Method and apparatus for controlling orientation of tools
AssigneeToshiba Kikai Kabushiki Kaisha
InventorsTakao Manabe, Shoichi Shin, Hitoshi Ebata
Life of this patent
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Abstract
When cutting a groove of a predetermined contour through a plate shaped workpiece with a fret saw blade, various program data regarding the direction of movements of the fret saw blade and the contour of the groove to be cut are stored in a memory device. The fret saw blade is moved in a direction instructed by the memory device and the orientation of the saw blade is controlled at the starting point of each segment of the groove.
Claims3
Apparatus for forming a discontinuous groove through a die board, said groove being adapted to be embedded with cutting blades for punching a pattern, comprising:
- a fret saw machine including a drill, and a fret saw blade and a table supporting said die board, means for moving said table in X and Y directions of rectangular coordinates with respect to said drill and said fret saw blade, means for controlling an orientation of said fret saw blade;
- a numerical control means for applying instructions for varying an orientation of said fret saw and movement of said table during machining of said groove;
- said numerical control means comprising:
- (1) memory means for storing a present orientation .sup..theta. ABS of said fret saw blade measured from a reference direction,
- (2) means for successively supplying program data G.sub.1, XL and YL (where G.sub.1 represents a code meaning a straight line interpolation, and XL and YL rectangular coordinates of an end point of a linear movement), and G.sub.2 (or G.sub.3), XL, YL, I and J (where G.sub.2 and G.sub.3 represent codes meaning clockwise and counter-clockwise arcuate interpolations respectively, XL and YL have the same meaning as above defined, and I and J represent increments from centers of arcuate movements in clockwise and counter-clockwise directions respectively with reference to starting points or said arcuate movements) for moving said fret saw blade relative to said die board with reference to a segment portion of a groove to be cut,
- (3) means for changing an orientation of said blade in a tangential direction according to data given by said program data at a starting point of a new segment through which a hole for inserting said fret saw blade has already been formed,
- (4) means for confirming the fact that said present orientation coincides with an orientation instructed by said memory means,
- (5) means for starting a cutting operation by moving said fret saw blade relative to said die board after said confirmation,
- (6) means for storing a switch back length (.DELTA.L) determined by a width (SW) of said fret saw blade given from program data with reference to informations regarding said tools.
A method of forming a groove including a straight portion and an arcuate portion through a die board, said groove being adapted to be embedded with cutting blades for punching a pattern by using a numerically controlled fret saw machine including a drill, a fret saw blade, a table for supporting said die board, and means for moving said table in X and Y directions of rectangular coordinates with respect to said drill and said fret saw blade, said method comprising the steps of:
- forming openings with said drill near one end of the straight and arcuate portions of said groove;
- inserting said fret saw blade into said openings for cutting said straight and arcuate portions of said groove;
- effecting a switch back operation at a portion of said groove where the orientation of said fret saw blade is changed, and
- determining the orientation of said fret saw blade before the same is inserted into said opening according to the following steps:
- (a) predetermining G.sub.1, XL, YL for a linear movement, G.sub.2, XL, YL, I, J, or G.sub.3, XL, YL, I, J for an arcuate movement of said fret saw blade as program data for relatively moving said fret saw blade with respect to said die board, where G.sub.1 represents a code meaning a straight line interpolation
- (b) judging whether given data relates to a straight line segment (G.sub.1) or an arcuate segment (G.sub.2) or (G.sub.3),
- (c) storing data XL and YL in buffer registers (XBUF) and (YBUF) respectively where the result of jugment of said step (b) shows a straight line segment and storing data I and J in said buffer registers (XBUF) and (YBUF) respectively where the results show an arcuate movement,
- (d) comparing the absolute values of the contents of said buffer registers (XBUF) and (YBUF),
- (e) calculating an angle.theta.=tan.sup.-1 .vertline..alpha..vertline. when .vertline.XBUF.vertline..gtoreq..vertline.YBUF.vertline., where ##EQU8## and XBUF and YBUF represent the contents of the buffer registers (XBUF) and (YBUF) respectively,
- (f) calculating an angle .theta.=tan.sup.-1 .vertline..alpha..vertline. when .vertline.XBUF.vertline.<.vertline.YBUF.vertline. where ##EQU9## (g) judging whether the signs of XBUF and YBUF are one of the combinations (+, +), (+, -), (-, +) and (-, -) or not, provided that + sign includes zero,
- (h) combining the results of steps (d) and (g) to add to .theta..sub.ABS one of .pi./2+.theta., 2/3.pi.-.theta., (.pi./2) -.theta., (3/2).pi.+.theta., .theta.,.pi.-.theta.and 22.pi.-.theta. as the value of .theta..sub.ABS in accordance with the result of said combination, thus determining an angle of orientation of said tool, and
- (i) where an arc is judged as a result of step (b), judging whether working is made in the clockwise (G.sub.2) or counter-clockwise direction CG.sub.3), and when G.sub.2 is judged, subtracting .pi./2 from .theta..sub.ABS given by step (h) to determine a new .theta..sub.ABS, whereas when G.sub.3 is judged, adding .pi./2 to .theta..sub.ABS to form an another new .theta..sub.ABS.
Dependencies are inferred from the claim text.