Using the parallel light projection method and the high precision linear CCD as the measuring sensor, combined with the mechanical scanning method, the hole diameter of the drawing die nibs was quickly detected. The circuit design of anti - spot interference in CCD aperture detection is proposed.

High-speed wire drawing production line is an important production equipment in the metal products industry. The quality of each process in wire-drawing production depends on whether the aperture of the wire-drawing die in the process is qualified. The axial section of the die hole is shown in figure 1, which is composed of four parts: inlet area, working area, sizing area and outlet area. Die diameter is the diameter of the specified diameter zone. Because the die hole is a cone Angle change hole, it is difficult to directly measure its minimum diameter, currently in the metal products industry is usually put silicone injection die hole to silicon gel solidification and then pull out, through the measurement of silicon punch die to obtain the die diameter. This kind of measurement method has low efficiency and is not suitable for the requirement of mass production. The range of the instrument:Φ 2 ~ 10 mm, accuracy < 0.01 mm.

The instrument adopts the method of parallel light projection and USES the high-precision linear CCD as the measuring sensor to extract the dimension information of thedrawing die nibshole. As shown in FIG. 2, the light source 1 forms parallel light through the condenser 2, the light column 3 and the collimating lens 4. Under the irradiation of parallel light, the wire-drawing die hole is imformed on the photosensitive surface of CCD through the imaging objective 6 and the light column 7. Optical system using remote fangyuan's heart light path, lighting and material can be reduced when installing drawing die sizing with position deviation, the measuring error caused by the light source to choose 6 v, 25 w halogen tungsten lamp step-down use, in order to improve the life and collimating mirror, choose standard photographic lens imaging lens, CCD and the use of Toshiba TCD106C, 5000 photosensitive pixels, center distance of adjacent pixels of 7 microns, the total size of 35 mm.

Measuring aperture with linear CCD is different from measuring diameter of outer circle. If the axis of measured rod and optical axis of measuring system are perpendicular to each other, the outer diameter can be measured by projection method. When measuring the inner diameter, the axis of the measured hole must be parallel to the optical axis. After the hole passes through the optical path imaging, the linear array CCD cannot directly measure the aperture. What the CCD cuts is the string of the hole. As long as the sampling frequency of CCD and the motion speed of the mechanical scanning mechanism are reasonably set, the scanning error can be controlled within the range that does not affect the accuracy.

Posted by: hannahgwendolyn at 09:42 AM | No Comments | Add Comment
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