Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a pulse laser high-speed same-point interval multiple processing system and a processing method, which utilize incident laser pulses output by MHz frequency to realize the full utilization of the pulses generated by a short/ultra-short pulse laser; meanwhile, the deflection module can be used for realizing the deflection of pulse laser at the MHz level, the scanning speed of hundreds of meters per second is realized by the laser focus on a focal plane, the scanning range reaches the mm level, and the effect of considering both the processing quality and the efficiency is achieved; in addition, by the processing method of the same point at intervals for multiple times, not only is negative heat effect accumulation effectively avoided, but also the processing morphology can be accurately controlled, and the high-precision processing of the linear groove is realized.
The present invention achieves the above-described object by the following technical means.
A pulse laser high-speed same-point interval multi-processing system comprises a laser light source, a deflection module, a focusing module and a control system;
the laser light source is used for generating pulse laser, and the pulse laser passes through the deflection module and the focusing module and then is injected into a processing surface; the deflection module is used for deflecting and emitting the pulse laser into the focusing module; according to the parameters of the pulse Laser, the parameters of the feature to be processed, the characteristic parameters of the deflection module and the characteristic parameters of the focusing module, the control system outputs the pulse Laser parameters Laser required by processing the featureGrooveA set of deflection module control signals corresponding to the focus offset in the morphology processing process and a system output frequency fm;
the control system is used for controlling the Laser according to the pulse Laser parameters required by the shape to be processedGrooveAnd the system output frequency fm controls the laser light source to output pulse laser required by processing morphology; and the control system controls the deflection module according to the set of deflection module control signals corresponding to the focus offset in the morphology processing process and the system output frequency fm.
Further, the control system comprises a laser parameter calculation unit, a tail end laser scanning capability calculation unit, a scanning parameter calculation unit, a system frequency calculation unit and a processing control unit;
the Laser parameter calculating unit obtains a pulse Laser parameter Laser required by processing morphology according to the parameters of the pulse Laser and the parameters of the morphology to be processedGrooveAnd number of pulses NPulseAnd the pulse Laser parameter needed by the processing shape is usederooveAnd number of pulses NPulseInputting a processing control unit;
the tail end laser scanning capability calculation unit obtains a tail end laser focus offset parameter according to the deflection module characteristic parameter and the focusing module characteristic parameter;
the scanning parameter calculating unit obtains a segmentation parameter of the morphology to be processed, a laser scanning parameter and a set of deflection module control signals corresponding to the focus offset in the morphology processing process according to the tail end laser focus offset parameter and the morphology parameter to be processed, and inputs the segmentation parameter of the morphology to be processed, the laser scanning parameter and the set of deflection module control signals corresponding to the focus offset in the morphology processing process into the processing control unit;
the system frequency calculation unit obtains a system output frequency fm according to the pulse laser output frequency and the deflection module frequency, and inputs the system output frequency fm into the processing control unit;
and the processing control unit controls the laser light source and the deflection module and is used for realizing the processing of the feature to be processed at the same point and multiple times at intervals.
Further, the pulse laser is a single pulse laser or a pulse train laser, and specifically includes:
the single pulse laser parameters are as follows:
the laser parameters of the pulse train are as follows:
wherein: laser is a set of pulsed Laser parameters; paIs the average power of the laser; widthPulseIs the laser pulse width; m2A laser pulse mode; sumBurstThe number of laser pulses in a pulse train; fBurstThe maximum output frequency of the laser pulse in the pulse train; dFocusThe diameter of a laser focus spot; fPulseThe maximum output frequency of the pulse laser; asfPulseAnd a safety factor is used for the maximum output frequency of the pulse laser.
