introduction
In recent years, in the extrusion molding of cables and the like, the use of microcomputers and small computers for program monitoring or program control has rapidly progressed. These devices are widely used in high-speed extrusion lines for foamed insulating cores of communication cables, and Cross-linked polyethylene power cable with cross-linking reaction is extruded on a chain line. This article will provide an overview of these applications, thickness and diameter measurement and monitoring devices.
Photoelectric measurement products adopt the telecentric light path and imaging method for on-line dimension detection. The core component of the detection is the photoelectricity measuring head. Each group of the measuring head is composed of a transmitting lens and a receiving lens. The light emitted by the point source of the transmitting lens is formed by the emission lens. The parallel light field of view is directed at the receiving lens. The collimated light is then focused by the receiving lens and imaged on the receiving unit via the aperture in the focus position. When the object passes through the object to be measured in the field of view, the area covered by the object to be measured will be On the chip of the receiving unit, a clear boundary shadow appears. Through photoelectric conversion and digital processing, the diameter of the measured object can be calculated by the width of the shadow.
Measurement of cable diameter using a single diameter measuring instrument can be used to detect and control the diameter of the wire. The single diameter measuring instrument performs non-destructive testing with the principle of photoelectric measurement, through the built-in incremental PID system frequency converter, electronic governor, and air compression. Machines and other external devices provide precise control over the size of the workpiece.
In order to ensure that the line can be extruded at high speed without breaking the heart, the device uses speed control in program control. It uses a PID (Proportional Integral Differentiation) control method to control the sample value of the differential advance type. The value of each parameter can be calculated based on the experimental data to achieve the best control state. Also, the outside diameter can be controlled by changing the extruder screw speed or the speed of the tractor (line speed).
In general, the automatic control of wire diameter and thickness is achieved through a control device connected to the measuring device. The simplest and most frequently used method is to control the speed of the manufacturing line. Usually, we use double measurement for thickness measurement. Diameter gauge linkage thickness to control the thickness of the cable diameter.
The single-gauge's automatic measurement and control device can reduce the useless material consumed in extrusion formation, thereby saving a considerable amount of raw materials. While saving money, it also increases the diameter of the cable, single-channel measurement Diameter meter is very convenient and practical for cable diameter measurement.
The measurement accuracy is the basic performance index of the cable's outer diameter measurement. The accuracy must be taken into consideration when designing. The main error factors are the quantization error and lens aberration. In addition, when the in-line measurement is performed, the device under test is subject to vibration due to motion. , Dynamic measurement should be considered when measuring. We use a variety of techniques to completely eliminate the measurement error caused by the jitter. With respect to the precision maintenance problem after installation, there is no analog processing and mechanical moving parts, and the principle will not produce precision drift.
The single-path gauge is a non-contact measuring device with high-speed measurement and high reliability. Two gauges can perform linkage control to detect the cable thickness, and two-path gauges (the two probes are vertically distributed). The size of Figure 1 can be detected. The single path diameter gauge can perform operations such as outer diameter value, deviation, over limit alarm, display and statistical processing, and can transmit data. It has accuracy correction function to ensure long-term running accuracy.
Single path gauge advantages
1 No mechanical moving parts
The image sensor is a CCD chip, the peripheral circuit can handle all electrical signals, the parallel light source, the detector has no mechanical moving parts, its lifetime is semi-permanent, and the single diameter gauge has a service life of more than eight years. In addition, the power is applied. At the same time, testing can be started without preheating time.
2 High frequency measurement
Using high-frequency measurement, the measurement frequency reaches 500Hz. If necessary, it can be customized to 1000Hz. That is, the single-path gauge can detect 500 data per second.
3 no jitter error
The use of a number of synchronization techniques, high-speed measurement technology and other technologies, completely eliminate the error caused by the measured cable jitter.
4 Automatic control
Through the built-in incremental PID system frequency converter, electronic governor, air compressor and other external devices to accurately control the size of the workpiece production. Single path diameter gauge using incremental PID control system, can dock a variety of external Equipment, forming closed-loop control.
Conclusion
The cable diameter measurement using a single diameter measuring device is a high-precision measuring device, which can effectively perform high-precision detection on the rolled material of the measured object, and the measurement accuracy can reach 0.003mm, achieving micrometer-level measurement. At the same time, the control function , Also makes the diameter gauge to ensure the quality of the cable, saving raw materials and funds, is an essential equipment for the detection of wire diameter in modern industrial production.
This article consists of Baoding Lanpeng Measurement & Control Technology Co., Ltd. write
