CN1295052C - Laser milling method and system - Google Patents

Abstract

The present invention discloses a method for producing milled structures in a fixed material using a laser beam (207), wherein a picosecond laser (205) provides short pulses of light energy to produce a desired exposure segment, wherein the laser beam (207) moves at a variable rate to mill the material, the movement of the laser beam (207) causes the milling to be performed on the material, the laser beam tool path guides the milling process to produce high-quality and repeatable milled holes, and the experience of how to measure these three quantities is returned as feedback to the laser system (200).

Description

Laser milling method and system

technical field

The present invention relates to material ablation using pulsed light sources, in particular to laser drilling and laser milling.

Background technique

Material ablation by pulsed light sources has been studied since the invention of the laser. A 1982 report of polymers etched using ultraviolet (UV) excimer laser radiation stimulated extensive research into micromachining methods. Since then, scientific and industrial research in this field has been advancing rapidly, mainly due to the ability to use lasers to drill, mill and replicate very small parts.

Ultrafast lasers generate intense laser pulses with a duration of approximately from 10 ⁻¹¹ seconds (10 picoseconds) to 10 ⁻¹⁴ seconds (10 femtoseconds). Short pulse lasers generate intense laser pulses with a duration of approximately from 10 ⁻¹⁰ seconds (100 picoseconds) to 10 ⁻¹¹ seconds (10 picoseconds). Various potential applications of ultrafast lasers in medicine, chemistry and communications are becoming a reality. These lasers are also useful tools for milling or drilling a variety of materials. They can easily drill holes as small as a few microns, or even sub-micron in size. Holes with high aspect ratios can also be drilled in hard materials, such as cooling channels in turbine blades, nozzles in inkjet printers or through-holes in printed circuit boards.

The ability to drill holes down to micron-scale diameters is an essential requirement in many high-tech manufacturing industries. Simultaneous high resolution, high accuracy, high speed and high flexibility enable laser processing to be used in many industries including the manufacture of integrated circuits, hard disks, printing equipment, displays, interconnects and telecommunications equipment.

There are several methods of laser machining; however, when it comes to drilling small parts, the final product tolerances are much tighter in laser micromachining. In this case, the machining process used must provide consistent, predictable and repeatable results for the end application. Computer control via algorithms and software in laser micromachining offers the opportunity for the fine control of hole geometry and consistency required for profitable mass-production fabrication facilities. Although there are still many problems with micromachining, such opportunities should not be wasted.

A continuing problem in this field relates to avoiding micromachining to produce off-spec products. The reason this problem persists is that in micromachining, tolerances are low and consistency requirements from product to product are extremely stringent. For example, the orifices of inkjet nozzles must be manufactured to be uniform to provide an equal ejection of ink from each orifice in use. When processes are inconsistent or not repeatable, the manufacturing line will produce out-of-spec product that must be reworked, wasting time and energy, and reducing throughput. This in turn reduces profit margins for manufacturing facilities. Thus, there is a need for a method of avoiding micromachining to produce out-of-spec products. Another ongoing problem with micromachining involves producing consistent and repeatable results in milling. As mentioned above, consistency and repeatability are important factors in producing technically acceptable high quality micromachined products. However, current milling methods cannot guarantee consistent hole geometry for each product in the manufacturing line. Thus, there is a need for a method to produce consistent and repeatable results in milling.

Yet another ongoing problem with micromachining concerns providing guidelines for establishing toolpath geometries; in recent years, milling techniques that produce predictable and repeatable hole geometries have proven difficult to implement. The desired hole geometry has been fabricated using a trial and error method: iteratively varying parameters to achieve the desired shape. A typical procedure is to step the desired toolpath radius linearly over time; however, this technique results in non-uniform pitches in the helical path, causing variations in radial overlap. The resulting uneven ablation is undesirable. One algorithmic approximation was relatively successful because it produced the desired shape with constant angular velocity and tool pitch. However, this processing method cannot compensate for the pitch of the exposed segments produced near the center of the hole as shown in FIG. 1 . Thus, there is a need for a method that provides guidelines for establishing toolpath geometry.

