JP3241119B2 - Sheet material cutting method and cutting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet material cutting method and apparatus for cutting a sheet material such as cloth into a desired pattern, particularly in a laminated state.

[0002]

2. Description of the Related Art Conventionally, for sewing clothes and the like,
It is necessary to stretch the fabric and cut it along the marked outline. For example, as shown in FIG. 12, the component pattern 1 is cut out along the contour of the desired component pattern.
For cutting, a blade is formed along the longitudinal direction of the rectangle, and a straight blade that moves vertically to perform cutting is generally used in many cases. This is because cutting at an acute angle is possible and a large number of fabrics can be laminated.

[0003] An electric cutting machine in which the cutting blade is moved up and down by using electric power as a power source to move the cutting blade manually and an automatic cutting machine in which a cutting head to which the cutting blade is attached are automatically moved to perform cutting. There is a cutting machine. In an automatic cutting machine, a cutting head moves two-dimensionally on an XY table. In the cutting head, the cutting blade moves up and down and performs an angular displacement to change the cutting direction. When cutting the curved contour line 2 as shown in FIG. 12, the cutting head moves along the contour line 2 and the cutting blade is also angularly displaced.
Prior art regarding such cutting of the sheet material is disclosed in, for example, Japanese Patent Publication No. 57-61557.

[0004]

Conventionally, a component pattern 1 as shown in FIG. 12 has been cut by guiding a cutting blade along an outline 2 thereof. However, when the sheet material is laminated and cut, the error of d with respect to the actual cutting line 3 in the curved portion increases as the number of cut sheets increases. For example, when cutting 60 sheets of 100% cotton cloth in a state of being 18 mm thick, the error d is about 1 mm. 100% cotton
When cutting only three fabrics, the error d is almost zero, and the contour line 2 and the cutting line 3 almost coincide with each other. As a cause of the error d shown in FIG. 12, as shown in FIG. 13, the force of F is applied to the cutting blade 4 moving along the cutting line 3 so that the cutting edge of the cutting blade 4 is bent. It is expected that the displacement angle of the cutting blade is further increased due to "backlash" such as slack, twist, or so-called clearance of the angular displacement mechanism of the cutting blade 4. The cutting blade 4 moves up and down at a high speed, and is angularly displaced in that state. The cutting blade 4 is supported by rollers and the like in the cutting head. Outside the cutting head, the cutting blade 4 receives a load on its free end as a cantilever. As the number of sheets stacked increases, the force that the cutting blade 4 receives from the portion protruding from the cutting head increases, and the bending and torsion also increase.
Further, since the cutting blade 4 is supported so as to be vertically movable, some "backlash" occurs in the angular displacement direction.

An object of the present invention is to provide a sheet material cutting method and a sheet material cutting apparatus which can reduce errors in cutting due to bending of a cutting blade and "backlash".

[0006]

According to the present invention, a cutting blade having a cutting edge formed in a longitudinal direction is reciprocally displaced in a state of being pierced in a direction perpendicular to a sheet material surface, and a sheet is contacted with the cutting edge at a contact portion with the cutting edge. In a sheet material cutting method in which the material is cut and the angle of the cutting blade is changed so that the cutting is performed along the contour line to be cut, the angle of the cutting blade is calculated at each point on the contour line to be cut. A method of cutting a sheet material, wherein the calculated angle is corrected by a predetermined angle in a direction opposite to the direction of change in accordance with the direction of change in the angle of the cutting blade.

Further, according to the present invention, a cutting blade having a cutting edge formed along the longitudinal direction is reciprocated while being pierced in a direction perpendicular to the sheet material surface, and the sheet material is cut at a contact portion with the cutting edge. In a sheet material cutting apparatus for angularly displacing a cutting blade so that cutting is performed along a contour line to be cut, a contour line input means for inputting and storing a contour shape of a part to be cut from the sheet material; Reading out the stored contents of the contour input means, calculating an angle representing the direction of the cutting blade at each point on the contour to be cut, and setting a predetermined angle corresponding to the direction in which the angle of the cutting blade is changing. The sheet material cutting device, comprising: a control unit that corrects only in a direction opposite to the change direction; and an angular displacement unit that responds to an output from the control unit and angularly displaces the cutting blade to a corrected angle. is there.

