JP3047766B2 - Cutting plotter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting plotter for cutting out characters and figures from paper or vinyl sheet, and more particularly to a curve processing function of the cutting plotter.

[0002]

2. Description of the Related Art There is known a cutting plotter in which a cutter tool having a cutter blade rotatably mounted in a XY direction on a cutter holder is mounted on a cutter head. In this type of cutter tool, the tip of the cutter blade is offset with respect to the center of rotation of the cutter blade, and the cutter blade rotates according to the movement of the cutter head of the cutting plotter in the XY directions. A material such as a vinyl sheet is cut in the head moving direction.

In the above-described cutter tool, since the tip of the cutter blade is offset, the offset amount causes a position error on the XY coordinates at the start point and end point of the line segment, the connection between the straight line and the curve, and the like. become. Therefore, a cutting plotter using this kind of cutting tool has a function of correcting cutting data based on the offset amount of the cutting tool. In general, a curve part in the cutting data is used to control a cutter head by calculating a Bezier curve by a Bezier calculation algorithm.

[0004] Figure 4 shows an example of a curve processing by cutting plotter as described above, the broken line represents a Bezier curve C ₁ obtained by Bezier operation, the solid line with the cutting result C ₂ are shown. First, the cutter head is moved so that the axis of the cutter tool is located at coordinates (Xb ₀ , Yb ₀ ) displaced along the tangent to the starting point (X ₀ , Y ₀ ) of the Bezier curve and equal to the offset amount of the cutter blade. After that, the cutter blades land. Subsequently, starting points (X ₀ , Y ₀ ) and two control points (X
_{1, Y 1) (X 2} , Y 2), moves the axis of the cutter tool to Bezier curve C ₁ above on the basis of the Bezier curve data consisting of four coordinates of the end point (X _3, Y _3), Bezier Curve C
_The cutter head is driven along ₁ and ends at a point (Xb ₃ , Yb ₃ ) advanced by an offset amount on a tangent to the end point (X ₃ , Y ₃ ). Since the tip during curve cutting the cutter blade is going to follow the inside of the trajectory of the axis, a problem that a Bezier curve C ₁ as a target, as shown in the figures and the cutting line C ₂ does not perfectly match the Occurs.

Further, in order to eliminate the above-mentioned error, correction coordinates displaced by the same amount as the offset amount of the cutter blade are obtained on a tangent line to the coordinates of each division point obtained by the Bezier operation, and along the line connecting the correction coordinates. There is also known a cutting plotter configured to match a target curve with a cutting result by moving an axis of a cutter tool.

[0006] Figure 5 shows a curve processing of cutting plotter, correction coordinates for each division point of the Bezier curve C ₁ (Xbt, Ybt) is obtained, the axis of the cutter tool on correction Bezier curve C ₃ move, tip of the cutter blade and the cutting line C ₂ moving on the Bezier curve C ₁ is a target and Bezier curve C ₁ coincide.

[0007]

In the conventional cutting plotter, which corrects the offset of the cutter blade only at the starting point and the ending point of the curve, an error occurs in the cutting position with respect to the target curve. On the other hand, the one that performs the offset correction calculation on each of the division points of the Bezier curve has a disadvantage that the processing speed is reduced due to an increase in the amount of calculation, although an accurate cutting result is obtained.

Therefore, there arises a technical problem to be solved in order to improve the performance of the cutting plotter by simultaneously improving the cutting accuracy and the processing speed, and the present invention solves the above problem. With the goal.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in order to achieve the above-mentioned object, and a cutter blade is rotatably supported by a cutter holder, and the cutter blade is rotatable with respect to the center of rotation of the cutter blade. A cutting plotter in which a cutter tool having a pointed end offset is attached to a cutter head for use, wherein the Bezier curve data comprising coordinates of a starting point, two control points, and an ending point of a curve and Bezier curve data and division coefficient data are used. In a cutting plotter provided with a Bezier operation unit that calculates coordinates of each division point by an operation algorithm, a coordinate and a tangent are obtained for a starting point and an ending point of a Bezier curve and at least two arbitrary points between the starting point and the ending point. Calculating correction coordinates displaced from each of the points on each of the tangent lines to be equal to the offset amount of the tip of the cutter blade, and A correction operation function for back-calculating Bezier curve data including a starting point, two control points, and an end point based on a Bezier curve connecting coordinates is provided, and a curve cutting process is performed using the Bezier curve data calculated by the correction operation function. The present invention proposes a cutting plotter configured as described above.

