JPH11277372A - Working method for work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent decrease in roundness due to actual working, particularly, in working precision at an approaching part and a releasing part by finishing the working by an up-cutting work such that the relative motion direction of a work and a tool is reverse to the rotating direction of the tool when the work is made apart from the tool. SOLUTION: A work 21 is set to a table of a machine tool, and a tool 20 is rotated clockwise. Next, with respect to the relative position of the work 21 and the tool 20, the work 21 and the tool 20 are moved to a height position (a) to enable a circular arc to be worked promptly in the tangential line direction of the circular arc to be desired upon finishing the circular arc working. Further, the table is moved until the tool 20 reaches a position b as an approaching operation. After that, the table is moved so that a start point and an end point are set to the position (b) and a circular arc interpolation is executed by diameter of the circular arc to be finished. Finally, the table is moved until the tool 20 reaches a position (c) as a releasing operation. As described above, in the case of circular arc working, the working precision upon up-cutting work is always improved.

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 workpiece with a tool, and more particularly to a method including a curve processing.

[0002]

2. Description of the Related Art Conventionally, when a work is machined by a machine tool, as shown in FIG. 5A of Japanese Patent Application Laid-Open No. 9-11020, the relative movement direction A and rotation direction B of the work 21 and the tool 20 are changed. It is common sense to perform a down cut process in which the same direction is applied. In the up-cut processing in which the relative movement direction A and the rotation direction B of the workpiece 21 and the tool 20 are opposite to each other, the cutting of the tool 20 into the workpiece 21 gradually increases from 0 as shown in FIG. This is because, when trying to perform high-speed machining, the bite of the cutting edge is inevitably deteriorated, and the blade is liable to slip on the machined surface due to upper sliding.

[0003] Therefore, even when processing an arc shape (pin, pin hole, etc.), processing has been performed by down-cut processing.

On the other hand, the processing accuracy (roundness in the case of circular interpolation) when processing a work is basically controlled by a numerical controller for controlling the movement of a table on which the work is mounted or a column having a spindle. (NC) performance (circular interpolation accuracy).

[0005]

However, in the above-described down-cut processing, the NC performance (circular interpolation accuracy)
However, even if the workpiece shape was improved, the workpiece processed into an arc shape could not obtain the processing accuracy (roundness) that made full use of the NC performance (circular interpolation accuracy). In other words, when measuring the processing accuracy (roundness) of the workpiece, the roundness is determined by the performance of the NC (circular interpolation accuracy) due to various effects due to actual machining.
It will be much worse compared to his ability. In particular, there is a problem in that the approach in which the tool starts machining on the workpiece and the machining accuracy of the workpiece in a release portion where the workpiece and the tool are separated deteriorate.

The present invention has been made in order to solve the above-mentioned problems, and processes a workpiece which can prevent a reduction in processing accuracy in roundness in actual processing, particularly in an approach and a release portion. It is intended to provide a way.

[0007]

According to a first aspect of the present invention, there is provided a method of processing a workpiece, comprising: performing a processing including a curve on the workpiece by a relative motion between the workpiece and a tool. Then, when the workpiece and the tool are separated from each other, the up-cut processing in which the relative movement direction between the workpiece and the tool and the rotation direction of the tool are opposite to each other is finished.

Therefore, when the workpiece and the tool are separated from each other, the workpiece is processed by the up-cut processing, so that the processing accuracy can be increased as is apparent from the data shown in Table 1 described later.

According to a second aspect of the present invention, when the workpiece comes into contact with the tool, the direction of relative movement between the workpiece and the tool and the direction of rotation of the tool are opposite. May be started with the up-cut processing.

In this case, the machining can be performed without changing the rotation direction of the tool for performing the up-cutting at the end of the machining.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A work processing method according to an embodiment of the present invention will be described below with reference to the drawings.

First, a mechanical configuration of a machine tool 10 according to the present embodiment will be described with reference to FIGS.

As shown in FIG. 1, the machine tool 10 includes:
Splash guard 12 to prevent scattering of cutting chips
A table 14 for mounting a work (not shown), an ATC magazine 16 for exchanging tools such as drills and taps, a machine tool main body (hereinafter also simply referred to as a main body) 20 and the like are arranged inside. I have. In addition, the splash guard 12 is provided with an operation panel 22, a work exchange port 24 for entering and exiting and maintaining a work, and an inspection hatch 26 mainly for maintenance. The operation panel 22 includes a state switch 23 for switching an operation mode of the main body 20, a liquid crystal display 25 for displaying an operation state and the like, and a ten-key panel for inputting a processing program for operating the main body 20 and the like. 27 etc. are provided.

As shown in FIG. 2, the main body 20 includes a main shaft 28 for holding a tool such as a drill and a tap, a main shaft motor 30 for driving the main shaft 28 to rotate, and a large number of hard balls. A ball screw mechanism 36 including a nut 32 fixed to the main shaft side and a ball screw 34 inserted in the nut 32, a Z-axis motor 38 for rotating and driving the ball screw 34, and a ball screw 34 are disposed in parallel with the ball screw 34. And a slide 42 for connecting the guide rail 40 to the main shaft. Note that the Z-axis motor 38 corresponds to a drive motor for the feed shaft.