Further, the Laser parameter calculation unit obtains a pulse Laser parameter Laser required by the processing morphology according to the parameter of the pulse Laser and the parameter of the morphology to be processedGrooveAnd number of pulses NPulseThe method specifically comprises the following steps:
establishing an equation set according to a pulse laser same-point interval multiple processing rule:
wherein: laserGroovePulse laser parameters required for processing the morphology;
NPulsethe number of pulses required to machine the feature;
BGroovethe width of the shape to be processed;
DepthGroovethe depth of the shape to be processed;
fD() The method is a functional expression of a set Laser of pulse Laser parameters and the diameter of the feature to be processed when the number of single pulses is large, and the diameter of the feature to be processed is the same as the width of the feature to be processed;
fDepth() In the number of single pulses, a set Laser of pulse Laser parameters and a function expression of the depth of the feature to be processed;
solving an equation to obtain a pulse Laser parameter needed by processing morphologyGrooveAnd number of pulses NPulse。
Further, the terminal laser scanning capability calculating unit obtains a terminal laser focus offset parameter according to the deflection module characteristic parameter and the focusing module characteristic parameter, and specifically includes:
determining the highest response frequency F according to the characteristic parameters of the deflection module
CyMaximum response frequency use safety factor Asf of deflection module
CyCorresponding relation between deflection angle and deflection module control electric signal
Wherein: zeta is the deflection module control electrical signal; alpha is the deflection angle of the laser at the tail end controlled by the deflection module; alpha is alphamaxControlling the maximum deflection angle of the tail end laser for the deflection module;
calculating the theoretical offset distance of the laser without lens at the tail end of the processing surface according to the characteristic parameters of the deflection module and the characteristic parameters of the focusing module, and specifically comprises the following steps:
wherein: asfαUsing a safety factor for controlling the maximum deflection angle of the tail end laser by the deflection module; w is a0The theoretical deflection of the end laser without lens on the focal plane is shown; l is1Is the distance between the deflection module and the focal plane; f is the focal length of the focusing lens;
correcting theoretical offset distance through a process test according to the relative position of the deflection module and the focusing module, and establishing the corresponding relation between the offset of the tail end laser focus position and a control electric signal of the deflection module, wherein the specific relation is as follows:
Wherein: w is the offset of the position of the tail end laser focus on the focal plane; sigma is a correction coefficient of the offset distance of the tail end laser focus position on the focal plane; l is2Is the distance between the deflection module and the focal point of the focusing lens, L2=L1-f;
Calculating the maximum scanning range w of the end laser focusmaxThe method specifically comprises the following steps: w is amax=1/Asfα*αmax*L1*σ。
Further, the scanning parameter calculating unit obtains a set of segment parameters of the feature to be processed, laser scanning parameters and deflection module control signals corresponding to the focus offset in the feature processing process according to the end laser focus offset parameter and the feature to be processed, and specifically includes:
maximum scan range w with end laser focus
maxFor the basis, the length direction of the shape to be processed is evenly divided,
each section of the shape to be processed has the length of
Wherein: n is a radical of
SecSegmenting the number of the features to be processed; l is
0The length of the shape to be processed;
the scanning parameter calculating unit calculates the length L of each section of the feature to be processed
eObtaining the step size number N contained in each section of morphology to be processed
1And corrected deflection module scanning step length w
esThe method specifically comprises the following steps:
wherein w
sFor preliminary setting of the deflection module scanning step, w
s∈(B
Groove,L
e);B
GrooveThe width of the shape to be processed;
the scanning parameter calculating unit scans the step length w according to the corrected deflection module
esCalculating the feed amount w in each scanning step
eqAnd the number of feeds N per scanning step
2The method specifically comprises the following steps:
wherein: lambda is the linear groove scanning overlapping rate;
the scanning parameter calculation unit calculates a focus offset set of each section of morphology to be processed in the processing process, and the specific calculation method is as follows:
wherein: w is akThe k-th focus offset of each section of the feature to be processed in the processing process; w is a focus offset set of each section of morphology to be processed in the processing process; k is the focal point deviation sequence of each section of the morphology to be processed in the processing process; i is the order of feed in each scanning step; j is the step length sequence in each section of the morphology to be processed;
the scanning parameter calculation unit obtains a set gamma of deflection module control signals corresponding to the focus offset in the processing process of each section of feature to be processed according to the focus offset set W and the tail end laser focus offset parameter in the processing process of each section of feature to be processed, and specifically comprises the following steps:
in the formula k
max=N
1*N
2,
Wherein: k is a radical ofmaxThe number of focus offsets contained in each section of the morphology to be processed in the laser processing process is calculated; zetakA deflection module control signal corresponding to the k-th focus offset of each section of the morphology to be processed in the laser processing process; f is a set of deflection module control signals corresponding to the focus offset in the processing process of each section of the feature to be processed;
and the set of deflection module control signals corresponding to the focus offset in the profile machining process is a set gamma of deflection module control signals corresponding to the focus offset in the profile machining process of each section to be machined.
