JP7036068B2 - Cutting tools for slab surface care and slab surface care methods - Google Patents

Description

The present invention relates to a cutting tool for slab surface care for caring for the surface of a steel slab and a slab surface care method.

Generally, steel plates (thick plates, thin plates) are manufactured by hot rolling or cold rolling using slabs (hereinafter referred to as slabs) such as continuously cast slabs and slabs. Rolling with the oxide scale layer and surface defects left on the surface of the slab causes deterioration of the surface texture of the product and cracking.

In addition, the slab often has a complicated shape such as warpage, bending, swelling, and dent due to non-uniform thermal stress in the cooling process during manufacturing, and often does not have a constant shape.

Conventionally, as shown in Patent Document 1 and Patent Document 2, the slab shape is measured using a contact type sensor or a laser range finder for a slab having a complicated shape that requires surface maintenance. , A machine tool such as a portal milling cutter is used to cut the slab surface with a milling tool to remove the oxide scale layer and surface defects on the slab surface.

Further, for a surface orthogonal to the motor rotation axis such as a portal milling cutter such as the side surface of a slab, the rotation transmission direction of the spindle is changed by using a gearbox as shown in Patent Document 3. , Cutting with a milling tool is also performed.

Specific examples of such conventional slab surface care will be described with reference to FIGS. 7 and 8. FIG. 7 is a front view when the upper surface of the slab is cared for, and FIG. 8 is a front view when the side surface of the slab is cared for.

As shown in FIGS. 7 and 8, the slab surface care device 10 used for surface care of the slab includes a slab fixing bed 11 for fixing the target slab 1 (top surface 1a, side surface 1b) and a portal frame 12 (upper part). Frame 12a, strut 12b), strut moving rail 14, cross rail 15 spanning between strut 12b, 12b on both sides, front head 16 installed on the cross rail 15, and spindle attached to the front head 16. A 17 and a rotating shaft 18 attached to the main shaft 17 are provided.

Further, as shown in FIG. 7, the upper surface milling tool 20 fixed to the rotating shaft 18, the upper surface laser displacement meter 19a attached to the cross rail 15, and the upper surface laser displacement meter 19a are connected to the rotating shaft 18 as shown in FIG. The gearbox 21 is provided, a side milling tool 22 that rotates via the gearbox 21, and a side laser displacement meter 19b attached to the support column 12b. The upper surface milling tool 20 and the side surface milling tool 22 are both cutting tools for the front surface milling cutter.

Then, the column 12b moves along the column moving rail 14 in the longitudinal direction of the slab fixing bed 11 (perpendicular to the paper surface in FIGS. 7 and 8: X direction). Further, the front head 16 moves along the cross rail 15 in the width direction of the slab fixed bed 11 (horizontal direction of the paper surface in FIGS. 7 and 8: Y direction). Further, the spindle 17 moves in the vertical direction (Z direction).

Thereby, when cutting the upper surface 1a of the slab, first, while emitting the laser beam for length measurement from the laser displacement meter 19a for the upper surface, the longitudinal direction (X direction) of the slab fixing bed 11 and the width direction of the slab fixing bed 11 By moving in the (Y direction), the shape of the upper surface 1a of the slab is measured.

After that, a machining program that imitates the slab surface shape is created based on the shape measurement results, and based on this, the slab surface is cut with the tool cutting edge while the top surface milling tool 20 rotates, thereby cutting the slab top surface 1a ( Surface care).

As a pattern of this movement, a locus in which the upper surface milling tool 20 moves in the longitudinal direction (X direction) of the slab fixing bed 11 while moving in the vertical direction (Z direction) following the shape of the upper surface of the slab is "passed" or. It is called a "machining path".

When the upper surface milling tool 20 goes from the start end to the end in the slab longitudinal direction by this pass, the upper surface milling tool 20 is moved in the width direction (Y direction) of the slab fixing bed 11 and the pass is performed again. This is repeated a plurality of times to cut the entire area of the slab upper surface 1a.

Similarly, when cutting the slab side surface 1b, first, while emitting the laser beam for length measurement from the laser displacement meter 19b for the side surface, the longitudinal direction (X direction) of the slab fixing bed 11 and the slab fixing bed 11 By moving in the height direction (Z direction), the shape of the slab side surface 1b is measured.

