JP7677301B2 - Method for estimating wear amount of a rotary blade for trimming and method for trimming - Google Patents

Description

The present invention relates to a method for trimming a metal strip (trim material), and in particular to a method for estimating the amount of wear of a trimming rotary blade and a trimming method when trimming using a trimming device having a pair of upper and lower rotary blades.

Traditionally, in the manufacturing process of steel strips, a trimming device is used to trim both ends of the steel strip to ensure the width dimensional accuracy and edge quality of the steel strip. In recent years, the demand for high-strength thin steel strips has increased, and the load on the trimming devices used has increased. This has led to wear on the trimming blade and a decrease in clearance accuracy due to device backlash, etc., which has resulted in a tendency for edge defects to occur. For these reasons, there is a demand for higher-precision clearance during trimming.

In response to such demands, for example, Patent Document 1 discloses a method for measuring and adjusting the shear clearance of a shear device. Patent Document 1 describes a method for automatically adjusting the shear clearance to an appropriate range by arranging a non-contact distance meter on the side of the shear device to measure the shear clearance between the upper blade and the lower blade. Patent Document 2 describes a method for diagnosing the shear clearance of a double-cut shear device. The technology described in Patent Document 2 blows compressed air through multiple through holes provided on a surface perpendicular to the line of the lower shear blade of the double-cut shear device, and measures the back pressure. The obtained actual shear clearance value is then compared with a reference clearance value to calculate a shear clearance deviation value and determine whether the shear clearance is good or bad.

Patent Document 3 also discloses a method for trimming trim material. It describes that when trimming is performed using a trimming device having a pair of rotary blades, the amount of wear on the rotary blades is actually measured, and a relationship equation is obtained between the thickness, tensile strength, and length (distance of use) of the trim material, and the amount of wear that progresses during trimming. Then, from the obtained relationship equation and the thickness, tensile strength, and length (distance of use) of the trim material to be trimmed, the amount of wear on the rotary blades after a specified trimming is predicted, and the clearance of the rotary blades is corrected.

Patent Document 4 also discloses a method for predicting the lifespan of a trimmer blade. Patent Document 4 describes that when trimming a steel strip using a side trimmer, the degree of wear of the trimmer blade is determined in advance for each material and thickness of the steel strip. Then, each time the steel strip is trimmed, the amount of wear of the trimmer blade is calculated according to the trimmed length of the steel strip and the previously determined degree of wear of the trimmer blade for each material and thickness of the steel strip to obtain an accumulated amount of wear and to predict the lifespan of the trimmer blade.

Japanese Patent Application Publication No. 06-262425 Japanese Patent Application Publication No. 08-215924 JP 2017-64803 A Japanese Patent Application Publication No. 06-155138

However, the techniques described in Patent Documents 1 and 2 require the introduction of new equipment to measure the clearance, which requires securing an installation location and increases equipment costs. Furthermore, the techniques described in Patent Documents 3 and 4 require the actual measurement of the wear of the trimmer blade in advance and the determination of a relationship between the obtained wear of the trimmer blade and the material, thickness, etc. of the steel strip. However, there are many types of steel strips handled in the actual process, including differences in surface conditions such as the presence or absence of oiling, and determining the above-mentioned relationship for each type of steel strip, etc., requires many line stoppages in a continuously operating production line, which leads to a problem of reduced productivity.

The present invention aims to solve the problems of the conventional technology and provide a method for estimating the wear amount of a trimming rotary blade that can easily estimate the wear amount of the rotary blade of a trimming device that uses a pair of rotary blades, and a trimming method that can improve the trimming clearance accuracy.

When a metal strip (trim material) is trimmed using a trimming device that uses a pair of upper and lower rotary blades, the sides of the rotary blades wear as the trimming distance increases. The gap between the rotary blades becomes wider than the initially set gap by the amount of wear. As the gap between the rotary blades widens, trim defects eventually occur. In the past, when trim defects occurred, the production line was stopped and the gap between the rotary blades was measured with a gap gauge or the like and adjusted to the appropriate value. This resulted in a significant drop in productivity.