[0008]

According to the present invention, the angle of the cutting blade is corrected by a predetermined angle in a direction opposite to the direction of change. When the direction of change in the angle of the cutting blade changes from one direction to the other, the absolute value of the angle of change in the direction of the cutting blade decreases. When the direction of change of the direction of the cutting blade changes in one direction, the effects of bending, twisting and "backlash" of the cutting blade appear in the same manner. When the direction of change shifts from one direction to the other,
The angle of change increases due to the effects of bending, twisting, and “backlash”. For this reason, by making the absolute value of the change angle small, for example, to offset the large change angle, it is possible to reduce the error when cutting the contour line.

Further, according to the present invention, the control means calculates an angle representing the direction of the cutting blade at each point on the contour from the contents stored in the contour input means. When transitioning from a state in which the angle of the cutting blade changes in one direction to a state in which the angle changes in the other direction, the absolute value of the angle of the cutting blade is corrected to be small. Since the angular displacement means angularly displaces the cutting blade to the corrected angle, the deviation from the contour line to be cut should be small even if the angle of change becomes large due to bending, twisting or "backlash" of the cutting blade. Can be.

[0010]

FIG. 1 shows a schematic electrical configuration of a cutting apparatus according to an embodiment of the present invention. The pattern input means 11 receives and stores the contour shape of the part to be cut from the sheet material. Such a pattern input means 11
For example, it is composed of a CAD device for designing clothes and a floppy disk device for storing data created by the CAD device. The contents stored in the pattern input means 11 are as follows:
It is coordinate data of continuous points constituting a contour of a part, and is read by the control device 12 including a computer. The control device 12 sets the cutting blade 2 along the contour of the part.
The X-axis motor 13 and the Y-axis motor 14 are controlled to move in a three-dimensional manner. The control means 12 also controls the Z-axis air cylinder 15 for piercing the cutting blade into the sheet material when cutting the sheet material, and for lifting the cutting blade from the sheet material surface when not cutting the sheet material. The control means 12 further controls an R-axis motor 16 which is an angular displacement means for angularly displacing the cutting blade for cutting along the contour line.

FIG. 2 shows the control operation of the R-axis motor 16 when the control means 12 shown in FIG. 1 performs cutting along the contour line in accordance with the contents stored in the pattern input means 11. The operation is started from step a1 for each point constituting the contour. In step a2, the angle of the cutting blade is calculated as the angle formed by the straight line connecting the next point and the current point with the X axis. As for the angle of the cutting blade, the counterclockwise direction is the positive direction.
As a difference between the angle of the cutting blade at the current point and the angle of the cutting blade at the previous point, a change angle with the counterclockwise direction being the positive direction is calculated. In step a3, a straight line and a curve are distinguished based on the distance and the angle of change between the previous point and the current point. If it is a curve, the sign of the change angle is determined in step a4. If negative, the process proceeds to step a5, and if positive, the process proceeds to step a6. In step a5, a correction amount for clockwise rotation is added to the angle of the cutting blade. In step a6, the correction amount in the counterclockwise direction is reduced from the angle of the cutting blade. That is, the angle of the cutting blade is corrected in a direction opposite to the sign of the change angle. When the operations of step a3, step a5, and step a6 are completed, the process proceeds to step a7, and the current process is completed.

FIG. 3 shows an error in the cutting direction generated in the cutting blade. In the state where the cutting blade is angularly displaced left or right as indicated by reference numeral 18 or 19 from the reference state of the cutting blade indicated by reference numeral 17 due to bending or torsion of the cutting blade, backlash in the angular displacement direction, etc. Alternatively, the amount of angular displacement increases by the angle of α. Here, it is assumed that α> 0 and β> 0.

FIGS. 4 and 5 show how the angle of the blade changes when the angle in the tangential direction changes using a cutting blade having an angular displacement error as shown in FIG. In FIG. 4, although cutting is performed in a straight line from A to B and from B to C, the cutting direction changes by γ degrees at point B. Therefore, the actual change in the angle of the cutting blade becomes γ-β whose absolute value is smaller by β. In FIG. 5, points at which the sign of the change angle changes are indicated by M, N, O, and P. Assuming that the angles of the cutting blade calculated at the points M, N, O, and P are m, n, o, and p, respectively, the corrected angles are m-β, n + α, o-β, and p + α.
Becomes Although the error of α and β differs depending on the machine, it is almost impossible to make them zero.

It is assumed that point K shown in FIG. 5 is a point immediately before point N. When the calculated value of the angle of the cutting blade at the point K is k, the correction value is k-β. Therefore, the difference in the correction value between the point M and the point K, in which the direction of change in the angle of the cutting blade is the same, is (k−β) − (m−β) = km, and the influence of the correction appears. Absent. The difference between the correction values between the point K and the point N where the changing direction of the angle of the cutting blade is different is (n + α) − (k−β) =
− {(Kn) − (α + β)}. As shown in FIG. 5, when k> n and the difference j = kn−0,
Since the actual values of α and β are smaller than j, the absolute value of the changed angle after correction is j− (α + β), which is smaller due to the influence of the correction.

