JPS6094254A - 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 concaved 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 concaved 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 is parallel to the plane in contact with the outer curved shape of the work at the second-work starting point Ps and includes the first-work completion point Pe is obtained by using the three-dimensional position data at the point Ps, the direction data of the center shaft of the tool, at the point Ps, and the position data of the point Pe. 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 point Ps is obtained. After the tool TL is shifted 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 Def> The present invention relates to a machining method for a machine tool, and in particular, a first machining is performed by moving a tool relative to a workpiece, and then the tool is moved relative to the workpiece. A big feed is performed relative to the workpiece, and after the big feed, the tool is moved relative to the workpiece in the opposite direction to the aforementioned machining direction to perform a second machining, and these machining operations and pick feed operations are repeated until 191. This is a machining method for a machine tool including a rotating shaft that performs desired machining, and relates to a machining method for a machine tool that prevents the tool from coming into contact with the workpiece during pink feed.

<Prior art> In numerically controlled machining of curved surfaces, as shown in Fig. 1, a tool T is
The first machining is performed by moving L in the direction of the arrow at cutting speed, and after the machining of the passage is completed, the next machining pass Q P is started from the end point Pa.
Big feed the tool to the starting point Pss of T2, then move the tool along the machining path P'r2 in the direction of the arrow with a cutting feed to perform the second machining, and thereafter perform the pink feed and the first machining. , second machining (reciprocating cutting type 1: l'
: Repeat step l to process the curved surface.

By the way, in numerically controlled machining of such curved surfaces, the tool T
Machining may be performed while controlling the central axis of L (the dashed dotted line in FIG. 1) to always be inclined in the normal direction of the workpiece WK or in the normal direction to the cutting direction. For you,
For example, the tool is moved in the direction of three-dimensional orthogonal axes and rotated at the same time, so that machining can be performed while the tool center axis direction exactly coincides 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 (position vector) that specifies the tool center axis direction.
B-axis, C-axis direction position or tool center axis vector).

Now, even if the movement path of the tool T L of a machine tool including the rotating axis is a straight line LN in the three dimensions of x, y, and z as shown in FIG. When the tool rotates in the C-axis direction, the path at the tip of the tool does not become a straight line, but curves as shown by the dotted line. Therefore, the first machining end point Pc
If the pick feed path from the pick feed path to the second machining start point Ps is not properly arranged, the tip of the tool will contact the workpiece at high speed during big feed, resulting in erroneous cutting or breakage of the tool.

For this reason, conventionally, a big feed path was defined so that the tip of the tool would not hit the workpiece during big feed, and the pick feed path was programmed one by one as NC data.

<Disadvantages of the Prior Art> However, in this conventional method, the shape data of the curved surface must be calculated by 81 to find the pick feed passage, so there is a drawback that the NC data of the pick feed passage is created on the west side.

<Object of the Invention> An object of the present invention is to provide a machining method for a machine tool that can easily determine a pick feed path in which a tool does not hit a workpiece during a big feed.

Another object of the present invention is to perform the first machining along the first machining path, the bin wide, and the second machining direction opposite to the first machining direction.
NC to process the curved surface by repeating JJII 1m of
Data can be easily created from data that specifies curved surfaces.
Moreover, it is an object of the present invention to provide a machining method for a machine tool that machines a curved surface using the NC data.

Another object of the present invention is to insert a big feed command into the NC program, and use the command to automatically find a pick feed path where the tool does not hit the workpiece. An object of the present invention is to provide a machining method for a machine tool in which a tool can be moved along the following directions.

<Summary of the Invention> FIG. 3 is a schematic explanatory diagram of the present invention. The present invention is a tool TL
is moved relative to the workpiece WK having a concave pink feed portion to perform the first machining along the path PTI, and then the tool is moved from the end point Pe of the first machining path to the start point Pss of the second machining path. big feed L relative to
After the big feed, the tool is moved to the second machining path PT2 in the opposite direction to the workpiece to perform the second machining, and these machining operations and the big feed operation are repeated to obtain the desired result. This is a processing method for a machine tool that has a rotating axis for processing. In the present invention, the three-dimensional position data of the machining start point Ps of the second machining, the tool center axis direction data at the machining start point, and the machining end point Pe of the first machining.
Using the position data of Intersection point P between the direct MSL in the direction of the tool center axis and the approach plane AP at the machining start point
c, move the tool from the machining end point Pe toward the intersection Pc, and then move the tool from the intersection to the machining start point P of the second machining.
Move the tool to s, pick feed f-, and then move the tool to cylinder 2.
This is the machining method for Machining III 11 in which the machining is performed.

