JPS6141672B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a processing method such as cutting using a laser, and particularly to a laser processing method that improves processing efficiency.

Recently, laser pulses are focused, and the focused spot is irradiated onto the workpiece to make a hole, or the focused spot is moved along the cutout line of the workpiece while overlapping to create a hollow groove in the workpiece. Various processing methods have been put into practical use, such as forming and hollowing out holes of predetermined shapes. On the other hand, recently, sintered magnetic materials have been used for motors, audio components, etc., and it is often necessary to drill holes with a diameter of about 1 mm to 2 mm in this material. By the way, when drilling such a hole using a laser beam, the spot size is 1.
When irradiated with a pulse laser of mm to 2 mmφ, cracks occur around the hole due to thermal shock due to the nature of the sintered body, making it impossible to perform the desired processing. Therefore, in the past, the laser beam was further focused and moved sequentially along the circumference of the hole in which a minute focusing spot was to be drilled, forming a hollow groove and hollowing out the center of the hole. Processing methods are implemented. However, when drilling holes using this method, particles that evaporate and scatter due to laser beam irradiation accumulate as residue in the hollowed out grooves that have already been drilled, making it impossible to drill the holes cleanly or Cannot make holes. Therefore, in order to obtain a clean machined hole with no residue, it is necessary to scan the condensing spot many times along the circumference and process while removing the residue that accumulates in the hollowed groove, which reduces the processing time. Not only did it become longer, but once it was molten, it re-solidified inside the hollowed-out groove, which caused problems such as heating the area around the groove and forming a heat-affected layer.

The present invention was made in view of the above circumstances, and it is an object of the present invention to provide a laser machining method that allows efficient machining work without allowing particles evaporated and scattered by laser beam irradiation to accumulate in hollowed out grooves that have already been machined. The purpose is to

Embodiments of the present invention will be specifically described below with reference to the drawings. In the figure, 1 is a cylindrical rotating body that rotates freely via a bearing 2, and this rotating body 1
A workpiece 4 is removably fitted into the stepped opening 3 at the upper end, and the workpiece 4 is fixed by a fixing ring 5 which is removably attached to the upper opening end of the rotating body 1. ing. The workpiece 4 is a sintered magnetic material with a diameter of 3 mm and a thickness of 1 mm, and a hole of about 1 mm in diameter is drilled in the center thereof. Further, a gear 6 is fitted into the outer periphery of the lower part of the rotating body 1, and a gear 8 fixed to the rotating shaft of the pulse motor 7 is meshed with this gear 6, so that the rotating body 1 is connected to the pulse motor 7.
I am trying to drive it by. Further, the pulse motor 7 is driven and controlled by drive pulses output from the rotation control section 9. On the other hand, a laser oscillator 10 is disposed above the workpiece 4, and a laser beam outputted from the laser oscillator 10 is focused through a lens 11, and the focusing spot is directed from the center of the workpiece 4. The beam is irradiated at a position that is eccentric by the radius of the hole to be drilled. Further, the laser oscillator 10 outputs a laser pulse according to a pulse signal output by the laser control section 12. Furthermore, the rotation control section 9 and the laser control section 12
Both are controlled by the timing control section 13. The rotation control section 9 is energized by the timing pulse output from the timing control section 13, outputs a drive pulse to the pulse motor 7, and rotates the rotary body 1 by a rotation angle θ. On the other hand, the laser control section 12 is energized by the timing pulse output from the timing control section 13, and the laser oscillator 10
Outputs a pulse signal with a constant period. By the way, the rotation angle θ of the rotating body 1 is such that the holes a, b, c, etc., bored along the cutout line 14 set on the workpiece 4 overlap each other, as shown in FIG. and the rotating body 1 is predetermined so that the shortest distance D between adjacent holes a, b, c........ is smaller than the diameter d of each of the holes a, b, c.... This is the rotation angle to rotate in pitch increments.

