JPH0356846B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method of profile milling while changing the posture of a model.

Conventionally, for example, when cutting a turbine blade,
While rotating the model, the stylus is moved back and forth to trace the surface of the model, and the workpiece is cut using a ball end mill accordingly. That is, as shown in FIG. 5, when the model 1 of a turbine blade is held by the shaft 2 and rotated around the shaft 2 while the stylus 3 is reciprocated, the posture of the stylus 3 with respect to the model 1 is as shown in A to F. Depending on the various changes, a ball end mill (not shown) cuts the workpiece in the same posture as the stylus 3. In postures A, B, D, and E, the ball end mill corresponding to the stylus 3 will perform machining with its tip, and in postures C and F, machining will occur with the side of the ball end mill. In this method, the ball end mill processes the workpiece at various positions from the tip to the side, and cutting conditions cannot be properly controlled. In other words, when cutting with the tip of the ball end mill and cutting with the side, if the rotational speed of the ball end mill is held constant, the cutting edge moves at different speeds, which inevitably results in inappropriate cutting conditions. . Also,
If you use both the side and head of a ball end mill, the workpiece will vibrate in thin walled areas, causing vibrations.
Effective cutting is not performed. Moreover, since the outer diameter of the end mill is worn down to the side, when the end mill is reground, the diameter becomes smaller, creating a dimensional difference between the end mill and the stylus, which has the disadvantage that machining accuracy of the workpiece cannot be maintained.

This invention was made in order to eliminate these conventional drawbacks, and allows machining to be performed using only the tip of the ball end mill, thereby ensuring that cutting conditions are always appropriate. This enables highly efficient profile milling.

That is, in profile milling in which a workpiece is machined with a ball end mill along the movement trajectory of a tracer, the workpiece and model are held so that their posture can be changed, and the stylus of the tracer is configured to be rotatable around its axis. At the same time, a sensor is provided to detect whether the tracing surface is an ascending surface or a descending surface in the direction of travel of the stylus, and the stylus is reciprocated along the model surface with the sensor of the stylus always facing the direction of travel of the stylus.
The attitude of the workpiece and the model is changed in a direction in which the tracing surface of the stylus approaches a horizontal surface based on the signal from the sensor.

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a model 1 is held rotatably about an axis 2, and a stylus 4 is configured to reciprocate along its surface. Stylus 4
As shown in FIGS. 2 and 3, a sensor 5 is provided at the tip, and this sensor 5 is held rotatably around a shaft 50 in a groove 6, and a lead wire 7 is connected to the sensor 5. The rotation angle around the axis 50 is detected by a control device (not shown). That is, the contact surface of the stylus 1 is the horizontal surface 1.
When moving from the horizontal surface 11 to the inclined surface 12, the sensor 5 rotates counterclockwise, and the signal is sent to the control device to detect the inclination angle and direction of the inclined surface 12, and when moving from the horizontal surface 11 to the inclined surface 13. The sensor 5 rotates clockwise to detect its tilt angle and direction, and the posture of the model and workpiece is changed based on this signal as described later.

When the stylus 4 moves back and forth, the sensor 5 always
The stylus 4 is rotated 180° about its axis when switching between forward and return travel so that it faces forward.

Next, a method for performing profile milling using the stylus 4 will be explained with reference to FIG. 4. First, as shown in FIG. 1, the model 1 is rotated around its axis 2 while the stylus 4 is reciprocated to trace the surface of the model 1 at a constant fine pitch, and the corresponding workpiece (not shown) is also model 1. The workpiece is cut into the shape of the model 1 using a ball end mill (not shown) which has the same shape and the same movement as the stylus 4. In FIG. 4A, the stylus 4 is moved from the side of the model 1 in the direction of the arrow and brought into contact with the L side end of the model 1 at position P. In this state, the stylus 4 is on an uphill slope, so the sensor 5 is detected and a signal is sent to the control device, which causes the model 1 and the workpiece to rotate clockwise. As a result, the stylus 1 comes into contact with a horizontal surface, and as the model 1 moves further in the direction of the arrow, the model 1 is rotated counterclockwise by the control device because it becomes a downhill slope at the Q position. In Fig. 4B, when moving from the P position to the Q position, the stylus 4 gradually rises uphill.
The control device rotates the model 1 clockwise so that the stylus always contacts the horizontal surface, and when it reaches the R side end of the model 1 as shown in Fig. 4C, the curvature of the contact surface of the stylus 4 is reversed. To do this, the model 1 is rotated counterclockwise, and when it reaches the end as shown in D, the stylus 4 leaves the model 1 and moves to its side, rotating 180° around the axis at the end of the outward path. Move on to the return trip with sensor 5 facing forward.

When the stylus 4 leaves the surface of the model 1, the model 1 rotates so that the convex surface faces upward, and the control of the model 1 by the control device is also switched by the rotation of the stylus 4. That is, on the outbound trip, when the sensor 5 detected an uphill slope, the model 1 was rotated clockwise, but on the return trip, when the uphill slope was detected, the model 1 rotated.
so that it rotates counterclockwise. Figure 4E
When the stylus 4 comes into contact with the L side end and detects the angle and direction of inclination of the surface as shown in FIG. From the state to the H state, trace and cut to the R side end, leave the model 1 and rotate 180° at the end of the return path,
The state shown in FIG. 4A is again achieved. Thereafter, similar operations are repeated to perform profile milling on the entire surface as shown in Fig. 1.Although the above embodiments have only shown the machining of turbine blades, the present invention can be similarly applied to the machining of other objects. In addition to being able to detect only the front of the stylus in the direction of travel, the sensor can also detect objects diagonally in front of the stylus in the direction of travel. A semicircular sensor may also be provided. Further, in the above method, since only the tip of the ball end mill is used, it is preferable to use a ball end mill with a so-called spiral blade shape, which has excellent cutting performance.

As explained above, in this invention, the stylus is equipped with a sensor to detect the contact surface, and by adjusting the posture of the model, machining can always be performed using the tip of the ball end mill. The conditions can always be set optimally, the cutting edge only needs to be polished at the tip, the re-grinding procedure is simple, and the dimensional relationship between the end mill and stylus can be maintained over a long period of time. be.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a stylus and model used in carrying out the present invention, Fig. 2 is an enlarged perspective view of the tip of the stylus, Fig. 3 is a cross-sectional view thereof, and Fig. 4
Figures A to H are explanatory views showing the profiling state of the stylus, and Fig. 5 is an explanatory view showing the conventional profiling milling method. 1...Model, 2...Rotation axis, 4...Stylus, 5...Sensor.

Claims (1)

[Claims] 1 In profile milling, in which the workpiece is machined with a ball end mill along the movement trajectory of the tracer, the workpiece and model are held so that their posture can be changed,
The stylus of the tracer is configured to be rotatable around its axis, and is equipped with a sensor that detects whether the tracing surface is an ascending surface or a descending surface in the direction in which the stylus is traveling. A profile milling method characterized in that the stylus is reciprocated along the model surface, and the attitude of the workpiece and model is changed in a direction in which the profile surface of the stylus approaches a horizontal surface based on a signal from the sensor.