Boots – shoes – and leggings
Patent
1987-03-17
1988-08-16
Smith, Jerry
Boots, shoes, and leggings
364170, 318572, B23Q 1500, G05B 1900
Patent
active
047648775
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a surface cutting method and, more particularly, to a surface cutting method for cutting a surface within an area bounded by a closed curve by moving a tool along a cutting path to cut the surface within the area, thenceforth moving the tool along an adjacent cutting path, obtained by a shift of a predetermined amount, to cut the surface, and repeating these surface cutting operations.
BACKGROUND ART
A form of numerically controlled machining is one in which there is an area bounded by a closed curve, wherein surface cutting is applied to a portion (convex portion) projecting from an area on the outer side of the closed curve.
Such an area cutting (surface cutting) method includes the following steps:
(a) inputting data specifying a closed curve CCL of an area AR shown in FIG. 6, cutting direction (direction of arrow A) along cutting path PT.sub.i (i=1, 2, . . . ), shift direction (direction of arrow B) in which a tool TL is shifted by a predetermined amount of cut-in whenever surface cutting along the cutting path PT.sub.i ends, and cut-in amount P;
(b) generating the cutting path PT.sub.i on the basis of the inputted data;
(c) performing cutting by moving the tool along the cutting path PT.sub.i from a cutting starting point P.sub.i to a cutting end point Q.sub.i on the generated cutting path PT.sub.i ;
(d) obtaining the next cutting path PT.sub.i+1, which results when the tool is shifted by the amount of cut-in P following the end of cutting along the preceding cutting path;
(e) thereafter performing cutting (unidirectional cutting) by moving the tool from point P.sub.i+1 to point Q.sub.i+1, in which point P.sub.i+1 is taken as the cutting starting point of cutting path PT.sub.i+1 and point Q.sub.i+1 is taken as the cutting end point of cutting path PT.sub.i+1, or performing cutting (back-and-forth cutting) by moving the tool from point Q.sub.i+1 to point P.sub.i+1, in which point Q.sub.i+1 is taken as the cutting starting point of cutting path PT.sub.i+1 and point P.sub.i+1 is taken as the cutting end point of cutting path PT.sub.i +1 ; and
(f) repeating the unidirectional or back-and-forth cutting operation from this point onward to surface-cut the area AR.
In the conventional surface cutting method, the positions of the cutting starting point and cutting end point of each cutting path PTi are set appropriately. This results in a long tool pass, namely in a lengthy period of time during which surface cutting is not carried out. Consequently, machining efficiency is poor.
In addition, since the actual cut-in amount P is decided appropriately in the prior art, the amount of cut-in is too small and results in a large number of cutting strokes (cutting paths) and diminished cutting efficiency, or the amount of cut-in may be non-uniform (e.g. the last cut-in being very small in comparison with the others).
Accordingly, an object of the present invention is to provide a surface cutting method through which tool pass can be shortened, the number of cutting strokes reduced and the amount of cut-in made uniform.
DISCLOSURE OF THE INVENTION
The present invention relates to a surface cutting method for cutting a surface within an area bounded by a predetermined closed curve by moving a tool along a cutting path in a predetermined direction to cut the surface within the area, thenceforth moving the tool along an adjacent cutting path, obtained by a shift of a predetermined amount, to cut the surface, and repeating these surface cutting operations.
The surface cutting method includes obtaining an offset curve offset by a predetermined amount to the outer side of the closed curve, obtaining width W, in a shift direction, of the area bounded by the offset curve, finding, from among lengths of line segments obtained by dividing the width W into n equal parts, a length closest to a predetermined maximum cut-in amount without exceeding the same, adopting this length as an actual cut-in amount P, and performing surface cutting by shifting the tool by the cut-in amount P i
REFERENCES:
patent: 4621959 (1986-11-01), Kishi et al.
patent: 4706200 (1987-11-01), Kishi et al.
patent: 4706201 (1987-11-01), Kishi et al.
Onishi Yasushi
Tanaka Kunio
Fanuc Ltd.
MacDonald Allen
Smith Jerry
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