JPS6094253A - Working by machine tool - Google Patents

Abstract

PURPOSE:To permit the automatic preparation of the data with which a tool does not contact with a workpiece in case of pick feed by using the NC data for working a convex surface through the repetition of the first work along a working passage, pick feed, and the second work in the reverse direction to that of the first work. CONSTITUTION:In working, a workpiece WK having a convex pick-feed part is applied with the first work along a passage PT1 by a tool TL, and then an approach flat surface AP which contacts with the workpiece WK at the second-work starting point Ps by using the three-dimensional position data of the point Ps and the direction data of the center shaft of the tool at the point Ps. The crossing point Pc between the above-described flat surface AP and the straight line SL in the direction of the center shaft of the tool which passes through the first-work completion point Pe is obtained by using the three-dimensional position data at the point Pe and the direction data of the center shaft of the tool at the point Pe. After the tool TL is advanced towards the crossing point Pc, the tool is pick-fed towards the second-work starting point Ps, and then transferred along a passage PT2, and then the second work is applied.

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a machining method for a machine tool, and in particular to a method in which a first machining is performed by moving a tool relative to a workpiece, and then the tool is tweeded relative to the workpiece. , a machine tool including a rotating shaft that performs a second machining by moving the tool relative to the workpiece in a direction opposite to the machining direction after the pick feed, and repeats these machining operations and the pick feed operation to perform the desired machining. The present invention relates to a machine-machine processing method that prevents a tool from coming into contact with a workpiece during pick-feeding. <Prior art> In numerically controlled machining of curved surfaces, the first machining is performed by moving the tool TL in the direction of the arrow at a cutting speed along a predetermined path PTI on the workpiece WK, as shown in FIG. After completing machining of the passage, pick feed the tool from the end point Pe to the start point Ps of the next machining passage M8PT2, and then move the tool along the machining passage FI8P T'' 2 in the direction of the arrow with the cutting feed to feed the second machining passage. After that, the curved surface is processed by repeating the second big feed and the first and second processing (reciprocating cutting). By the way, in numerically controlled machining of such curved surfaces, the center axis of the tool TL (1-dot chain S in Figure 1) is always at an inclination angle from the normal direction to the workpiece WK or from the normal direction to the cutting direction. It is necessary to control the process so that it has the following properties. Therefore, in the machine tool area, for example, the tool can be moved in the direction of three-dimensional orthogonal axes and rotated at the same time, so that machining can be performed while always aligning the tool center axis direction with the normal direction of the workpiece. The NC data that specifies the passage includes position data (position vector) that specifies the tool tip position and tool center axis direction data (B axis,
The first position in the C-axis direction includes the tool center axis vector). Now, as shown in Fig. 2, the moving path of the tool TL of the machine tool including the rotation axis is a straight line IIL in the three dimensions of x, y, and z.
Even if it is N, if the tool rotates in the B-axis and C-axis directions at the same time as the linear movement, the path at the tip of the tool will not be a straight line but will be shown as a dotted line. Therefore, if the pick feed path from the first machining end point Pe to the second machining start point Ps is not properly created, the tip of the tool will contact the workpiece at high speed during big feed, resulting in incorrect cutting or The tool will break. For this reason, conventionally, a pick feed path was defined so that the tip of the tool would not hit the workpiece during pink feeding, and the pick feed path was programmed one by one as NC data. <Disadvantages of the Prior Art> However, this conventional method has the disadvantage that it is troublesome to create NC data for the pick-feed passage. <Object of the Invention> The object of the present invention is to provide a machining method for a machine tool area that can easily determine a pick feed path in which the tool does not hit the workpiece without processing the curved surface itself during big feed. be. Another object of the present invention is to perform a first process in a first process path, a pick feed, and a second process in the opposite direction to the first process path.
