The technology of laser small hole of material of crystal of man-made gem corundum studies

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Carry theoretical analysis and experimental research, discussed small hole of material of crystal of man-made gem corundum width of the energy of pulse of the laser in parameter of craft of laser beam machining, pulse, smooth from swash of anxious quantity, arteries and veins repeat frequency to be opposite the influence of small hole diameter and hole depth, those who decided small Kong Jiguang machines craft parameter is effective match assorted method. 1 foreword grows as the synthesis of lapidary corundum crystal rapidder development of the technology, the material of crystal of man-made gem corundum that good general interest accumulates character is increasing. Crystal of man-made gem corundum is one kind has the good heat, report, electron, optical, stuff that exceeds strong fragile performance, with the precision that its make small hole component is used extensively at the domain such as medical treatment of mechanical electron, biology, aerospace and photoelectricity technology in recent years, but its machinability is poorer, easy generation " crackle " and " collapse break " blemish, want to make component of nicety small hole with its, small Kong Jia is versed in craft and the research that decide corresponding parameter are very significant. In ruby at present small Kong Jia is versed in the respect precedes is Switzerland, in sapphirine nicety planar treatment respect has larger dominant position is Japan and United States, and our country still is in primary level in material of lapidary corundum crystal. Article union space navigation controls the nicety in a powerful person with aerobic nicety core of ruby a powerful person is developed (main technique parameter sees a picture 1) actual production experiments, discuss what small hole machines each parameter to adjust the rule, those who decide each craft parameter is effective match assorted method, raise aperture to machine quality and precision. 2 treatment method is opposite on international at present the aperture of ruby crystal component machines a method, basically be laser and ultrasonic treatment. Classics experiment, ultrasonic is machined to the aperture of lapidary corundum crystal, laser beam machining is inferior to in precision and efficiency respect, machine a respect in small hole especially, ultrasonic processing technique cannot satisfy production to machine a requirement. We choose laser stiletto. Laser is YAG laser, it is laser of a kind of solid, the matrix material of its laser club is yttric aluminous garnet, wavelengh of its feature output is 1.

06um, can make pulse output, also can make successive output. YAG laser basically has the following 3 kinds of advantages: The optical data with the usable and average light that is output is delivered. 2 it is material of lapidary corundum crystal taller to YAG laser absorptivity. 3 it is a wave accident, stability is good, output energy is bigger. Output energy sees energy of transition of the following electron is formulary: The C in type is velocity of light, v is wavelengh, f is frequency, h is constant of Pu Lang gram, h=6.

Joule of 6 X 10*-34.

Second the process of the characteristic laser stiletto of 3 treatment parameter is the heat with laser and treatment material extremely complex interaction, physics, chemical process, material purify basically reachs the motion that destroys generation content to concern with the destruction of the material inside laser action area, can express to be commonly: Horny T falls in type, r, a, t expresses incident, reflex respectively, absorb, the energy of transmission. The kinetic problem that hole wall of edge of material of the steam of the generation when the cause of formation that analyses laser stiletto strictly needs to solve laser stiletto, aerification flows and treatment material are characteristic, consider to heat for an instant all elements of the process. This discusses very complex, and experimental data collects difficulty, undertake hard, also do not have the report with this successful respect at present. We use a test estimated parameter of craft of stiletto of methodological choice laser, amend stage by stage in treatment perfect. Union produces practice, the feature that through using YAG laser to production each craft parameter and Kong Jia are versed in and the experiment that material purify quantity concerns study, obtained the energy that includes laser pulse, pulse width, smooth from swash of anxious quantity, arteries and veins repeat frequency and be waited to machine parameter by the property of treatment material specific and effective match combination. 3.

