JP2717179B2 - Laser forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to metal, ceramics,
Cutting, drilling, welding, quenching, surface treatment, plating, overlaying, polymerization reaction, living body surgery, plastics, composites, bones, etc.
The present invention relates to an improvement in a laser forming apparatus for performing treatment, suturing, and other processes.

[Prior art and problems]

Conventionally, an irradiation device that focuses a laser beam and irradiates a spot is provided opposite to an NC control table that fixes the workpiece, and the workpiece is NC-controlled to a predetermined program shape while irradiating pulse laser by the irradiation device There are known devices for cutting and welding metal and the like. In processing using this laser light, light energy concentrates on the irradiation spot and acts to increase the power density, causing the evaporation of the substance and removing the melt from the processing area. Processing such as cutting is performed by moving and changing the irradiation spot position of the laser, but the penetration processing depth due to evaporation and melting of the substance due to spot irradiation at each irradiation position is not necessarily constant, so a high-precision forming process is required. To do so, it is necessary to control the movement of the irradiation spot by detecting the progress of processing. Conventionally, the processing depth is detected based on a change in the amount of reflected light by receiving the reflected light from the irradiation surface, but there is a disadvantage that sufficient formation accuracy cannot be obtained due to poor detection accuracy. Also, since the focal position changes with the penetration depth of the irradiation position, the energy density of the beam spot changes, and the degree of convergence changes, there is a disadvantage that the penetration state changes due to a plurality of pulses and the formation accuracy deteriorates. is there.

[Solution for problem]

The present invention was invented in order to improve such points, and is not limited to cutting, but also welding, surface treatment, plating,
An optical device that can be used for various formation processes such as polymerization reaction and biological treatment, and an optical device that forms an image of reflected light from an irradiated surface irradiated with a spot through a lens. A detecting device for detecting as a signal, a processing depth by the spot irradiation is determined from a change signal of the image forming position detected by the detecting device, and when the processing depth reaches a predetermined value, a next spot irradiation position is determined. And a determination output circuit that outputs a signal permitting movement to the control device to the control device.

In addition, an automatic energy control device that controls the increase or decrease of the energy of the irradiation laser based on a signal that detects the processing depth position, or moves a condenser lens based on the signal that detects the processing depth position to move the surface of the portion to be formed. An automatic focus control device for controlling the distance between the two is provided.

[Action]

The present invention detects the depth of penetration or swelling processing by spot irradiation on the surface of the portion to be formed of the irradiation laser, and moves the irradiation spot to the next spot irradiation position every time it reaches a predetermined value. Since the irradiation process is controlled, the amount of penetration or swelling at each irradiation point is always constant, and this spot irradiation position is controlled by moving it one-dimensionally, two-dimensionally, or three-dimensionally. Laser processing with extremely high forming accuracy can be performed by processing into the shape of the laser beam, and the wavelength of the laser beam is selected, and the amount of penetration or swelling of the irradiation point is minutely controlled to achieve extremely fine precision. It is possible to perform various forming processes.

Also, by providing an automatic energy control device of pulse laser or an automatic focus control device to control a plurality of pulses at the spot irradiation point, always irradiate the irradiation surface with constant energy regardless of the change of the processing depth of penetration or ridge. Can be repeated, processing can be performed with a constant penetration groove width, and formation accuracy can be increased.

〔Example〕

Hereinafter, the present invention will be described with reference to one embodiment of the drawings. FIG. 1 shows an embodiment of a processing apparatus for performing NC control. 1 is an NC control table, 2 is a head opposed to the table, and focuses a pulse laser output from a laser oscillator 3 by a condenser lens 4 to irradiate a spot. Then, the reflected wave having the irradiation angle θ passes through the light receiving lens 5 and the light receiving element 6 through the CCD image sensor.
To receive light. The light reflected from the irradiation surface is imaged on the light receiving element 6 by the light receiving lens 5, and a change in the image forming position is detected by the light receiving element 6 as an electric signal. 7 compares the detection signal of the light receiving element 6 with the set value and determines the movement permission signal to the next NC.
A discrimination output circuit 8 for outputting to the control unit is an NC control unit for outputting a programmed movement control signal. The NC control unit 8 controls the X-axis drive motor 9, the Y-axis drive motor 10 of the table 1 and the Z-axis drive motor 11 of the head 2. Output a signal.