The inventor therefore focused on the output value of the rotary blade drive motor in a trimming device that uses a pair of rotary blades. As trimming progresses, the rotary blades wear and the gap between the rotary blades widens, and the output value of the rotary blade drive motor decreases. The inventor then came up with the idea that by regarding an increase in the amount of wear on the rotary blades as an increase in the gap between the rotary blades, it would be possible to estimate the amount of wear on the rotary blades from the relationship between the output value of the rotary blade drive motor and the clearance between the rotary blades.

Then, the relationship between the clearance between the pair of rotary blades and the output value of the rotary blade drive motor is obtained in advance for each type and thickness of the target trim material (metal strip). This relationship can be easily obtained by changing the clearance C (%) during trimming with a new rotary blade at a constant line speed, measuring the output value M (kW) of the rotary blade drive motor at each change, and performing linear regression. The relationship is expressed by the following formula: M = aC + b ... (1)
Here, a and b are coefficients.

The clearance C (%) between a pair of rotary blades is calculated by the following formula, where the distance between the pair of rotary blades is X (mm): C = (X/t) x 100 (%)
Where, t: thickness of trim material (metal strip) (mm)
is defined as:

In addition, when the rotary blades are new blades and the clearance between the pair of rotary blades is trimmed at C _SP (%), the output value M _SP (kW) of the rotary blade drive motor is calculated using the above formula (1) as follows: M _SP = aC _SP + b ... (A)
The clearance C _SP (%) between the pair of rotary blades when replaced with new blades can be expressed by the following formula, where the distance between the pair of rotary blades is X _SP (mm): C _SP = (X _SP /t) x 100 (%) (B)
Where, t: thickness of trim material (metal strip) (mm)
is defined as:

In addition, if the above formula (1) is previously obtained, the output value M _Y (kW) of the rotary blade drive motor measured when the rotary blade is worn during trimming can be expressed in relation to the clearance C _Y (%) between the pair of rotary blades by the following formula:
M _Y =aC _Y +b (C)
If the amount of wear of the pair of rotary blades during trimming is Y, the distance between the pair of rotary blades at that time can be regarded as X _SP +Y, and the clearance C _Y can be expressed by the following formula: C _Y = [(X _SP +Y)/t] × 100 (%) (D)
is defined as:

Using the above formulas (A), (B), (C), and (D), the wear amount Y of the rotary blade is calculated by the following formula: Y = [(M _Y - M _SP )/a] x (t/100) (2)
It can be calculated using the following formula:

In other words, they found that the amount of wear on the rotary blades can be estimated from the output value of the rotary blade drive motor without actually measuring it.

The present invention was completed based on these findings and further investigations.
[1] When trimming a metal strip using a trimming device having a pair of rotary blades consisting of upper and lower rotary blades,
For the metal strip, the relationship between the output value M (kW) of the rotation drive motor during trimming and the clearance C (%) of the rotary blade is linearly regression-based to obtain the following formula (1):
M=aC+b (1)
Where M: output value of the rotary blade drive motor (kW),
C: Clearance between a pair of rotary blades (%)
a, b: coefficients,
Calculate the following:
A method for estimating the amount of wear of a rotary blade for trimming, comprising measuring an output value of a drive motor for rotating the pair of rotary blades during trimming, and estimating the amount of wear of the pair of rotary blades from the output value using equation (1).
[2] The estimation of the wear amount of the pair of rotary blades is
Trimming is performed with a new rotary blade, with the clearance between the rotary blades being C _SP (%), and the output value M _SP (kW) _of the rotary blade drive motor is measured.
From the output value M _Y (kW) measured during trimming, the following formula (2) is used: Y = [(M _Y - M _SP )/a] x (t/100) (2)
Where Y is the wear amount of a pair of rotary blades (mm),
M _Y : Output value (kW) of the rotary blade drive motor when trimming with a pair of rotary blades,
M _SP : output value (kW) of the rotary blade drive motor when trimming with the rotary blade as a new blade and the clearance between the pair of rotary blades as C _SP ,
t: thickness of metal strip (mm),
a: Coefficient of the formula (1) M = aC + b
The wear amount estimation method for a trim rotary blade according to claim 1, wherein the wear amount Y (mm) of the pair of rotary blades is calculated using the above formula.
[3] When trimming a metal strip using a trimming device having a pair of upper and lower rotary blades,
A method for trimming a metal strip, characterized in that the amount of wear of the pair of rotary blades is estimated during the trimming, and the clearance between the pair of rotary blades is adjusted by reducing the space between the pair of rotary blades by the amount of wear of the pair of rotary blades thus estimated, thereby performing trimming.
[4] A method for trimming a metal strip as described in [3], characterized in that the wear amount of the pair of rotary blades is estimated using the wear amount estimation method for a trim rotary blade as described in [2].