[0010]

The correction operation function of the Bezier operation unit of the cutting plotter according to the present invention calculates the starting and ending points of the Bezier curve and the coordinates of any two points from the inputted Bezier curve data.
Correction coordinates displaced on the tangent line of the four points on the Bezier curve by the same amount as the offset amount are obtained. Then, based on the corrected coordinates, the Bezier curve data of the correction curve offset from the Bezier curve based on the input data is obtained, and the cutting tool is controlled based on the corrected Bezier curve data. Therefore, the cutting position is offset-corrected over the entire area of the Bezier curve, and the inputted Bezier curve data and the cutting result match.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIGS. FIG. 1 shows a circuit block of a cutting plotter, in which cutting data is input to a cutting control device 4 from a keyboard attachment 1 via an interface 2 and an output control device 3. The cutting control device 4 is composed of a buffer memory, a CPU, a ROM, a RAM, and other peripheral processing devices, develops input character and graphic data into vector data, and outputs the vector data to the cutting device 5 through the input / output control device 3. I do. The cutting control device 4 is provided with a Bezier operation unit 6 for calculating curve data by Bezier operation, and the Bezier operation unit 6 is further provided with a correction operation function 7.

The cutting device 5 includes drive circuits 8, 9, 10 in three directions of XYZ and an X-axis drive motor 11, Y
It has a shaft drive motor 12 and a Z-axis drive electromagnetic actuator 13, and performs cutting by driving the cutter head in the Y and Z directions while feeding the cutting material in the X direction.
As described above, a cutter tool in which the cutter blade is rotatable about the Z axis as a rotation center and the tip of the cutter blade is offset from the rotation center is attached to the cutter head.

Next, the Bezier operation function and the correction operation function will be described with reference to the flowchart of FIG. 2 and the explanatory diagram of FIG. First, when processing Bezier curve data during input data processing, the Bezier calculation function and the correction calculation function are activated (step 101), and the starting point (X ₀ , Y ₀ ) and the two control points (X ₁ , Y ₁₎ . _{1) (X 2, Y 2} ), the end point (X _3, Y ₃₎
Are read (step 102).

In the Bezier operation of the first stage, the division coefficient t is t = 0 and t = 1 and any two of 0 <t <1 so that the coordinates of at least two points can be obtained in addition to the start point and the end point.
The points (t _n1 , t _n2 ) are set so as to select a total of four points and perform Bezier operation, and the XY coordinates of the four points are obtained.

First, t = 0 is set (step 10).
3), starting point coordinates (X
a ₀ , Ya ₀ ) is obtained (step 104). (Equation 1) X (t) = X 0 (1-t) 3 + X 1 · 3t (1-t) 2 + X 2 · 3t 2 (1-t) + X 3 t 3 Y (t) = Y 0 (1 _{^{-t) 3 + Y 1 · 3t}} (1-t) 2 + Y 2 · 3t 2 (1-t) + Y 3 t 3 and increments the t to t is 1 (step 105
106), the above calculation routine 104 is executed four times, and the XY coordinates (Xa ₀ , Ya ₀ ) (Xa ₁ , Ya ₁ ) (Xa ₂ ,
Ya ₂ ) (Xa ₃ , Ya ₃ ).