The NC data for machining a curved surface by repeating the machining of
It can be easily created from data specifying a curved surface, and the corresponding N
It is an object of the present invention to provide a machining method in the machine tool area for machining curved surfaces using C data. Another object of the present invention is to insert a pick feed command into an NC program, and to automatically create a pick feed path where the tool does not hit the workpiece and has a short stroke length. An object of the present invention is to provide a processing method for a machine tool that can move a tool along the determined pick feed path. T.L.
is moved relative to the workpiece WK in which the pick feed portion is convex to perform the first machining with the path PTI fixed, and then the tool is moved from the end point Pa of the first machining path to the start point Ps of the second machining path. Pick feed relative to the workpiece,
After the pick feed, the tool moves in the second machining path PT2 in the opposite direction to the machining direction to perform the second machining, and the desired machining is performed by repeating these machining operations and the pick feed operation. This is a processing method for a machine tool that has a rotating axis. In the present invention, the three-dimensional position data of the machining start point Ps of the second machining and the tool center axis direction data at the machining start point are used to estimate the approximate plane ifi'iAP that is in contact with the workpiece WK at the machining start point. , Also, using the three-dimensional position data of the machining end point Pa of the first machining and the tool center axis direction data at the machining end point, a straight line Sl- passing through the machining end point and in the direction of the complete tool rotation is determined. Find the intersection point Pc between and the approach plane AP, move the tool toward the intersection, move the tool from the intersection to the second machining start point, pick feed, and then execute the second machining. . <Embodiment> FIG. 4 1 is a block diagram of an embodiment of the present invention. NC tape or memory

[Hereafter referred to as NC tape] 101 has an NC tape.
Data is stored. In addition, the NC data is for tool T.
L is milled along the first machining path PTI in Fig. 3 in the direction of the arrow at the end point Pe, and then pick-feeded from the end point Pe to the machining start point Ps of the second machining path PT2.
After that, cutting is performed in the direction of the arrow along the second processing path,
The structure is such that the above-mentioned reciprocating cutting operation is repeated thereafter. In addition, each passage PTI, PT2 is approximated by a polygonal line using minute straight lines, and furthermore, a pick feed is indicated by the MPJ function command (M4th). NC data reading device w102ba1
NC data is read from the NG tape 101 block by block and stored in the input memory 103. The numerical control unit 104 inputs the N stored in the input memo 'J103.
Decode the C data, and if the NC data is path data, input it to the Iios (pulse distribution), and if the NC data is M function command, S function command, or T function command to be output to the machine side. These are processed via the strong electric circuit 106.
33tJ1.107, and if the NC data is big feed command M4th, the NC data reading device 10
2 to read the next NC data (starting point data of the next machining path). Then, if NCt-Y is the passage data, the numerical control unit 104 calculates the incremental values Xi, Yi, Zi,
Bi, billing melody. Numerical control unit 104 (command linear velocity F in three-dimensional direction and incremental values Xi, Yi, Zi in each three-dimensional axis direction. Using Bi, ci, velocity component in each axis direction F Mr F
WrFZ, Fb, and Fc are calculated using the following formula % formula % (1) (1 (from 1, then predetermined) time Δ]
Movement amount Δx1 to be moved in each axis direction during 6 msec
ΔY1ΔZ, ΔB, 80 from the following formula 6 % (2) (2) (2 (2) (2) These ΔX, ΔY, ΔZ, ΔB, ΔC can be expressed as time Δ
It outputs to the pulse distribution type 105 every T. The pulse distribution type 105 performs simultaneous five-axis pulse distribution calculation based on the input signal and generates the distribution pulse Xp. Y P r Z P r Bpr CP is generated and output to a servo circuit (not shown) for each axis to move the tool along the cutting path. The numerical control unit 104 also stores the current position memory 108 every ΔT seconds.
