JPH06206112A - Working for large-sized runner vane blade surface - Google Patents

Abstract

(57) [Summary] [Purpose] To machine large-sized runner vane blade surfaces smoothly and quickly by a simultaneous 3-axis machine tool. [Structure] Using a simultaneous 3-axis control machine, a process of fixing an object to be processed to the center of rotation of the rotary table or a position eccentric from the center of rotation by a processing jig, and dividing the blade surface into a plurality of processing ranges for processing Runner vane baseline and X for each range
The process of setting the machining angle formed by the axis and the tool path corresponding to the machining angle, and fixing the runner vane to the rotary table at the angle to be machined, and machining the predetermined machining range with the simultaneous 3-axis control machine tool According to the process, the blade surface of the runner vane can be processed smoothly and quickly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a large runner vane blade surface of a Kaplan turbine or a valve turbine.

[0002]

2. Description of the Related Art Conventionally, there is one that performs simultaneous three-axis control. Three
Simultaneous three-axis control machining with a machining object with a dimensional curved surface fixed to the machining table so that the machining surface is horizontal or vertical, and with one machining posture and a cutting rotary axis in the horizontal or vertical direction. Depending on the machine, a processing method using a cutting tool such as a ball end mill having cutting blades arranged in a semicircular shape is used.

FIG. 6 shows a curved surface NC by a front milling cutter.
It is a perspective view showing a control axis of processing. The cutter is attached to the Z axis, and if the three axes of the X axis, the Y axis, and the Z axis, the A axis that is the rotation axis around the X axis, and the C axis that is the rotation axis around the Z axis are included, the cutter becomes five axes. . 5 is a face milling cutter, and 8 is an NC horizontal boring machine. FIG. 7 is a view showing a processing state by a simultaneous three-axis control machine tool, (A) is a perspective view showing a processing direction of a front milling cutter, (B) is a sectional view taken along line BB of (A),
(C) is CC sectional drawing of (A). In FIG. 7A, the cutter 5 moves in the Z axis direction while rotating, and the table moves in the X axis and Y axis directions. In FIG. 7B, the cutter center coincides with the Z axis regardless of the normal direction of the surface of the workpiece. In FIG. 7C, since a wavy cutter mark remains on the flat surface of the workpiece, the surface was polished with a grinder after machining.

FIG. 8 is a view showing a processing state by a simultaneous 5-axis control machine tool, (A) is a view showing a processing direction of a front milling cutter, (B) is a sectional view taken along line BB of (A), and (C). 8A is a sectional view taken along line CC of FIG. In FIG. 8A, the cutter 5 moves in the Z-axis direction while rotating, and the table moves in the X-axis direction.
Move in the axis and Y-axis directions. At that time, the cutter 5 has an A-axis rotating in the X-axis direction and a C-axis rotating in the Z-axis direction.
Therefore, the angle between the milling cutter center and the normal to the workpiece is always constant, and the processing conditions are almost constant. In FIG. 8C, the surface after the cutter processing is smooth.

[0005]

[Problems to be Solved by the Invention]

(1) Problem of Improving Cutting Efficiency A ball end mill type cutting tool that is commonly used in simultaneous three-axis control machining is generally used, and it is impossible to have many cutting edges because of its structure. Therefore, cutting blade 1
It is impossible to increase the cutting speed per sheet, the rotation speed of the machining axis limited by the cutting load applied to each cutting blade, and the cutting tool feed rate. The ball end mill type cutting tool has a problem that the cutting efficiency is low as compared with a milling type cutting tool which has many cutting blades and can increase the cutting tool feed rate. For simultaneous multi-axis (more than 3 axes) controlled machining, use of a milling type machining tool that has more cutting edges than ball end mill type machining tools and has higher machining efficiency than ball end mill type machining tools Is possible. However, in machine tools capable of simultaneous multi-axis control, the number of bearings and drive devices that support the cutting rotary shaft and the number of bearings and drive devices that support the tartary table that fixes the workpiece increase. Therefore, when trying to obtain the same cutting capacity, cutting amount, and cutting accuracy as those of a simultaneous 3-axis machine tool with simultaneous multi-axis control,
Since the rigidity of the machine tool itself is increased, the machine tool becomes complicated, large-scale, and expensive. Further, in a simultaneous multi-axis control machine tool having the same scale and price as the simultaneous three-axis control machine tool, the cutting ability is reduced. Therefore, when the same cutting tool is used and the same workpiece is subjected to simultaneous 3-axis control machining and simultaneous multi-axis control machining, the latter has a lower machining efficiency with respect to the scale of the machine tool than the former. In the conventional technology, machining with a three-axis controlled machine tool cannot increase the feed rate in the machining direction, and the size of the tool cannot be increased. Furthermore, since the cutter mark has a wavy shape, the machined surface must be smoothed by a grinder after machining. On the other hand, in multi-axis control, the milling cutter has a large number of blades and can increase the feed rate. Even if the processing pitch is made rough, the processed surface is smooth. However, since the number of control shafts increases, the machine becomes expensive and the rigidity of the machine decreases.

