JPH0360908A - Method for processing oblong hole - Google Patents

Abstract

PURPOSE:To obviate the complicated contour control of a cutting edge, to shorten the working time and to prevent the hole bent of an end face by performing the drillings of both end parts in the longitudinal direction with the use of the cutting edge in the same diameter as the short diameter of an oblong hole and linearly working this space. CONSTITUTION:A hole 1 with a point (a) as the center is pierced at one end side of the oblong hole to be formed, an end mill is then moved by a specific distance l and the center is moved to a point D. The end mill is moved toward points (a), (b) after piercing a hole 2 by its drawing out of a work and its moving to the other end side point C of the oblong hole, subjected to linear working and stopped when the center reaches the intermediate point (d) of the point (a) and the point (b). Both side faces along the longitudinal direction of the oblong hole are simultaneously worked with the movement of the end mill once, the working time is shortened, the working accuracy of the same side face part is improved because of a cutting edge being difficult to be deflected, the need for a complicated contour control is obviated, the twice abutments to the end face of the hole 1 side is eliminated and the hole bent is prevented.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for machining precise long holes.

(Prior art) Conventionally, numerically controlled machine tools, etc., have been used as shown in Figure 2! r1
When drilling a dense long hole, use a cutting tool 51 such as an end mill whose diameter is smaller than the short diameter of the long hole, and after drilling the hole at the determined coordinate position, move it along the profile to form the long hole. After processing, the shape was measured to ensure quality.

(Problem to be solved by the invention) However, in the conventional case, various factors such as the size of the cutting tool diameter, the material of the workpiece, the size of the long hole, etc. are complicatedly intertwined, and the long hole that requires precision is deformed. In particular, errors caused by the deflection of the cutting tool had a large effect on the dimension tolerance.

(Means for Solving the Problems) In order to solve this problem, in the present invention, holes are formed on both ends of the long hole using a cutting tool having the same diameter as the short diameter of the long hole, and a straight line is formed between these ends. The width of the hole on the end side is expanded in the longitudinal direction in advance, and the cutting tool that has been machining a straight line from the hole on the other end side is stopped at the midpoint of the hole width to complete the machining.

(Function) Both sides along the longitudinal direction of the hole are not deformed and can be processed more quickly than before. In addition, the width of the hole drilled at one end is expanded, and the cutting tool moving from the other end is stopped at the midpoint of the hole width, so it does not hit the front side of the cutting tool or the end of the long hole. , hole bending does not occur in the same part due to deflection in the direction of movement of the cutting tool.

(Example) An example of the method for machining a long hole of the present invention will be described based on the attached drawings.

The method for machining a long hole of the present invention is applied to a numerically controlled machine tool, and a hole having a diameter of 100'°1 is used to match that of an end mill as a cutting tool.

Machining performed using such an end mill begins with the first step.
- (A) As shown in the figure, drill a first hole 1 centered at point a on one end side of the elongated hole to be formed, and then use an end mill to drill a predetermined amount i) as shown in the figure (B). Move it slightly. Therefore, the center of the end mill moves to the point, and an expanded hole with an expanded hole width is formed.

Next, once pull out the end mill from the workpiece, (C)
After moving to point C on the other end of the elongated hole shown in the figure and drilling the second hole 2, move the end bolt toward points a and b to perform straight line machining, as shown in figure (D). The center of the end mill is at point a
When it reaches the midpoint d between the points and points, the movement is stopped and the machining is completed.

During this time, both sides along the length of the elongated hole can be machined simultaneously without leaving any unprocessed parts due to endless round-trip movement, resulting in a reduction in machining time. Also, unlike conventional blades with a small diameter, the cutting tool does not bend easily, improving machining accuracy on the same side surface and eliminating the need for complicated contour control. Also the first
Since the end face of one example of the hole is not hit by a mitaka, the hole does not bend in the same part.

(Effects of the Invention) As described above, the method for machining a long hole of the present invention involves drilling both ends in the longitudinal direction using a cutting tool having the same diameter as the short diameter of the long hole.
Then, since straight line machining is performed in this space, there is no need for complicated contour control of the cutting tool as in the past, which shortens the working time and improves machining accuracy.

Furthermore, since one end side is an expanded hole and the movement of the cutting tool is stopped at the midpoint of the expanded hole, it is possible to prevent the hole from bending at the end surface.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing the processing steps of the processing method of the present invention, Figure 2
The figure is an explanatory diagram showing a conventional processing method. In the figure, 1 indicates a first hole, 2 a second hole, and 51 a cutting tool.

Claims (1)

[Claims] In a processing method for drilling a long hole in a workpiece, this method includes a first step of drilling a first hole in the workpiece with a cutting tool having the same diameter as the short diameter of the long hole, and a first step of drilling the cutting tool in a predetermined direction from the first hole. a second step in which the hole width is expanded in one predetermined direction by slightly moving the hole width; and a third step in which the cutting tool is once pulled out and a second hole is formed in a predetermined portion on the extension line of the first hole width in the expansion direction. and a fourth step of moving the cutting tool from the second hole toward the first hole and stopping at the midpoint of the expanded hole width to finish the machining. .