According to the present invention, the clearance accuracy of the rotary blade during trimming is improved, the occurrence of edge defects after trimming can be prevented, and the edge quality is improved. In addition, according to the present invention, normal trimming can be performed even with a rotary blade that has been used long distances and has progressed wear, so the blade replacement cycle can be extended, and the life of the rotary blade can be extended. In addition, according to the present invention, the amount of wear of the rotary blade can be estimated while the line is operating without stopping the line to actually measure the wear of the rotary blade tip, which contributes to improving productivity.

FIG. 2 is an explanatory diagram illustrating an example of a trimming device. FIG. 4 is an explanatory diagram illustrating a typical wear state of a rotary blade. 10 is a graph showing the relationship between the rotary blade drive motor output value and the rotary blade clearance.

The present invention will be explained below with reference to the drawings.

An example of a trimming device that uses a pair of rotary blades is shown in Figure 1. A pair of rotary blades consisting of an upper rotary blade (upper blade) 2a and a lower rotary blade (lower blade) 2b trims a metal strip (steel strip) 1, which is the trim material. 3 is a housing, and 4 is a drive motor for the rotary blades, consisting of an upper blade drive motor 4a and a lower blade drive motor 4b.

As trimming is performed, the sides of the rotary blades 2a, 2b wear over time, and the distance (clearance) between the rotary blades increases by the amount of wear. If the initially set horizontal distance between the rotary blades 2a, 2b is X, the distance between the rotary blades increases by the amount of wear Y, and the distance between the rotary blades after trimming and wear can be considered to be (X+Y). Figure 2 shows this situation. In Figure 2, the dotted line shows the cross-sectional shape of the cutting edge of the original rotary blade. The clearance C (%) is calculated by the thickness t (mm) of the metal strip to be trimmed and the horizontal distance X (mm) between the rotary blades, and is expressed by the following formula: C=(X/t)×100
is defined as:

In the present invention, a trimming device having a pair of upper and lower rotary blades is used to trim a metal strip (trim material). Then, for a metal strip of a specified thickness, the output value of the drive motor for rotating the pair of rotary blades is measured while the rotary blades wear over time during trimming, and the amount of wear of the pair of rotary blades is estimated from the output value.

In the method of estimating the wear amount of a pair of rotary blades according to the present invention, the relationship between the output value M (kW) of the rotation drive motor during trimming and the clearance C (%) of the rotary blades is linearly regression-based to obtain the following equation (1):
M=aC+b (1)
Where M: output value of the rotary blade drive motor (kW),
C: Clearance between a pair of rotary blades (%) (=(X/t)×100),
X: Horizontal distance between a pair of rotary blades (mm),
a, b: coefficients when linearly regressed,
I will ask for it as follows.