Further, the system frequency calculation unit obtains a system output frequency fm according to the pulse laser output frequency and the deflection module frequency, specifically:
fm=MIN(1/AsfCy*FCy,1/AsfPulse*FPulse) Wherein: fm is the system output frequency, namely the deflection module deflection frequency or the pulse laser output frequency; asfCyUsing a safety factor for the highest response frequency of the deflection module, FCyAt the highest response frequency, AsfPulseSafety factor for maximum output frequency of pulse laser, FPulseThe maximum output frequency of the pulse laser.
A processing method of a pulse laser high-speed same-point interval multiple processing system comprises the following steps:
the scanning parameter calculating unit segments the to-be-processed appearance, and determines the segmentation number N of the to-be-processed appearanceSec,;
The processing control unit controls the laser light source and the deflection module to measure the nmSecNm of segmental processing morphologyPulseThe layer is laser-processed in nmSecFor the order of segmented processing of the processing features, nmSec∈[1,NSec];nmPulseProcessing layering sequence for segmented processing features, nmPulse∈[1,NPulse](ii) a When nmSec=NSecAnd then finishing the appearance processing.
Further, the processing control unit controls the processing steps of the laser light source and the deflection module to be as follows:
s1: setting the order nm of segmented processing of the processing morphology Sec1, process layering order nm of segmented process featuresPulse1, the focal point shift sequence k of each section of the morphology to be processed is 1 in the processing process;
s2: to the nmSecNm of segmental processing morphologyPulseLaser processing of the layer, in particular the following steps:
s2-1: the processing control unit controls the Laser light source to output pulse Laser parameters required by processing morphologyGrooveAnd the output frequency f of the pulsed lasermThe pulse laser sequentially passes through the deflection module and the focusing module and is focused on the surface of the material;
s2-2: while the pulsed laser is output, the deflection module deflects the frequency f according to the deflection modulemA deflection module control signal zeta corresponding to the k-th focus offset of each section of to-be-processed appearance in the laser processing processkDeflecting the pulsed laser light passing through the deflection module by alphakThe deflected pulse laser is focused on a processing surface through a focusing module, and is deflected by w according to step length in each section of processing morphology through a focuskAt the nm ofSecNm of segmental processing morphologyPulseRemoving material of the kth point of the layer for processing at intervals of the same point for multiple times;
S2-3:k=k+1;
s2-4: judging whether the nm-th step is finishedSecNm of segmental processing morphologyPulseLaser processing of the layer:
if k is<kmaxAnd the process proceeds to S2-2,
if k is equal to kmaxThen S2-5 is executed;
S2-5:k=1,nmPulse=nmPulse+1, go to S3;
s3: judging whether the nm-th step is finishedSecLaser processing of segment processing appearance:
if nmPulse<NPulseThen the process proceeds to S2,
if nmPulse=NPulseThen execution proceeds to S4;
s4: moving the laser focus to the nm by moving the working surfaceSec+1 real position of the processing morphology;
S5:nmPulse=1,nmSec=nmSec+1;
s6: judging whether laser processing of all processing appearances is finished:
if nmSec<NSecThen the process proceeds to S2,
if nmSec=NSecAnd finishing the processing.
The invention has the beneficial effects that:
1. the pulse laser high-speed same-point interval multiple processing system can utilize incident laser pulses output by MHz frequency, and compared with a galvanometer scanning system, the pulse laser output frequency is improved by 2-3 orders of magnitude, so that the full utilization of pulses generated by a short/ultrashort pulse laser is realized.
2. According to the pulse laser high-speed same-point interval multiple processing system, deflection of pulse laser at the MHz level can be realized by utilizing the deflection module, the scanning speed of hundreds of meters per second is realized by the laser focus on the focal plane, the scanning range reaches the mm level, and the effect of considering both processing quality and efficiency is achieved.
3. According to the high-speed same-point interval multiple processing method of the pulse laser, negative heat effect accumulation is effectively avoided, the processing morphology can be accurately controlled, and high-precision processing of the linear groove is realized.
4. The high-speed pulse laser same-point interval multiple processing method provided by the invention aims at the laser processing of the linear groove, can realize area processing by combining multiple sections of grooves, and is convenient to integrate and use in the later period.
Detailed Description
The invention will be further described with reference to the following figures and specific examples, but the scope of the invention is not limited thereto.