The NC controller 8 is programmed with a required forming shape signal, outputs a distributed digital signal according to the program, and controls the driving of the motors 9, 10, and 11. The object 12 to be formed is fixed on the moving table 1, and the pulse beam output from the laser oscillator 3 is focused by the lens 4 to irradiate a spot, and the irradiation energy is melted and evaporated by the heat energy of the laser. Perform the penetration,
The spot irradiation point is continuously moved by the movement under the NC control to perform a forming process according to the movement locus.

FIG. 2 is a view for explaining a penetration state of a formed body by spot irradiation. By repeating pulse irradiation without moving a position, craters I,
The penetration depth increases sequentially such that crater II is formed by two shots, crater III is formed by three shots, and crater IV is formed by four shots, but the penetration depth by each repetition pulse is not always constant, It depends on the material of the object, the temperature, the atmosphere, the oscillation state of the laser oscillator, and the like.

The processing position of the irradiation surface due to this penetration can be detected by using a reflected wave. FIG. 3 is an explanatory diagram for detecting the processing depth position of the irradiation surface, which is output from the laser oscillator 3 and focused by the lens 4. the beam L ₁ incident at an angle θ impinges on the surface a of the forming body at the beginning processing is performed, imaged substantially in the center portion a of the image sensor 6 through the reflected wave L ₂ is lens 5 at that time I do. Similarly, when pulse irradiation is repeated without changing the spot point, the penetration depth of the crater gradually increases as shown in FIG. 2, and when the processing depth of the irradiation surface reaches level B in FIG. the reflected wave from here becomes L _3. This light L ₃ forms an image on another portion b of the image sensor 6 through the light receiving lens 5. The image sensor of the light-receiving element 6 has a linearly arranged photosensitive image on the light-receiving surface, and the light-receiving signal is photoelectrically converted by the photodiode at the incident portion and the signal charge is read out. Can be determined.

That is, assuming that the element pitch of the image sensor 6 is l ₀ , and the number of elements existing at an interval between the imaging positions a and b is n, the moving distance (distance between a and b) Δx ′ of the imaging position is It is expressed by the following equation.

Δx ′ = l ₀ · n Then, assuming that the magnification of the optical system is M and the incident angle of the laser beam is θ / 2, the change Δx (distance between levels AB) of the processing depth position of the irradiation surface is Δx = l ₀ · n / (2 · M · sin θ / 2). Here, M and l ₀ are fixed values, and the incident angle θ
Since / 2 is a set value, Δx can be obtained by counting and detecting the number n of elements between the imaging positions a and b from the output signal of the image sensor 6.

If the irradiation surface level B shown in FIG. 3 is set to the set value depth in this way, when the pulse beam is repeatedly irradiated to detect the crater depth AB = Δx, the detection signal is a discrimination output. The circuit 7 compares the signals and outputs a movement permission signal to the NC control device 8.
Drive 9, 10, 11 to move the laser beam spot irradiation to the next position. When the penetration depth due to the spot irradiation at the moved position is detected and determined and the penetration is performed to the set predetermined depth, the discrimination output circuit 7 further controls the NC control device to move the irradiation point to the next position. 8 to output a signal. By controlling the movement of the spot irradiation point of the laser beam in one, two or three dimensions according to a program by the NC controller 8 while detecting and determining the depth of the irradiation point in this manner, extremely precise high precision Can be formed.

FIG. 4 shows an example in which penetration craters a to q are sequentially formed in the workpiece 12 to form and process a mold 12C as indicated by a dotted line, and the depth of each crater is controlled to be constant.

In FIG. 1, the irradiation angle θ of the laser beam is set to 45 ° or less at most. Further, the distance between the lens 4 and the object irradiation surface is set to about 3 to 5 mm. Motor 9,10,
The control of 11 can be configured such that the gate is opened and driven by the logical product of the NC signal and the movement permission signal of the control circuit. In addition, imitation control or the like can be used for movement control.

