Figure 1.
Schematic design of the experimental setup consisting of a standard cutting head with an integrated highly dynamic scanner to initiate beam oscillation and a camera unit for the high spatial and high frequency temporal resolution temperature measurement.
Figure 1.
Schematic design of the experimental setup consisting of a standard cutting head with an integrated highly dynamic scanner to initiate beam oscillation and a camera unit for the high spatial and high frequency temporal resolution temperature measurement.
Figure 2.
Schematic beam movement of (a) Static beam shaping; (b) Longitudinal, linear beam oscillation.
Figure 2.
Schematic beam movement of (a) Static beam shaping; (b) Longitudinal, linear beam oscillation.
Figure 3.
Temperature–gray value–calibration curves for different emission coefficients.
Figure 3.
Temperature–gray value–calibration curves for different emission coefficients.
Figure 4.
Measurement uncertainty as a function of the real temperature and different emission coefficients to correct the measured temperatures.
Figure 4.
Measurement uncertainty as a function of the real temperature and different emission coefficients to correct the measured temperatures.
Figure 5.
Cross-sectional view along the cutting direction verifies the cut edge quality: maximum burr height was detected in five sections, surface roughness Rz was measured along three lines.
Figure 5.
Cross-sectional view along the cutting direction verifies the cut edge quality: maximum burr height was detected in five sections, surface roughness Rz was measured along three lines.
Figure 6.
Principle of the camera field of view (FOV): (a) Perspective view of the process zone with cut kerf and front; (b) Top view of the cut front with camera FOVs.
Figure 6.
Principle of the camera field of view (FOV): (a) Perspective view of the process zone with cut kerf and front; (b) Top view of the cut front with camera FOVs.
Figure 7.
Derivation of absorptivity based on cut front topography: (
a) Scheme of the angle of incidence φ
in; (
b) Dependence between angle of incidence φ
in and absorptivity A
Cir for liquid iron and radiation wavelength λ = 1.07 µm [
2].
Figure 7.
Derivation of absorptivity based on cut front topography: (
a) Scheme of the angle of incidence φ
in; (
b) Dependence between angle of incidence φ
in and absorptivity A
Cir for liquid iron and radiation wavelength λ = 1.07 µm [
2].
Figure 8.
Correlation between thermographic and geometric information of the process: (a) Gray value of the process light during the cut; (b) Conversion of the gray value into corresponding temperature distribution super positioned with geometry of the cut kerf.
Figure 8.
Correlation between thermographic and geometric information of the process: (a) Gray value of the process light during the cut; (b) Conversion of the gray value into corresponding temperature distribution super positioned with geometry of the cut kerf.
Figure 9.
Cut edges of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters; (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 9.
Cut edges of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters; (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 10.
Position of the cut front und cut kerf regarding the camera image of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping and different values of the longitudinal, linear beam oscillation parameters: (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 10.
Position of the cut front und cut kerf regarding the camera image of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping and different values of the longitudinal, linear beam oscillation parameters: (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 11.
Topography of the cut front of 12 mm stainless steel cut with the following parameters: Set #1: Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters; Set #2: 300 µm amplitude and 500 Hz frequency; Set #3: 550 µm amplitude and 500 Hz frequency; Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 11.
Topography of the cut front of 12 mm stainless steel cut with the following parameters: Set #1: Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters; Set #2: 300 µm amplitude and 500 Hz frequency; Set #3: 550 µm amplitude and 500 Hz frequency; Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 12.
Local absorptivity along the cut front of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters; (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 12.
Local absorptivity along the cut front of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters; (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 13.
Sequence of four measurement moments for temperature distribution Ti,j(t) calculated with e = 1 of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping with 488 fps; and different values of the longitudinal, linear beam oscillation parameters with 1360 fps; (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 13.
Sequence of four measurement moments for temperature distribution Ti,j(t) calculated with e = 1 of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping with 488 fps; and different values of the longitudinal, linear beam oscillation parameters with 1360 fps; (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 14.
Spatially resolved temperature profiles Ti(t) calculated with e = 1 along the symmetry axis of the cut front for four measurement moments of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping with 488 fps; and different values of the longitudinal, linear beam oscillation parameters with 1360 fps: (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 14.
Spatially resolved temperature profiles Ti(t) calculated with e = 1 along the symmetry axis of the cut front for four measurement moments of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping with 488 fps; and different values of the longitudinal, linear beam oscillation parameters with 1360 fps: (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 15.
Distribution of average temperature calculated with e = 1 from all single images within the complete measurement period of 500 ms of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters: (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency; the square marks the submatrix positioned at the highest average temperature.
Figure 15.
Distribution of average temperature calculated with e = 1 from all single images within the complete measurement period of 500 ms of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters: (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency; the square marks the submatrix positioned at the highest average temperature.
Figure 16.
Distribution of maximum temperature calculated with e = 1 from all single images within the complete measurement period of 500 ms of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters: (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency; the square marks the submatrix positioned at the highest maximum temperature.
Figure 16.
Distribution of maximum temperature calculated with e = 1 from all single images within the complete measurement period of 500 ms of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters: (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency; the square marks the submatrix positioned at the highest maximum temperature.