Club of laser of energy of 1 laser pulse and optical system parameter decide the size of the laser facula diameter on anxious plane. The change of its pulse energy is to pass the change that to lamp of pump riverside xenon two end input voltage to come true. If the graph is shown 2 times,be diagram of principle of laser stiletto geometry. The diameter of beam of light that Nextpage assumes laser is outputted is D, horn of disperse the internal heat with sudorifics is A, be in through convergent lens material apparently focusing, its assemble horn namely the horn of diverge of laser light beam after assemble is 2B, laser stays radius is R0, , r is in the underside radius of T hour aperture (T) , aperture as H (T) , have: Evaporate from hole bottom considering material, the material of aerification erodes from hole wall high speed flow, the equation of conversation of energy of T hour is: In type, lb sends aerification to compare for evaporate can, lm is compared to fuse can. Left expresses the energy increment that T hour laser offers, right evaporates the first times for hole bottom the energy increment that use up, the 2nd Bian Rong that it is aperture changes the energy increment that use up. When H (T) >> when R0, OK and approximate solution gives the total energy with laser beam machining - denotive hole depth and aperture are: By type (5) reach (6) knowable, the hole depth that laser calls is spent and bore diameter and laser pulse energy are become nonlinear relation, as laser energy drab increase by degrees.


Diameter of 2 smooth diaphragm is in laser beam machining, be in intensity attenuation than the focus commonly the between 2 o'clock distance definition of 10% is " Jiao Shen " , its can state with next type the Z in type is Jiao Shen, d0 is diameter of laser light beam, for laser wavelengh. By (7) type is knowable, when hours the diameter that changes laser light beam is big, can change the Jiao Shen of laser, change the appearance of stiletto and size thereby. We design the diameter of the diaphragm that connect light that installs different diameter to have stiletto test, reached the diaphragm that chooses different diameter and the metabolic rule that machine the deepness of aperture and aperture, specific see next tables 1: From the watch the test data of 1 is knowable, when energy is constant, diaphragm diameter is when broad limits change, the deepness change of aperture is tiny. When the diaphragm with use lesser diameter, the deepness of aperture and diameter produced markedder change. Case study: When laser energy is changeless, when change diaphragm diameter, do not change stimulate the power density inside cross section of beam of light, changed the horn of disperse the internal heat with sudorifics that stimulates beam of light and diameter of beam of light however, changed the anxious deep size of laser thereby, also changed the ratio of pit-depth to pit-diameter of aperture. Classics experiment, increase when laser energy, when at the same time diaphragm diameter is reduced, the ratio of pit-depth to pit-diameter of aperture is bigger. 3.

E of energy of pulse of radiant of laser of 3 pulse width can express with the following relation: The P(t) in type, the instantaneous radiate power in T instant, t, for pulse width. By (8) knowable time when pulse energy, arteries and veins is wide narrower, density of the energy between meantime is bigger, the proportion of gas phase material that stiletto place produces is larger, the pressure that generates thereby is greater also. The change with so broad arteries and veins is mixed to hole depth, aperture the impact of aperture appearance is bigger. Experiment via treatment, reached the to aperture deepness and aperture change when choosing wide value of different arteries and veins concerns. Specific see 2:n issueing a listThe test data of 2 is expressed on Extpage knowable, dig deep and small hole, appropriate chooses bigger pulse width; Dig big and shallow hole, criterion appropriate chooses lesser pulse width. The pulse width limits of the YAG laser that produces on the market at present is 0.

20--130ms. But when machining lapidary corundum crystal, when arteries and veins broad shift arrives 1.

The aperture defect that makes when 2ms above is more, main show bursts apart for crackle, orifice serious, destroy a layer to wait for blemish very greatly. Classics experiment reachs stiletto of pair of lapidary corundum crystal when, the pulse width limits that chooses commonly is 0.


2ms. Hit small Kong Shiyi to choose pulse width limits for 0.


55ms, the hole that digs destroys a layer lesser. 3.