According to experiments, using a 100 W YAG laser,
When pulse irradiation was performed at 0 ns to form a steel material, the amount of reflected wave was detected at a detection angle θ = 30 °, and when the NC movement control was performed, the maximum unevenness of the treated surface was about 0.03 mm. In contrast, the maximum unevenness is about 0.01 mm when moving the irradiation spot by detecting the change in the imaging position by CCD and determining the processing depth position and determining the processing depth position, and the maximum unevenness is about 0.008 mm when pulse irradiation of 5 ns is performed. became.

Note that the detection accuracy was 5 μm when the processing depth of the irradiation surface was detected by the amount of reflected light, and 0.1 μm when the processing depth was detected from the change in the imaging position using a CCD. In addition, when plating by laser irradiation, processing was performed at a wavelength of 8600 mm, and when processing while detecting the amount of reflected light, the deposition surface temperature was about 0.02 mm. When the height (rising height) was detected, the precision of the deposited surface was about 0.003 mm.

In the laser irradiation, the beam output from the oscillator 3 may be turned on / off by a chopper or the like so as to be intermittently irradiated.

FIG. 5 shows the condenser lens 4 of FIG. 1 in which a sliding surface 13 is provided in a vertically movable state, and a driving coil 14 is provided on the sliding surface 13 to control the vertical movement. Reference numeral 15 denotes a half mirror, which transmits and irradiates the output laser beam of the oscillator 3, bends the reflected light at a right angle, and makes it incident on the light receiving element 6. 14
Is operated to move the condenser lens 4 in the vertical direction to control the distance between the condenser lens 4 and the surface of the formation portion. This lens control always focuses on the irradiation surface portion of the penetration crater so that laser spot irradiation with automatic focus control can be performed.

The crater depth position signal can be detected by receiving the reflected wave from the irradiation surface to the light receiving element 6 through the half mirror 15, and this signal is added to an automatic focus control circuit 16 including a comparison discrimination circuit and the like. Even if the crater is deepened by the near-far control of the object, even if the crater becomes deeper, it is automatically controlled to always focus on the crater irradiation surface. The focus of the spot is controlled automatically by following the depth of the crater, and the irradiation surface is always irradiated with a constant energy at a constant spot, so that the penetration process can be performed. It can be significantly improved.

FIG. 6 is provided with an automatic energy control circuit 17 for controlling the laser oscillator 3 (controlling the oscillator operating power supply) by the detection signal of the light receiving element 6 corresponding to the crater depth and controlling the output power. In this case, the condenser lens 4
When the focus is not fixed and the focus control is not performed, the action energy of the irradiation surface due to repeated irradiation gradually decreases as the crater becomes deeper, but the pulse irradiation energy is increased and controlled as the crater becomes deeper by the operation of the automatic energy control circuit. Therefore, the processing portion of the crater is always irradiated with a beam of constant energy, whereby the forming speed and accuracy can be improved.

FIG. 7 shows an embodiment in which a change in the processing depth position of the laser irradiation surface is detected using a positioning sensor, and a positioning sensor is used as the light receiving element 6 for receiving the reflected light from the reflection surface. Positioning sensor is P, Q2 as shown
A plurality of photodiodes or phototransistors are mounted side by side at a small interval on a plane, and the output changes linearly according to the area on which light is applied.

When the laser beam is focused by the output beam lens 4 of the laser oscillator 3 and hits the irradiation surface at the position A, the reflected light passes through the lens 5 and forms an image at point a on the light receiving surface.

In this case, as shown in FIG. 8 (a), if it is the midpoint between the two photodiodes P and Q, the detection signals proportional to the area are equal. When the light reaches the irradiation position B due to the processing, the reflected light passes through the lens 5 and forms an image at the point b on the light receiving surface, and the reflected light forms the eighth position.
The light receiving area of the photodiode is P> Q as shown in FIG.
become. Assuming that the signal of the photodiode P is (P) and the signal of the photodiode Q is (Q), (P) and (Q) are applied to the discrimination output circuit 7, and are amplified by the amplifiers 71 and 72, respectively.
The sum operation circuit 73 calculates (P) + (Q), and the difference operation circuit 74
, (P)-(Q) is calculated and output, and the divider circuit 75 outputs (P)-(Q) / (P) + (Q).

