外文翻譯--cnc機(jī)器上自由形態(tài)表面非連絡(luò)自動(dòng)機(jī)械測(cè)量-其他專業(yè)(編輯修改稿)
2025-02-24 09:49 本頁(yè)面
【文章內(nèi)容簡(jiǎn)介】 rately, . the technique of probe radius pensation is more difficult, . the probe tip is subject to be worn quickly, and . some dynamic errors of the machine structure and the servo controller may occur. In order to improve the abovementioned drawbacks, some laser probes have been developed for noncontact measurement of freeform surfaces during the past years39。4. In addition, when applying this kind of probe to the CNC type of CMM, the system accuracy and the measuring speed can be significantly increased539。6, and the CAD/CAM integration can be easily achieved for the purpose of reverse engineering739。8. This paper describes the work which employed a low cost laser probe to a DCC (Direct Computer Controlled) type CMM to develop an automatic noncontact measuring system for 3D freeform surfaces, and its integration with some PC based CAD/CAM softwares for reverse engineering. Such technique was also applied to a CNC machining center to build up an onmachine measurement system. An indepth calibration of the laser probe was primarily investigated with respect to the material, the surface slope, the color, and the edge detection of the workpiece to be measured. Having employed the surface painting technique, the shape error of the reproduced workpiece relative to its master piece was found within 30 jrn, which is deemed adequate enough to the requirement by the mold industry. 2. OPERATING PRINCIPLE OF LASER PROBE The laser probe used in this study is a Keyence LC2220 sensor head with LC2100 controller. This low cost and visible laser probe provides displacement measurement via laser triangulation technique. As seen in Fig. 1, the focused laser beam emitted from the semiconductor laser is projected onto the object surface. Due to the surface roughness, the reflected beam will be scattered and partly collected by the laser receiving lens. Through this lens, the beam will be focused and projected onto the position sensitive detector (PSD) in the sensor head. If the object to be measured moves (Lx, in the figure), the reflected laser light spot also moves (6) by means of the PSD. Then, this spot displacement is converted to an analog or a digital signal through a data processing unit which is also called the controller here. Finally, the controller carries out data processing, such as linearity pensation and average value calculation, displaying and outputting the measured results. 3. PERFORMANCE TESTS OF LASER PROBE For all of the noncontact type displacement sensors, such as the eddy current type, the ultrasonic type, the pneumatic type, and the laser beam reflected type, their performance curves are related to the surface properties of the tested objects. Some important parameters of the surface property with respect to the laser probe may include the material, the color, the roughness, and the slope of the object surface. Most of the specifications of laser probes, however, do not provide sufficient information in the operational manuals. The listed data reflecting the performace characteristics of any particular laser probe provided by the manufacturer uaually are not directly applicable to a particular object to be measured. Therefore, primary accuracy calibration of the adopted laser probe with respect to the adopted workpiece has to
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