System of 4 focusing focusing basically reachs focusing device composition by focusing lens. Given to for YAG laser beam drilling machine, the main property of its optics system is already certain, but the effect that producing what optical system discovers in using actually to adjust pair of treatment quality is very big, machining side of data of lapidary corundum crystal especially its result is more clear. If the graph is shown 3 times, the least place that laser gathers together calls a central issue, the face that its are located in calls anxious plane. The anxious plane that alleged focusing condition is the focal length that points to focusing system and this system is machined relatively the displacement of workpiece surface. When focusing lens undertakes laser light beam focusing, can make around anxious plane laser light beam appears " bundle form " tubal form gathers together phenomenon, the diameter of focusing facula expresses approximately to be: The D in type is incident laser bundle diameter, f is lenticular focal length, v is laser wavelengh. From this knowable it is besides anxious plane, focusing spot diameter greatened. Below the condition that keeps changeless in laser general power, focusing spot is smaller mean power density more bigger. Conversely, power density is smaller. When laser focusing is machining the surface of material, the hole that digs is deeper, taper is lesser. When the focus is in position of the some below the surface, below same condition, the hole that digs is the deepest; And exorbitant can make from anxious quantity laser power density is reduced greatly, as a result is hit into blind aperture, leaving anxious amount is to point to the distance between the surface on material and lenticular focus. In the experiment, undertake steep to stiletto workpiece umbriferous detect, discovery leaves the bulk of anxious quantity, to Kong Jia industry figure has very big effect. When leaving anxious quantity bigger, the aperture form of treatment is parabola form or round cone-shaped shape; When the position of anxious plane stands by position of workpiece surface some, the Kongwei of treatment is cylindrical; Be being machined when anxious plane when deepness of some of interior of work spare parts, the aperture of treatment is flask appearance. By on type (9) knowable use focal length to compare short lens to be able to dig the hole with a lesser diameter, because use the lens of short focal distance, bigger power density can be obtained on the focus, hit hole is small and deep. It is through choosing focal length F 20- - the focusing lens stiletto of 120mm limits experiments, undertake steep to stiletto result umbriferous detect, reach to be being chosen when stiletto of lapidary corundum crystal focal length is F=35mm, f=45mm, f=55mm, f=75mm, the lenticular stiletto quality of F=100mm is better; Hitting small Kong Shi, the lens that chooses F=45mm is best. 3.

Treatment of much pulse of treatment of 5 much pulse pledges actually even if hole is not formed by a pulse, form by the place of a group of pulse that has parameter of same laser radiate however, these pulse have certain energy and arteries and veins wide, continuous undertake machining to workpiece, arrive at a product to machine craft to ask continuously. Much pulse treatment can make of the energy on workpiece transverse diffuse reduce the smallest, and conduce to the size dimensions of control aperture and appearance requirement. Integrated afore-mentioned, we produce experimental stiletto place to use the main parameter of YAG laser to be as follows: Stimulate smooth wavelengh: 1.

06um; Laser outputs energy: 70J; Laser pulse frequency: 1- - 100Hz; Laser pulse width: 0.


0ms; Horn of diverge of beam of light: <10mrad. 4 use auxiliary technique and measure to raise treatment quality experiment to prove, use the following and auxiliary method the quality of stiletto of laser of material of crystal of lapidary to rising corundum has effect very much. 1) bring to bear on in the surface of workpiece to pressure, or it is the opposite in workpiece installs a low-pressure storehouse, in can conducing to stiletto process, be opposite generation is residual and cleared, raise residual eduction rate, reduce the loss of laser energy radiation in machining a process thereby. 2) in machining a process, use compress air to undertake blowing washing to the workpiece aperture of treatment, can help photograph of treatment process fluid and residual eduction, melt of OK and abate treatment does not suffer the effect that pilot distributings afresh and causes to the dimension of aperture and appearance, return the focusing lens area that can protect optical system, because pass a choice to compress airy to carry heading, but better prevent residual splatter, agglomeration arrives on focusing lens face, destroy the plated film layer of focusing lens face, avoid laser attenuation aggravate, the influence machines quality and efficiency. 3) the exterior situation that uses a few auxiliary methods to change treatment workpiece, in order to improve its the absorption to laser state, if will machine color of workpiece surface besmear, hit the method such as wool, measure in order to reduce treatment workpiece surface to the reflex of laser. 5 brief summary the article is a foundation with producing a test, tie concerned theory, analysed laser to be in stiletto of material of lapidary corundum crystal the influence that each parameter machines to aperture, discussed laser each parameter is in in material of lapidary corundum crystal the metabolic rule in stiletto, width of the energy that includes laser pulse, pulse, smooth from swash of anxious quantity, arteries and veins repeat frequency and was waited for by the property of treatment material more meticulous research experimentation, use actual production in the center, the quality in solving small in the past Kong Pisheng to produce treatment the problem such as difficulty of not stable, treatment, summary gave a few good technique and auxiliary way, make laser stiletto quality got rising. CNC Milling