The current positions Xa, Ya, Zn, Ba, Ca are calculated using the following formula: (3d) Ca±ΔC→Ca (3e) The updated sign depends on the moving direction), and similarly the remaining moving amount X stored in the remaining moving amount memory 109 every ΔT seconds
r, Yr, Zr, Br, Cr (initial value is Xi
, Yi, Zi, Bi, Cil by the following formula: 4dlCr-Δ
C−+Cr −・(Update 4el. Then′(, Numerical control unit 104 calculates Xr=Yr=Zr=Br=Cr=
0...(If it is 51, the NC data reading device 10
2 and performs pulse distribution processing or other processing based on the next NC data that is read in advance. On the other hand, when the pick feed command M4 is read from the NC tape 101, the numerical control unit 104 immediately causes the next block of NC data to be read and stored in the input memory 103. Note that the N command following the pick feed command
C data is position data Xn of the machining start point Ps of the second machining path PT2. Yn, Zn, Bn, On, these are input memory 1
It is stored in 03. Thereafter, the tool center axis vector calculation unit 110 calculates the tool center axis vector Va (+a, ja , ka) and the tool center axis vector Vn (+n, Jn, knl) at the machining start point Ps of the second machining path P i' 2 are stored in the tool center axis vector memory 111. If the horizontal rotational direction position is C, then the tool center axis vector: yoi = sint cosc (6a 14
= 5inb-sinc (6b)k = cos
It can be calculated by b (6c). Therefore, the tool center axis vector calculation unit 110 calculates the vertical rotational direction position (Ba, Bnl), horizontal rotational direction position (C
a, Cn)) and the tool center axis vector Va from equations (6a) to (6C). I can be proud of myself. Next, the approach plane calculation unit 112 inputs the input memory 10
3-dimensional position data (Xn, Yn, Zn) of the machining start point Ps stored in 3 and tool center axis vector memory 1
Using the tool center axis vector Vn (+n, in.kn) at the position stored in 11, the work W
Find the plane equation of the approach plane AP (Fig. 3) that is in contact with K. Now, the general formula of the plane is ax+by-1-cz=d, and the normal vector i of the flat plane is Iln+In+kn
), so 1n1x+1n-y-1-kn-z=d-1 (7al holds true. Therefore, d in the above equation is determined by the it+f plane equation. Now, from the approach plane AP+, the machining start point Ps
(A force including Xn, Yn, Znl) and 1n-
Xn+1n-Yn+kn"Zn=d (7b) holds, so the approach plane AP is (7al, ・(7b)
Be specified by the formula. Thereafter, the intersection calculation unit 113 calculates the three-dimensional position coordinates of the intersection Pc between the approach plane AP and the straight line SL. Now,
If the distance σ) from the machining end point PC to the intersection point Fc is -, then Fc-H-iJ-n (8a 1 holds true.However, pc, , 5-% is the position vector at the intersection Pc and the machining end point Pe← Since the intersection point Pc exists on the approach plane AP, VnPc=d...(8bl) is established. However, d is the value obtained from equation (7b). (8a) , (From the Sb1 formula, Vn・(Pe+j−V
al=d HH(8c) holds, and from equation (8C), l
By substituting 4 into equation (8a), the position vector PcfXc, Yc, Zc) of the intersection Pc can be determined. In addition, l is 1-
(d-Vn-Pa) /Vn·Va, and becomes. The numerical control unit 104 calculates the three-dimensional coordinate value (X c
r Y c + Zc ) is input, the machining start point P
The direction from e to the intersection Pc is the tool center axis vector Va
It is determined whether the direction matches the direction of , and if it matches, the shape of the workpiece in the big feed section is convex, so the following processing is performed. If they do not match, it means that the workpiece shape in the big feed section is concave, and therefore, a process is performed in the case of a concave shape, but this process will not be explained. Now, if the workpiece shape in the big feed section is convex, the numerical control unit 104 calculates the distance from the machining end point Pe to the intersection point Pc using the following formula: Calculate the incremental values Xi, Yi, and Zi of each three-dimensional axis, and then calculate ΔX, ΔY, ΔZ by calculating (1al ~ (1cl), (2a) ~ (2C) in the same way as above, and calculate this as follows. It is input to the pulse distributor 105 every 61 seconds.
04 is (3a)~(3cl, (4al~() every Δ'r seconds)
4c) is performed. Then, the numerical control unit 104
If r = Y r = Z r = 0, that is, if the tool reaches the intersection Pc, then calculate Bn-Bi-*B1 Cn-Ca-*C4 to determine the vertical rotation direction and horizontal rotation direction. Incremental values Bi and Ci are calculated. After that, (1dl
-C1e), (2jl -(2e) and calculate ΔB
, ΔC are input to the pulse distributor 105 every 61 seconds. Also, the numerical control unit 104 outputs (3dl) every 61 seconds.
-(3e) and (4d) to (4e) are performed. Then, when Br=Cr=0, the numerical control unit 104 next calculates Incremental values of each axis in three dimensions X i , Y i . Calculate Zi, similarly find Δx1ΔY, ΔZ, and convert this to 6
It is input to the pulse distribution N105 every second. Then, when Xr=Yr=Zr=0, the NCC data purchase 102 is performed to read the NC data of the next block, and thereafter the tool is moved along the second machining path based on the NC data. Performs two-path processing. Then, by repeating the above operations, a curved surface is finally processed. Incidentally, in the above description, the data for specifying the tool center axis direction is input from the vertical rotation direction position B and the horizontal rotation direction position C1e from the NC tape, but B. Instead of C, the tool center axis vector v (1+ it k)
may be given. However, in such cases (1a) to (
Prior to calculating equation 1e), it is necessary to calculate the vertical and horizontal rotational direction positions 81C from the tool center axis vector using the following equation. B = j a n −' (r/k IC=tan
”(i/kl In addition, the tool center axis vector calculation unit 110 becomes unnecessary ((
6al to (6C) become unnecessary). Also, in the above, a pick feed command is inserted in the NG program, and the NC is executed after machining along the first machining path is completed.