As shown in fig. 1, the pulsed laser high-speed same-point interval multiple processing system of the present invention includes a laser light source 1, a deflection module 3, a focusing module 4 and a control system 7;
the laser light source 1 is used for generating pulse laser 2, and the pulse laser 2 is injected into a processing surface after passing through the deflection module 3 and the focusing module 4; the processing surface is located on a working table 6, and the working table 6 can move in a plane. The deflection module 3 is used for deflecting the pulse laser 2 to be emitted into the focusing module 4; according to the parameters of the pulse Laser 2, the parameters of the feature to be processed, the characteristic parameters of the deflection module 3 and the characteristic parameters of the focusing module 4, the control system 7 outputs the pulse Laser parameters Laser required by the feature processingGrooveA set of deflection module control signals corresponding to the focus offset in the morphology processing process and a system output frequency fm;
the control system 7 is used for controlling the pulse Laser parameters according to the shape to be processedGrooveAnd the system output frequency fm controls the laser light source 1 to output the pulse laser required by the processing morphology; and the control system controls the deflection module 3 according to the set of deflection module control signals corresponding to the focus offset in the feature processing process and the system output frequency fm, and is used for realizing the multipoint interval multiple processing of the feature to be processed.
The control system 7 comprises a laser parameter calculation unit, a tail end laser scanning capability calculation unit, a scanning parameter calculation unit, a system frequency calculation unit and a processing control unit;
as shown in fig. 5, the Laser parameter calculating unit obtains a pulse Laser parameter Laser required for processing the feature according to the parameter of the pulse Laser 2 and the parameter of the feature to be processedGroovAnd number of pulses NPulseAnd the pulse Laser parameter needed by the processing shape is usedGrooveAnd number of pulses NPulseInputting a processing control unit;
as shown in fig. 6, the terminal laser scanning capability calculating unit obtains a terminal laser focus offset parameter according to the characteristic parameter of the deflection module 3 and the characteristic parameter of the focusing module 4; the scanning parameter calculating unit obtains a segmentation parameter of the morphology to be processed, a laser scanning parameter and a set of deflection module control signals corresponding to the focus offset in the morphology processing process according to the tail end laser focus offset parameter and the morphology parameter to be processed, and inputs the segmentation parameter of the morphology to be processed, the laser scanning parameter and the set of deflection module control signals corresponding to the focus offset in the morphology processing process into the processing control unit;
as shown in fig. 7, the system frequency calculation unit obtains a system output frequency fm according to the pulse laser output frequency and the deflection module frequency, and inputs the system output frequency fm into the processing control unit; the processing control unit controls the laser light source 1 and the deflection module 3 and is used for realizing the processing of the feature to be processed at the same point and multiple times.
In the invention f appearsD() And fDept() Determination of these two functionsThe solution can be solved by:
as shown in fig. 2, a multiple processing rule of the pulse laser 2 at the same point interval is determined, specifically, a corresponding relationship between the pulse laser parameters, the number of pulses and the shape parameters of the micro-pits formed by laser removal is established, and the specific determination method of the rule is as follows:
firstly, utilizing incident pulse laser 2 to pass through a deflection module and a focusing module in turn and then focus on the surface of a material, wherein the deflection module does not work, the incident pulse laser does not deflect, the pulse laser acts on the same point on the surface of the material, and the action interval time T of the pulse laser 2PulseRealizing the processing effect of the pulse laser at the same point and multiple times, and measuring the pulse number n along with the pulse laserPulseIncreasing, the shape parameter change of the micro-pits formed by material removal, and the obtaining rule is as follows:
in the formula: theta epsilon (0.1, 0.4);
then, combining the general rule of material laser removal, the influence of the pulse quantity of the pulse laser at the same point and multiple intervals on the profile diameter of the formed micro-pit is small, the profile depth of the micro-pit is basically in a linear relation, and the obtained rule is corrected:
in the formula:
∈(0.1,0.4)。
wherein: n isPulseThe number of pulses of the pulsed laser; dDimpleThe micro-pit morphology diameter formed for pulsed laser removal of material; depthDimpleThe micro-pit morphology depth formed for pulsed laser removal of material; (Depth)Dimple)maxThe maximum depth of the micro-pit morphology formed for pulsed laser removal of material; theta is the depth-diameter ratio coefficient of the micro-pit morphology. The action interval time T of the pulse laserPulseSetting a constant for pulsed laser output, typically TPulse=0.1ms。
The following results are obtained: f. ofD() The method is a functional expression of a set Laser of pulse Laser parameters and the shape and diameter of the micro-pits when the number of single pulses is large; f. ofDept() When the number of single pulses is large, a function expression of a set Laser of pulse Laser parameters and the shape depth of the micro-pits is obtained;
the following is a detailed description of the 2 examples:
embodiment 1, the processing surface is subjected to linear groove processing of multiple times at the same point interval of pulse laser by single pulse laser:
as shown in fig. 3, the parameters of the single pulse laser are:
in the examples, WidthPulse=10ps,FPulse=10MHz,AsfPulse=1.1,dFocus=40μm。
Wherein: laser is a set of pulsed Laser parameters; paIs the average power of the laser; widthPulseIs the laser pulse width; m2A laser pulse mode; dFocusThe diameter of a laser focus spot; fPulseThe maximum output frequency of the pulse laser; asfPulseAnd a safety factor is used for the maximum output frequency of the pulse laser.
