JPH04360704A - Premachining method for boring - Google Patents

Abstract

PURPOSE:To prevent chip from coiling around a boring bar at boring work by previously machining a groove in the axial direction with a bar cutter having smaller diameter than the boring diameter in one part of boring allowance. CONSTITUTION:The boring center of a work piece W fixedly secured on a table is positioned so as to be concentrical with a bar cutter T mounted on a main spindle. Next, the spindle head is moved in the vertical direction, positioned so that the extreme end of the bar cutter T is a little over the upper end face of the work piece W, the table is moved left side in the X-axis direction by A, and the bar cutter T is positioned on the cutting start position of a groove Wa. Next, the main spindle is rotated, the spindle head is moved in the vertical direction at cutting feed speed to cut the groove Wa. These operations are set in a working program so as to output a premachining command by a simple input method of a fixed cycle form, and the groove machining is automatically performed by a NC command.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pre-processing method for breaking up chips during boring with a machine tool such as a machining center.

0002

[Prior Art] Conventionally, boring of workpieces that tend to generate continuous chips, such as steel or aluminum materials, is different from the general boring process in which a prepared hole with a machining allowance 101 is cut using a boring bar 102, as shown in FIGS. 7 and 8. A processing method that is not used is used.

0003

[Problems to be Solved by the Invention] In the machining method described in the prior art, continuous curled chips 103 come out during boring, wrap around the boring bar, and damage the finished surface, making continuous machining impossible. However, there is a problem in that it becomes difficult to dispose of chips using a chip conveyor or the like. The present invention was developed in view of the problems of the conventional technology, and its purpose is to generate chips that are easy to post-process without damaging the finished surface during boring. The purpose is to provide a pre-processing method that can be used.

0004

[Means for Solving the Problems] In order to achieve the above object, the pre-boring method of the present invention involves grooving a part of the cutting allowance in the axial direction using a bar cutter having a diameter smaller than the diameter of the bored hole. A boring process was then performed to break up the chips.

[0005]

[Operation] Before boring, a part of the cutting allowance is grooved in the axial direction using a bar cutter with a diameter smaller than the boring diameter. Grooving programs are created using a simple fixed cycle input method, and when the boring diameter is large, the number of grooving locations is automatically increased to prevent long chips from being generated during boring.

[0006]

[Embodiment] An embodiment will be described with reference to FIGS. 1 to 6. In the vertical machining center shown in FIG. 4, a saddle 2 is placed on a guide in the Y-axis (back and forth) direction provided on a bed 1 installed on the floor so that it can be moved and positioned. A table 3 is placed on the guide in the X-axis (left and right) direction so as to be movable and positionable.

A column 4 is installed on the rear side of the bed 1, and a spindle head 5 is mounted so that it can be moved and positioned along a guide in the Z-axis (up and down) direction provided on the front of the column. A main shaft 6 is rotatably supported. Column 4
A tool magazine 7 is attached to the left side surface of the machine, and a twin-arm tool exchange arm device 8 is attached between the tool magazine 7 and the spindle head 5. As shown in FIG. 1, a workpiece W is mounted on the table 3, which has a pilot hole that leaves a machining allowance δ for one side of the boring diameter (2R).

The block diagram in FIG. 5 is a fixed cycle control circuit for performing boring pre-processing on this workpiece. The machining program interpretation section 11 is a section that interprets the input program contents and sorts them into necessary parts, the tool diameter storage section 12 is a section that stores the radius dimension D1 of the bar cutter T, and the parameter storage section 13 is a section that stores the radial dimension D1 of the bar cutter T. This is a part that stores the dimension from the bottom surface of the axial groove Wa to be machined by T to the boring diameter, that is, the boring allowance C of the axial groove portion.

The arithmetic circuit 14 subtracts D1 and C from the radius dimension R of the boring diameter inputted in the program.
Distance A from the center of the bored hole to the center of the bar cutter T
The A value positive/negative determination circuit 15 is a circuit for determining whether the calculated A value is greater than 0, and the alarm generation circuit 1 is a circuit for determining whether the calculated A value is greater than 0.
6 is a circuit that generates an alarm signal when A≧0.

The first fixed cycle execution circuit 17 is a circuit for executing a fixed cycle in which the center of the bar cutter T is moved by an amount A in the X-axis direction from the center of the bored hole to machine an axial groove Wa. Setting value to be stored For example, if the setting value is 50 mm, this and R are compared, and if R>50, a circuit that outputs a signal to the second fixed cycle execution circuit 19, the fixed cycle execution circuit 19 is a bar cutter. The 1-sequence end processing circuit 21, which is a circuit that executes a fixed cycle of moving the T center by -A in the X-axis direction from the boring processing center and machining the second axial groove Wb, interprets the sequence end signal as a machining program. This circuit outputs the signal to the unit 12 to cancel the fixed cycle.