In the case of FIG. 8A, since the light receiving signal (P) = (Q), (P) − (Q) / (P) + (Q) = 0, and in the case of FIG. Because (P)> (Q), 1>
(P)-(Q) / (P) + (Q)> 0. Also, the eighth
In the case of FIG. 9C, since (Q) = 0, (P)-(Q)
/ (P) + (Q) = 1. Conversely, when the light moves as shown in FIG. 8 (d), (P) = 0, so that (P) −
(Q) / (P) + (Q) = − 1. Therefore, 1 ≧ (P) − (Q) / (P) +
(Q) ≧ −1.

The output (P)-(Q) / (P) +
(Q) is determined by the next comparison determination circuit 76. As shown in FIG. 9, a Schmitt circuit of transistors Tr ₁ and Tr ₂ is used as the discriminating circuit 76. If the comparison reference value H is set to a certain value of 1 ≧ H> 0, the input (P) − (Q ) / (P) + (Q)
There outputs a signal O ₁ when became equal to H. If the irradiation surface level B is set to the set depth, then (P)-(Q) /
(P) + (Q) = outputs an H level signal O _1, commands the movement of the irradiation point by adding it to the NC control device 8.

FIG. 10 shows an embodiment in which the control of the motor 14 is detected and controlled by a positioning sensor when the condensing lens 4 shown in FIG.

Now, when the output beam of the laser oscillator 3 is focused by the lens 4 and hits the irradiation surface at the position A, the reflected light is
And is bent at a right angle by the half mirror 15 to enter the point a on the light receiving surface. When the irradiation surface is at the processing position B,
The reflected wave hits point b on the light receiving surface. As described above, the light receiving position of the reflected wave on the light receiving surface moves in accordance with the change in the irradiation surface position, whereby the detection signal outputs (P) and (Q) of the two photodiodes P and Q change, and this is processed. As described above, the signal output (P)-(Q) / (P) + (Q) can be obtained. This output signal is sent to the next control signal generation circuit.
It can be a vertical automatic focus control of the lens 4 by addition to 77 outputs a forward and reverse control signals O ₂ for driving the motor 14. The control signal generating circuit 77 is constituted by the transistors Tr _3, Tr ₄ as Fig. 11, the input to the signal (P) -
By adding (Q) / (P) + (Q), 1 ≧ (P) −
According to (Q) / (P) + (Q) ≧ −1, a forward / reverse drive signal can be applied to the motor 14 to perform automatic focus control of the lens 4.

Note that a signal is input to the input terminal of the control signal generation circuit 77 in FIG.
Even if (P)-(Q) is added, it is possible to drive the motor 14 to cause the lens 4 to follow the change in the processing position on the irradiation surface, and focus the laser beam on the processing position for processing. it can.

FIG. 12 shows another embodiment in which the penetration depth is detected by using a change signal of the image forming position of the reflected light, which uses an astigmatism optical system with a semi-cylindrical lens 18. FIG. (A)
The figure shows a case where the focal point of the lens 4 coincides with the surface A of the object, and the parallel beam is tilted by
And the surface A is focused. When the reflected light from the surface A is extracted by the half mirror 15 and applied to the semicircular lens 18, a circular spot is formed on the light receiving surface 20. The light-receiving surface is provided with a four-divided light-receiving element 21 as shown in the front view on the right, and the signals of the opposing elements are added and the circuit is connected so that the adjacent elements are subtracted. Is 0 because the outputs cancel each other. Next, as shown in FIG. 3B, when the penetration proceeds due to the pulse irradiation and the depth reaches the irradiation surface B, the reflection surface becomes deeper than the focal point of the lens 4. Since a horizontally long elliptical spot is formed on the light receiving element 20 and is received by the light receiving element 21, a negative signal is output. On the other hand, when the irradiation surface B rises (welding, plating, polymerization, etc.) as shown in FIG.
When the reflected light is applied to the lens 18, a vertically long elliptical spot is detected on the light receiving surface 20, and a + signal is output to the output of the light receiving element 21. Also, in FIG.
As for the signal, the minus signal value increases as the penetration depth increases, and the plus signal in FIG.
Since the signal value increases, it is possible to easily and accurately detect the position of the machined surface of the penetration or swell up to a predetermined set value by determining the signal amount. This detection signal controls the shape feed in addition to the NC control device 8 shown in FIG.
Precision control can be performed by controlling the condenser lens in addition to the automatic focus control circuit 16 in FIG. 5 and controlling the laser oscillator in addition to the automatic energy control circuit 17 in FIG. .

