JPS5828424A - Taper working guide for electric discharge machine and electric discharge machining method - Google Patents

Abstract

PURPOSE:To maintain a taper angle in working a taper at a certain angle and perform high precision working, by forming an inlet of an upper guide and an outlet of a lower guide so as to have respectively the arcuate section of radius R. CONSTITUTION:An inlet of the upper guide UG and an outlet of the lower guide DG are respectively formed to have the arcuate section of radius R. This radius R is to be at least three or five times the diameter of a wire. The correction of displacement of a fulcrum based upon taper angle is carried out by obtaining the vertical distance Hc or horizontal distance Dc between fulcrums A,A' as a function of taper angle alpha and the diameter phi of wire WR.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a taper machining guide for an electric discharge machine and an electric discharge machining method using the taper machining guide.

As is well known, a wire-cut electric discharge machine is a wire electrode (hereinafter simply referred to as a wire) that is stretched between an upper guide and a lower guide, and an electrical discharge is generated between the wire and the workpiece to machine the workpiece. The work is placed on the table.
It is moved in the X and Y directions according to commands from the numerical control device according to the machining shape. In this case, if the wire is stretched in the vertical direction with respect to the table (work) K, the machining shape of the upper and lower surfaces of the workpiece will be the same, and the master guide will be aligned in the X and Y directions (U axis, V axis). The shaft is configured to be able to move KM, for example, in a direction KM perpendicular to the direction of movement of the workpiece.
If the upper guide is displaced to tilt the wire relative to the workpiece, the machining shapes of the upper and lower surfaces of the workpiece will not be the same, and so-called taper machining, in which the wire machining surface is inclined, will be performed.

Figure 1 shows a schematic diagram of a 4-axis controlled wire-cut electrical discharge machine.The workpiece WK is moved in the X and Y directions by motors MX and MY, respectively, on an X-Y table T.
It is fixed on B. On the other hand, the wire WR is the reel RL
, and is wound onto the reel RL while being stretched between the lower guide DG and the upper guide UG, and a voltage is applied by a contact electrode (not shown) so that an electric discharge occurs between the workpiece WK and the workpiece WK. In addition, the upper guide UG
is provided with a column CMK movable in the X and Y directions for motors MU and MY, respectively.
, MY, MU, MY are numerical controller NCC) drive circuit D
VX, DVY, DVU, DVVK! D drive-a. Incidentally, when the contents of the command tape TPO are read, distribution processing for each axis is performed by the distribution circuit DS. In such a wire-cut electric discharge machine, taper machining can be performed by displacing the upper guide UG in the X and Y directions and tilting the wire WR with respect to the workpiece WK.

Figure 2 is an explanatory diagram of the taper process, upper guide U.
A wire WR is stretched between G and the lower guide DG so as to be inclined at a predetermined angle with respect to the workpiece WK. Now, the lower surface PL of the work WK is set to a program shape (the upper surface QU of the work WK may be set to a program shape), and the taper angle α,
Distance H1 between upper guide UG and lower guide DG Lower guide DG
If the distance from to the lower surface of the workpiece WK is the offset amount d of the lower guide DG and the offset amount d of the upper guide UG with respect to the lower surface PLK of the workpiece, respectively, d, = h@-
α+■ ・・・・・・・・・(1) d,=H”
−α−h−−α−■ =H・−α−dl ・・・・・・・・・(2
) can be expressed as Note that d is the processing width.

Therefore, the offset amount d, depending on the movement of the workpiece.

By controlling the movement of the upper guide UG on which the wire WR is stretched so that d is constant, taper processing with a taper angle α as shown in FIG. 5 can be performed. In addition, in the figure, the dotted line and the dashed-dotted line are the upper guide UG, respectively.

This is the passage of the lower guide DG. In addition, when performing taper machining, as mentioned above, the program path on the lower or upper surface of the workpiece, the feeding speed on the wrinkle program path, the taper angle α, the distances H, h, etc. are generally commanded. The instructions are processed.

By the way, when performing taper machining with a wire-cut electric discharge machine, a circular hole die is usually used. FIG. 4 is an explanatory cross-sectional view of the circular hole die used as an upper guide UG and a lower guide DG. In the figure, CH is a circular hole, NSU is a wrinkled portion of the upper guide UG, and NSD is a wrinkled portion of the lower guide DG, all of which have an acute angle or a small radius. Well then, huh?
In an electrical discharge machine that uses circular hole dies as the upper and lower guides, the central part of the wrinkled parts NSU and NSD (
Black circle) Upper guide UG is considered as the fulcrum for changing the taper angle.
The motion is controlled by determining the amount of relative movement.