(2) Problems in Control When performing simultaneous multi-axis control including simultaneous 3-axis control of a machine tool, a numerical sequence for determining a tool path corresponding to the number of axes requiring control is created and controlled. . When a three-dimensional free-form surface is to be processed, the number sequence is large, so generally a number sequence is created by a program based on an algorithm that creates a control number sequence using a computer. Generally, as the number of control axes increases, the algorithm becomes more complicated, and it takes much time to obtain the numerical sequence. Therefore, there is a problem that the number of simultaneous control axes must be reduced and the number of control sequences must be reduced as much as possible.

An object of the present invention is to provide a machining method capable of smoothly and quickly machining a large-sized runner vane blade surface with a simultaneous three-axis control machine tool.

[0008]

[Means for Solving the Problem] The machining axis is X in the horizontal direction.
The three sides of the axis, the vertical Y-axis, and the Z-axis of the main shaft feeding direction are numerically controlled at the same time, and a horizontal boring machine equipped with a rotary table that can rotate in the horizontal plane by numerical control allows the cutting teeth to be cylindrical. In the machining method of the large runner vane blade surface, which processes the three-dimensional curved surface of the large runner vane using the milling type cutting tool arranged in the shape,
The process of fixing the object to be processed to the center of rotation of the rotary table or a position eccentric from the center of rotation with a processing jig, and (b) dividing the blade surface into a plurality of processing ranges based on the shape of the designed blade surface. A step of setting a machining angle formed by the runner vane reference line and the X-axis corresponding to each machining range, and a tool path corresponding to each machining angle,
(C) A step of rotating the rotary table for each of the set machining angles to fix the workpiece to the rotary table at the angle to be machined, and machining a predetermined machining range by the simultaneous three-axis control machine tool, , To achieve the above objective.

[0009]

In the present invention, the runner vane is fixed to the center of rotation of the rotary table when the object to be machined is symmetrical with respect to the axis of the runner vane, and the runner vane is fixed to the rotary table when the object to be machined is asymmetric with respect to the axis of the runner vane. It is fixed to the rotary table while being eccentric from the center of rotation. In addition, the blade surface is divided into multiple machining ranges, and each machining path is defined by the machining angle that corresponds to each machining range and the angle between the rotary table and the milling cutter spindle is changed. Since processing is performed by a 3-axis control processing machine, the working time can be greatly shortened compared to the conventional grinder work.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view of an NC horizontal boring machine as a simultaneous three-axis control machine tool used in the method for machining a large runner vane blade surface of the present invention. Horizontal X axis, vertical Y
It has three axes, the Z axis, which is the direction in which the shaft and the main spindle 4 are extended,
The cutter is attached to the shaft, the work piece is placed on the rotary table, and the rotary table is rotated around the B axis parallel to the Y axis to determine the angle between the X axis of the rotary table and the runner vane reference line. Fix it. FIG. 2 is a perspective view showing a state in which runner vanes are fixed to the NC horizontal boring machine of FIG. FIG. 3 is a front view showing a state in which a runner vane to be processed by a processing jig is fixed to a rotary table. A runner vane 6 to be machined is fixed to the rotary table 1 by a machining jig 7. FIG. 4 is a view on arrow IV in FIG. In FIG. 4, the center 6 a of the shaft of the runner vane 6 is the center of rotation 1 of the rotary table 1.
It is fixed by being displaced from a.