The apparatus of the above-described three examples, which detects and determines the processing depth position based on a change signal of the imaging position of the reflected light from the irradiation surface, is used for both movement control of the spot irradiation position and automatic energy control or automatic focus control. Can be.

FIG. 13 shows an artificial dental implant (implant) to be implanted in the oral endosteum, a flat implant 22 to be implanted in the alveolar bone, a neck 23 erected from the implant, and a cervix. Followed by a head that is exposed in the oral cavity and serves as an abutment for artificial teeth
It is a single metal structure consisting of 24 metal elements. A large number of holes 22a having a diameter of about 1 to 3 mm are formed in the flat plate to increase bone holding power.

FIG. 14 shows a state in which an implant implantation operation has been performed, and the flat plate portion 22 is deeply embedded in the jawbone 26. Reference numeral 25 denotes an artificial tooth, which is bonded and fixed to the head 24 fixed and embedded with cement. The laser apparatus of the present invention is suitable for forming such an implant. The implant cannot fit into the alveolar bone unless it is precisely formed and processed to the designed dimensions and shape, and neurovascular, mandibular canal and other anatomical structures pass through the implant adjacent to the implant. Implants can cause damage to these natural structures, and the dimensions are precise, but castings, injection extrusions,
It is possible to extremely precisely form and process a rolled or cast implant by a laser device.
Using an apparatus as shown in Fig. 1, the contour of the implant material, holes in the implanted part, etc. are easily formed and processed by controlling the program movement while detecting the penetration depth of the irradiation spot according to the NC program. be able to. Also, since the implant is implanted in the alveolar bone, the head
Although the teeth 25 are adhered to the teeth 24, there is a slight sense of incongruity depending on the support state, and it is necessary to correct the dimensions and shape of the head 24 in the implanted part. In such a correction process, the processing and the forming process can be performed precisely and cleanly by the laser while controlling the optical fiber by the manipulator and controlling the light irradiation and the detection of the reflected wave. For precision formation, the 3rd to 5th harmonics of YAG laser (wavelength 2000mm or less), excimer laser (wavelength 193nm)
By using the following, a highly accurate forming process can be performed.

FIG. 15 shows a disk wheel of diamond, cBN, or the like, that is, a groove is formed in the alveolar bone when the implant is implanted in the jaw bone. This is an application example of a laser device when making a laser beam. A laser beam is condensed and irradiated on the peripheral edge of the disk plate 27 to perform processing such as cutting with a blade, electrodeposition of abrasive grains, sharpening, and quenching. By rotating and moving the disk while detecting the height, the entire circumference of the disk plate can be uniformly and precisely bladed.

When forming ridges such as plating, it becomes impossible to focus on the illuminated surface as the ridges rise.In that case, processing is performed while performing automatic focus control by detecting the illuminated surface position signal to achieve high precision with high precision. Can be processed.

In addition, the implant as shown in FIG.
If the heads 24 are not integrally manufactured by casting or the like, they are separately manufactured and fixed by welding, but a laser device can also be used for this welding. Not only for artificial roots, but also for artificial teeth, artificial joints, ceramics, plastics, and composite materials, not only for metals, but also for bone formation and cutting in vivo,
It can also be used for surgery on various organs, excision of tumors, suturing, sterilization, injection of anesthesia, etc. At this time, a laser beam is guided by a fiber, irradiation, depth detection is performed, energy control, focus control, movement of irradiation shape By performing the control, it is possible to perform a precise forming process on an arbitrary portion in the living body.