After that, a machining program that follows the shape of the slab surface is created based on the shape measurement results, and the side milling tool 22 rotates based on the machining program, and the width direction (Y direction) of the slab fixing bed 11 follows the shape of the side surface of the slab. ), The "pass" that moves in the longitudinal direction (X direction) of the slab fixing bed 11 is repeated once, or multiple times while moving in the vertical direction (Z direction), and the slab side surface 1b is cut (surface care). )I do.

Japanese Unexamined Patent Publication No. 9-108725 Japanese Unexamined Patent Publication No. 2016-68251 Japanese Unexamined Patent Publication No. 2014-69304

As described above, when the slab surface is cut by milling, the problem is when cutting the vicinity of the four corners (called the corners) where the upper and lower surfaces of the slab and the side surfaces intersect. In addition, there is a problem that the processing efficiency (surface maintenance efficiency) is lowered due to uncut parts and deep cutting as described below.

The corners of the slab have a chamfered shape (relatively dented compared to other places) due to heat shrinkage when the cast or forged slab is cooled to room temperature, pressure during transportation, etc. Shape) in many cases.

When cutting a corner with such a shape, uncut parts will be left at the same cutting depth as other places, and reworking will result in an increase in the number of passes and an increase in machining time. This leads to a decrease in processing efficiency.

FIG. 9 shows the risk of uncut portion when cutting the slab corner portion as described above, and each tool in a cross section of the slab 1 (top surface milling tool 20 (cutter body 20a, cutting tip 20b, cutting edge locus). 20c), detailed view of the side surface milling tool 22 (cutter body 22a, cutting tip 22b, cutting edge locus 22c)) and the cutting removal part 23 of each upper surface path (upper surface 1st pass cutting removal part 23a, upper surface 2nd pass cutting). The removal unit 23b, the upper surface third pass cutting removal unit 23c), and the side surface cutting removal unit 24 are shown.

At this time, if the notch of the upper surface processing path (first upper surface pass) of the corner portion is cut as the same normal notch 25 as the other upper surface processing path (upper surface second pass, ...), the shape is dented. Uncut portion (uncut portion) 26 is generated at the corner portion of.

If such uncut portion 26 remains, surface defects and the like may remain, which adversely affects the product quality. Therefore, it is usually removed by cutting again. This re-cutting increases the actual number of passes and reduces the machining efficiency.

On the other hand, in the case of milling without leaving the corner portion uncut, it is necessary to make a deep cut in the machining path including that portion, so that the tool feed rate is lowered and the machining efficiency is also lowered. In addition, in order to increase the tool feed rate while deepening the cut, it is necessary to narrow the machining path width only at the relevant corner and divide the machining path, so the overall machining path will eventually increase and the machining efficiency will increase. Decreases.

FIG. 10 shows the deep cutting risk when cutting the slab corner portion as described above, and similarly to FIG. 9, each tool (top surface milling tool 20, side surface milling tool 20) in a cross section of the slab 1 is shown. A detailed view of 22) and a cutting removal portion 23 of each path on the upper surface and a cutting removal portion 24 on the side surface are shown.

In order to avoid the uncut portion 26 as shown in FIG. 9, the processing path on the upper surface of the corner portion (first upper surface path) is deeper than the notch 25 of the other upper surface processing path (second upper surface path, ...). When the cut is 27, the cutting removal portion 23a on the first pass on the upper surface becomes very large as compared with the other passes, and the cutting load increases. When such high-load machining is performed, the feed rate generally decreases and the machining efficiency decreases.

The present invention has been made in view of the above circumstances, and when the surface of the slab is cared for by cutting, it accurately prevents a decrease in processing efficiency due to uncut parts at the corners of the slab and deep cutting. It is an object of the present invention to provide a cutting tool for slab surface care and a slab surface care method capable of efficiently caring for the surface of the slab.

In order to solve the above problems, the present invention has the following features.

[1] A cutting tool for caring for the surface of a slab used for caring for the surface of a slab. The end mill portion is provided, and the front milling portion and the end mill portion are positioned concentrically and rotate integrally, and the height position at which the uppermost end of the cutting tip of the cutting tip of the end mill portion is located is set. A cutting tool for caring for the surface of a slab, which is equal to or higher than the height position at which the lowermost end of the cutting edge tip of the cutting tip of the front milling cutter is located.

[2] The cutting tool for slab surface maintenance according to the above [1], wherein the upper surface of the corner portion of the slab is cut by the front milling cutter portion, and the side surface of the slab is cut by the end mill portion.

