JP5861659B2 - Trimming waste cutting method - Google Patents

Description

  The present invention relates to cutting of trimming waste generated when a metal strip such as a steel strip is continuously passed through and trimming the edge portion thereof, and cutting of trimming waste by cutting the trimming scrap into a strip shape by a chopper rotor. Regarding the method.

  When the trimming waste generated when trimming the edge portion of a metal strip such as a steel strip has high rigidity, a method of cutting the trimming waste to a length of about 200 mm is generally used as a treatment method. Is. FIG. 1 is a diagram showing such a cutting method. The edge portion of the metal strip 1 that is continuously passed is trimmed by a side trimmer 3 that is provided with a pair of rotary blades 2 at the top and bottom. The trimmed scrap 4 cut out is sent to the scrap chopper 6 through the guide 5 and cut into a strip shape by the pair of chopper rotors 7. FIG. 2 is a diagram showing the structure of the scrap chopper 6 described above. A blade 8 is attached to each chopper rotor 7 at equal intervals in the circumferential direction. Both the chopper rotors 7 are rotated in opposite directions and the cutting tool 8 is engaged to cut the trimming waste 4. And in order to improve the biting property of the blade 8 to the trimming waste 4, the rotational speed control of the chopper rotor 7 is performed so that the rotational speed of the chopper rotor 7 becomes larger than the approach speed of the trimming waste 4.

  Patent Document 1 discloses a technique using such a cutting method. Further, Patent Document 2 discloses a technique in which biting into trimming waste is reliably performed by controlling the rotation speed of the chopper rotor.

Japanese Patent Application Laid-Open No. 09-253921 JP 2009-23015 A

  However, in the cutting methods of Patent Document 1 and Patent Document 2, when the line operation is stopped due to the inspection of the metal band and other factors and the conveyance of the trimming waste is stopped, the chopper rotor continues to rotate, and wasteful power is consumed. There are problems such as consuming. On the other hand, there is also a method in which the chopper rotor is stopped when the conveyance of the trimming waste is stopped, and the trimming waste is cut into strips by rotating the chopper rotor before the trimming waste is conveyed. However, if the chopper rotor is rotated before the trimming waste is conveyed, there is a problem in that the chopper rotor blades are chipped, the load current of the chopper rotor power source increases, and the equipment stops due to overload abnormalities. .

  The present invention has been made in view of the above problems, and can cut power consumption and cut trimming waste that can cut trimming waste into strips without causing a load on the chopper rotor at the time of cutting. It aims to provide a method.

The gist of the present invention is as follows.
[1] In a trimming scrap cutting method for cutting trimming scrap generated by trimming an edge portion of a continuously passing metal strip into a strip shape by rotation of a chopper rotor, when the transport of the trimming scrap is stopped Trimming waste cutting method, wherein the chopper rotor is rotated simultaneously with the start of conveyance of the trimming waste or after the start of conveyance of the trimming waste when stopping the rotation of the chopper rotor and transporting the trimming waste again. .
[2] When the rotation of the chopper rotor stops, the tip of the blade that is attached to the chopper rotor and cuts the trimming waste stops at a position shifted from a direction perpendicular to the trimming waste. The cutting method of the trimming waste of Claim 1 characterized by these.

  In the present invention, when the trimming waste is transported again, the chopper rotor is rotated simultaneously with the transport of the trimming waste or after the start of the transport of the trimming waste, so that power saving can be achieved and a load on the chopper rotor at the time of cutting is generated. The trimming waste can be cut into strips. Therefore, the equipment stoppage due to the load on the chopper rotor at the time of cutting can be prevented, and the operation can be performed without impairing the productivity due to the equipment stoppage.

It is the schematic showing the trimming process of a metal strip. It is a figure showing the structure of a scrap chopper. It is a figure which shows the specific example of the stop position of a scrap chopper. It is a figure which shows the relationship between the advancing speed of trimming waste, the rotational speed of a chopper rotor, and load current in the conventional cutting method. It is a figure which shows the relationship of the advancing speed of trimming waste, the rotational speed of a chopper rotor, and load current in the cutting method of this invention.

  In the trimming process of the metal strip as shown in FIG. 1, the present inventors have examined the load current of the chopper rotor power source in order to examine the timing at which the blade chipping or the chopper rotor overload abnormality has occurred. Measurements were made. As a result, it was found that an excessive load current was generated when the chopper rotor was rotated before the start of line operation. This is because when the chopper rotor is rotated before the line operation starts, the chopper rotor rotates with the trimming waste stopped. For this reason, a load and an impact are applied to the chopper rotor at the time of cutting, for example, the chopper rotor tears off the trimming waste that has stopped. As a result, it is considered that a blade chip or an overload abnormality of the chopper rotor power source has occurred.