As shown in fig. 4, the Laser parameter calculating unit obtains a pulse Laser parameter Laser required for processing the shape of the linear groove according to the parameter of the pulse Laser 2 and the parameter of the shape to be processedGrooveAnd number of pulses NPulseThe method specifically comprises the following steps:
according to the fact that the influence of the number of pulses obtained last time at intervals of the same point of the pulse laser on the diameter of the formed micro-pit shape is small, the depth of the micro-pit shape is basically in a linear relation, and an equation set is established:
Namely, the method is simplified as follows:
solving to obtain the required pulse Laser parameter Laser
GrooveAnd number of pulses N
Pulse。
Wherein: laserGroovePulse laser parameters required by the linear groove to be processed; n is a radical ofPulseThe required number of pulse laser pulses; b isGrooveThe width of the linear groove to be processed is defined; depthGrooveIs the depth of the linear groove to be processed.
As shown in fig. 5, the terminal laser scanning capability calculating unit obtains a terminal laser focus offset parameter according to the characteristic parameter of the deflection module 3 and the characteristic parameter of the focusing module 4, specifically:
determining the highest response frequency F according to the characteristic parameters of the
deflection module 3
CyMaximum response frequency use safety factor Asf of deflection module
CyCorresponding relation between deflection angle and deflection module control electric signal
Wherein: zeta is the deflection module control electrical signal; alpha is the deflection angle of the laser at the tail end controlled by the deflection module; alpha is alphamaxControlling the maximum deflection angle, alpha, of the terminal laser for the deflection modulemax=100mrad;FCyIs the highest response frequency FCy=50MHz;AsfCyUsing a safety factor Asf for the highest response frequency of the deflection moduleCy=1.1。
Calculating the theoretical offset distance of the laser without lens at the tail end of the processing surface according to the characteristic parameters of the
deflection module 3 and the characteristic parameters of the focusing
module 4, specifically:
in the formula: l is
1=f+60mm,f=40mm,Asf
α=1.1;
Wherein: asfαControlling the maximum deflection angle of the laser at the end of the deflection moduleUsing safety factors; w is a0The theoretical deflection of the end laser without lens on the focal plane is shown; l is1Is the distance between the deflection module and the focal plane; f is the focal length of the focusing lens;
correcting theoretical offset distance through a process test according to the relative position of the deflection module and the focusing module, and establishing the corresponding relation between the offset of the tail end laser focus position and a control electric signal of the deflection module, wherein the specific relation is as follows:
Wherein: w is the offset of the position of the tail end laser focus on the focal plane; sigma is a correction coefficient sigma epsilon (0,1) of the offset distance of the tail end laser focus position on the focal plane; l is2Is the distance between the deflection module and the focal point of the focusing lens, L2=L1-f;
Calculating the maximum scanning range of the tail end laser focus, specifically: w is amax=1/Asfα*αmax*L1*σ。
As shown in fig. 5, the scanning parameter calculating unit obtains a set of segment parameters of the feature to be processed, laser scanning parameters and deflection module control signals corresponding to the focus offset in the feature processing process according to the parameter of the end laser focus offset and the parameter of the feature to be processed, specifically:
maximum scan range w with end laser focus
maxFor the basis, the length direction of the linear groove to be processed is evenly divided,
each section of the linear groove to be processed has the length of
Wherein: n is a radical of
SecThe number of the linear grooves to be processed is divided into sections; l is
0The length of the linear groove to be processed is defined;
the scanning parameter calculation unit calculates the length L of each section of linear groove to be processed