[3] When cleaning the surface of the slab, the slab is characterized in that the corners and side surfaces of the slab are cleaned by using the cutting tool for cleaning the surface of the slab according to the above [1] or [2]. Surface care method.

In the present invention, when the surface of the slab is cared for by cutting, the surface of the slab can be cared for efficiently by accurately preventing a decrease in processing efficiency due to uncut parts at the corners of the slab and deep cutting. ..

It is a front view which shows one Embodiment of this invention. It is a figure which shows the cutting state of the cutting tool used in one Embodiment of this invention. It is a perspective view of the cutting tool used in one Embodiment of this invention. It is a vertical sectional view of the cutting tool used in one Embodiment of this invention. It is a horizontal sectional view of the cutting tool used in one Embodiment of this invention. It is a figure which shows the comparison result of the processing time in the Example of this invention. It is a front view which shows the prior art. It is a front view which shows the prior art. It is a figure which shows the problem of the prior invention (risk of uncut corner part). It is a figure which shows the problem of the prior invention (the risk of deep cutting of a corner portion).

An embodiment of the present invention will be described with reference to the drawings.

The slab surface care device used in one embodiment of the present invention has the same basic configuration as the slab surface care device 10 shown in FIGS. 7 and 8 described above, but has the same basic configuration as the side milling tool 22 shown in FIG. The difference is that a new surface care cutting tool (new tool) 28 is used instead of the above, as shown in FIG. 1 for the front view corresponding to FIG.

First, also in this embodiment, when cutting the upper surface of the slab, the upper surface milling tool 20 is used in the same manner as shown in FIG. 7 above.

On the other hand, in this embodiment, as shown in FIG. 1, a new surface maintenance cutting tool (new tool) 28 is used to cut the corner portion and the side surface of the slab 1 at the same time. The details of the new tool 28 will be described later, but the upper portion is provided with a front milling cutter portion for cutting the upper surface of the corner portion of the slab, and the lower portion is provided with an end mill portion for cutting the side surface of the slab.

Specifically, in FIG. 1, first, the longitudinal direction (X direction) of the slab fixed bed 11 while emitting the laser beam for length measurement from the laser displacement meter 19a for top surface measurement and the laser displacement meter 19b for side surface measurement. By moving in the height direction (Z direction) of the slab fixed bed 11, the shape of the slab side surface 1b is measured.

After that, a machining program that imitates the slab surface shape is created based on the shape measurement results, and based on this, the new tool 28 rotates in the width direction (Y direction) and height direction (Z direction) of the slab fixing bed 11. By moving in the longitudinal direction (X direction) of the slab fixing bed 11 while following the shape of the slab corner portion, the corner portion and the side surface of the slab are cut.

FIG. 2 is a diagram schematically showing a cutting state (cutting removal portion) in the vicinity of the slab corner portion when the new tool 28 is used.

As described above, the new tool 28 is provided with a front milling portion (front milling cutter body 28a, front milling cutting tip 28b) having a structure of a cutting tool for a face milling cutter at the upper part, and a cutting tool for an end mill at the lower part. It is provided with an end mill portion (end mill portion cutter body 28c, end mill portion cutting tip 28d) having the above structure. Then, the front milling cutter portion and the end mill portion are located concentrically and rotate as one. In FIG. 2, 28e is the cutting edge trajectory of the new tool 28, and 29 is the cutting removal portion of the new tool 28.

As shown in FIG. 2, by using the new tool 28, the upper surface of the corner portion of the slab (the upper end portion of the slab) is subjected to the front milling portion cutting tip 28b, and the side surface of the slab (including the side surface of the corner portion) is the end mill portion. The cutting tip 28d enables simultaneous cutting, avoiding the uncut risk shown in FIG. 9 and the deep cutting risk shown in FIG. 10, and making the area of the cutting removal portion 29 an appropriate size. It is possible.

As a result, re-cutting is not required because uncut parts can be suppressed, the cutting load is reduced and the tool feed rate is increased by reducing the depth of cut on the upper surface, and the upper end can be machined at the same time as the side surface, resulting in a machining path. Benefits such as reduction can be obtained.

The new tool 28 will be described in detail below.

FIG. 3 is a perspective view of the new tool 28.

The new tool 28 has a shape in which the upper front milling portion and the lower end mill portion are connected on the same rotation axis. In the front milling cutter, the front milling cutter cutting tip 28b is attached to the lower outer peripheral surface of the disk-shaped front milling cutter body (front milling body) 28a, and the end mill is a cylindrical or conical end mill. On the outer peripheral surface of the portion cutter body (end mill portion main body) 28c, a plurality of rows of end mill portion cutting chips 28d are attached in a plurality of stages in the height direction and in the circumferential direction. The cutting tips 28b and 28d are fixed by a back support 30 having an appropriate shape.