Yet another ongoing problem with micromachining relates to providing a laser drilling system toolpath that allows for constant material removal. Current milling requirements require total material ablation on the target area of the workpiece. Previous techniques include methods such as excimer laser ablation and constant angular velocity approximation as shown in FIG. 1 . However, these techniques do not provide the flat surfaces required by user specifications. Thus, there is a need for a method of providing a laser drilling system toolpath that allows for constant material removal. Yet another persistent problem with micromachining involves maintaining a constant exposure of the laser source on the workpiece as the toolpath changes. In a constant-pulse laser system, the laser pulses at a fixed repetition rate; thus, uniform ablation translates into a desired constant propagation velocity at the point of laser impact on the workpiece. When using a semi-circular motion such as a helical type motion, the linear velocity at the point of impact should be constant throughout the laser milling process to maintain constant ablation. There is therefore a need for a method of maintaining a constant exposure of the laser source to the workpiece as the toolpath changes.

Contents of the invention

In a first aspect, the present invention is a method of producing milled structures in a stationary material using a moving laser beam, wherein a picosecond laser delivers short pulses of optical energy to produce the desired exposure segment, the rate of change of the laser beam's motion is on the material Milling is performed with a laser beam toolpath guiding the milling process to produce high quality and repeatable milled holes, and the experience of how to measure these three quantities is returned to the laser system as feedback.

In a second aspect, the invention is a helical milling toolpath capable of achieving a user-specified tapered hole shape. To produce a user-specified tapered hole, a constant arc velocity toolpath is required.

It will be apparent from the following detailed description that the present invention can be applied to other aspects. For example, although the invention is described herein with reference to the modification of the angular velocity as a function of the radius of a circular helical toolpath, it will be appreciated that for different applications requiring a helix other than circular, it can be achieved in different ways. Get a constant arc speed. Thus, more generally the rate of movement of the laser beam relative to the workpiece surface can be modified as a function of distance from at least one fixed axis (eg an ellipse has two associated axes). It should be understood that the detailed description and specific examples of the preferred embodiment of the invention are provided for illustration only and are not intended to limit the scope of the invention.

Description of drawings

The present invention is described in more detail below by detailed description and accompanying drawing, wherein:

Figure 1 is a block diagram of a constant angular velocity toolpath;

2 is a block diagram illustrating a simplified schematic diagram of a laser drilling system;

Figure 3A is a block diagram of a constant arc velocity toolpath corresponding to a circular inward spiral;

Figure 3B is a block diagram of a constant arc velocity toolpath corresponding to a circular outward spiral;

Figure 4 is a flow chart illustrating the laser milling method;

Fig. 5 is a perspective view showing main constituent parts of the inkjet printer;

Fig. 6 is a schematic cross-sectional view of an inkjet head.

Detailed ways

The following descriptions of preferred embodiments are merely exemplary in nature and are in no way intended to limit the invention and its application or uses.

The present invention is a method of milling using a constant toolpath algorithm (or "milling algorithm") that can be used to produce holes in a consistent, repeatable process. Furthermore, this machining process can be used to machine multiple milled holes in parallel at the same time.

As mentioned above, the approximation algorithm is relatively successful because it can produce the desired hole with constant angular velocity and tool pitch. Also as mentioned above, this process cannot compensate for the spacing of the exposed segments produced near the center of the hole.

Referring to FIG. 1 , a constant angular velocity toolpath (toolpath) 100 includes an initial voltage (V _max ) 110 outside a contoured milling surface, laser exposure segments 120 and pitch 130 of the tool pitch. With this approximation, a large number of exposed segments 120 are generated near the center of the target, resulting in excessive ablation in this area. In this example, approximately 10,000 laser exposure segments 120 were used to create the helical toolpath 100 .