According to such a configuration, the workpiece 4 is first fixed at a predetermined position on the rotating body 1, and the timing control section 1
3, the timing control section 13
According to the timing chart shown in the figure, a timing signal T ₁ is sent to the laser control unit 12 for a period of time from t ₁ to t ₂ .
The laser oscillator 10 outputs laser pulses L ₁ , L ₂ , L ₃ , and L ₄ with a constant period. On the other hand, since the rotation control section 9 does not receive the input signal from the timing control section 13, the pulse motor 7 remains stopped, and the pulse motor 7 remains stopped, and the pulse motor 7 remains stopped, and the pulse motor 7 remains stopped when the rotation control section 9 receives the input signal from the timing control section 13. A hole a is drilled. Next, the timing control unit 13 outputs a timing signal S ₁ to the rotation control unit 9 from t ₃ to _{t 4} , and the pulse motor 7 rotates the rotating body 1 by the rotation angle θ. next,
The timing control section 13 outputs the timing signal _T2 to the laser control section 12 for a period of time from _t5 to _t6 , and the laser oscillator 10 again generates a laser pulse of a constant period.
Output L ₁ , L ₂ , L ₃ , and L ₄ to drill the next hole b in the workpiece 4. Similarly, cut out line 1
Holes a, b, and holes for one circumference passing through the workpiece 4 are formed on the
c............ are continuously drilled. Next, the rotating body 1 is shifted by θ/2 from the current stop position, that is, the convergence spot of the laser oscillator 10 is placed at an intermediate position between the holes a, b, c, etc., which have already been drilled. and repeat the same process as the first step. Then, the workpiece 4 is moved along the cutout line 14.
Holes A, B, C, etc. for one circumference are drilled through the. Each of the above holes A, B, C……………… has the same diameter as each of the above holes a, b, c………………, and between the adjacent holes a, b, c……………… Shortest distance D
is smaller than the diameter d of each of the holes A, B, C, etc., so the workpiece 4 is hollowed out along the hollow line 14. By the way, cutout line 14
In the first step, holes a, b, c, etc. are drilled along the workpiece 4 at predetermined intervals.
...... are drilled, but each hole a, b, c......
... are each drilled independently at a predetermined distance D, so that particles evaporated and scattered from the holes during drilling will not accumulate as residue in adjacent holes that have already been drilled. In addition, the drilling process for each hole starts from the surface of the workpiece 4, and the molten material inside the hole is scattered upward and progresses inside, so the laser convergence spot is focused on the holes that are formed one after another. It reaches the interior while reflecting off the inner wall of the hole, and the drilling process proceeds while removing any residue remaining on the inner wall of the hole. Furthermore, when the laser beam reaches the back side of the workpiece 4, the molten material is discharged to the outside from the top and bottom of the hole, so that the residue inside the hole is completely removed, making it possible to drill a clean hole. When the first step is completed, most of the workpiece 4 on the cutout line 14 is removed, and only the residue 15 remains between the holes a, b, c, . . . . Therefore, if the second step is carried out in such a state, the remaining portion 15 is a region that has already been divided in the circumferential direction by the holes a, b, c, and so on. The temperature of No. 15 increases easily, and the hole A,
B, C……………… can be drilled. In this case, the particles that have evaporated and scattered will also enter the holes a, b, c, etc. that have already been drilled, but the particles that will be scattered from the hole A that is drilled in the second step will be The amount is not large enough to cover the holes a and b that have already been drilled on both sides, but it is enough to adhere to a portion of the holes a and b. Therefore, the workpiece 4 has a cutout line 14
The desired hole can be bored out along the line very efficiently. In this example, the first
The second process is carried out when the process of 1 is completed for one round along the cutout line 14, but the first process and the second process are carried out alternately, and the adjacent two steps are carried out in the first process. The second step may be performed on the remaining portion between the holes each time a hole is drilled.

Therefore, according to the present invention, the drilling work can be carried out extremely efficiently without the molten particles scattered from the hole being processed being accumulated in the hole that has already been drilled. Moreover, it can be widely applied not only to drilling work but also to cutting straight or curved grooves. Grooves can be applied not only to through holes but also to intermediate depth grooves.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the present invention, Fig. 2 is an explanatory diagram showing the machining position of a hole to be drilled in a workpiece in the same embodiment, and Fig. 3 is a timing chart of the same embodiment. FIG. 4 is an explanatory diagram showing the processing procedure of the same embodiment. 1... Rotating body, 4... Workpiece, 7... Pulse motor, 10... Laser oscillator, 14... Hollowed out wire.

Claims (1)

[Scope of Claims] 1. A method for drilling a predetermined shape in a workpiece by forming a cutout groove along a cutout line set in the workpiece using a spot focused laser beam on the workpiece. a first step of drilling adjacent holes on the cutout line of the workpiece at the spot and leaving an interval smaller than the diameter of the hole between the adjacent holes; A laser processing method comprising a second step of drilling a hole at the spot in a remaining portion between adjacent holes drilled in the first step, and communicating the adjacent holes. 2. Claim 1, characterized in that the first step is continuously carried out for one round along the cutout line, and then the second step is carried out continuously for one turn along the cutout line. Laser processing method described in section. 3. The laser processing method according to claim 1, wherein the first step and the second step are alternately repeated along the cut-out line.