eObtaining the step size number N contained in each section of morphology to be processed
1And corrected deflection module scanning step length w
esThe method specifically comprises the following steps:
wherein w
sFor preliminary setting of the deflection module scanning step, w
s=2*B
Groove;B
GrooveThe width of the linear groove to be processed;
the scanning parameter calculating unit scans the step length w according to the corrected deflection module
esCalculating the feed amount w in each scanning step
eqAnd the number of feeds N per scanning step
2The method specifically comprises the following steps:
wherein: λ is the linear groove scanning overlap ratio λ of 95%;
the scanning parameter calculation unit calculates a focus offset set of each section of morphology to be processed in the processing process, and the specific calculation method is as follows:
wherein: w is akThe k-th focus offset of each section of linear groove to be machined in the machining process; w is a focus offset set of each section of linear groove to be machined in the machining process; k is the focal point deviation sequence of each section of the morphology to be processed in the processing process; i is the order of feed in each scanning step; j is the step length sequence in each section of the morphology to be processed;
the scanning parameter calculation unit obtains a set gamma of deflection module control signals corresponding to the focus offset in the processing process of each section of linear groove to be processed according to the focus offset set W and the tail end laser focus offset parameter in the processing process of each section of linear groove to be processed, and specifically comprises the following steps:
in the formula k
max=N
1*N
2,
Wherein: k is a radical ofmaxThe number of focus offsets contained in each section of linear groove to be processed in the laser processing process is calculated; zetakControlling a signal for a deflection module corresponding to the k-th focus offset of each section of linear groove to be processed in the laser processing process; f is a set of deflection module control signals corresponding to the focus offset in the machining process of each section of linear groove to be machined;
and the set of deflection module control signals corresponding to the focus offset in the morphology machining process is a set gamma of deflection module control signals corresponding to the focus offset in the machining process of each section of linear groove to be machined.
As shown in fig. 7, the system frequency calculating unit obtains a system output frequency fm according to the pulse laser output frequency and the deflection module frequency, specifically:
fm=MIN(1/AsfCy*FCy,1/AsfPulse*FPulse) Wherein: fm is the system output frequency and is also the deflection frequency of the deflection module or the output frequency of the pulse laser; asfCyUsing a safety factor for the highest response frequency of the deflection module, FCyAt the highest response frequency, AsfPulseSafety factor for maximum output frequency of pulse laser, FPulseThe maximum output frequency of the pulse laser.
As shown in fig. 8, 9, 10, 11, 12, 13 and 14, the method for processing multiple times at the same point interval in high speed by using pulsed laser according to the present invention includes the following steps:
the scanning parameter calculating unit segments the to-be-processed appearance, and determines the segmentation number N of the to-be-processed appearanceSec,;
The processing control unit controls the laser light source 1 and the deflection module 3 to measure the nm-th wavelengthSecNm of segmental processing morphologyPulseThe layer is laser-processed in nmSecFor the order of segmented processing of the processing features, nmSec∈(1,NSec);nmPulseIs segmentedProcessing layering sequence of processing morphology; when nmSec=NSecAnd then finishing the appearance processing, specifically comprising the following steps:
s1: initializing the system circulation quantity, specifically comprising:
s1-1: linear groove segmentation processing order nmSec=1,
S1-2: linear groove processing layering sequence nmPulse=1,
S1-3: the focus offset in each section of linear groove is sequentially k equal to 1;