FIG. 6 shows the appearance of the automatic cutting machine 20 used in the embodiment shown in FIG. The brush table 21 on which a large number of bristles are planted can be held in a state where a sheet material such as cloth is laminated on the surface thereof by vacuum suction from below. The cutting head 22 can reciprocate on the Y beam 23. The Y beam 23 is located on the brush table 21
Can reciprocate vertically along the longitudinal direction of the Y-beam 23. The longitudinal direction of the brush table 21 is the X axis, and the longitudinal direction of the Y beam 23 is the Y direction. The cutting head 22 is movable in the X direction by the movement of the Y beam 23, and is movable in the Y direction by the movement of the cutting head 22 itself on the Y beam 23. An operation unit 24 is provided at one end of the Y beam 23. The movement of the cutting head 22 is controlled by cutting data on a floppy disk inserted into the floppy disk device 25. The floppy disk device 25 stores data of parts to be cut created by a CAD device for design or the like. The dough, which is a sheet material, is supplied from the dough loading side via the air table 26. The air table 26 ejects air when supplying the dough to float the dough. The brush table 21 is formed of a horizontal surface above the conveyor loop, and conveys the supplied dough to the dough unloading side while vacuum-suctioning.

When the cloth is spread on the brush table 21, the brush table 21 stops and the cutting head 22 moves to perform cutting. When the cutting is completed, the brush table 21 starts to be conveyed again, and the cut parts are carried out in a state of being suspended by the air jetted from the air table 27 on the material discharge side. A vinyl sheet 28 is placed on the surface of the laminated fabric to ensure vacuum suction during cutting. The cutting head 22 cuts the cloth covered with the vinyl sheet 28. When cut, air leaks along the cutting line, and the sealed vinyl sheet 29 covers the cut parts in order to further ensure the holding of the fabric by vacuum suction. For safety, an emergency stop switch 30 is provided at each of the four corners of the automatic cutting machine 20.

FIG. 7 shows the internal structure of the cutting head 22 shown in FIG. Below the cutting head 22, a presser foot 31 for holding the fabric is provided. A cover 32 is provided above the presser foot 31, and a mechanism for supporting the cutting blade is housed inside the cover 32. Perforated drill 3
3 is driven by a drill motor 34 and is used for perforating. An R-axis motor 16 for angularly displacing the cutting blade is also provided in the cutting head 22.

FIG. 8 shows the structure near the presser foot 31 with the cover 32 shown in FIG. 7 removed. A fabric presser 35 is formed below the presser foot 31. A positioning pin 36 is provided upright on the upper part of the presser foot 31. The knife guide 37 guides the cutting blade along the groove 38. The grindstone 40 attached to the grindstone holder 39 grinds the cutting blade.

FIG. 9 shows a cutting state by the cutting blade 41. The cutting blade 41 is displaced up and down to the state of 41a. The R-axis motor for angular displacement is mounted on the mounting member 42. The R-axis drive pulley 43 includes an R-axis motor shaft 44.
Fixed to From the R-axis drive pulley 43, a timing belt 45 is stretched around an R-axis driven pulley 46. R
The shaft driven pulley 46 is fixed to an angular displacement mechanism of the cutting blade 41 supported by a bearing 47. The cutting blade 41 is connected to an upper and lower drive mechanism by a joint 48. The cutting blade 41 is vertically movably supported by knife guide rollers 49 and 50. The dough presser 35 below the presser foot 31 presses the plurality of doughs 51 to 59, the surfaces of which are covered with the vinyl sheet 28, from above. The fabrics 51 to 59 are stacked on the surface of the brush table 21. The brush table 21 has many bristles, and the cutting blade 4
In the part where 1 entered, the bristle escaped and the cutting blade was designated by reference numeral 4.
It is allowed to enter to the state of 1a.

