Geometric Parameters Evolution Experiment of Hole During Femtosecond Laser Helical Drilling

Fig. 10. SEM images of the machined holes in different focus down rates with the processing time of 100 s. Focus down rates: (a) 0; (b) 0.005 mm/s; (c) 0.010 mm/s; (d) 0.015 mm/s; (e) 0.020 mm/s

Download full size

Fig. 11. Transmission characteristics and light intensity distribution of the Gaussian beam

Download full size

Table 1. Related parameters of laser and machine
View table
Table 1. Related parameters of laser and machine
Parameter Range
Pulse width /fs 250
Wavelength /nm 1064
Repetition rate /kHz 60-600
Average power /W 0-15
Rotation rate /(r·min^-1) 600-2400
Air-blowing pressure /MPa 0-0.5
Spot radius /μm 15-25

Table 2. Factors and levels of orthogonal experiment

View table

Table 2. Factors and levels of orthogonal experiment

Factor	Processparameter	Level1	Level2	Level3	Level4	Level5
A	Single pulseenergy /μJ	20	22	24	26	28
B	Repetitionrate /kHz	100	200	300	400	500
C	Air-blowingpressure /MPa	0.1	0.2	0.3	0.4	0.5
D	Rotation rate /(r·min^-1)	600	1050	1500	1950	2400
E	Rate of focusdown /(mm·s^-1)	0	0.005	0.01	0.015	0.02

Table 3. Schedule of focus down test

View table

Table 3. Schedule of focus down test

Rate of focusdown /(mm·s^-1)	Drilling time /s
Rate of focusdown /(mm·s^-1)		Hole1															Hole2	Hole3	Hole4	Hole5	Hole6	Hole7	Hole8	Hole9	Hole10	Hole11	Hole12	Hole13	Hole14	Hole15
0	1		2	3	6	10	15	20	30	40	50	60	70	80	90	100
0.005	1		2	3	6	10	15	20	30	40	50	60	70	80	90	100
0.010	1		2	3	6	10	15	20	30	40	50	60	70	80	90	100
0.015	1		2	3	6	10	15	20	30	40	50	60	70	80	90	100
0.020	1		2	3	6	10	15	20	30	40	50	60	70	80	90	100

Table 4. Range analysis of orthogonal experimental data

View table

Table 4. Range analysis of orthogonal experimental data

Level	Column number/Factor
Level						1/A	2/B	3/C	4/D	5/E	6/None
$\begin{matrix} \bar{I} \end{matrix}$	207.056	195.378	204.742	206.422	230.002	226.208
$\begin{matrix} \bar{II} \end{matrix}$	197.594	204.326	205.804	222.628	225.840	223.050
$\begin{matrix} \bar{III} \end{matrix}$	225.480	207.150	225.068	212.850	222.076	224.577
$\begin{matrix} \bar{IV} \end{matrix}$	236.082	236.838	233.638	234.718	215.496	209.452
$\begin{matrix} \bar{V} \end{matrix}$	241.576	264.096	238.536	231.170	214.374	224.196
$\begin{matrix} \bar{R} \end{matrix}$	43.982	68.718	33.794	28.296	15.628	16.756

Table 5. Variance analysis of orthogonal experimental data

View table

Table 5. Variance analysis of orthogonal experimental data

Source of variation	Sum of squares	Freedom	Variance	F-value	Critical valueof F-test	Significance
Single pulse energy	7058.151	4	1764.538	7.515		^*
Repetition rate	16164.423	4	4041.106	17.210		^**
Air-blowing pressure	4887.327	4	1221.832	5.203	F_0.05,(4,4)=6.39
Rotation rate	2858.244	4	714.561	3.043	F_0.01,(4,4)=15.98
Rate offocus down	891.313	4	222.828	0.949
Error	939.260	4	234.815
Total	32798.718	24	1366.613

Table 6. Verification experimental data and network simulation results

View table

Table 6. Verification experimental data and network simulation results

Serialnumber	Singlepulseenergy /μJ	Repetitionrate /kHz	Air-blowingpressure /MPa	Rotationrate /(r·min^-1)	Rate offocus down /(mm·s^-1)	Ablation depth /μm		Relativeerror /%
Serialnumber	Singlepulseenergy /μJ	Repetitionrate /kHz	Air-blowingpressure /MPa	Rotationrate /(r·min^-1)	Rate offocus down /(mm·s^-1)		Experimentalvalue	Simulationvalue
1	20	500	0.3	1050	0.010	240.91	235.48	-2.25
2	22	400	0.2	2400	0.015	278.19	276.51	-0.61
3	24	500	0.1	2400	0.020	248.38	250.22	0.74
4	26	400	0.3	1050	0.015	248.64	245.32	-1.34
5	28	200	0.4	600	0.010	182.18	184.35	1.19

Tools

Get Citation

Copy Citation Text

Li Xiaoji, Dong Yiwei, Yin Chunping, Zhao Qi, You Yancheng. Geometric Parameters Evolution Experiment of Hole During Femtosecond Laser Helical Drilling[J]. Chinese Journal of Lasers, 2018, 45(5): 502008

Download Citation

EndNote(RIS)BibTex Plain Text

Set citation alerts for article

Save article for my favorites