JPH04101710A - Back finishing method of sheet metal small hole - Google Patents

Abstract

PURPOSE:To remove a burr easily without damaging a cutting edge by feeding a deburring tool into a small hole to rotate, and stopping its rotation after cutting the burr to retract it from the small hole, in the case of removing the burr of the small hole machine in a sheet metal. CONSTITUTION:A small hole 3 has been already machined on a sheet metal 1 and a burr 7 remains on a back 5 thereof. In a deburring tool 9 a cutting edge 13 is retractably provided via a spring on the side of a top end of a rotary cylindrical shaft 11. In order to feed the deburring tool 9 into the small hole 3, the tool 9 is advanced for rapid feeding while rotation thereof is stopped. Then, when the cutting edge 13 provided on the side of the top end of the tool 9 reaches the back of the small hole 3, the tool is rotated while being retracted to start cutting of the burr 7. At this time, the tool 9 is energized in the retreating direction by means of the spring so that the edge 13 is not brought into strong contact with the burr 7. After the burr 7 is removed, the tool 9 is stopped to rotate and retracted for quick return motion.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for removing burrs remaining in small holes machined in sheet metal.

BACKGROUND ART When a small hole is drilled into a metal material, such as a casting, a burr remains on the back side of the hole. In order to remove this burr, a tool called a ballaway tool has conventionally been used. This breakaway tool has a cutting blade that protrudes in and out from the side surface of the tip of a rotating cylindrical shaft via a spring. When performing back chamfering work, the ballaway tool is rotated around its axis and fed into the small hole. Then, the cutting blade elastically moves in and out due to the spring while contacting the edge of the narrow hole, thereby cutting away the burr existing at the edge of the back surface of the narrow hole.

Problems to be Solved by the Invention However, when the metal material is a casting, the burrs are brittle, and the burrs can easily be removed by conventional chamfering. In the case of wood, burrs are difficult to remove. For this reason, when the ballaway tool is fed into a small hole while rotating,
The cutting edge of the baraway tool meets the strong resistance of the burr,
They tended to break and fly off. This kind of problem is caused by the fact that when the hole drilled in the sheet metal is a narrow hole, the diameter of the cylindrical shaft through which the cutting blade enters and exits is also small, and therefore the cutting blade cannot be supported with a strong enough force against the resistance in the circumferential direction. It was noticeable because I couldn't do it.

The present invention was made in order to solve the above problems, and it is possible to easily remove the hard-to-remove burrs remaining on the back side of small holes machined in the sheet metal without damaging the cutting blade. The purpose of the present invention is to provide a method for chamfering the back side of a small hole.

Means for Solving the Problems The present invention has been made to achieve the above object, and is a method for cutting and removing burrs remaining on the back side of a small hole machined in a sheet metal. Using a breakaway tool whose cutting blade protrudes in and out from the side of the shaft tip via a spring and is biased in the backward direction by the spring, first feed the ballaway tool into a small hole with the rotation stopped, and then The burr is cut by the cutting blade by rotating the burraway tool, and after the cutting is finished, the burraway tool is stopped and returned from the small hole.

Breaking off of the active cutting edge occurs when the breakaway tool is fed into and returned from the slot, i.e. when the cutting edge passes through the slot. This is because when passing through a small hole, the cutting edge comes into contact with a burr or the like with strong force and is subjected to large resistance in the circumferential direction. Therefore, as in the present invention, a ballaway tool is sent into a small hole,
When returning from a narrow hole, by stopping the rotation of the breakaway tool, large resistance in the circumferential direction is not applied to the cutting edge, and the tool only needs to contact the edge of the narrow hole in the front-rear direction. This prevents the cutting blade from breaking and flying off when passing through the small hole. In addition, burrs are cut by rotating the -degree breakaway tool after feeding it into the small hole, but at this time, the contact of the cutting blade with the burrs is
The force provided by the spring can be kept constant and prevent large forces from being applied. Therefore, it is possible to prevent the cutting blade from breaking during cutting.

EXAMPLE Hereinafter, an example of the present invention will be explained with reference to FIGS. 1 to 9.