<Embodiment> FIG. 4 is a block diagram of an embodiment of the present invention. +, t N to NC tape or memory (hereinafter referred to as NG tape) 101
C-day has been looked down on. Incidentally, the NC data indicates that the tool TL is cut along the first machining path P T 1 in FIG. It is configured to pick-feed until then, then cut in the direction of the arrow along the second machining path, and thereafter repeat the above-mentioned reciprocating cutting operation. Also, each letter #5PT1. PT2 is approximated by a polygonal line using a minute straight line, and furthermore, a big feed is instructed by an M function command (M1 port). NC data reading device 10
2 reads NC data from the NG tape +01 one block at a time and stores it in the input memory 103.

The numerical control unit 104 decodes the NC data stored in the manual memo IJ 103, and if the NC data is path data, inputs it to the pulse arrangement 105, and outputs the NC data to the machine side. If it is a command, S function command, or T function command, these are input to the machine tool 107 via the power circuit Q106, and furthermore, the NC data is the pick feed command M4 days -nt+f, and the NC data reading device 102
and next NC data (starting point data of next machining path)
have them read.

If the NC data is passage data, the numerical control unit 104 controls each axis (orthogonal coordinate axes x, y, z, vertical, horizontal rotation
* Incremental values in the s, c) directions X i, Y i
, Z i, B i, Ci. The numerical control unit 104 outputs a command linear velocity F in three-dimensional directions and incremental values Xi, Yi, and Zi in each three-dimensional axis direction.

Velocity components in each axis direction Fy, Fy using Bi and Ci.

Fz, Fb, Fc are calculated using the following formula (% formula %) (1)
Amount of movement Δx1Δ that should be moved in each axis direction during msec
Y1ΔZ, ΔB, 80 are expressed by the following formula 6 % (2 (2) (2) (2) (2) From this, these ΔX, ΔY, ΔZ, ΔB, ΔC are expressed as time Δ
It is outputted to the pulse distributor 105 every ゛l゛.

The pulse arrangement 105 performs simultaneous five-axis pulse distribution calculation based on the input data, and calculates the distribution pulse X p + Ypr.
Zp, Bp+cp are generated and output to the servo circuit of each axis to move the tool along the cutting path.

The numerical control unit 104 also updates the current position memory 10 every Δ′r seconds.
The current positions Xa, Ya, Za, Ba, Ca of 8 are calculated by the following formula: Soil ΔB−
4Ba ・ ・ (3d) Ca±ΔC→Ca ・・ (
3e) The sign of the update depends on the direction of movement), and similarly Δ′r
The remaining movement amounts Xr, Yr, Zr, Br, and Cr (initial values are Xl, 'yi, Zi, Bi, and Ci, respectively) stored in the remaining movement amount memory 109 every second are calculated as Xr- by the following formula. Δx-4xr −-+4 a) Yr-ΔY-4Yr ・・ (4b) Zr-ΔZ → Zr −・ (4c) Br-ΔB-4Br ・・ (4d) Cr-ΔG-4Cr ・ ・ (Update 4el Then, the numerical control unit 104 sets Xr=Yr=Zr=I3r=
Cr=OH-(51, NC data reading device 102
and the next NC data is not read.

On the other hand, if the pick feed command M4 is read from the NC tape 101, the numerical control unit 104 immediately starts the next block +j.
The NC data of the target is read and stored in the input memory 103. Incidentally, the NC data commanded next to the pink feed command is position data X n of the machining start point Ps of the second machining pass 9PT2.

Y n r Z n r B n + (/n), and these are stored in the human memory 103.