FIG. 10 shows a mechanism for angularly displacing the cutting blade 41 viewed from the cutting plane line XX shown in FIG. 9, and FIG.
Presser foot 3 as viewed from cut line XI-XI shown
1 shows a mechanism for holding the cutting blade 41 on the upper side 1. Cutting blade 41
Is supported by the knife guide 31 and the guide holder 60, and is inserted into a knife hole 61 provided at the center of the presser foot 31. The cutting blade 41 is supported by knife guide rollers 49 and 50 so as to be vertically movable. However, in order for the guide rollers 49, 50 and the like to be rotatable, some "backlash" is required on the rotating shaft. The timing belt 45 also expands and contracts. These accumulations become “backlash” with respect to the rotation of the cutting blade 41.

According to this embodiment, the bending and twisting of the cutting blade,
Alternatively, the influence of “backlash” or the like due to the angular displacement direction can be corrected when cutting the curve, so that the deviation of the cutting line from the contour can be reduced.

[0022]

As described above, according to the present invention, when the angle of the cutting blade changes from one direction to the other, the absolute value of the angle of change of the cutting blade is reduced by a predetermined amount.
By making the angle to be reduced correspond to "backlash" relating to the bending, torsion, and angular displacement axis of the cutting blade, the deviation from the contour line to be cut can be reduced.

Further, according to the present invention, the control section reads out the contour shape of the part which is inputted to and stored in the contour input section, and calculates the angle of the cutting blade in accordance with the tangential direction of the contour line. When the angle of the cutting blade shifts from a state in which the angle changes in one direction to a state in which the angle changes in the other direction, the absolute value of the angle of change is corrected to be small. Even if the angle of change at the time of cutting increases due to torsion or "backlash" of the angular displacement axis, the deviation from the contour line to be cut can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic electrical configuration of a cutting device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the control means shown in FIG.

FIG. 3 is a schematic plan view showing displacement of a cutting blade.

FIG. 4 is a schematic plan view showing a cutting line for performing cutting according to the embodiment shown in FIG. 1;

FIG. 5 is a schematic plan view showing a cutting line for performing cutting according to the embodiment shown in FIG. 1;

FIG. 6 is a perspective view showing an appearance of the automatic cutting machine according to the embodiment shown in FIG. 1;

FIG. 7 is a perspective view showing an internal configuration of the cutting head 22 shown in FIG. 6;

8 is a perspective view showing a state where a cover 32 shown in FIG. 7 is removed.

9 is a cross-sectional view showing a cutting state by the cutting head 22 shown in FIG. 6;

10 is a cutting blade 4 viewed from the cutting plane line XX shown in FIG. 9;
FIG. 3 is a plan view showing a mechanism for angularly displacing 1;

FIG. 11 is a cross-sectional view taken along the line XI-XI of FIG. 9;

FIG. 12 is a plan view showing a cutting line by a conventional cutting method.

FIG. 13 is a schematic plan view showing a force acting on cutting in a cutting state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Pattern input means 12 Control means 13 X-axis motor 14 Y-axis motor 15 Z-axis air cylinder 16 R-axis motor 20 Automatic cutter 21 Brush table 22 Cutting head 25 Floppy disk device 28 Vinyl sheet 31 Presser foot 32 Cover 35 Fabric holder 37 Knife guide 38 Groove 40 Grinding stone 41 Cutting blade 45 Timing belt 49, 50 Knife guide roller 51-59 Fabric 60 Guide holder

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B26D 5/00 B23Q 5/56

Claims (2)

(57) [Claims] 1. A cutting blade having a cutting edge formed along a longitudinal direction is reciprocally displaced in a state of being pierced in a direction perpendicular to a sheet material surface, and the sheet material is cut at a contact portion with the cutting edge to be cut. In a sheet material cutting method in which the angle of the cutting blade is changed so that the cutting is performed along the contour, the angle of the cutting blade is calculated at each point on the contour to be cut,
A sheet material cutting method, wherein the calculated angle is corrected in a direction opposite to the change direction by a predetermined angle in accordance with the direction in which the angle of the cutting blade changes. 2. A cutting blade having a cutting edge formed in a longitudinal direction is reciprocated while being pierced in a direction perpendicular to a sheet material surface, and the sheet material is cut at a contact portion with the cutting edge to be cut. In a sheet material cutting apparatus for angularly displacing a cutting blade so as to perform cutting along a contour line, contour line input means for inputting and storing a contour shape of a part to be cut from the sheet material; The stored contents of the input means are read out, and at each point on the contour line to be cut, an angle representing the direction of the cutting blade is calculated, and the direction of change by a predetermined angle corresponding to the direction in which the angle of the cutting blade is changing. A sheet material cutting device, comprising: a control means for correcting the cutting direction in the opposite direction; and an angular displacement means for responding to an output from the control means and for angularly displacing the cutting blade to the corrected angle.