JP2658505B2 - Laser oscillation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser oscillation device that suppresses fluctuations in laser output by suppressing leakage of cooling water at both ends of a glass tube containing a laser rod therein.

[Prior art]

A conventional example will be described with reference to FIG. 2 which is a sectional side view of a main part thereof. In FIG. 2, 1 is a YAG rod as a laser medium, 2 is a holder for holding the YAG rod at both ends, 7 is a glass tube, and 6 and 8 are side plates, respectively. The glass tube 7 accommodates the YAG rod 1 therein with its axis aligned. Each of the side plates 6 and 8 holds the glass tube 7 with play at both ends in the axial direction and the radial direction.
Providing a play is a measure against the brittleness of the glass tube 7. With a structure in which both ends are fixed, thermal deformation and the like cannot be escaped, leading to breakage. Therefore, it is necessary to provide a structure that allows deformation and displacement of the glass tube 7 in each direction of the axis and the radius. This clearance is 0.5 to 1 mm in the axial direction and 0.2 to 1 in the radial direction.
It is relatively large, about 0.4 mm. The reason for this is that the dimensions of the glass tube 7 vary in nature. For example, if the inner diameter, outer diameter, and length dimensions are 9.2,11.
2,80mm, each tolerance is ± 0.2mm. Since the mating side plates 6, 8 are made of a copper alloy material, the dimensional tolerance can be reduced by machining. Although not shown here, an excitation lamp and a reflector are provided in the space facing each side plate 6, 8, and cooling water for absorbing and discharging heat generated by the excitation lamp circulates. The cooling water for the YAG rod 1 which systematically communicates with the cooling water for the excitation lamp flows along the outer periphery of the left holder 2 as shown by the solid line arrow, passes through the center hole of the side plate 8, and Rod 1
Flows through the gap between the glass tube 7 and the right side plate 6
And flows out along the outer periphery of the right holder 2. The glass tube 7 forms a flow path of the cooling water for the YAG rod and has a role of a UV filter for the excitation lamp.

[Problems to be solved by the invention]

In the prior art described above, the right end face of the glass tube 7 is pressed against the receiving face of the side plate 6 by the dynamic pressure of the cooling water for the YAG rod 1 as shown in FIG. Of the cooling water is almost prevented. However, there is a clearance of about 0.2 to 0.4 mm between the outer peripheral surface of the glass tube 7 on the inflow side (upstream side) of the cooling water and the inner peripheral surface of the receiving portion of the side plate 8. There is also a gap of about 0.5 to 1 mm between the left end face and the receiving face of the side plate 8. Therefore, leakage of the cooling water from this location occurs as indicated by the broken arrow. The main cause of the leakage is the play between the outer peripheral surface of the glass tube 7 and the inner peripheral surface of the receiving portion of the side plate 8, that is, the play in the radial direction. This leakage of cooling water itself is not good because it deteriorates the cooling efficiency, but since the degree of leakage varies more finely,
There is a problem that the degree of cooling of the G rod 1 fluctuates and, consequently, the laser output fluctuates. This fluctuation in the laser output, when the laser is used for processing, changes the processing capability and lowers the processing quality. The object of the present invention is to solve the above problems of the prior art, and to suppress cooling water leakage at both ends of a glass tube containing a laser rod therein, thereby suppressing laser output fluctuation. It is to provide a device.

[Means for Solving the Problems]

In order to solve this problem, a laser oscillation device according to the present invention comprises: a glass tube which accommodates a laser rod coaxially in a hollow portion; and a flange-shaped fixture at least at one end of the glass tube to obtain dimensional accuracy. An easy ring; and respective receiving portions for supporting the ring or the end portion of the glass tube with play in the axial direction and the radial direction thereof; and a center hole of the receiving portion on one side corresponding to the ring. Cooling water flowing in and flowing out of a center hole of the receiving portion on the other side through a gap formed between the outer peripheral surface of the laser rod and the inner peripheral surface of the glass tube; The end face of the glass tube or the end face of the ring on the downstream side is pressed against the receiving face of the corresponding receiving part by the dynamic pressure of water.