Next, the Bezier curve C expressed by the above four points
The respective tangent lines dt of the four points in ₁ are calculated (step 10).
7), corrected coordinates (Xb ₀ , Yb ₀ ) displaced on each tangent dt equal to the known offset amount of the tip of the cutter blade
(Xb _1, Yb ₁₎ seek _{(Xb 2, Yb 2) (} Xb 3, Yb 3) ( step 108).

Subsequently, the starting point (Xc ₀ , Yc ₀ ), the control points (Xc ₁ , Yc ₁ ) (Xc ₂ , Yc ₂ ), and the ending point (Xc ₃ ) of the Bezier curve C ₃ passing through the above-mentioned correction coordinates by the Bezier calculation function. , Yc ₃ ) (step 109).

Hereinafter, the Bezier calculated in step 109 will be described.
Curve C_ThreeBezier curve data (Xc₀, Yc₀) (Xc₁, Y
c₁) (Xc_Two, Yc_Two) (Xc_Three, Yc_Three) And the division factor t
The normal Bezier operation routine (step 110)
Executed and corrected Bezier curve C _ThreeThe coordinates of each division point are calculated
Is done. The calculated coordinate data is stored in the cutting controller
4 (step 111), and stores the curve data
The process ends (step 112).

The correction coordinate data from the cutting control unit 4 to the cutting device 5 are sequentially outputted at the time of cutting run, the axis of the cutter tool, by moving the upper correction Bezier curve C ₃ shown in FIG. 3, the tip of the cutter blade parts are moved on Bezier curve C ₁ by the input data, a result of the cutting result and the input data C ₂ and the match is obtained.

[0020]

According to the present invention, as described in detail in the above-described embodiment, when calculating the corrected Bezier curve data for eliminating the offset error caused by the offset amount between the rotation center of the cutter blade and the pointed end. Next, four points of the Bezier curve are obtained from the input data. Then, the corrected coordinates obtained by offset-correcting the coordinates of the obtained four points are obtained, the corrected Bezier curve data passing through the corrected coordinates is back-calculated, and the Bezier operation is performed on the corrected Bezier curve data to obtain an offset error over the entire length of the curve. Is eliminated.

Accordingly, the offset correction processing only involves an increase in the number of calculation processings for obtaining four corrected coordinates and back-calculating the Bezier curve data. The tangents are obtained for all the division points of the Bezier curve, and the offset amount is further calculated. The same correction result as that of the conventional cutting plotter that calculates the corrected coordinates that has been corrected is obtained, and the amount of calculation is greatly reduced as compared with the conventional cutting plotter, so the processing speed is increased and the performance of the cutting plotter is improved. Can contribute to

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a cutting plotter according to an embodiment of the present invention.

FIG. 2 is a flowchart of a curve process of the cutting plotter shown in FIG. 1;

FIG. 3 is an explanatory diagram of curve processing of the cutting plotter shown in FIG. 1;

FIG. 4 is an explanatory diagram of curve processing of a conventional cutting plotter.

FIG. 5 is an explanatory diagram of curve processing of a conventional cutting plotter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Keyboard device 2 Interface 3 I / O control device 4 Cutting control device 5 Cutting device 6 Bezier calculation part 7 Correction calculation function

Claims (1)

(57) [Claims] 1. A cutting plotter in which a cutter blade is rotatably supported by a cutter holder, and a cutter tool in which a tip end of the cutter blade is offset with respect to a rotation center of the cutter blade is mounted on a cutter head and used. A cutting plotter provided with a Bezier operation unit for calculating the coordinates of each division point by a Bezier operation algorithm from Bezier curve data including the coordinates of the starting point, two control points and the end point of the curve and the division coefficient data. The starting point and the end point of the Bezier curve, and the coordinates and tangents of at least two points between the starting point and the ending point are obtained, and the offset amount of the tip of the cutter blade from each point on each tangent line is equal to the offset amount. A Bezier curve having a starting point, two control points, and an end point is obtained based on a Bezier curve connecting the corrected coordinates. A cutting plotter, comprising a correction operation function for back-calculating line data, and executing a curve cutting process using Bezier curve data calculated by the correction operation function.