Thereafter, the tool center axis vector calculation unit 110 calculates the current position (tool center axis vector Va (+a, ia・ka ) and 2nd Ka2 I
- Passage 1) 'l' 2 Machining start point P s I Tool center axis vector Vn (+ n, Jn, 1cnl
is stored in the tool center axis vector memory 111. In addition, the vertical rotation direction position of the tool is C, and the horizontal rotation direction position is C.
Then, the tool center axis vector is i = 5inb-co
sc (6a IJ= 5inb°5inc (6b
It can be calculated by 1k = cosb (6c). Therefore, the tool center axis vector calculation unit 110 calculates the vertical rotational direction position (Ba, Bn) of the machining end point Pe and machining start point Ps stored in the current position memory 108 and input memory 103, and the horizontal rotational direction [(C
The tool center axis vector Va is obtained from equations (6a) to (6C) using a and Cnl.

Vn can be set.

Next, approach plane calculation [112let arch-f calculates the plane formula of the approach plane AP.

Now, the plane equation of the plane PL that is in contact with the external curve of the concave workpiece WK at the machining start point Ps (Xn, Yn, Zn) is 1n-x-t-in-y+knx=d--(7a 1
is given by However, d is d=in-Xn+1n-Yn+kn-Zn...(7b
). The general formula for the surface is given by ax+by4-cz=d, and the normal vector V of the plane 11ii P+-
This is because n is (in, in, kn), and the plane PL includes the processing start point Ps (Xn, Yn, Zn). Since the normal vector of the plane PL is Vn, equation (7Q) is derived, and the plane PL is the machining starting point P.
Since s is included, in equation (7a), x=Xn,
Equation (7b) is derived by setting y=Yn and z=Zn. Approach plane calculation unit 104 (if the plane PL is formed, find the intersection Pc'' of the plane and the perpendicular 11sL'', and determine whether the direction from the machining end point Pe to the intersection Pc' matches the direction of the tool center axis vector Va) Then, if they match, it is determined that the workpiece shape in the big feed part is convex, and processing is performed in the case of convexity.The processing for convexity will not be described in detail. If not, it is determined that the workpiece shape in the big feed part is concave,
The approach plane calculation section performs the following processing.

Now, since the approach plane AP is parallel to the plane F%L, it is expressed by 1n-x+in pipe y+knφz=d' (8a) 3 Therefore, by determining d', the plane equation of the approach plane can be determined. The approach plane AP is the machining end point Pe
(Since it includes Xa, Ya, and Zal, i n-Xa+jn Ya+kn Za=d'-(8b
l holds true, so the approach plane AP is (8al.

It is specified by equation (8a).

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 from the machining start point Ps to the intersection Pc is l, then Pc=Ps+1-Vn (9a) holds true.However, Pc and Ps are position vectors at the intersection Pc and the machining start point Ps.The intersection PC is the approach point Since it exists on the plane AP, Vnl'c=d' ・
...(9b 1 holds true. However, d' is the value obtained from equation (8b). (9nl, (QbJ from equation Vn ・(Ps-l
I Vnl = d″ ・ ・ (9c) holds true, and (9
c) Substituting 4 from equation (9a) yields the position vector Pc(Xc, Yc, lcl) of intersection point Pc. Note that l is 1 = (d - Vn - Psi /Vn
-Vn, Xc=Xn0N -1n Yc=Yn+Z + in... (9dlZc=Zn
-IJ Hkn.

The numerical control unit 104 calculates the three-dimensional coordinate value (Xc,
If Yc and Zcl are input, X c -X a→X i Y c -Y a→Y 1 Zc-Za-*Zi The three-dimensional incremental value Xi of each axis from the machining end point Pr+ to the intersection Pc is calculated using the following formula. , Yi, and Zi, and then calculate ΔX and ΔY by computing equations (1a) to (1c) and equations (2a) to (2C) in the same manner as described above.

ΔZ is determined and input to the pulse distributor 105 every ΔT seconds. Also, the numerical control unit 104 performs (3a) to () every 61 seconds.
3cl, performs calculations of equations (4a) to (4c). Then, in the numerical control section 104, Xr=Y r = Z r =
If it becomes 0, that is, if the tool reaches the intersection point Pc,
Next, Bn-Ba-+B1 Cn-○a-4Ci is calculated to calculate incremental values Bi and Ci in the vertical rotation direction and the horizontal rotation direction. After that, (1dl
~(1el, (2dl - (2Q)) is calculated to obtain ΔB and ΔC, which are sent to the pulse distributor 10 every 61 seconds.
Enter 5. Further, the numerical control unit 104 controls the speed of (3
dl~(3a).