[Action]

Since the cooling water can reduce the play between the outer peripheral surface of the ring and the inner peripheral surface of the corresponding receiving portion, leakage from the upstream end portion of the glass tube is suppressed, and also regarding the downstream end portion, Since the end face of the glass tube or the end face of the ring is pressed against the receiving surface of the corresponding receiving portion by the dynamic pressure, leakage therefrom is suppressed.

【Example】

An embodiment of the laser oscillation device according to the present invention will be described below with reference to FIG. FIG. 1 is a side sectional view of a main part of the embodiment. In FIG. 1, this embodiment is different from the conventional example of FIG. 2 in that a ring having an outer diameter dimensional accuracy is fixed to the upstream end of the glass tube in a flange shape, and a corresponding receiving portion of the side plate is provided. Is to reduce the play between them. That is, reference numeral 4 denotes a ring having a rectangular cross section made of Teflon (registered trademark of DuPont), which can provide sufficient dimensional accuracy by machining. Side plate 5
Since the side plate 5 is made of a copper alloy material, the receiving portion of the cylindrical hollow portion formed in the center hole of the above can also provide sufficient dimensional accuracy by machining. Specifically, the clearance between the outer peripheral surface of the ring 4 and the inner peripheral surface of the receiving portion of the side plate 5, that is, the clearance in the radial direction can be reduced to about 0.1 mm or less, and the flow resistance of the cooling water at this point can be reduced. Can be greatly increased. The play between the left end face of the ring 4 and the receiving surface of the side plate 5, that is, the influence of the play in the axial direction on the flow resistance is smaller than that in the play in the radial direction. Therefore, in order to increase the flow resistance at this point, it is sufficient to reduce only the play in the radial direction. Therefore, leakage of the flow of the cooling water from the left end portion of the glass tube 3 is suppressed. In addition, leakage from the right end of the glass tube 3 is originally suppressed. This is because, similarly to the conventional example, the right end face of the glass tube 3 and the receiving face of the side plate 6 are pressed by the dynamic pressure of the cooling water to be in close contact with each other. By the way, the ring in the embodiment is fixed only to the cooling water inflow side (upstream side) end of the glass tube, whereby the leakage of the cooling water and, consequently, the fluctuation of the laser output are suppressed to a level that does not hinder practical use. Was. However, it is considered that, when the ring is fixed to each end on both sides of the glass tube, the leakage of the cooling water can be further suppressed, and the effect of suppressing the fluctuation of the laser output is further increased.

【The invention's effect】

As described above, in the present invention, since the cooling water can reduce the play gap between the outer peripheral surface of the ring and the inner peripheral surface of the corresponding receiving portion, the leakage from the upstream end portion of the glass tube is suppressed. At the downstream end portion, the end face of the glass tube or the end face of the ring is pressed against the receiving surface of the corresponding receiving portion by the dynamic pressure, so that leakage therefrom is suppressed. Therefore, according to the present invention, the following excellent effects are obtained as compared with the related art. (1) Cooling water is prevented from leaking from the upstream and downstream ends of the glass tube, so that the flow is stabilized and the fluctuation of the laser output is suppressed, and the laser is processed. When it is used for, the processing ability is improved. (2) Further, since it is not necessary to particularly suppress the dimensional tolerance of the glass tube in relation to the item (1), productivity can be improved and cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a main part of an embodiment according to the present invention, and FIG. 2 is a side sectional view of a main part of a conventional example. Description of symbols 1: YAG rod, 2: holder, 3: glass tube, 4: ring, 5, 6:
Side plate.

Claims (1)

(57) [Claims] 1. A glass tube in which a laser rod is coaxially accommodated in a hollow portion; a ring easily fixed in a flange shape to at least one end of the glass tube; And a receiving portion for supporting the portion with a play in the axial direction and the radial direction, respectively; and a central portion of the receiving portion on one side corresponding to the ring, and an outer peripheral surface of the laser rod and the outer peripheral surface of the laser rod. Cooling water flowing out of a center hole of the receiving portion on the other side through a gap formed between the glass tube and the inner peripheral surface of the glass tube; Or an end surface of the ring is pressed against a corresponding receiving surface of the receiving portion.