Extrusion Asia Edition 3-2016

SIKORA AG Bruchweide 2, 28307 Bremen, Germany www.sikora.net 毫米波技术 FMCW（调频连续波）雷达技术是一项用于测量尺寸和记录 下垂度的创新型技术，其投入成本更低。此类系统在亚太赫 兹范围内工作，并且于汽车工业中用于距离测量已有一段时 间。它们采用了半导体技术，价格便宜并且使用寿命长。在 80 至 300 GHz 的选定区域内，塑料材料都能够被穿透，吸收 率小，因此可用来测量壁厚。通过采用一个或两个围绕管周 连续旋转的收发器，系统同时连续地发送和接收调频毫米 波，或者也可以选择采用两个固定收发器进行四点的管材壁 厚及内外径测量。当需要围绕管的整个圆周测量其完整壁厚 时，可使用旋转测量头；在这种模式下，还可以精确测量材 料的下垂。该系统的测量原理是通过由塑料材料前后边界层 反射信号的时间差来计算壁厚，测量精度仅数微米，采样速 率为每秒 500 次。该毫米波测量技术可适用于直径为 120 至 2,500 mm 的产品，无需耦合介质，不受温度或材料的影响。 而且，测量系统对挤出材料具有自适应性，故无需进行校 准。通过该技术的应用，为挤出生产线上的调偏及温度控制 提供了技术保障，测量数值可用于优化同心度及最小壁厚。 总结 随着对管材生产品质要求的提高，通过非破坏性测试 （NDT）在挤出时对塑料管进行精确和可靠的品质控制变得 非常重要。 此外，成本节省及材料的有效使用也是工厂管理 的重点。测量和控制系统可在线监测和控制重要的产品参数 以确保在控制品质的同时兼顾成本的节省。 因此，管材制造 商可以从具有不同功能和不同应用的各种技术中选择适当的 技术手段以满足自己的需求。 通过激光测量技术可对外径在 0.05 到 500 mm 的物体进行可 靠的在线测量。而 X 射线测量系统可测量直径达 270 mm 的 产品的壁厚和偏心率。另一种采用创新型毫米波的测量技术 可适用于高达 2,500 mm 的大规格管道挤出生产线， 该技术 适用于精确测量不同材料类型及常规管材的尺寸以及下垂 度。 因此，在挤出生产线中使用哪种测量技术取决于应用领 域和用户对测量和控制技术在品质保障、工艺优化和成本节 约方面的要求。 tinuously rotating transceiver continuous- ly send and receive frequency modulated millimeter waves while moving around the tube. As an alternative, a static system measures selectively the wall thickness and outer and inner diameter of a tube with two transceiver at four points. A ro- tating gauge head is used when the com- plete measurement of the wall thickness around the whole circumference of the tube is required. In this version, also the sagging is measured and displayed preci- sely. The measurement uses the time dif- ference of the signals that are reflected by the boundary layers of the front and back site of the plastic material. The measure- ment is realized with an accuracy of few micrometers and a measuring rate of 500 single measurements per second. The mil- limeter waves technology measures pro- ducts with a diameter from 120 to 2,500 mm precisely, around the complete circumference, with no need for coupling medi- um and is not influenced by the temperature or plastic materi- al. Furthermore, the measuring system adapts the properties of the extruded plastics by itself – a calibration by the user is re- dundant. Furthermore, the technology provides information for centering the extrusion tool and thermal control of the line. Thereby, the measuring values are used to ensure an optimal concentricity and minimal wall thickness. Summary With the increasing quality requirements at the production of hoses and tubes, the precise and reliable quality control for plastic pipes at the extrusion by a Non-Destructive Testing (NDT) becomes significantly important. Furthermore, an efficient usa- ge of materials for costs savings is in focus of the plant ma- nagement. Measuring and control systems monitor and control important product parameters continuously. Thereby, hose and tube manufacturers may choose from various technologies with different functions and diverse applications. The laser technology offers a reliable online measurement of the diameter from 0.05 to 500 mm. Additionally, X-ray measur- ing systems measure the wall thickness and eccentricity of pro- ducts with a diameter up to 270 mm. A further innovative tech- nology, based on millimeter waves, is used for extrusion lines where large plastic pipes up to 2,500 mm are produced. The technology is applicable for different material types and mea- sures common tube dimensions as well as the sagging precise- ly. Which measuring technology should be used in an extrusion line depends, therefore, on the application area and the re- quirements of the user regarding measuring and control tech- nology for quality assurance, process optimization and cost sav- ings. 图 5：采用毫米波技术的测量系统，用于反射 信号时间差测量物体外径、壁厚和下垂度的毫 米波技术 Image 5: The measuring system based on millimeter waves technology for the deter- mination of the diameter, wall thickness and the sagging based on the time diffe- rence analysis of reflected signals 35 Extrusion Asia Edition 3/2016