The calculations of equations (4d) to (4e) are performed. When B r = Cr = 0, the numerical control unit 104 then calculates Xn-Xa-4Xi Yn-Ya-+Yi Zn-Za-*Z i to move from the intersection point Pc to the machining start point Ps. up to 3
Incremental values for each axis of the dimension Xi, Yi.

Calculate Zi, find Δx1ΔY1ΔZ in the same way, and convert this to 6
It is input to the pulse distributor 105 every 11 seconds.

Then, when Xr = Yr = Zr = 0, the NG data reading device 102 is made 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. Process the second passage.

Then, by repeating the operations described in section 2 above, a curved surface will finally be machined.

Incidentally, in the above example, the vertical rotation direction position B and the horizontal rotation direction position C are input from the NC tape as data for specifying the tool center axis direction.B.

Instead of C, the tool center axis vector v ('+ j+ kl
may be given. Tat! In such a case, (1a)~
(Prior to calculating the lcl formula, it is necessary to calculate the vertical and horizontal rotational direction positions 81C from the tool center axis vector using the following formula.

B=tnn ”(P stone”/k) c-=tan (J/kl Note that the tool center axis direction calculation unit 110 is no longer required f f6
(a) to (6c) are no longer necessary).

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 instruction is read from the tape,
This is a case where 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. 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 manually applied to an NC device to process the curved surface. Furthermore, the NC data for the cutting α1 passage in which the tool is moved in advance in the first machining passage, the NC data for the cutting passage in which the tool is moved in the second machining passage, and these A series of NC consisting of a pick feed command inserted between both NC data
Prepare the data and input it into the NC tape creation device,
The pick feed path is determined using the above-described method using the pink feed command to create NC data that specifies the pick feed path, the pick feed command is replaced with the NC data, and the pick feed path data is used instead of the big feed command. Re-create the NC tape containing the N
It is also possible to input the C tape into an NC device and process the curved surface. FIG. 015 is a block diagram C of an embodiment of the present invention, in which the same parts as in FIG. 4 are given the same reference numerals. The NC tape or memory 101 contains NC data specifying the tool movement along the first machining path and a second addition.
A large number of NC data are stored, each consisting of NC data specifying tool movement along eight paths and a big feed command inserted 1ζ between these image data. Note that the data for specifying the passage does not necessarily have to be NC data, and may be data for specifying the end points of each minute straight line when a curve is approximated by a polygonal line using minute straight lines, and data for specifying the tool center axis direction. .

NCC data reading device 102: Reads NC data from the NC tape 101 block by block and inputs it to the input memory 1031.
Store ζ. Note that the input memory 103 is capable of storing path data for two blocks. If the command is not a big feed command, the NC data is output directly to the NC data output device (paper tape puncher,
(magnetic tape device, etc.) 2o2, 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 memo IJ 103 is a pick fee) command, the NC tape creation processing unit 2
011.1 The NCC data reading device 102 reads the NCC deck of the next block, in other words, the three-dimensional position data Xn, Yn, Zn of the machining start point Pq of the second machining path, as well as the vertical rotation direction and horizontal rotation direction positions. Data Bn and Cn'e 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 P e of the first machining path.

Ya, Za, vertical and horizontal rotational direction positions Ba and Ca are also stored.

After that, the evaporator central axis direction calculation unit] 10 receives the calculation start signal from the NC tape creation processing unit 201 and inputs the input memo IJ.
10: Vertical rotation position Ba stored in (
Using the horizontal rotation position Ca, the current position (K2 [end point pc) of the first processing path PT1] is determined from equations (6a) to (6c).
ζζTool center axis vector Va (+ a, i 1
1. Also, the vertical rotational position r3 of the machining start point PS stored in the input memo IJ 103
Using n and horizontal rotation position Cn, (6al~(6c
) formula, the tool center axis vector V at the machining start point
″'n(in, jn, knl) and store them in the tool center axis vector memory 111.

Next, approach plane calculation unit 112, intersection calculation unit 1]
3 performs the above calculation to obtain the three-dimensional coordinate value (Xc
, Yc, Zcl Request, l If tL is N, the work shape of the pisic feed section is convex, so NC in the case of convex
The data is created, but its details (, L' are not described. On the other hand, if they do not match, it is a concave shape, and in this case, the NC tape creation processing unit 201 processes it if the three-dimensional coordinate values of the intersection point Pc are input. Positioning data from end point Pe to intersection point Pc G 01 X X c, Y Y c, Z Z c
H is created and output to the NC data output device 202.