That is, the angle between the straight line connecting the two fulcrums and the workpiece is the taper angle α, and the vertical distance between the two fulcrums is the distance from the fulcrum of the H1 lower guide DG to the bottom surface of the workpiece is h, and the relative movement amount of the upper guide UG is The movement of the upper guide is controlled based on the calculated movement amount.

By the way, if the buried parts NSU and NSD of the circular hole die are machined to have an acute angle or a minute B, since the wire actually has a predetermined thickness and has a certain bending rigidity, When the taper angle α increases, the locus of the center of the wire becomes as shown by the broken line in FIG. 4, and the angle α is no longer indicated correctly. In addition, since the wire bends suddenly, the wire position fluctuates during wire feeding, making it impossible to perform high-precision machining.

From the above, the present invention provides a guide for taper machining of an electric discharge machine, which can set the taper angle to a command angle, and can perform highly accurate taper machining without changing the position of the wire while feeding the wire. The purpose is to provide a processing method.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 5 is a cross-sectional explanatory view of a guide for taper machining of an electrical discharge machine according to the present invention, and in the figure, WR is a wire, UGd is an upper guide, and DG is a lower guide. Although not shown, a workpiece is disposed between the upper guide UG and the lower guide DG. Now, each of the upper guide UG and lower guide DG has a part UGW on the side where the work is present and where the wire WR is guided.
, UGW' (upper guide), DGW, and DGW' (lower guide) are machined into circular arc shapes with a medium diameter R, and the sides UGυ and DGυ of each guide where no work is present are each formed into a circular ring shape. There is. That is, both the inlet portion of the upper guide UG and the outlet portion of the lower guide DG are formed to have an arcuate cross section (spherical shape) with a medium diameter R. Note that it is desirable that the radius be at least three times, preferably five times or more, the wire diameter. As described above, when the inlet and outlet portions of the guide are processed to have a half IIR, the problem of bending of the wire WR as in the conventional example is eliminated. In other words, the wire WR is smoothly guided inside the die and is stretched tightly, and if it becomes slack, it will not come loose.
This eliminates the disturbance of the Taber angle due to ear positional fluctuations and wire rigidity.

Now, when a guide having the structure shown in FIG. 5 is used, the actual wire fulcrums shift to point A and point A', respectively. still,
Point A and point A' are both intersection points of the straight part WRn of the wire WR and the center of the tapered part WRt. When programming with Totoro, the program path, distances H, h, and taper angle α are commanded assuming that the wire fulcrums are at the 0 point and the 07 point, respectively. Therefore, during actual machining, it is necessary to correct command data or other data based on the taper angle α.

Next, the correction method will be explained with reference to FIG.

Now, if the diameter of the wire WR is φ, the actual wire fulcrums A, A' and the programmed wire fulcrums c, c'
The distance between them is expressed as φ α L=(R+ −)tu −(1) 2 , and the substantial supporting points A and A′ move toward each other in the vertical direction. That is, the actual fulcrum A.

The -direct distance He and horizontal distance DC of A' are expressed by the following equations.

)1:6-H-2・(R+')tag'2 □
(2) DcMHc・−α φ α −(H−2・(R+7)・−■)・−α (3) Therefore, as a correction method, (A), if the distance between the 11 orthogonal supports is reached, (2 ) If we look at the method of determining He based on 2 and controlling the taper machining based on 1 kHz, and the distance between horizontal supports (CB), we can calculate the upper guide and lower guide based on 2. There is a method of correcting the moving distance of the guide. In other words, move the lower guide DG and move the upper guide UG to the right.
R+! ! −)・−1・−α Move 2 This is a method of moving.