Next, the processing method will be described. (A) When the runner vane 6 which is the object to be machined is symmetrical with respect to the axis of the runner vane, the runner vane 6 is fixed to the rotation center 1a of the rotary table. When the object to be machined is asymmetric with respect to the axis of the runner vane, the runner vane 6 is rotated. The table is fixed to the rotary table 1 while being eccentric from the rotation center 1a of the table. (B) Create a plurality of machining areas based on the designed blade surface shape. At that time, in order to optimize the contact angle between the blade edge of the milling cutter and the runner blade surface, a plurality of angles, for example, +5, between the X axis of the rotary table and the runner vane reference line.
Set five machining angles of °, -2.5 °, -23 °, +2.5 °, and +10 °, and set the tool path for each machining angle. FIG. 5 is a diagram showing a machining range and a tool path according to an embodiment when the machining angle φ formed by the X axis of the rotary table and the runner vane reference line in the machining method of the present invention is + 5 °, and (A) shows the runner vane. View from above, (B) is a view from the direction of B in (A), (C) is (A)
It is a C direction arrow view of. In FIG. 5, a vertical arrow 9
Indicates the tool path of the tool center of the milling cutter. The range of this arrow 9 is the working range at an angle (working angle) of 5 ° between the runner vane reference line and the X axis. (C) Similarly, the processing angle φ formed by the X axis of the rotary table and the runner vane reference line is −2.5 °, −23 °,
Machining the machining range defined for + 2.5 ° and + 10 °. (D) Remove the processed runner vanes from the horizontal boring machine and grind the surface of the runner vanes smoothly with a grinder.

[0012]

According to the present invention, when the finisher machining of the runner vane blade surface is performed by the simultaneous three-axis control machine tool and the cutter mark is removed by the grinder after the blade surface machining, the blade surface machining by this method and The total time required for finishing grinder work can be reduced by about 35% as compared with the conventional whole surface grinder finishing time.

[Brief description of drawings]

FIG. 1 is a perspective view of an NC horizontal boring machine as a simultaneous three-axis control machine tool used in the machining method of the present invention.

FIG. 2 is a perspective view showing a state where runner vanes are fixed to the NC horizontal boring machine of FIG.

FIG. 3 is a front view showing a state in which a runner vane is attached to a rotary table by a processing jig.

4 is a view on arrow IV in FIG.

FIG. 5 is a diagram showing a machining range and a tool path according to an embodiment when the machining angle is 5 ° in the machining method of the present invention,
(A) is a view seen from above the runner vane, (B) is a view in the direction B of (A), and (C) is a view in the direction C of (A).

FIG. 6 is a diagram showing a control axis of a front milling cutter.

7A and 7B are views showing a processing state by a simultaneous three-axis control machine tool, FIG. 7A is a perspective view showing a processing direction of a front milling cutter, FIG. 7B is a view in the direction B of FIG. FIG. 7A is a view from the direction of the arrow C in FIG.

8A and 8B are views showing a processing state by a simultaneous 5-axis control machine tool, in which FIG. 8A is a perspective view showing a processing direction of a front milling cutter, FIG. 8B is a view in the direction B of FIG. FIG. 7A is a view from the direction of the arrow C in FIG.

[Explanation of symbols]

 1 Rotary Table 1a Center of Rotary Table 2 X Axis 3 Y Axis 4 Spindle 5 Front Milling Cutter 6 Runner Vane 8 NC Horizontal Boring Machine as Simultaneous 3 Axis Control Machine Tool 9 Tool Path

Claims (1)

[Claims] 1. A machining axis is a horizontal X-axis and a vertical Y-axis.
A milling machine in which the cutting blades are arranged in a cylindrical shape by a horizontal boring machine equipped with a rotary table that can be numerically controlled simultaneously in three directions consisting of the Z-axis, which is the axis of rotation of the shaft and the main shaft, and can be rotated in the horizontal plane by numerical control. In a method of machining a large runner vane blade surface for machining a three-dimensional curved surface of a large runner vane using a shape cutting tool, (a) an object to be machined is eccentric from a rotation center of the rotary table by a processing jig. (B) Divide the blade surface into a plurality of machining areas based on the shape of the designed blade surface, and perform machining between the runner vane reference line and the X-axis corresponding to each machining area. The step of setting the angle and the tool path corresponding to each processing angle, and (c) the rotary table is rotated for each of the set processing angles to add the angle to be processed. To secure the object to the rotary table, the step of processing the processing a predetermined range by the simultaneous 3-axis control machine tool, a processing method of large runner vane blade surface, characterized in that it consists of.