  Therefore, in the present invention, when the conveyance of the trimming waste is stopped, the chopper rotor stops rotating, and when the trimming waste is conveyed again, the chopper rotor rotates simultaneously with the start of the conveyance of the trimming waste or after the start of the conveyance of the trimming waste. It is characterized by. In the present invention, it is assumed that the trimming waste carry-in speed is the same as the line speed.

  When line operation stops, the conveyance of trimming waste also stops. Therefore, power saving can be achieved by stopping the rotation of the chopper rotor with the stop of the conveyance of the trimming waste. Further, when the line operation is resumed, the conveyance of trimming waste is also resumed. When transporting the trimming waste again, if the chopper rotor is rotated simultaneously with the start of the transport of trimming waste or after the start of the transport of trimming waste, for example, the trimming waste is rotated by the chopper rotor by rotating the chopper rotor before starting the line operation. The load and impact on the chopper rotor at the time of cutting, such as tearing off, can be suppressed. In addition, trimming waste can be cut into strips without the occurrence of chipping or overloading of the chopper rotor power source.

  In the present invention, when the chopper rotor is rotated after the start of conveyance of trimming waste, it is preferable to rotate the chopper rotor at a timing of about 2 seconds after the line operation is resumed.

  In the present invention, when the rotation of the chopper rotor is stopped, it is preferable that the tip of the blade attached to the chopper rotor and cutting the trimming waste is stopped at a position shifted from a direction perpendicular to the trimming waste. . For example, as shown in FIG. 3, the tip of the pair of blades 8 is deviated from the direction in contact with the trimming waste 4 perpendicularly, so that sufficient acceleration time is secured when the chopper rotor 7 resumes rotation. Can do. As a result, the load and impact on the chopper rotor 7 at the time of cutting can be suppressed. Further, biting into the trimming waste 4 can be avoided. As for the position of the tip of the blade, it is preferable that the blade that first contacts the trimming waste after the chopper rotor 7 starts rotating is shifted by 50 to 80 ° from the direction that is perpendicular to the trimming waste.

  In addition, about the rotation position of a chopper rotor, as shown in FIG. 3, by providing the chopper rotor 8 with the rotation position detector 9, a rotation position can be grasped | ascertained and the position of a blade is adjusted suitably. Can do.

For the conventional cutting method and the cutting method of the present invention, the load current of each chopper rotor power source was measured. A current detector and a recorder were used to measure the load current of the chopper rotor power source. Other conditions are as follows.
Line speed: 0 to 250 mpm
Chopper rotor rotational speed: 0 to 250 mpm
Measurement time: 1 week The results are shown in FIGS. It can be seen from FIG. 4 that in the conventional cutting method, an excessive load current is generated when the chopper rotor is rotated before the line operation is started. On the other hand, from FIG. 5, in the cutting method of the present invention, since the chopper rotor is rotated at the same timing as the trimming waste proceeds, excessive load current at the time of rotating the chopper rotor as in the prior art can be reduced, and an overload abnormality occurs. Good results were obtained.

  Further, in the conventional cutting method, it is necessary to replace the blade by chipping of the chopper rotor due to abnormal overload of the chopper rotor every 3 to 6 months. On the other hand, since the cutting method of the present invention can reduce the load caused by the biting of the tip of the trimming waste, the blade replacement due to the chopper rotor chipping has not occurred for more than two years.

1 Metal strip (steel strip)
2 Rotating Blade 3 Side Trimmer 4 Trimming Waste 5 Guide 6 Scrap Chopper 7 Chopper Rotor 8 Blade 9 Rotation Position Detector

Claims (1)

In a trimming scrap cutting method for cutting trimming scrap generated by trimming an edge portion of a continuously passing metal strip into a strip shape by rotation of a chopper rotor, when the transport of the trimming scrap stops, the chopper rotor The chopper rotor is rotated simultaneously with the start of conveyance of the trimming debris or after the start of conveyance of the trimming debris when the trimming debris is conveyed again, and when the rotation of the chopper rotor is stopped, tip of the blade which is attached to the chopper rotor cutting the trimmings, the method of cutting trimmings characterized that you stopped at a position deviated from a direction in contact with the perpendicular to the trimmings.

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