FIG. 6 is a block diagram of the main parts of the numerical control device of the present invention which performs electric discharge machining by correcting the fulcrum distance in a straight direction. In the figure,
FTP is a paper tape with numerical control information perforated, TR is a tape league that reads information perforated on paper tape, and DEC
is a decoder that decodes information read from the paper tape FTP, REG is a register, and PAR is a parameter storage register with taper angle α, distance H between the upper guide and lower guide,
Stores the distance between the lower surface of the workpiece and the lower guide. CPS
is a correction circuit that corrects the distances H and h, the distance between the vertical supports is corrected based on (2) 2, and the distance between the lower surface of the workpiece and the lower guide is... φ α he=h-( R+7)・ta++7 (4)
Corrected based on The WCP is a well-known processing unit that executes wire-cut electrical discharge machining control. Parameters such as position data and taper angles α, H, and h are input to the WCP, and the incremental movement amount (ΔX, ΔY) of the workpiece and the incremental movement of the upper guide are input. The amount of movement (ΔU, ΔV) is calculated and output. INT is the incremental movement amount (j
Execute pulse distribution calculation (linear interpolation) based on X,, jY), (jU, jV)K to obtain distributed pulses
UP, VP generating P/L, J distribution circuit, DV
X.

DVY, DVU, and DVV are X-axis, Y-axis, U-axis, and V-axis tVV-bo control circuits, respectively, and MU, MY, MX, and MY are servo motors for each axis, respectively.

Now, when the vertical support distance H1, the distance between the lower surface of the workpiece and the lower guide, and the taper angle α are read from the paper tape FTP, these are determined by the decoder DECK.
Correction circuit CPSK is input. Correction circuit CPS is H, h
, α are inputted, they are output to the parameter storage register PAH and stored as corrections for equations (2) and (4).

Meanwhile, path data is stored in register REG. #&
The shoe part WCP performs well-known taper machining control based on the input path data and corrected parameters, etc., and calculates the incremental movement amount (ax, jY), ()U, ΔV).
is calculated and outputted from the pulse distribution circuit INTK. The pulse distributor INT has ΔX and ΔY.

Immediately after ΔU and jV are input, simultaneous 4-axis pulse distribution calculation (linear interpolation calculation) is executed, and the distribution pulses Xp and Yp are
, Up, and Vpt, respectively, t-bo control circuit DVX.

DVY, DVU, and DVV are input, and the desired taper processing is performed by rotating the tesser motors MX, MY, MU, and MY using a well-known method and moving the workpiece and upper guide.

As described above, according to the present invention, the inlet part of the upper guide and the outlet part of the lower guide are formed to have an arcuate cross-section with a radius R, and the wire is smoothly guided by resting on the spherical part, and the wire is not taut and sagging. There isn't. Therefore, the taper angle is a constant angle,
Furthermore, since the wire position does not change while the wire is running, highly accurate machining can be performed. : Also, if the guide has a radius R at the entrance or exit, the fulcrum will be displaced, but it is very easy to compensate for machining errors such as taper angle based on the displacement of this fulcrum by providing a simple correction circuit. be able to.

Although the present invention has been explained in detail above, the present invention is not limited to the embodiments and can be modified in various ways.

For example, although the outlet and inlet portions of the guide are formed to have an arcuate cross section, they are not limited to an arcuate shape and may be formed in a smooth curved shape.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a wire-cut electric discharge machine with four-axis control, Figures 2 and 3 are diagrams of taper machining, Figure 4 is a diagram of a conventional example using a circular hole die as a guide, FIG. 5 is a cross-sectional explanatory view of a taper guide according to the present invention, and FIG. 6 is a block diagram of an embodiment of the present invention. UG...upper guide, DG...lower guide, WR...
Wire, DEC...decoder, cps...correction circuit, wcp...processing section, INT...pulse distribution circuit. Patent applicant Fujitsu Fanuc Co., Ltd. Niyosha Agent Patent attorney Minoru Tsuji (2 others) 2nd No. 4121 Figure 5

Claims (3)

[Claims] (1) Machining an experimental workpiece by moving the wire electrode relative to the workpiece, and tilting one wire electrode with respect to the workpiece. Draw the machining guide K,
Cheek machining of an electrical discharge machine, characterized in that a part of the tapered machining guide on which the wire electrode is stretched, on which the work is present, is machined into a single-sided part where the wire electrode is guided. Guide for. (2) The portion that guides the wire electrode is half a liter! Patent claim osi characterized in that it is formed by processing R into a circular arc shape.
Made for electrical discharge machine O taper machining according to item s (1). (3) In an electric discharge machining method in which the wire electrode is moved relative to the workpiece and the wire electrode is tilted with respect to the workpiece, the workpiece is subjected to taper machining,
This is a device in which there is a guide work on which the wire electrode is stretched, and the part where the wire electrode is guided is formed in an arc shape, and the guide part is made into an arc shape. Klzu〈Electrical discharge machining direction characterized by being provided with a correction means for electrically correcting inclination angle errors〇