In the wear amount estimation method of the present invention, when a new blade (new blade) is replaced for each type and thickness of metal strip (trim material), the clearance C is changed in various ways, trimming is performed, and the output value M of the rotary blade drive motor at that time is measured. It is preferable to keep the rotary blade speed constant when measuring the drive motor output value. Then, the relationship between the obtained output value M of the rotary blade drive motor and the clearance C of the rotary blade is calculated by linear regression as shown in the above formula (1).

It is preferable to use the output value of the drive motor for the upper rotary blade (upper blade) as the output value of the drive motor for the rotary blade.

In order to increase the accuracy of the measurement, it is preferable to measure the output value of the rotary blade drive motor using the drive motor for the upper rotary blade (upper blade). If the measurement is performed using the drive motor for the lower rotary blade (lower blade), the weight of the metal strip being trimmed will act as a load, and disturbances other than the shear force will be large.

The output value of the rotary blade drive motor should be measured when the rotation speed of the rotary blade is constant or when the fluctuation in the rotation speed is within ±5%. When the rotation speed of the rotary blade suddenly decreases or increases, the motor output value varies more than usual, so it is preferable to measure the output value of the rotary blade drive motor when the rotation speed is constant for approximately 3 minutes or more.

Figure 3 shows an example of the relationship between the output value M of the rotary blade drive motor and the clearance C when using a new blade, obtained for various thicknesses and types of steel strips (metal strips). Note that the output value M of the rotary blade drive motor was taken from the output value of the upper blade drive motor to ensure high accuracy.

Next, trimming is performed with a new rotary blade to set the clearance between the rotary blades to an appropriate clearance C _SP (%), and the output value M _SP (kW) of the rotary blade drive motor is measured to obtain the output value M _SP .

Using the above formula (1), M _SP (kW) is:
M _SP (kW)=aC _SP +b (A)
It can be expressed as:

The clearance C _SP (%) is calculated by the following formula, where X _SP (mm) is the distance between the rotary blades: C _SP = (X _SP /t) x 100 (%) (B)
(where t is the thickness of the metal strip (mm))
is defined as:

Next, while the rotary blades are worn over time during trimming, the output value M _Y (kW) of the drive motor for rotating the pair of rotary blades is measured, and the amount of wear (Y mm) of the pair of rotary blades is estimated from the output value using equation (1). Using equation (1), M _Y (kW) can be calculated as follows:
M _Y (kW) = aC _Y +b (C)
It can be expressed as:

In addition, since an increase in the speed of the rotary blade also increases the load on the drive motor, in order to eliminate the effect of speed, it is preferable that the rotational speed of the rotary blade during trimming be the same as that used when formula (1) was calculated.

If the wear amount of the pair of rotary blades when measuring the output value _M of the rotary blade drive motor is Y (mm), the distance between the rotary blades at that time can be considered as (X _SP + Y) (mm).Then, the clearance C _Y during trimming is calculated by the following formula: C _Y = [(X _SP + Y)/t] x 100 (%) (D)
It can be expressed as:

In the present invention, the obtained M _Y and M _SP obtained by the above-mentioned measurement are used to calculate the following formula (2): Y=[(M _Y -M _SP )/a]×(t/100) (2)
The wear amount Y (mm) of the rotary blade is estimated using the above equation. Here, M _SP (kW) is the output value of the rotary blade drive motor when trimming is performed with the rotary blade as a new blade and the clearance between the rotary blades as C _SP (the interval is X _SP ). Also, t (mm) is the plate thickness of the target metal strip (trim material). Also, a is a coefficient in formula (1), M = aC + b.

In the present invention, a trimming device consisting of a pair of upper and lower rotary blades is used to trim a metal strip (steel strip).

First, it is preferable to replace the rotary blades with new blades and adjust the clearance between the pair of rotary blades to a clearance C _SP set according to the type and thickness of the metal strip to be processed. The clearance C _SP is defined as C _SP = (X _SP /t) x 100 (%), where X _SP is the horizontal distance between the pair of rotary blades. The horizontal distance (clearance) between the rotary blades is adjusted via a clearance control means disposed in the trimming device. Then, the output value M _SP of the rotary blade drive motor when trimming is performed with the clearance C _SP is measured and the output value M _SP is obtained.