s2: to the nmSecNm of segmental processing morphologyPulseLaser processing of the layer, in particular the following steps:
s2-1: the processing control unit controls the Laser light source 1 to output pulse Laser parameters required by processing linear groovesGrooveAnd the output frequency f of the pulsed lasermThe pulse laser sequentially passes through the deflection module and the focusing module and is focused on the surface of the material;
s2-2: while the pulsed laser is output, the deflection module deflects the frequency f according to the deflection modulemA deflection module control signal zeta corresponding to the k-th focus offset of each section of linear groove to be machined in the laser machining processkDeflecting the pulsed laser light 2 passing through the deflection module by alphakThe deflected pulse laser 2 is focused on a processing surface through a focusing module, and is deflected by w according to step length in each section of processing morphology through a focuskAt the nm ofSecNm of segmental processing morphologyPulseRemoving material of the kth point of the layer for processing at intervals of the same point for multiple times;
s2-3: changing a system circulation amount, wherein k is k + 1;
s2-4: judging whether the nm-th step is finishedSecNm of section linear groovePulseLaser processing of the layer:
if not (i.e., k)<kmax) And the process proceeds to S2-2,
if it is completed (i.e. k ═ k)max) Then S2-5 is executed;
s2-5: change in the amount of system circulation, k is 1, nmPulse=nmPulse+1, go to S3;
s3: judging whether the nm-th step is finishedSecLaser processing of the section straight line groove:
if not (i.e. nm)Pulse<NPulse) Then the process proceeds to S2,
if it is finished (i.e. nm)Pulse=NPulse) Then execution proceeds to S4;
s4: the system stops signal output, stops pulse laser output and stops the deflection module from working;
s5: the change of the initial position of the laser focus is completed by the movement of the working table top, specifically, the initial position of the laser focus is controlled to move L along the direction of the linear grooveeA length;
s6: change in systemic circulation, nmPulse=1,nmSec=nmSec+1;
S7: judging whether the laser processing of the whole linear groove is finished:
if not (i.e. nm)Sec<NSec) Then the process proceeds to S2,
if it is finished (i.e. nm)Sec=NSec) Then execution proceeds to S8;
s8: finishing the precision machining of the whole linear groove and finishing the circulation.
Embodiment 2, through pulse train formula laser, carry out many times of linear groove processing of pulse laser with the interval of some to the machined surface:
as shown in fig. 4, the parameters of the pulse-train laser are:
in the examples, WidthPulse=10ps,FPulse=50KHz,AsfPulse=1.1,dFocus=40μm,SumBurst=0.5K,FBurst=40MHz。
Wherein: laser is a set of pulsed Laser parameters; paIs the average power of the laser; widthPulseIs the laser pulse width; m2A laser pulse mode; sumBurstIs a laser pulse in a pulse trainPunching quantity; fBurstThe maximum output frequency of the laser pulse in the pulse train; dFocusThe diameter of a laser focus spot; fPulseThe maximum output frequency of the pulse laser; asfPulseAnd a safety factor is used for the maximum output frequency of the pulse laser.
As shown in fig. 4, the Laser parameter calculating unit obtains a pulse Laser parameter Laser required for processing the shape of the linear groove according to the parameter of the pulse Laser 2 and the parameter of the shape to be processedGrooveAnd number of pulses NPulseThe method specifically comprises the following steps:
according to the fact that the influence of the number of pulses obtained last time at intervals of the same point of the pulse laser on the diameter of the formed micro-pit shape is small, the depth of the micro-pit shape is basically in a linear relation, and an equation set is established:
Namely, the method is simplified as follows:
solving to obtain the required pulse Laser parameter Laser
GrooveAnd number of pulses N
Pulse。
Wherein: laserGroovePulse laser parameters required by the linear groove to be processed; n is a radical ofPulseThe required number of pulse laser pulses; b isGrooveThe width of the linear groove to be processed is defined; depthGrooveIs the depth of the linear groove to be processed.