1 to 9 sequentially explain the procedure for implementing the method of this embodiment.

As shown in FIG. 1, a thin hole 3 has already been formed in a sheet metal 1 having, for example, an L-shaped cross section. Along with this processing,
A crab ridge remains on the back side 5 of the sheet metal 1. The baraway tool 9 used to remove this crab riff is
A cutting blade 13 is provided so as to be movable in and out from the side surface of the tip of the rotating cylindrical shaft 11 in a state parallel to the shaft via a spring (not shown). In addition, in a machine tool body that moves the escape tool 9 forward and backward as well as rotates, a spring 15 (Fig. 5) provided in a tapping chuck portion that grips the base of the tool moves the escape tool 9 into the machine tool body. It is biased in the backward direction.

First, when sending the baraway tool 9 into the narrow hole 3,
With the rotation of the baraway tool 9 stopped, it is rapidly forwarded (FIG. 2). Then, the sending is completed sufficiently,
When the cutting edge 13 provided on the side surface of the tip of the breakaway tool 9 reaches the back side of the small hole 3 (Fig. 3), the breakaway tool 9 is rotated (Fig. 4), and the cutting feed, that is, the retreat, is performed to cut the canirif. Start cutting (Figure 5). At this time, the spring 15 urges the breakaway tool 9 in the retreating direction, and the cutting edge 13 and the cannulation rift are kept in contact with each other to prevent them from coming into too strong contact. Therefore, the cutting edge 13 is prevented from being subjected to large resistance in the circumferential direction by the cannibal. The baraway tool 9 completes cutting of the cannibal by the cutting blade 13 after two to three rotations, for example.

Once enough cannibals have been removed, use the baraway tool 9.
is moved forward while rotating (Fig. 6), then the rotation of the separation tool 9 is stopped (Fig. 7), and the separation tool 9 is quickly returned and retreated (Fig. 8).

In this way, the caniliff is removed (
Figure 9).

Conventionally, the reason why the cutting blade 13 breaks is when the cutting blade 13 breaks due to the small hole 3.
When passing through the narrow hole 3, i.e., when the flywheel 9 is sent into the narrow hole 3 or returned from the narrow hole 3, the rotating cutting blade 13 comes into strong contact with the canillary ridge and the inner circumferential surface of the narrow hole 3, and the circumference This was because there was a large amount of resistance in the direction. However, according to this embodiment, when the cutting blade 13 passes through the small hole 3, the rotation is stopped, and although the cutting blade 13 receives force in the front-rear direction, it does not receive any force in the circumferential direction. For this reason, the cutting blade 13 is not subjected to a force so large as to break it. Further, as described above, since the spring 15 urges the breakaway tool 9 in the backward direction, it is possible to prevent a large force from being applied to the cutting blade 13 even during cutting. Therefore, even when chamfering the back side of a small hole 3 where there is a burr that is difficult to remove, such as in sheet metal, it is possible to easily perform cannibal cutting without breaking the cutting blade 13.

As described in detail, according to the method for chamfering the back side of a thin hole in a sheet metal of the present invention, the cutting edge of the baraway tool not only passes through the hole, but also when cutting burrs on the back side of the sheet metal. ,
There is no large resistance in the circumferential direction due to the burrs, and it can be prevented from breaking and flying away.

[Brief explanation of drawings]

FIGS. 1 to 9 are explanatory diagrams sequentially showing a procedure for implementing a method according to an embodiment of the present invention. l...Sheet metal, 3...Small hole, 7...Burning, 9...Baraway tool, 11...Cylindrical shaft, 13...Cutting blade, 15...
spring.

Claims (1)

[Claims] In the method of cutting and removing burrs remaining on the back side of a small hole machined in a sheet metal, a cutting blade protrudes removably from the side of the tip of a rotating cylindrical shaft via a spring, and is biased in the backward direction by the spring. First, feed the ballaway tool into the small hole with the ballaway tool stopped rotating, then rotate the ballaway tool and cut the burr with the cutting blade. A method for back chamfering a thin hole in sheet metal, which is characterized by stopping rotation and returning from the thin hole.