As the distance the rotary blades are used increases, the rotary blades wear and the gap between the pair of rotary blades increases, making trimming defects (cutting defects) more likely to occur. Therefore, in the present invention, the gap between the pair of rotary blades is adjusted appropriately and further trimming is performed. Here, "appropriately" preferably means after trimming each coil or a specified distance.

In the trimming method of the present invention, the adjustment of the gap between the pair of rotary blades is preferably performed by estimating the amount of wear of the rotary blades and narrowing the gap between the pair of rotary blades by the amount of wear of the estimated rotary blades. The amount of wear of the rotary blades is estimated by the above-mentioned method for estimating the amount of wear of the trimming rotary blades. This makes it possible to maintain a constant clearance of the rotary blades and stabilize edge quality. This also improves the clearance accuracy during trimming and reduces or suppresses the occurrence of cutting defects such as poor edges.

By adjusting the gap between the pair of rotary blades as described above, the output value of the rotary blade drive motor after adjustment can be trimmed with an accuracy within ±5% (95 to 105% of M _SP ) of the output value M _SP of the rotary blade drive motor when trimmed at the initial clearance C _SP as a new blade.

The above-mentioned method for estimating the wear amount of a rotary blade for trimming of the present invention allows the wear amount of the rotary blade to be estimated using the output value of the rotary blade drive motor, and does not require actual measurement using a gap gauge or the like, allowing for safe and accurate estimation without errors between operators. Furthermore, the trimming method of the present invention allows for improved clearance accuracy in trimming without reducing productivity.

The present invention can be applied to both batch trimming, in which each metal strip is processed separately, and continuous trimming, in which metal strips are processed continuously. However, from the standpoint of improving productivity, applying the present invention to continuous trimming reduces line stoppages for clearance adjustment, and thus provides greater benefits.

In the case of continuous trimming, it is preferable to change the clearance at the joints of the metal strip so that the clearance becomes the clearance C _SP set according to the type and thickness of the metal strip.

The trimming device used in the present invention preferably includes, for example, a pair of upper and lower rotary blades, a rotary blade drive motor that drives the pair of rotary blades, and a clearance control means that adjusts the clearance between the pair of rotary blades. Furthermore, the trimming device used in the present invention preferably includes a detection means that detects the output value of the rotary blade drive motor, and further includes a calculation device having a calculation means, an instruction means, or a storage means.

Here, the calculation means estimates the amount of wear of the pair of rotary blades from the output value of the rotary blade drive motor obtained by the detection means and the relationship between the output value of the rotary blade drive motor and the clearance of the rotary blades, which has been measured in advance. Alternatively, the calculation means further calculates a correction amount for the clearance of the pair of rotary blades from the estimated amount of wear of the rotary blades. Furthermore, the instruction means instructs the clearance control means on the correction amount for the clearance of the pair of rotary blades obtained by the calculation means. Furthermore, it is preferable that the calculation device has a storage means for storing the relationship between the output value of the rotary blade drive motor and the clearance of the rotary blades, which has been measured in advance, and the like.

The present invention will be further explained below with reference to examples.

Using a trimming device with a pair of rotary blades, four coils were continuously trimmed using high-strength steel strip with a thickness of 1.4 mm and a tensile strength of 1180 MPa as the trimming material. The output value of the rotary blade drive motor was measured using the upper blade drive motor. Initially, the rotary blade was a new blade, and the initial clearance was adjusted to C _SP (10%, spacing X _SP 0.14 mm), and the output value M _SP of the rotary blade drive motor at that time was measured and the output value M _SP (kW) was obtained. Then, after each coil trimming, the output value M _Y (kW) of the rotary blade drive motor was measured, and the obtained output value M _Y (kW) of the rotary blade drive motor and the output value M _SP (kW) were used to calculate the following formula (2): Y = [(M _Y -M _SP )/a] x (t/100) (2)
The wear amount Y of the rotary blade was estimated using the following formula (1): M = aC + b (1) When the blade was replaced with a new one, the output value M of the rotary blade drive motor and the clearance C of the rotary blade were expressed as the relational expression:
The coefficient a was -0.25.