As shown in fig. 5, the terminal laser scanning capability calculating unit obtains a terminal laser focus offset parameter according to the characteristic parameter of the deflection module 3 and the characteristic parameter of the focusing module 4, specifically:
determining the highest response frequency F according to the characteristic parameters of the
deflection module 3
CyMaximum response frequency use safety factor Asf of deflection module
CyCorresponding relation between deflection angle and deflection module control electric signal
Wherein: zeta is the deflection module control electrical signal; alpha is the deflection angle of the laser at the tail end controlled by the deflection module; alpha is alphamaxControlling the maximum deflection angle, alpha, of the terminal laser for the deflection modulemax=100mrad;FCyIs the highest response frequency FCy=50MHz;AsfCyUsing a safety factor Asf for the highest response frequency of the deflection moduleCy=2。
Calculating the theoretical offset distance of the laser without lens at the tail end of the processing surface according to the characteristic parameters of the
deflection module 3 and the characteristic parameters of the focusing
module 4, specifically:
in the formula: l is
1=f+60mm,f=40mm,Asf
α=1.1;
Wherein: asfαUsing a safety factor for controlling the maximum deflection angle of the tail end laser by the deflection module; w is a0The theoretical deflection of the end laser without lens on the focal plane is shown; l is1Is the distance between the deflection module and the focal plane; f is the focal length of the focusing lens;
correcting theoretical offset distance through a process test according to the relative position of the deflection module and the focusing module, and establishing the corresponding relation between the offset of the tail end laser focus position and a control electric signal of the deflection module, wherein the specific relation is as follows:
Wherein: w is the offset of the position of the tail end laser focus on the focal plane; l is2The distance between the deflection module and the focal point of the focusing lens; sigma is a correction coefficient sigma epsilon (0,1) of the offset distance of the tail end laser focus position on the focal plane; l is2Is the distance between the deflection module and the focal point of the focusing lens, L2=L1-f;
Calculating the maximum scanning range of the tail end laser focus, specifically: w is amax=1/Asfα*αmax*L1*σ。
As shown in fig. 5, the scanning parameter calculating unit obtains a set of segment parameters of the feature to be processed, laser scanning parameters and deflection module control signals corresponding to the focus offset in the feature processing process according to the parameter of the end laser focus offset and the parameter of the feature to be processed, specifically:
maximum scan range w with end laser focus
maxFor the basis, the length direction of the linear groove to be processed is evenly divided,
each section of the linear groove to be processed has the length of
Wherein: n is a radical of
SecThe number of the linear grooves to be processed is divided into sections; l is
0The length of the linear groove to be processed is defined;
the scanning parameter calculation unit calculates the length L of each section of linear groove to be processed
eObtaining the step size number N contained in each section of morphology to be processed
1And corrected deflection module scanning step length w
esThe method specifically comprises the following steps:
wherein w
sFor preliminary setting of the deflection module scanning step, w
s=2*B
Groove;B
GrooveThe width of the linear groove to be processed;
the scanning parameter calculating unit scans the step length w according to the corrected deflection module
esCalculating the feed amount w in each scanning step
eqAnd the number of feeds N per scanning step
2The method specifically comprises the following steps:
wherein: λ is the linear groove scanning overlap ratio λ of 90%;
the scanning parameter calculation unit calculates a focus offset set of each section of morphology to be processed in the processing process, and the specific calculation method is as follows:
wherein: w is akThe k-th focus offset of each section of linear groove to be machined in the machining process; w is a focus offset set of each section of linear groove to be machined in the machining process; k is the focal point deviation sequence of each section of the morphology to be processed in the processing process; i is the order of feed in each scanning step; j is the step length sequence in each section of the morphology to be processed;
the scanning parameter calculation unit obtains a set gamma of deflection module control signals corresponding to the focus offset in the processing process of each section of linear groove to be processed according to the focus offset set W and the tail end laser focus offset parameter in the processing process of each section of linear groove to be processed, and specifically comprises the following steps:
in the formula k
max=N
1*N
2,
Wherein: k is a radical ofmaxThe number of focus offsets contained in each section of linear groove to be processed in the laser processing process is calculated; zetakControlling a signal for a deflection module corresponding to the k-th focus offset of each section of linear groove to be processed in the laser processing process; f is a set of deflection module control signals corresponding to the focus offset in the machining process of each section of linear groove to be machined;
and the set of deflection module control signals corresponding to the focus offset in the morphology machining process is a set gamma of deflection module control signals corresponding to the focus offset in the machining process of each section of linear groove to be machined.
As shown in fig. 7, the system frequency calculating unit obtains a system output frequency fm according to the pulse laser output frequency and the deflection module frequency, specifically:
fm=MIN(1/AsfCy*FCy,1/AsfPulse*FPulse) Wherein: fm is the system output frequencyIs the deflection frequency of the deflection module or the output frequency of the pulse laser; asfCyUsing a safety factor for the highest response frequency of the deflection module, FCyAt the highest response frequency, AsfPulseSafety factor for maximum output frequency of pulse laser, FPulseThe maximum output frequency of the pulse laser.
The processing method of example 2 is similar to that of example 1 and will not be described.
The present invention is not limited to the above-described embodiments, and any obvious improvements, substitutions or modifications can be made by those skilled in the art without departing from the spirit of the present invention.