Referring to FIG. 2, a simplified schematic diagram of a laser drilling system 200 includes: a laser 205, a light beam 207, a shutter 210, an attenuator 215, a beam expander 220, a rotating half-wave plate 225, a first mirror 208, a second mirror 217, Third mirror 221, fourth mirror 222, piezoelectric transducer (PZT) scan mirror 230, diffractive optical element (DOE) 235, multiple sub-beams 237, scan lens 240, microfilter 245, image transfer lens 250 and workpiece 255, which are arranged as shown in the figure. Although the present invention uses a picosecond laser system, other laser systems such as excimer, _CO2 and copper vapor laser systems can be used with the present invention.

The components and operation of the laser drilling system 200 are briefly described below. In alternate embodiments, it may be desirable to change elements of laser drilling system 200 . The present invention is not limited to the current selection and arrangement of components in laser drilling system 200 .

In operation, picosecond laser 205 emits light beam 207 along the optical path indicated in FIG. 2 . The light beam 207 propagates along the optical path and is incident on the first mirror 208 . The first mirror 208 changes the direction of the light beam 207 along the optical path, and makes the light beam 207 incident on the shutter 210 . Shutter 210 opens and closes to selectively illuminate workpiece material. Beam 207 exits shutter 210 and travels along the optical path to attenuator 215 . Attenuator 215 filters the energy of picosecond laser 205 to precisely control ablation parameters. The light beam 207 leaves the attenuator 215 , and propagates along the optical path, and is incident on the second mirror 217 . The second mirror 217 changes the direction of the light beam 207 along the optical path, so that the light beam 207 is incident on the beam expander 220 .

Beam expander 220 increases the size of beam 207 to serve two purposes. First, it increases the beam size to allow the DOE 235 to properly function as a beam splitter. In order for the DOE 235 to function properly, the beam size incident on the DOE 235 needs to be large enough to cover several cycles of the DOE 235. Second, it increases the beam size to match the scan lens pupil size. The light beam 207 leaves the beam expander 220 , propagates along the optical path, and enters the third mirror 221 . The third reflective mirror 221 changes the direction of the light beam 207 along the optical path, so that the light beam 207 is incident on the fourth reflective mirror 222 . The fourth mirror 222 changes the direction of the light beam 207 along the optical path, so that the light beam enters the rotating half-wave plate 225 . Rotating the half-wave plate 225 changes the polarization of the light beam 207 . After leaving the rotating half-wave plate 225 , the light beam 207 travels along the optical path and enters the PZT scanning mirror 230 . PZT scanning mirror 230 moves according to a pattern predefined using a milling algorithm (not shown) to drill holes in workpiece 255 . The PZT scan mirror 230 redirects the light beam 207 along the optical path so that it is incident on the DOE 235.

The DOE 235 splits the beam 207 into a plurality of sub-beams 237, enabling parallel drilling of the workpiece 255. Sub-beam 237 exits DOE 235, travels along the optical path, and is incident on scan lens 240. Scan lens 240 determines the spot size of sub-beam 237 on workpiece 255 . The sub-beam 237 leaves the scan lens 240 , propagates along the optical path, and enters the micro filter 245 . Microfilter 245 equalizes the intensity of sub-beams 237 . The sub-beam 237 leaves the micro filter 245 , travels along the optical path, and enters the image transmission lens 250 . Image transfer lens 250 reimages the focal spot of sub-beam 237 onto workpiece 255 . The beamlets 237 ablate the workpiece 255 in a pattern according to a predetermined milling algorithm.

Referring to FIG. 3A , a constant arc speed toolpath 300A includes an initial outer contour milling face exposure voltage (V _max ) 310 , multiple exposure segments 320 with constant arc speed and pitch, and tool pitch 330 pitch. In practice, in this example, the desired toolpath 300A consists of a number of lines of revolution separated by the tool pitch 330, and may be constant or variable depending on the desired final shape. Utilizing this constant arc speed toolpath provides a way to avoid manufacturing off-spec products and a way to produce repeatable results in milling. V _max 310 determines the outer radius of the helix in toolpath 300A. As shown, each line of revolution has a number of discrete exposure segments 320 as dictated by the software algorithm described in step 430 of method 400 described below. Referring to FIGS. 2 and 3 , uniform ablation translates into a constant propagation velocity of the PZT scanning mirror 230 as the laser 205 pulses at a fixed repetition rate to direct the laser impact point onto the exposure segment 320 of the workpiece 255 .