Next, the NC tape creation processing unit 201 rotates the tool in the vertical and horizontal directions at the intersection point PC, and generates rotational direction positioning data G'0 1 BB n, C for aligning the tool center axis vector with that at the machining start point Ps.
Cn; is created and outputted to the NC data output device 202ζ.

After that, the NC tape creation processing unit 201 (positioning data for moving the tool in a straight line from the intersection point Pc to the machining start point Ps)
; and outputs it to the NC data output device 2021. At the same time, the next NC data is read by the NC data reading device 102, and the above processing is repeated based on the read NC data. From the above, the N
The C tape 203 is created here. Furthermore, N.C.
The data shall be done in Abu Norut.

The NC data stored in the NC tape 203 created by the above processing is read by the NG device 204, and the NG data is
'A i(l 204 executes NG processing based on the read NC data. In other words, after cutting off along the first machining path, a big feed is performed, and after the big feed, the cylinder 2 Cutting is performed along the machining path iQl, and thereafter the above operation is repeated to process the curved surface.

Incidentally, the circuits shown in FIGS. 4 and 5 can also be constructed using a microcomputer. In that case, the flowcharts of the processing of the processor will be as shown in FIGS. 6 and 7, respectively.

Further, the present invention can be applied when 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, and the shape of the workpiece in the big feed section is concave. .

<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 processes a curved surface by repeating a big feed and a reciprocating cutting operation of a tool, machining starts after a big feed. Plane PL that touches the workpiece at point Ps
Find an approach plane AP that is parallel to and includes the machining end point Pa before the big feed, and connect the approach plane and the machining end point P
Intersection point PC of the tool center axis vector with the straight line SL at e
After that, the big feed operation is Pe→P c −
Since the feed is carried out along the h P s path, the big feed path can be easily set, and the situation where the tool hits the workpiece during the big feed can be reliably avoided, and the stroke length of the big feed can be reduced. short,
This reduces machining time. Also, by performing the process of filling the pink feed passage described above, Pe→P c −* P
It is also possible to easily create NC data for big-feeding the tool along the path of s, and in such cases, the NC data for the pick-feed path where the tool does not hit the workpiece can be easily created.
Can create data.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the tool path when machining a curved surface by repeating pink feed 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 an illustration of the big feed section. A schematic explanatory diagram of the present invention when the curved surface shape is concave, FIG. 4 is a block diagram of an embodiment, FIG. 5 is a block diagram of another embodiment of the present invention, and FIGS. 6 and 7 are diagrams of FIGS. Processing when the circuit shown in Figure 5 is configured with a microcomputer 101... NC tape, 102... NC data reading device, 103... Input memory, 104... Numerical control section, 10
5... Pulse distributor, 106... Strong electric circuit, 107...
Machine tool, 108...Current position memory, 109...Remaining travel amount memo IJ, 110...Tool center axis vector calculation unit,
111...Tool center axis vector memory, 112...Approach plane calculation unit, 113...Intersection calculation unit 201...NG tape creation processing unit, 202...NC data output device, 203...NC tape, 204...NG Applicant for device patent FANUC Co., Ltd. Patent attorney Chiki Saito

Claims (3)

[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 in the opposite direction to the machining direction]: Move the tool to the workpiece In a machining method for a machine tool including a rotary shaft that performs a second machining by moving the rotary shaft relative to the rotating shaft and repeating these machining operations and pick-feed operations to perform a desired machining,
Using the three-dimensional position data at the machining start point Ps of the second machining and the tool center axis direction data at the machining start point, a A straight line passing through an approach plane including a machining end point Pa of the first machining and then a machining start point Ps of the second machining, wherein a straight line in the direction of the tool center axis at the machining start point and the approach plane The tool is moved from the machining end point to the intersection point Pc, and then the tool is moved from the intersection point to the machining start point of the second machining for big feed, and then the second machining is started. A machining method for a machine tool characterized by performing the following. (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 workpiece shape of the pick feed portion is concave.Claim (fl) and (t) of the claim are characterized in that the workpiece shape of the pick feed portion is concave.