In the main body 20, a Z-axis feed mechanism for feeding in the Z-axis direction is constituted by the ball screw mechanism 36 and the Z-axis motor 38. The Z-axis motor 38 rotates the ball screw 34 to rotate the main shaft 28. The movement in the Z-axis direction is performed. The table 14 shown in FIG. 1 can be moved in the X-axis and Y-axis directions, and the relative position of the workpiece and the tool in the X, Y, and Z-axis directions can be changed in conjunction with the movement of the main shaft 28 in the Z-axis direction. Can be done.

Next, the case of performing arc machining as a method of machining a workpiece including a curve according to the present invention will be described with reference to FIG.

FIG. 3 is a top view showing a state where the work 21 is placed on the table 14.

First, the tool 20 for cutting the work held on the main shaft 28 shown in FIG. 2 is rotated in the cw direction. Next, the relative position of the work 21 and the tool 20 is
The table 14 and the tool 20 are moved so as to be at a position a which is a tangential direction of the arc to be finished and the height at which the machining can be performed immediately. Further, the work 21 is used as an approach operation.
The table 14 is moved until the tool 20 reaches the position b. Then, the table 14 is moved so that the start point and the end point are set to the position b and the circular interpolation is performed in the direction of the arrow A in the direction of the arrow A to perform the circular interpolation. Finally, as a release operation,
The table 14 is moved until the tool 20 reaches the position c. The operation of the arc processing is performed by a series of operations.

Next, FIG. 4 shows the measurement results of a workpiece that has been subjected to arc processing. FIG. 4 illustrates the results of measurement of a workpiece processed by down-cut processing and a workpiece processed by up-cut processing using a roundness measuring device.
In the down-cut processing, as shown in FIG. 4A, a dent occurs at the approach and release point p1. On the other hand, in the up-cut processing, as shown in FIG.
Indicates that no dent is formed.

Further, in any of the up-cut processing and the down-cut processing, the feed speed, the number of revolutions of the spindle,
Table 1 shows errors in the roundness when processing is performed by changing the conditions such as the diameter of the arc and whether the arc is processed inside or outside.

[0021]

[Table 1]

Looking at the feed speed, the feed speed is 37.
In the case of 5 mm / min, the roundness error is 1 μm when performed by up-cut processing for 19 μm of down-cut processing.
It becomes 3 μm and the arc processing accuracy is improved. Also, when the feed speed is 750 mm / min and 1500 mm / min, the roundness is 14 μm,
It is better than 15 μm compared to 20 μm and 21 μm of the down-cut processing.

Further, comparing the main shaft rotation speeds, the main shaft rotation speeds are 15,000 rpm and 22,000 rpm.
The roundness is 33 when down machining.
μm, 38μm, 23μm in up-cut processing,
It was 33 μm.

Also, in the case where the processing diameter of the arc is φ3 and φ20, the roundness is better if the processing is performed by the up-cut processing regardless of the size of the diameter.

Further, regardless of the type of the arc processing (inner circle and outer circle), the result that the roundness is better in the up-cut processing than in the down-cut processing is obtained.

From the above results, regardless of the type of arc (inner circle, outer circle), arc diameter and machining conditions (feed speed, spindle speed), etc., up-cut machining is always performed when arc machining is performed. It was found that the processing accuracy (roundness) was better when the processing was performed with.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

In this embodiment, an example in which an arc is machined as a process including a curve has been described, but any process may be used as long as the process includes a curve.

If a machining program for realizing a desired machining includes an arc command, the rotation direction (CW, CCW) of the arc command is detected, and the rotation direction of the spindle on which the tool is mounted is determined. It may be changed.

Conversely, when the rotation direction of the spindle is designated as a command, the rotation direction of the arc command may be automatically determined.

[0031]

As is apparent from the above description, according to the method of processing a work according to the first aspect, when the work and the tool are separated from each other, the work is processed by the up-cut processing. Processing accuracy can be increased as compared with the case of processing.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an external view of a machine tool according to the present embodiment.

FIG. 2 is a diagram illustrating a configuration of a machine tool.

FIG. 3 is a diagram illustrating a method of processing a workpiece according to the present embodiment.

FIGS. 4A and 4B are diagrams showing the results of measuring the roundness of a workpiece after performing arc cutting, in which FIG. 4A shows a result obtained by down-cutting and FIG. 4B shows a result obtained by up-cutting.

[Explanation of symbols]

 20 Tool 21 Work 28 Spindle 38 Z-axis motor

Claims (2)

[Claims] 1. A method of processing a workpiece for performing a processing including a curve on a workpiece by a relative motion between the workpiece and the tool, the relative motion between the workpiece and the tool when the workpiece is separated from the tool. A method of machining a workpiece, wherein the method ends with an up-cut process in which a direction is opposite to a rotation direction of the tool. 2. The method according to claim 1, wherein when the workpiece and the tool come into contact with each other, an up-cut process is started in which the direction of relative movement between the workpiece and the tool and the direction of rotation of the tool are opposite. Item 2. The method for processing a work according to Item 1.