In addition, the laser processing can be performed with the polyps formed in the body while directly measuring the irradiation surface position in various operations such as tumors and cancers, bone operations, and the like. In this case, a laser beam is injected into the affected part in the form of an injection needle while operating the optical fiber with the manipulator, and the operation can be performed accurately and reliably while detecting the processing depth position of the irradiation surface.
The wavelength of the laser to be irradiated is venous plaque 465 nm, blood vessel type 530 to 590 nm, cancer cells 600 to 700 nm, and gallstone 570 nm, all of which are 1
Select and use one with an energy of about 00mJoule. YAG
The second harmonic of the laser is 530 nm, the excimer laser is 193 nm, and if this laser is used for bone surgery, micromachining can be performed in a non-contact manner, and the incision is made by scanning the manipulator while detecting the incision depth. Surgery can be performed with complete precision.

〔The invention's effect〕

As described above, according to the present invention, the processing depth (penetration depth or swelling height) of a pulse or on / off control laser irradiated onto the surface of a portion to be formed by spot irradiation is determined by combining reflected light from the irradiated surface. By configuring to detect by the change signal of the image position, it is possible to detect the processing depth with high accuracy compared to the conventional technology that detects the processing depth by the change in the amount of reflected light from the irradiation surface, Since the detection signal of the processing depth is determined and the irradiation spot is moved to the next spot irradiation position each time the processing depth reaches a predetermined value, the penetration or swell amount of each irradiation point is reduced. Constantly constant, one-dimensional, two-dimensional, or three-dimensional movement control of this spot irradiation position and laser processing with extremely high molding accuracy can be performed by forming and processing to the required shape,
Further, by selecting the wavelength of the laser beam and finely controlling the amount of penetration or swelling of the irradiation point, it is possible to perform an extremely fine and precise forming process.

In addition, by performing automatic energy control or automatic focus control of the pulse laser based on the processing depth detection signal that detects the level of the penetration depth or the rising height at the irradiation spot, a plurality of repetitive pulses at the spot irradiation point The energy or focal point of the surface is changed and controlled by the change in the level of the penetration or swelling surface, so that the irradiation surface can always be repeatedly irradiated with a constant pulse energy with a constant spot diameter regardless of the depth change. The processing can be performed with a constant width and the processing precision can be finely and precisely processed.

And according to this, artificial roots, artificial teeth, artificial joints,
It is extremely effective using a forming process that requires precision and fine processing such as living bone, an in-vivo organ, or a surgical operation thereof, or a tool used therefor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of one embodiment of the present invention, FIGS. 2 to 4 are explanatory diagrams thereof, FIGS. 5 to 12 are partial block diagrams of other embodiments, FIG. 13 to FIG. 15 are explanatory diagrams of use examples of the present invention. 3 Laser oscillator 4 Condensing lens 5 Light receiving lens 6 Light receiving element 7 Discrimination output circuit 8 NC control device 9,10,11 Drive motor 14 Lens drive coil 16 … Automatic focus control circuit 17 …… Automatic energy control circuit

Claims (3)

(57) [Claims] An irradiation device for converging a pulse laser output from a laser oscillator or a laser whose on / off control is performed by a condensing lens and irradiating a spot on a surface of a portion to be formed. In a laser forming apparatus comprising: a moving device for moving the moving device; and a control device for controlling the operation of the moving device to form and process the surface of the portion to be formed into a required shape. Optical device that forms an image through a lens, a detection device that detects a change in the imaging device by the optical device as an electric signal, and a processing depth by the spot irradiation from a change signal of the imaging position detected by the detection device. A discrimination output circuit for outputting to the control device a signal permitting movement to the next spot irradiation position when the processing depth reaches a predetermined value. Laser forming apparatus, characterized in that the. 2. The laser forming apparatus according to claim 1, wherein a detection signal of the detection device or a detection signal of another detection device for detecting the processing depth is used.
A laser forming apparatus, comprising: an automatic energy control device that controls increase and decrease of the energy of the irradiation laser. 3. The laser forming apparatus according to claim 1, wherein a detection signal of the detection device or a detection signal of another detection device for detecting the processing depth is used.
A laser forming apparatus, further comprising an automatic focus control device for controlling the distance between the condensing lens and the surface of the portion to be formed by moving the condenser lens.