When the big feed command is read from the tape, the big feed path is automatically set, the tool is moved along the big feed path, and then machining is performed along the second machining path. be. However, the present invention is not limited to such a case. For example, input data specifying a curved surface and data instructing big feed, create NC data for specifying a cutting path using the curved surface data, and use the data instructing pick feed to create a pick feed path using the method described above. It is also possible to create a configuration in which NC data is created to obtain an NC tape, and the NC tape is input to an NC device to process the curved surface. Furthermore, NC data for the cutting path that moves the tool along the first machining path, NC data for the cutting path that moves the tool along the second machining path, and NG data are inserted between these two NG data. Prepare a series of NC data consisting of pick feed commands,
This is input to the NC tape creation device, the big feed path is determined by the method described above using the big feed command, NC data for specifying the big feed path is created, and the NC
It is also possible to replace the big feed command with data, thereby re-creating an NC tape that includes big feed path data instead of the big feed command, and inputting the NC tape to the 9NG device to process the curved surface. Ru. FIG. 5 is a block diagram of an embodiment of the present invention,
The same parts as in FIG. 4 are given the same reference numerals. The NC tape or memory 101 contains NC data for specifying tool movement along the first machining path, NC data for specifying tool movement along the second machining path, and a big feed command inserted between these data. A large number of NC data are stored. Note that the data specifying the passage is not necessarily NC.
It does not have to be data, and may be position data that specifies the end point of each minute straight line when a curve is approximated by a polygonal line using minute straight lines, and data that specifies the direction of the tool center axis. The NC data reading device 102 reads NC data one block at a time from the NC tape [0] and stores it in the input memory 103. It should be noted that the manual memory 103 is capable of storing two blocks of path data. The NC tape creation processing unit 2o1 determines whether or not the current block of NC data stored in the input memory 103 is a big feed command, and if it is not a big feed command, the NC data is directly transferred to the NC data output device (paper tape pan). Ya,
(magnetic tape device, etc.) 202, and then causes the NC data reading device 102 to read the next NC data. On the other hand, if the NC data stored in the input memory 103 is a big feed command, the NC tape creation processing unit 201 uses the NC data reading device 102 to read the NC data of the next block, in other words, the processing start point of the second processing path. Three-dimensional position data Xn, Yn, Zn and vertical rotation direction and horizontal rotation direction position data Bn, Cn of Ps are read and stored in the input memory 103. Note that the input memory 103 contains three-dimensional position data Xa of the machining end point Pe of the first machining path. Yn, Za, vertical and horizontal rotation directions 11iBa and Ca are also stored. Thereafter, the tool center axis vector calculation unit 110 receives a calculation start signal from the NC tape creation processing unit 201 to set the vertical rotation position stored in the input memory 103 +3 n
, the current position (the machining end point P e of the first machining path PTI) is determined from (6B) to (6c) using the horizontal rotation position Ca.
Tool center axis vector Va (in, ja, k
al, and using the vertical rotational position Bn and horizontal rotational position Cn of the machining start point Ps stored in the input memo IJ 103 for Mr. Kero tool center axis vector -〇. jn and knl, and store them in the tool center axis vector memory 111. Next, the intersection plane M calculation unit 1 and the intersection calculation unit 1
13 performs the above calculation to obtain the three-dimensional coordinate value (X
c, Yc, and Zcl, and send them to the NC tape creation processing section 2.
Enter 01. When the three-dimensional coordinate values of the intersection point Pc are input, the NC tape creation processing unit 201 determines whether the direction from the machining end point Pe to the intersection point Pc matches the direction of the tool center axis vector 731, and if they match. Positioning data from Pe to Pe G OI X X c, Y Y c, Z Z (!
; is created and output to the NC data output device 202. If they do not match, the workpiece shape at the big feed section is concave, and NC data will be created in the case of a concave shape.
I will not explain this. Next, the NC tape creation processing unit 201 rotates the tool in the vertical and horizontal directions at the intersection point Pc, and sets the tool center axis vector to the machining start point Ps.
