JP3288799B2 - Wire electric discharge machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire electric discharge machine.

[0002]

2. Description of the Related Art When machining an inclined surface, machining is performed by designating an inclination angle of a wire with reference to one of an upper surface and a lower surface of a work. However, since the wire has rigidity, as shown in FIG.
_{On the} other hand, the actual wire 1 has an actual inclination angle θ shown by a solid line. That is, the support point of the upper guide 2 is A, and the lower guide 3 is
When the supporting point B is assumed to be B, the wire 1 is supported by the apparent supporting point C of the upper guide 2 and the apparent supporting point D of the lower guide 3. Therefore, in Japanese Patent Publication No. 4-51285, the position of the guide is corrected using the lengths Wu and Wd of the wire 1 that can be regarded as straight lines and the distance h between the support points A and B, and the actual tilt angle θ of the wire 1 is corrected. Is set to the command inclination angle θ ₀ to improve the processing accuracy. As a result,
An inclined surface where the inclination angle of the wire 1 does not change with respect to the horizontal plane, for example, a side surface of a truncated cone whose upper surface and lower surface are similar and whose central axis is perpendicular, could be machined with high precision.
In the case of a brass wire having a diameter of 0.3 mm, the lengths Wu and Wd are about 0.6 mm, and are located inside the end 4 of the upper guide 2 and the end 5 of the lower guide 3 indicated by a two-dot chain line. I do.

[0003]

However, in the case of a workpiece whose upper surface and lower surface are not similar to each other or a workpiece whose upper surface and lower surface are similar but the center axes of the upper surface and lower surface are not perpendicular to each other, the inclination angle of the wire 1 is reduced. The above-mentioned prior art cannot be applied since the value of the conventional technology changes every moment. The object of the present invention is to solve the above-mentioned problem, and to accurately determine the inclined surface of a workpiece whose upper surface and lower surface are not similar to each other or a workpiece whose upper surface and lower surface are similar but whose center axes are not perpendicular to each other. An object of the present invention is to provide a wire electric discharge machine capable of performing good machining.

[0004]

The above-mentioned problem is solved by determining the position of the upper guide and the position of the lower guide in association with the finish machining shape specified by the machining program, and determining the position of the lower guide corresponding to the position of the upper guide. This problem can be solved by providing a controller that calculates the inclination angle of the wire from the position and corrects the inclination angle of the wire using a predetermined correction amount.

[0005]

The angle of the lower guide corresponding to the position of the upper guide and the position of the lower guide corresponding to the horizontal plane are calculated and corrected, so that the accuracy of the inclined surface is improved.

[0006]

FIG. 1 is a block diagram of a control device 6 showing an embodiment of the present invention, where MX, MY, MU and MV are X-axis and Y-axis.
Axis, U axis, and V axis servo motors. FIG. 2 is a diagram showing functions of the servo motors MX, MY, MU, MV. The servo motors MX, MY move the table 8 on which the work 7 is placed in the horizontal direction, and the servo motors MU, MV move the upper guide 2 The lower guide 3 is moved in the horizontal direction. When the coordinate positions U and V of the upper guide 2 are both 0, the wire 1 is perpendicular to the horizontal plane. The operation will be described below, taking as an example a case of processing the side surface PQRS of the work 7 whose plan view is shown in FIG. 3 and whose bird's-eye view is shown in FIG. The control device 6 has the lengths Wu and Wd corresponding to the material and diameter of the wire 1 used for processing, the wire tension and the distance h.
Is stored in advance as data. Also,
In the processing direction, the upper guide 1 changes from P to Q, and the lower guide 2 changes to R
To S. ◆ The control device 6 ◆: NC tape 11 in NC program analysis unit 12
, The finish machining shape instructed by the machining program is read, and a machining path for actually moving the wire 1 is obtained. In this embodiment, the movement path of the upper guide 2 is pq indicated by a two-dot chain line, and the movement path of the lower guide 3 is rs indicated by a two-dot chain line. ◆: vertices p and r, q at both ends in the movement position calculation unit 13
And s are made to correspond to each other, and then the position of the upper guide 2 and the position of the lower guide 3 are calculated at predetermined time intervals (for example, 10 msec) with reference to p and r. Here, the position of the lower guide 3 is a point N (X ₁ , Y ₁ ) on the line segment rs, and
The position of the upper guide 2 is at a point M (X ₁ + U ₁ , Y ₁₎ on the line segment pq.
+ V ₁ ). ◆: A line segment M in the interpolation processing unit 14 according to the following equation 1.
N. The theoretical angle of inclination with respect to the horizontal plane, ie wire 1
Obtain the tilt angle command value θ ₀ . _{◆ tanθ 0 = √ (U 1} 2 + V 1 2) / h Formula 1 ◆ where the inclination angle command value of the wire 1 theta ₀ and actual inclination angle theta
Is on the plane including the line segment MN as shown in FIG. Then, in order to make the actual inclination angle θ coincide with the inclination angle command value θ ₀ , the point C and the point D in FIG. Therefore, ◆: the position correction amounts ΔX, ΔY of the lower guide 3 and the position correction amounts ΔU, Δ of the upper guide 2 in the taper angle correction unit 15.
Find V. ◆ First, when obtaining the ΔX, ◆ ΔX = Wd · tanθ 0 · U 1 / √ (U 1 2 + V 1 2) becomes equation 2 ◆. Here, when Equation 1 is substituted into Equation 2, Equation 3 is obtained. ΔX = Wd · U ₁ / h Equation 3 Hereafter, similarly, ΔY, ΔU, and ΔV are calculated by Equations 4 to 6.
Is obtained. ΔY = Wd · V ₁ / h Equation 4 ΔU = − (Wd + Wu) · U ₁ / h Equation 5 ΔV = − (Wd + Wu) · V ₁ / h Equation 6 ◆: The servo control unit 16 Position in X direction
ΔY in X and Y directions, and position of upper guide 2 in U direction
ΔV is moved in the U and V directions. ◆: The following is repeated. In the present embodiment, the lower guide 3 is fixed, and the table 8 and the upper guide 2 are moved. Needless to say, this can also be applied.

[0007]

As described above, according to the present invention, an inclined surface of a workpiece whose upper surface and lower surface are not similar or whose central axis is not perpendicular even if the upper surface and lower surface are similar. Has the effect that it can be processed with high accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control device showing one embodiment of the present invention.

FIG. 2 is a diagram showing functions of servo motors MX, MY, MU, and MV.

FIG. 3 is a plan view of a work 7;

FIG. 4 is a bird's-eye view of the work 7;

FIG. 5 is a diagram illustrating a method of correcting a taper angle.

[Description of Signs] 1 wire 2 upper guide 3 lower guide 6 control device 7 work

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinichi Kaneko 2100 Kamiimaizumi, Ebina-shi, Kanagawa Examiner, Hitachi Seiko Co., Ltd. Kazuyuki Fukushima (56) References JP-A-61-219528 (JP, A) 1-193126 (JP, A) JP-A-60-56824 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23H 7/06 B23H 7/02

Claims (1)

(57) [Claims] 1. A position of an upper guide and a position of a lower guide are determined in correspondence with a finish processing shape instructed by a processing program, and an inclination angle of a wire is calculated from the position of the upper guide and the position of the lower guide. A wire electric discharge machine comprising a control device for correcting the inclination angle of the wire using a predetermined correction amount.