Next, the operation of this embodiment will be explained in the order of the flowchart shown in FIG. In step S1, the value of A is calculated in the arithmetic circuit 14, and in step S2, it is confirmed whether A is equal to or smaller than 0. If YES, the alarm is stopped in step S3. If no, the table 3 is moved in the X and Y axis directions at a rapid traverse speed in step S4, and the center of the bored hole of the workpiece W fixed on the table is aligned with the bar cutter T mounted on the spindle 6. They are positioned concentrically.

Next, in step S5, the spindle head 5 is moved downward in the Z-axis direction at a rapid traverse speed, and the tip of the bar cutter T is positioned slightly above the upper end surface of the workpiece, and in step S6, the table 3 is moved downward in the Z-axis direction. The bar cutter T is moved to the left in the X-axis direction by A at a rapid traverse speed, and the bar cutter T is positioned at the cutting start position of the groove Wa.

Next, in step S7, the spindle 6 is rotated, and the spindle head 5 moves downward in the Z-axis direction at a cutting feed rate to cut the groove Wa up to the Z-axis command value. For example, in the case of FIG. The movement stops at the position where the tip of the T reaches slightly below the lower surface of the workpiece W. In step S8, the table 3 moves to the right in the X-axis direction at a rapid traverse speed so that the bar cutter T is 1 mm away from the groove Wa, and in step S
At 9, the spindle ram 5 is moved upward in the Z-axis direction at a rapid feed speed and returns to the Z-axis cutting feed start position.

Next, in step S10, it is checked whether the radius dimension R of the boring diameter is smaller than 50. If YES, a sequence end signal is output, and one sequence command of the fixed cycle ends. If no, in step S11, the table 3 moves to the right in the X-axis direction at a rapid traverse speed so that the center of the bar cutter T coincides with the center of the bored hole, and then continues to move by -A in the right row of the table 3. Then, the bar cutter T is positioned at the cutting start position of the groove Wb.

In step S12, the spindle head 5 is moved downward in the Z-axis direction at a cutting feed rate, and the cutting of the groove Wb is performed at the Z-axis direction.
The movement is continued until the axis command value is reached, and the movement is stopped at the position where the tip of the bar cutter T reaches slightly below the lower end surface of the workpiece W. In step S13, the table 3 moves 1 mm to the left in the X-axis direction at a rapid traverse speed, and the bar cutter T cuts the groove Tb.
In step S14, the spindle head 5 moves upward in the Z-axis direction at a rapid traverse speed and returns to the Z-axis cutting feed start position, and a 1-sequence end signal is output.

[0016]

[Effects of the Invention] Since the present invention is constructed as described above, it produces the following effects. For workpieces such as steel or aluminum materials where chips tend to get wrapped around, a part of the machining allowance during boring is machined with an axial groove so that the chips are separated during boring, making it possible to use a boring bar. This eliminates the possibility of continuing machining with chips wrapped around the surface and damaging the finished surface, making it possible to perform automatic continuous machining with improved surface finish accuracy, and making it easier to discharge chips using a chip conveyor or the like. Furthermore, since the program can be commanded using a simple fixed cycle input method, the effort required to create a program is greatly reduced. Furthermore, as the diameter of the bored hole increases, the number of axial grooves is automatically increased, so even if the diameter of the bored hole increases, long chips will not come out and the effectiveness will not decrease.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the boring pre-processing method of the present embodiment, and is a diagram showing an example of a relatively small-diameter hole.

FIG. 2 is an explanatory diagram of the boring pre-processing method of the present embodiment, and is a diagram showing an example of a relatively large diameter hole.

FIG. 3 is a side view of FIG. 2;

FIG. 4 is a diagram of a vertical machining center.

FIG. 5 is a block diagram of a control circuit for a pre-boring processing fixed cycle.

FIG. 6 is a flowchart diagram for explaining the operation of this embodiment.

FIG. 7 is an enlarged view of a hole in a workpiece showing a boring allowance in a conventional technique.

FIG. 8 is a diagram illustrating a state in which chips are wrapped around a boring bar in the prior art.

[Explanation of symbols]

W Workpiece Wa, Wb Axial groove T bar cutter

Claims (1)

[Claims] [Claim 1] Boring characterized in that a part of the cutting allowance is grooved in the axial direction using a rod cutter with a diameter smaller than the diameter of the boring hole, and then boring is performed to break up chips. Pre-processing method.