How to measure the length of the steel pipe
According to the technical requirements of different manufacturers, steel length measuring system has a variety of methods. Mainly as follows:
1, grating length measurement
The basic principle is: set two fixed-length steel grating in the outer ends of each pipe, use rodless cylinder drive the grating approaching both ends of the steel , achieved by optical interference phenomenon to measure the length of the pipe.
Characterization: high accuracy. However, grating is expensive and difficult to maintain,and the impact of dust and vibration is sensitive to the venue.
2, the camera length measurement.
Camera length measurement is achieved by using image processing. The principle is equidistant installed in a steel roller conveyor section on a series of photoelectric switches, plus light and camera on the other section. When the pipe goes through this area, pipe length can be determined by the camera taking an image on a screen at a position based on a photoelectric switch.
Characterization: available for online measurement. Pipe length can be obtained by measuring the length of the data in the area, with no interval.
Shortage is: If you do not ad hoc light source, the pipe will be subject to outside interference of the light, and after the use of ad hoc light, due to the end of steel tube become very bright after chamfering and strengthen the light reflection,it become easier to cause reading errors.
3, the encoder measuring length
The basic principle is mounted on the cylinder of the encoder, to promote the use of cylinder rollers pipe movement, equidistant series of photoelectric switches mounted on the other side of the pipe when the photoelectric switch is touched by hydraulic cylinder tube end, the reading from the recording encoder , the translation of the cylinder stroke, so you can calculate the length of the tubes.
Characterization: need to lift the pipe up when measuring. In addition, there are some error when doing photoelectric switch detecting, it may take the full measurement.
4, improved encoder measuring length
This method is an indirect measurement by measuring the distance between the respective end faces of two pipe and the reference point.Set a car at both ends of each pipe, the initial position of zero bits, spacing L. Then move to the respective pipe length editor walking distance of the pipe end (L2, L3), L-L2-L3--- the length of the pipe.
This way overcomes the difficulties of huge volume, complex production environment , measuring mechanism can not pass through the lower part of the supporting steel gantry and other difficulties. This method is easy to operate, with measurement accuracy within ±10mm, repeatability ≤ 5mm.