Upgrade and modification features of CMM

The Coordinate Measuring Machine (CMM) enables the shop to test for increasingly demanding part tolerances. However, the time and effort required to perform precision measurements with CMMs (depending on the length of service and complexity of the CMM) can often be a bottleneck in the production process. By selectively upgrading the CMM and adopting multi-functional CMM technology, it helps to improve the measurement speed and flexibility of the CMM.

Upgrade of CMM: When upgrading CMM, the first problem that must be considered is the mechanical performance of CMM. To do this, you need to check the status of the CMM. If the mechanical part is in good condition and can be calibrated and maintained with accuracy, it is suitable for upgrading. If the mechanical system is damaged and the accuracy is lost, there is no need to upgrade it. If a CMM has good mechanical performance, the more economical upgrade is to update its measurement software. Software upgrade is the focus of CMM transformation. A typical example is to upgrade a CMM that has been in use for 15 years and has a good hardware state but the software running platform is still a DOS operating system. After updating and upgrading with a new Windows-based measurement software, you can enter CAD files, select measurement ranges, and automatically create measurement programs. This operator-oriented software allows offline programming to prepare for the detection of new parts without interrupting the measurement. If a shop has multiple CMMs of different brands, you can upgrade them to the same measurement package so that operators can easily rotate between multiple CMMs. The standardization of the 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, 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 functions such as information acquisition, random diagnosis, and pre-repair procedures can be provided for the CMM. After completing the software and controller upgrades, updating the probe technology can also significantly improve the performance of the CMM. The CMM's standard probe is a touch-type probe. When the probe is in contact with the workpiece to be tested, it activates a signal switch and records a data point. The performance of many touch probes is constantly improving and improving. For example, contact scanning probes can keep in contact with the workpiece at the touch point and provide analog feedback to continuously and quickly record large numbers of data points. The combination of new measurement software, controllers and probe technology can greatly increase the speed of CMM detection.

Improvements in sensing technology: Further developments in sensor technology include the ability to acquire dimensional data without touching the workpiece. When using a laser probe for detection, a beam of coherent light is projected onto the surface of the workpiece to be measured. By analyzing the reflected light signal, single-point or multi-point size data can be recorded (as with a contact-scanning probe). ). The video sensing system uses a camera and a lighting system that simultaneously records a large number of data points, accurately measures the edges of the workpiece, and records the small features that are difficult to detect with contact probes. Non-contact sensors are best suited for measuring ductile soft materials and small-sized workpiece topography. The use of non-contact laser scanning probes enables fast, large-scale, medium-accuracy inspections (such as the inspection of the size of the instrument panel installed outside the car). The use of contact scanning probes to detect thin-walled metal workpieces may damage the workpiece due to excessive force. The accuracy requirements for detecting such workpieces may be 10 to 20 times lower than the typical accuracy requirements (<2 μm) for detecting engine cylinder blocks. . The new scanning probe can make up for the lack of traditional probe measurement functions. The traditional trigger probe can only be used for the size/position measurement of a single point, while the scanning probe has a multi-point fast measurement function, which is the first choice for workpiece topography measurement. For example, Renishow's newly developed scanning probes have a much higher scanning speed than conventional probes, while retaining the ability to quickly measure individual data points that trigger the probe. Increasing the scanning speed of the scanning probe is significant. But in the past, when trying to increase the scanning speed, the momentum and inertia of the measuring machine caused the measurement accuracy to decrease. When the measuring machine drives the probe to quickly sweep across the workpiece and change the direction of motion, an ever-changing dynamic error is generated, limiting the scanning speed to less than 20 mm/sec. In order to minimize the effects of dynamic errors, Renishow has developed new software and hardware. Recently, the company introduced a 5-axis control technology from Renscan5 measuring machine, Revo high-speed scanning probe, laser calibration probe and UCC2 universal. A scanning measurement system composed of a CMM controller or the like. The CMM with this technology enables high-speed measurement of high-precision workpiece parameters over a larger data range at a scan speed of 500 mm/sec. Multi-functionality of CMM: Just as the multi-function machine that combines the control software and the tool changer can complete the multi-process machining of the workpiece in one setup, the CMM with multi-sensing technology can also be implemented on the same instrument. The detection of various error items of the workpiece can save the time and effort of measuring the error of moving the workpiece from one instrument to another, and the possibility of damage to the workpiece during transfer and loading and unloading. Measurement errors introduced with multiple setups are minimized. For example, after the workpiece to be tested is clamped once, the video probe can be used to sample all the parts suitable for video measurement; for some parts of the video probe that cannot be measured (such as the bottom of the hole whose depth exceeds the focal length of the video probe) ), you can use the trigger probe to sample point by point; for those complex surface tops that have not been designed with precise geometry CAD, you can use a laser probe to scan the surface. The data points collected by the various sensors are analyzed in a software package and the results are compared to the initial CAD file to determine if the workpiece is correct. A typical application example for a multi-sensing probe is the measurement of a semi-metallic gasket. For the metal base material part of the gasket, the contact probe can be used to measure its dimensional parameters (such as the aperture); for a soft material part that cannot be measured with the contact probe, if there is a multi-function CMM, you can switch to video camera. The probe is used to obtain a continuous digital image of the workpiece. Integrating multiple measurement functions into one measuring machine is fully achievable. In the future, it is entirely possible to replace all single-function measuring machines with a comprehensive measuring machine.

The upgrade and modification of the CMM has been improved in many aspects. There is a significant improvement in both accuracy and speed, providing excellent quality assurance during use. At the same time, the upgrade and transformation of the CMM also reflects some new technologies, the emergence of new technologies, improved work efficiency and better optimization.