of movement, it will produce constantly changing dynamic errors, thus limiting the scanning speed to 20mm/sec following. In order to minimize the impact of dynamic errors, RENISHOW developed new software and hardware, including a 2-axis universal positioning probe. Recently, the company launched a scanning measurement system composed of renscan5 measuring machine 5-axis control technology, Revo high-speed scanning probe, laser calibration probe and ucc2 universal CMM controller. CMM with this complete set of technology can operate at 500mm/sec High speed measurement of high-precision workpiece parameters can cover a larger range of data

versatility of CMM: just as the multifunctional machine tool combining the control software with the tool change device can complete the multi process processing of the workpiece in one clamping, the CMM using the multi-sensor technology can also detect a variety of error items of the workpiece on the same instrument, which can save the time and energy spent on moving the workpiece from one instrument to another instrument to measure each error respectively, and can transfer the workpiece The possibility of damage during loading and unloading and the measurement error introduced by multiple clamping are minimized. However, there are also some problems to be solved in the transformation of old CMM with multi-sensor technology. Although it is quite common to upgrade the single trigger probe of CMM to scan trigger probe at present, the installation of video probe on CMM is limited. This is because the video probe is usually much heavier than the trigger probe, and the mechanical structure design of the old CMM is difficult to bear this weight. In addition, the use of video sensing systems also requires special lighting devices, which are usually not available on CMM using trigger probe. Another problem is the integration of trigger probe and video measurement software. The measurement method of trigger probe CMM is to sample a single point or a group of points, while the video measurement system uses a camera to quickly sample a dot matrix. Therefore, in order to quickly switch different sensors in the measurement without stopping the machine and recalibrating other sensors before continuing the measurement, it is very important to integrate different sensors into the measurement software. OPG is trying to solve the multifunctional problem of CMM with another idea, that is, it is better to install a single point sampling sensor on the video measuring machine, rather than a video probe on the single point measuring machine. Because the video measuring machine has the ability to process multi-point data at the same time, it can also process single point data and scanning input data. The multi-sensor probe CMM designed by the company is based on the video measuring machine, and can be equipped with contact probe, laser probe and other types of sensor probes, that is, on the same given measuring platform, it can decline as the export of this year's extruder as a whole, and 4-5 different sensor probes can be used. The integrated multi probe CMM can greatly improve the measurement ability and detection efficiency. For example, after the workpiece to be measured is clamped at one time, the video probe can be used to sample the data of all parts suitable for video measurement; For some parts that cannot be measured by the video probe (such as the bottom of the hole whose depth exceeds the focal length of the video probe), the trigger probe can be used to sample point by point; For those complex surface topography that have not been designed by precise geometric CAD, laser probe can be used to scan the surface. The data points collected by various sensors are analyzed with a software package, and the analysis results are compared with the initial CAD file to determine whether the workpiece is correct. A typical application example of multi-sensor probe is the measurement of semi-metallic sealing washers. The gold composite structure of the gasket is about 25% lighter than the metal of the same volume (3) 0% belongs to the base material part, and the contact probe can be used to measure its dimensional parameters (such as aperture); For the soft material part that cannot be measured with the contact probe, if there is a multi-function CMM, you can switch to the video camera probe to obtain the continuous digital image of the workpiece. It is completely possible to integrate multiple measurement functions into a measuring machine. The versatility of CMM will greatly reduce the demand for a single function measuring machine for measuring each specific workpiece parameter. With the continuous development of coordinate measurement technology, CMM may eventually reach the following ideal state: just put the measured workpiece on the measuring machine and press the button to obtain all the required measurement results. In the future, it is also possible to replace all single function measuring machines with an integrated measuring machine

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