Here, the positions of the cutting tips 28b and 28d in the circumferential direction are determined in consideration of chip evacuation and cutting conditions. Further, the positions of the cutting tips 28b and 28d in the height direction are determined based on the shape to be removed by cutting. In particular, the cutting tip 28d is arranged so that an uncut portion does not occur between the upper cutting tip 28d and the lower cutting tip 28d.

Although the reason will be described later, a recess (recess in the lower part of the front milling cutter) 31 is provided in the lower part of the front milling cutter.

FIG. 4 is a cross-sectional view of the new tool 28 cut in a vertical plane where the center line of the rotating shaft 18 is located. In the actual cross section, one or two cutting tips 28b and 28d appear in the height direction, but in FIG. 4, all the cutting tips 28b and 28d appear in the height direction in consideration of the rotation of the new tool 28. 28d is made to appear.

In FIG. 4, the line connecting the cutting edge tips of these cutting tips 28b and 28d is referred to as the cutting edge locus 32. The meaning of the cutting edge locus 32 is a shape that can be actually cut and removed by the new tool 28 when the new tool 28 rotates.

At this time, the important points of the new tool 28 are the shape that can be cut and removed by the upper front milling cutter alone (cutting tip trajectory only by the cutting tip 28b) and the shape that can be cut and removed by the lower end mill part alone (cutting tip). The cutting edge locus only in 28d) is not discontinuous in the height direction.

In other words, the height position where the uppermost end of the cutting tip 28d of the end mill portion is located is the same as or higher than the height position where the lowermost end of the cutting tip 28b of the front milling cutter is located. There is.

This is because if there is a discontinuity in the height direction between the cut-removable shape of the front milling portion and the cut-removable shape of the end mill portion, a portion that is not cut is generated at the slab corner portion.

Preferably, in consideration of the variation in the slab shape, the overlap portion 33 may be provided so that the cut-removable shape of the front milling cutter portion and the cut-removable shape of the end mill portion overlap in the height direction.

When the overlap amount 34 of the overlap portion 33 has a value of about 2 to 3 times the notch 25 on the upper surface of the slab, it is possible to appropriately prevent uncut parts due to variations in the slab shape.

As described above, the reason why the recess (the recess in the lower part of the front milling cutter) 31 is provided in the lower part of the front milling cutter is to make it easier to secure the overlapped portion 33.

When cutting the front surface and the back surface of the slab in order (when cutting the upper surface of the slab, then turning the slab over and cutting with the original lower surface facing the upper surface), the cuttable length of the end mill portion 35 By setting the value to be more than half the thickness of the slab, it is possible to prevent the side surface of the central portion of the thickness of the slab from being left uncut.

Further, when cutting the front surface and the back surface of the slab in order (when cutting the upper surface of the slab, then turning the slab over and cutting with the original lower surface facing the upper surface), the surface to which the cutting tip 28d of the end mill portion is attached. By having an end mill portion cutting surface angle 36 in the range of 0.5 to 3.0 °, it is possible to suppress a step on the side surface of the central portion of the thickness of the slab, and the steel plate edge portion after rolling the slab. It is possible to prevent folding scratches and the like.

FIG. 5 is a cross-sectional view taken along a horizontal plane orthogonal to the rotation axis 18 of the new tool 28. 5 (a) shows the AA cross section in FIG. 4 as a representative cross section of the front milling cutter portion, and FIG. 5 (b) shows the BB cross section in FIG. 4 as a representative cross section of the end mill portion. ing.

When the rotation speed of the new tool 28 is N, the representative blade diameter of the front milling cutter is Df, and the representative blade diameter of the end mill portion is De, the peripheral speeds Vf and Ve of the tool tips of each part are equations (1) and (2). Represented by.

Vf = N ・ π ・ Df ・ ・ ・ (1)
Ve = N ・ π ・ De ・ ・ ・ (2)
The relationship between the peripheral speeds Vf and Ve at the tip of the cutting edge of the front milling portion and the end mill portion is shown in the equation (3).

Vf / Ve = Df / De = Cv ... (3)
At this time, it is desirable to set the peripheral speed ratio (cutting edge diameter ratio) Cv in the range of 1.2 to 2.0 in order to make the cutting tip wear of the front milling portion and the end mill portion comparable.