The constant arc velocity toolpath shown in FIG. 3A provides a flat surface on the workpiece 255 being ablated. Maintaining such a flat surface in the workpiece 255 provides a laser drilling system tool path that allows for constant material removal. This constant arc speed toolpath also provides a means of providing a laser drilling system toolpath that allows for constant material removal.

In the manufacturing process using the present invention, milling is also carried out outwards in the second half of the milling process. When the laser milling reaches the end of the inward spiral at t=T, the point of action of the pilot laser is moved in the outward spiral tool path 300B as shown in FIG. 3B. When the laser action point reaches the maximum radius for milling the next layer at t=T', the next inward spiral begins.

Referring to FIG. 4 , a method 400 of laser milling includes several steps. In step 410, the operator or technician provides a control system (not shown), such as a computer, capable of running an algorithm through a software program. A control system is electronically connected to the PZT scanning mirror 230 to provide operational control signals implementing the algorithm. In step 420, the operator or technician determines the desired hole geometry including taper angle, discharge hole diameter and entry hole diameter using user specified information such as CAD files and technical annotations. The operator or technician determines the voltage V _max 310 by considering the entrance aperture diameter, laser spot size and the voltage response of the PZT scanning mirror 230 . The operator or technician also uses the spot size of the laser 205 to determine the minimum allowable tool pitch 330 for the tool path 300A. For example, if the spot size is 10 microns, then the cutter pitch 330 should be a maximum of 10 microns to prevent under-ablated ridges from forming along the outer wall of the radially contoured milling face. For a 10 micron laser spot, the pitch size is preferably around 2 microns. A typical 40 volt bias on the PZT scan mirror 130 deflects the beam 107 on the workpiece 255 by about 45 microns. In step 430, the operator or technician sends the software code (not shown) present in the control system indicated above in step 410 to calculate the radius and angular velocity through the laser drilling cycle T to make the desired hole geometric shapes. For example, the following equation (A) describes the radius "r" along the toolpath 300A at any given time "t" during laser drilling:

$\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\sqrt{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; min</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; )</span>$

Likewise, equation (B) below describes the angular velocity "ω" along toolpath 300A at any given time "t" during laser drilling for a constant arc velocity:

$\mathrm{<span\; class="notranslate">\; \&omega;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\frac{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; )</span>$

Furthermore, when the laser milling reaches the end point of the inward helical toolpath 300A at t=T, during T≤t≤T', the guiding laser action point moves in the outward helical toolpath 300B determined by the following equation . Equation (C) describes the radius "r" along the toolpath 300A at any given time "t" during laser drilling:

${\mathrm{<span\; class="notranslate">\; r</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; min</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; min</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; )</span>$

Likewise, equation (D) below describes the angular velocity "ω" along toolpath 300B at any given time "t" during laser drilling for a constant arc velocity:

${\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\frac{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}{{\mathrm{<span\; class="notranslate">\; r</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; )</span>$

These four formulas are used to clarify the toolpath for drilling the conical shape, and these formulas exist in the form of algorithms in the software on the control system. This step provides guidelines for establishing the geometry of the toolpath.

In step 440, the control system sends the results of the algorithm performed in step 430 to a toolpath controller (not shown), such as a microprocessor, to initiate execution of the toolpath and start laser drilling. In step 450 , the controller described in step 440 sends the voltage corresponding to the digital output of the algorithm executed in step 430 to PZT scan mirror 230 during this time. This voltage is applied to the PZT scan mirror 230 to translate its position according to the calculated tool path and desired hole geometry in the workpiece 255 . At step 460, laser drilling system 200 mills workpiece 255 in the pattern previously shown in FIG. 3 according to the tool path algorithm. In the present invention, laser milling is performed using a layer-by-layer helical algorithm ("toolpath") whereby a tapered hole is formed by reducing the V _max 310 of subsequent helices.