The rotational direction positioning data G OI BB n, C (, n; is generated to match that at the intersection point P
Positioning data for linear movement from c to machining start point Ps G OI X X n, Y Y n, Z Z n;
is created and output to the NC data output device 202, and at the same time, the next NC data is read by the NC data reading device 102, and the above processing is performed based on the read NC data.
P return. As described above, an NG tape 203 for processing a curved surface has been created from 1ζ. It is assumed that the NC data is created in absolute form. The NC data stored in the NG tape 203 created by the above processing (read by the NC device 204,
The device 204 executes NC processing based on the read NC data. That is, after cutting along the first machining path, pick feed is performed, and after big feed, the second
Cutting is performed along the machining path, and thereafter the above operation is repeated to process the curved surface. Incidentally, the circuits shown in FIGS. 4 and 5 can also be implemented as an IM using a microcomputer. In that case, the flowcharts of the process are shown in FIGS. 6 and 7, respectively. Further, in the present invention, the internal value of the tool center axis vector at the end point of the first machining path and the start point of the second machining path is positive,
Moreover, it can be applied when the workpiece shape of the pick feed section is convex. <Effects of the Invention> As explained above, according to the present invention, in a machining method for a machine tool including a rotary axis that machining a curved surface by repeating reciprocating cutting operations between a pink fill and a tool, machining starts after pick feeding. Find an approach plane AP that contacts the workpiece at a point Ps, find an intersection point Pc between the approach plane and a line 11sL in the direction of the tool center axis at a machining end point Pe,
After that, the pick feed operation is Pe→P c −P s
(Since the pick feed is carried out along the path D, the pick feed path can be easily set, and the situation where the tool hits the workpiece during pick feed can be reliably avoided, and the curved surface shape itself can be processed in the case of B. There is no need. Also, perform the process of filling the pick feed passage described above.
-4p c4P It is also possible to easily create NC data for pick-feeding a tool along the path, and in this case, it is possible to create NC data for a pick-feed path where the tool does not hit the workpiece.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the tool path when performing 'y + II + 1lii machining by repeating big fill and reciprocating cutting operations, Figure 2 is an explanatory diagram of the trajectory of the tool tip when it includes a rotating axis, and Figure 3 is Outline of the present invention when the curved surface shape of the big feed portion is convex 8AtyJ, FIG. 4 is a block diagram of an embodiment of the present invention in 1, FIG. 5 is a block diagram of another embodiment of the present invention, and FIG.
v! J and Figure 7 1. 1iliI in Figures 4 and 5
2 is a flowchart of processing when the computer is configured with a microcomputer. 101=Nc tape, 102...NCy-'1 reading device, 103...input memory, 104...numeric control section, 10
5...pulse distributor, 106...strong electric circuit, ]+07...
Machine tool, 108...Current position memory, 109...Remaining travel amount memory, 110...Tool center axis flat 1-roll calculation unit,
111...Tool center axis vector memory, 112...Approach plane calculation unit, +13...Intersection point calculation unit 201...NC tape creation processing unit, 202...NC data output device, 203=NCf-p, 204...NG Device

Claims (4)

[Claims] (1) Perform the first machining by moving the tool relatively to the workpiece, then pick-feed the tool relatively to the workpiece, and after big feed, move the tool to the workpiece in the opposite direction to the machining direction. In a machining method for a machine tool including a rotary shaft that moves to perform a second machining and repeats these machining operations and pick-feed operations to perform a desired machining, three-dimensional position data at a machining start point of the second machining. and the tool center axis direction data at the machining start point to determine the approach plane that contacts the workpiece at the second machining start point, and also calculate the three-dimensional position data of the machining end point of the first machining and the tool center axis direction data at the machining start point. Using the tool center axis direction data at the machining end point, find the intersection of a straight line passing through the machining end point and in the tool center axis direction and the approach plane, move the tool toward the intersection, and then 2nd point from the intersection
A machining method for a machine tool, characterized in that the tool is moved to a machining start point, big-feeded, and then the second machining is executed. (2) path data for the first and second processing;
2. A machining method for a machine tool according to claim 1, wherein NC data is created from the obtained pick feed path data and the workpiece is machined in accordance with the NC data. (3) The method for machining a machine tool as set forth in claim (1) or (2), wherein the workpiece shape in the pick feed portion is convex. (4) The machining method for reducing the workpiece Fa as set forth in claim (1) or (2), characterized by (B) generating a pick feed passage by a pick feed command.