For example, when the slab surface was cleaned with a rotation speed N of 400 rpm, a front milling cutter representative blade diameter Df of 250 mm, and an end mill portion representative blade diameter De of 200 mm, cutting tip wear was similar between the front milling cutter and the end mill. It is a standard.

When the feed rate of the new tool is F, the number of blades of the front milling cutter is Zf, and the number of blades of the end mill is Ze, the tip feed fzzf and fze of each part are shown by equations (4) and (5). Will be done.

fzf = F / (N ・ Zf) ・ ・ ・ (4)
fze = F / (N ・ Ze) ・ ・ ・ (5)
The relationship between the one-blade feed of the front milling cutter and the end mill is shown in Equation (6).

fzf / fze = Zf / Ze = Df ... (6)
At this time, in order to make the load applied to the cutting tip of the front milling part and the end mill part the same, it is desirable to set the tip one-blade feed ratio (tooth number ratio) Df in the range of 0.3 to 0.8. ..

For example, when the slab surface was cleaned with a feed speed F of 2400 mpm, a front milling cutter blade number Zf of 12 teeth, and an end mill blade blade number Ze of 5 teeth, the cutting chip was not chipped due to overload of the cutting chip, and the cutting edge was chipped. The level of small defects such as these is about the same in the front milling part and the end mill part.

In this way, in this embodiment, when the surface of the slab is cared for by cutting, the surface of the slab is efficiently prevented from being left uncut at the corners of the slab or a decrease in processing efficiency due to deep cutting. Can be cared for.

In order to confirm the effect of the present invention, as a conventional example, the surface of the slab is cared for by the conventional techniques shown in FIGS. 7 and 8, and as an example of the present invention, based on one embodiment of the present invention shown in FIG. 1 and the like. The surface of the slab was cleaned. FIG. 6 shows a comparison of the processing times between the conventional example and the example of the present invention.

As shown in FIG. 6, assuming that the processing time of the conventional example is 100, the processing time is 78 in the example of the present invention, and the processing efficiency is improved.

This confirmed the effectiveness of the present invention.

1 slab 1a slab top surface 1b slab side surface 10 slab surface care device 11 slab fixing bed 12 portal frame 12a top frame 12b stanchion 14 stanchion moving rail 15 cross rail 16 front head 17 spindle 18 rotating shaft 19a top surface laser displacement meter 19b for side surface Laser displacement meter 20 Top surface milling tool 20a Cutter body 20b Cutting tip 20c Cutting edge trajectory 21 Gearbox 22 Side surface milling tool 22a Cutter body 22b Cutting tip 22c Cutting edge trajectory 23 Top surface cutting removal part of each path 23a Top surface 1st pass cutting removal Part 23b Top surface 2nd pass cutting removal part 23c Top surface 3rd pass cutting removal part 24 Side surface cutting removal part 25 Notch 26 Leftover 27 Deep notch 28 New tool 28a Front milling part Cutter body 28b Front milling part Cutting tip 28c End mill part Cutter body 28d End mill part Cutting tip 28e New tool cutting edge locus 29 New tool cutting removal part 30 Back support 31 Front milling cutter lower recess 32 Cutting edge locus 33 Overlap part 34 Overlap amount 35 End mill part machinable length 36 End mill cutting surface angle

Claims (4)

A cutting tool for slab surface maintenance used to clean the surface of a slab, the upper part of which has a front milling part having the structure of a cutting tool for face milling, and the lower part of which has an end mill part having the structure of a cutting tool for end mills. The front milling cutter and the end milling cutter are located concentrically and rotate together, and a recess is provided in the lower part of the front milling cutter to provide the tip of the cutting tool of the end mill. A cutting tool for slab surface maintenance, characterized in that the height position where the upper end is located is higher than the height position where the lowermost end of the cutting tip of the cutting tip of the front milling cutter is located. The cutting tool for slab surface maintenance according to claim 1, wherein the upper surface of the corner portion of the slab is cut by the front milling cutter portion, and the side surface of the slab is cut by the end mill portion. The cutting tool for slab surface care according to claim 1 or 2, wherein the surface of the end mill portion to which the cutting tip is attached has a cutting surface angle in the range of 0.5 to 3.0 °. A method for cleaning the surface of a slab, which comprises using the cutting tool for cleaning the surface of the slab according to any one of claims 1 to 3 to clean the corners and side surfaces of the slab. ..

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