As noted above, the invention is not limited to helical shapes; in alternative embodiments, other toolpath algorithms that maintain uniform exposure of various shapes may be used. Furthermore, _Vmax can be reduced in various ways between successive layers to achieve the desired contoured milled face in the finished workpiece. The vertical profile of the axis containing the hole determines how _Vmax (i) develops, where i is the number of stages in which _Vmax is reduced. The linear function V _max (i+1) = V _max results in a constant cone with a fixed cone angle. Another function V _max (i+1)=V _max (i)-(ΔV _max *i) makes the taper steeper and steeper. On the other hand, V _max (i+1)=V _max (i)−(ΔV _max /i) makes the slope of the cone angle smaller and smaller as the radius decreases. V _max (i) generally needs to be determined by cross-sectional (or shape) specifications.

At step 470, the toolpath algorithm described in step 430 determines whether the desired hole geometry has been obtained. The hole geometry is obtained when the toolpath algorithm has completed a precalculated amount of necessary helical ablation. Customary measurement techniques such as confocal microscopy methods and optical profilometry can also be used to determine whether the desired pore geometry has been obtained. If yes, method 400 ends; if not, method 400 returns to step 450 .

As described in further detail below, the laser drilling system of the present invention can be used to construct nozzle plates for inkjet heads.

As shown in FIG. 5, an ink jet printer 500 has an ink jet head 502 capable of recording on a recording medium 504 via a pressure generator. Ink droplets ejected from the inkjet head 502 are deposited on a recording medium 504 such as copy paper, so that recording on the recording medium 504 is possible. The inkjet head 502 is mounted on a carriage 506 that can reciprocate along a carriage shaft 508 . More specifically, the inkjet head 502 is configured to reciprocate in a first scanning direction X parallel to the carriage axis 508 . The rollers 510 convey the recording medium 504 in the second scanning direction Y in good time. The roller 510 relatively moves the inkjet head 502 and the recording medium 504 .

Referring to FIG. 6, pressure generator 600 is preferably a piezoelectric system, thermal system, and/or equivalent. In this embodiment, the pressure generator 600 is equivalent to a piezoelectric system including an upper electrode 602 , a piezoelectric element 604 and a lower electrode 606 . Nozzle plate 608 includes a nozzle substrate 610 and a waterproof layer 612 . Nozzle chip 610 is made of metal, resin and/or equivalent material. The waterproof layer 612 is made of, for example, fluorine resin or silicone resin. In this embodiment, the nozzle substrate 610 is made of stainless steel and has a thickness of 50 µm, and the waterproof layer 612 is made of fluororesin and has a thickness of 0.1 µm. Jetted ink fills ink supply channel 614 , pressure chamber 616 , ink channel 618 and nozzle 620 . When the pressure generator 600 pushes the pressure chamber member 620 , ink droplets are ejected from the nozzle 620 .

The invention forms a very good nozzle free of burrs and impurities (carbon etc.) in the nozzle plate. In addition, the accuracy of the nozzle outlet diameter is 20 μm ± 1.5 μm.

The present invention has several advantages. A first advantage of the present invention is the avoidance of micromachining to produce off-spec products. A second advantage of the present invention is that it provides a way to produce consistent, repeatable results in milling. A third advantage of the present invention is that it provides a system and guidelines for establishing toolpath geometry. A fourth advantage of the present invention is that it maintains a constant exposure of the laser source to the workpiece without the need for current laser power control. A fifth advantage of the present invention is that it provides constant material removal. A sixth advantage of the present invention is that helical milling results in continuous, consistent and seamless laser ablation of the workpiece. A seventh advantage of the present invention is that helical milling provides a means of using laser ablation to machine tiny parts with cylindrical symmetry. An eighth advantage of the present invention is that it provides uniform material removal with predictable ablation rates so that arbitrary profiles can be created.

The present invention also has some disadvantages. One disadvantage of the present invention is that it is time consuming. However, any milling operation takes a similar amount of time to perform, so this is not a significant issue. A second disadvantage of the invention is the increased speed of operation under damage control conditions. However, alternative closed-loop systems that provide additional control are too slow for cost-effective volume manufacturing environments.