Then, the spacing between the rotary blades was narrowed by the amount of wear Y obtained, and the next coil was trimmed (example of the present invention).

By performing trimming while adjusting the spacing of the rotary blades using the above method, no edge defects were observed, and the rate of coils with edge defects was 0%. In the conventional method of adjusting and trimming with a gap gauge when edge defects occur, edge defects could not be prevented in advance, and the rate of coils with edge defects was 5%. In addition, in the present invention, in which trimming is performed while adjusting the spacing of the rotary blades using the above method, the clearance can be accurately corrected even in an environment where various materials and materials of various plate thicknesses are manufactured, so no edge defects occurred. As a result, it was possible to extend the replacement cycle of the rotary blades from the conventional two weeks to two months.

Even if the rotary blades become worn, the wear amount estimation method according to the present invention can be used to estimate the amount of wear, and the spacing between the rotary blades can be narrowed by the amount of wear to adjust the spacing to be approximately the same as that of new blades, improving clearance accuracy without reducing productivity.

1 Metal strips (steel strips, trim materials)
2 Pair of rotary blades 2a Rotary blade (upper blade)
2b Rotary blade (lower blade)
3 Housing 4 Rotary blade drive motor 4a Upper blade drive motor 4b Lower blade drive motor

Claims (2)

When trimming a metal strip using a trimming device having a pair of upper and lower rotary blades,
For the metal strip, the relationship between the output value M (kW) of the rotary blade drive motor during trimming and the clearance C (%) of the rotary blade is linearly regression-based to calculate the following formula (1):
Then, trimming is performed with a new rotary blade with the clearance between the rotary blades set to C _SP (%), and the output value M _SP (kW) of the rotary blade drive motor is measured to obtain the output value M _SP (kW),
a wear amount estimating _method for a rotary blade for trimming, comprising: measuring an output value M _Y (kW) of a rotary blade drive motor for the pair of rotary blades during trimming; and calculating an amount of wear Y (mm) of the pair of rotary blades from the obtained output value M _Y (kW) and the output value M SP (kW) using the following formula (2) :
Note
M=aC+b (1)
Where M: output value of the rotary blade drive motor (kW),
C: Clearance between a pair of rotary blades (%) (=(X/t)×100),
X: Horizontal distance between a pair of rotary blades (mm),
t: thickness of metal strip (mm),
a, b: coefficients
Y=[(MY _- MSP ₎ /a]×(t/100) (2)
Where Y is the wear amount of a pair of rotary blades (mm),
M _Y : Output value (kW) of the rotary blade drive motor when trimming with a pair of rotary blades,
M _SP : output value (kW) of the rotary blade drive motor when trimming with the rotary blade as a new blade and the clearance between the pair of rotary blades as C _SP (%),
C _SP : Clearance between a pair of rotary blades when the rotary blade is a new blade (%) (= (X _SP / t) × 100),
XSP : Horizontal distance between a pair of rotary blades when the rotary blades are new blades (mm) _,
t: thickness of metal strip (mm),
a: Coefficient of formula (1) M = aC + b When trimming a metal strip using a trimming device having a pair of upper and lower rotary blades,
A method for trimming a metal strip, comprising: estimating the amount of wear of the pair of rotary blades during trimming using the method for estimating the amount of wear of the trimming rotary blades as described in claim 1; and reducing the gap between the pair of rotary blades by the amount of wear of the pair of rotary blades thus estimated, thereby adjusting the clearance of the pair of rotary blades and performing trimming.

Images