Another way to solve the same problem is to fire the laser at a faster rate when the hole radius is outside the exposure segment. However, this approach requires additional process control that is difficult to synchronize and manage within the laser system.

The description of the present invention is for illustration purposes only, and thus various changes that do not depart from the gist of the present invention are included in the scope of the present invention. These changes do not depart from the spirit and scope of the invention.

Claims (22)

1. method of carrying out laser milling comprises:

Determine with the cutter path of laser from the exposed surface ablation layer of material of workpiece;

According to cutter path with the exposed surface ablation layer of material of laser from workpiece,

Wherein cutter path has defined a constant camber line speed.

2. method according to claim 1, wherein said definite cutter path is corresponding to using equation expression radius and local angular speed.

3. method according to claim 2 is wherein controlled radius as the function of the voltage of the PZT scanning mirror that outputs to the laser system of being operated by control system, and wherein said definite cutter path comprises definite initial voltage.

4. method according to claim 3, wherein radius can change according to the cutter pitch that reduces corresponding to each revolution voltage, and wherein said definite cutter path comprises according to the spot size of laser system and determines cutter pitch.

5. method according to claim 2, wherein control system can be operated, and with the angular speed of modification as the function of radius, thereby obtains constant camber line speed.

6. method according to claim 2, comprise that further revising cutter path removes follow-up material layer to finish from a new surface of the work that exposes, wherein subsequent layers of material reduces respectively on area, thereby influences the required contour milling face of laser milling workpiece.

7. method according to claim 6, wherein said modification is corresponding to reducing radius and improving local angle's speed.

8. method according to claim 1 further comprises the ablation of carrying out a plurality of workpiece according to cutter path simultaneously.

9. method according to claim 1 further comprises the ablation of carrying out a plurality of districts of a workpiece according to cutter path simultaneously.

10. laser milling system comprises:

Can operate to determine the utilizing cutter path module of laser instrument from the cutter path of the exposed surface ablation layer of material of workpiece for one, wherein cutter path has been described a constant camber line speed;

A plurality of can the operation to carry out the laser instrument of the ablation of a plurality of workpiece according to cutter path;

Can operate to utilize the control module of a laser instrument according to cutter path for one from an exposed surface ablation layer of material of workpiece.

11. system according to claim 10, wherein said cutter path module can be operated, to use equation expression radius and local angular speed.

12. system according to claim 11, wherein said control module can be operated, so that radius is controlled as the function of the voltage of a PZT scanning mirror that outputs to a plurality of laser instruments, and wherein said cutter path module can operate, to determine an initial voltage.

13. system according to claim 12, wherein said control module can be operated, to change radius according to a cutter pitch corresponding to the reduction of each revolution voltage, and wherein said cutter path module can be operated, to determine cutter pitch according to the spot size of a plurality of laser instruments.

14. system according to claim 11, wherein said control module can be operated, with angular speed as a function of radius and control, thereby obtain constant camber line speed.

15. system according to claim 11, wherein said control module can be operated, to revise cutter path, thereby finish from a new exposed surface of workpiece and remove subsequent layers of material, wherein subsequent layers of material reduces respectively on area, thereby influences the required contour milling face in the workpiece of laser milling.

16. system according to claim 15, wherein said control module can be operated, with by reducing radius and improving local angle's speed and revise cutter path.

17. system according to claim 10 further comprises the ablation of carrying out a plurality of workpiece according to cutter path simultaneously.

18. system according to claim 10 further comprises the ablation of carrying out a plurality of districts of a workpiece according to cutter path simultaneously.

19. the workpiece of a laser milling, comprise that has the laser ablation that passes through workpiece material and the workpiece layer that forms a hole therein, wherein laser ablation is to carry out according to cutter path on the surface of described workpiece layer by the laser drilling system of drive laser beam, and wherein cutter path has constant camber line speed.

20. workpiece according to claim 19, wherein said workpiece layer further are ink jet nozzle plates, and the hole further is an inkjet nozzle.

21. an ink gun has the inkjet nozzle in the workpiece according to claim 20.

22. an ink-jet printer has ink gun according to claim 21.

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