Figure 17.
Spatially resolved temperature profiles along the symmetry axes of the cut front for average temperature and maximum temperature calculated with e = 1 from all single images within the complete measurement period of 500 ms of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters: (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 17.
Spatially resolved temperature profiles along the symmetry axes of the cut front for average temperature and maximum temperature calculated with e = 1 from all single images within the complete measurement period of 500 ms of 12 mm stainless steel cut with the following parameters: (a) Set #1: Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters: (b) Set #2: 300 µm amplitude and 500 Hz frequency; (c) Set #3: 550 µm amplitude and 500 Hz frequency; (d) Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 18.
Temporally resolved temperature sequences at the position of the submatrix
in
Figure 16 of 12 mm stainless steel cut with: (
a) Set #1: Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters: (
b) Set #2: 300 µm amplitude and 500 Hz frequency; (
c) Set #3: 550 µm amplitude and 500 Hz frequency; (
d) Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 18.
Temporally resolved temperature sequences at the position of the submatrix
in
Figure 16 of 12 mm stainless steel cut with: (
a) Set #1: Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters: (
b) Set #2: 300 µm amplitude and 500 Hz frequency; (
c) Set #3: 550 µm amplitude and 500 Hz frequency; (
d) Set #4: 300 µm amplitude and 2000 Hz frequency.
Figure 19.
Global histogram of the temperature distribution, averaged for a period of 500 ms of 12 mm stainless steel cut with static beam shaping (set #1) and different values of the longitudinal, linear beam oscillation: 300 µm amplitude and 500 Hz frequency (set #2), 550 µm amplitude and 500 Hz frequency (set #3), 300 µm amplitude and 2000 Hz frequency (set #4).
Figure 19.
Global histogram of the temperature distribution, averaged for a period of 500 ms of 12 mm stainless steel cut with static beam shaping (set #1) and different values of the longitudinal, linear beam oscillation: 300 µm amplitude and 500 Hz frequency (set #2), 550 µm amplitude and 500 Hz frequency (set #3), 300 µm amplitude and 2000 Hz frequency (set #4).
Figure 20.
Comparison of the local intensity profile and energy deposition for one certain material position along the cut path as function of time for the following parameters: (a) Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters: (b) 300 µm amplitude and 500 Hz frequency; (c) 550 µm amplitude and 500 Hz frequency; (d) 300 µm amplitude and 2000 Hz frequency; heat conduction as well as melt ejection have been disregard.
Figure 20.
Comparison of the local intensity profile and energy deposition for one certain material position along the cut path as function of time for the following parameters: (a) Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters: (b) 300 µm amplitude and 500 Hz frequency; (c) 550 µm amplitude and 500 Hz frequency; (d) 300 µm amplitude and 2000 Hz frequency; heat conduction as well as melt ejection have been disregard.
Figure 21.
Comparison of the local temperature for the submatrix calculated with e = 1 showing one certain material position of 12 mm stainless steel along the cut path as function of time for the following: (a) Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters: (b) 300 µm amplitude and 500 Hz frequency; (c) 550 µm amplitude and 500 Hz frequency; (d) 300 µm amplitude and 2000 Hz frequency.
Figure 21.
Comparison of the local temperature for the submatrix calculated with e = 1 showing one certain material position of 12 mm stainless steel along the cut path as function of time for the following: (a) Static beam shaping; and different values of the longitudinal, linear beam oscillation parameters: (b) 300 µm amplitude and 500 Hz frequency; (c) 550 µm amplitude and 500 Hz frequency; (d) 300 µm amplitude and 2000 Hz frequency.
Figure 22.
Abstract representation of the explanatory model.
Figure 22.
Abstract representation of the explanatory model.
Table 1.
Overview of the analyzed sets of static beam shaping and longitudinal, linear beam oscillation.
Table 1.
Overview of the analyzed sets of static beam shaping and longitudinal, linear beam oscillation.
Parameter | Set #1 | Set #2 | Set # 3 | Set #4 |
---|
beam shaping | static | longitudinal, linear |
amplitude [µm] | 0 | 300 | 550 | 300 |
frequency [Hz] | 0 | 500 | 500 | 2000 |
Table 2.
Characteristics of the developed camera-based temperature measurement setup.
Table 2.
Characteristics of the developed camera-based temperature measurement setup.
Characteristics | Data |
---|
wavelength | 740 nm ± 10 nm |
sensor | CMOS 1/1.2″ (1936 × 1216 px2) |
magnification | 2:1 |
dynamic range | 73 dB |
quantum efficiency | appx. 30% (@740 nm) |
sensitivity threshold | 7.2 e− |
saturation capacity | 32,000 e− |
Table 3.
Overview of the camera’s FOV in dependence of the analyzed sets.
Table 3.
Overview of the camera’s FOV in dependence of the analyzed sets.
Parameter | FOV 1 | FOV 2 |
---|
set | #1 | #2–#4 |
m × n [px] | 1200 × 300 | 1200 × 80 |
image size [mm2] | 3.6 × 0.9 | 3.6 × 0.24 |
frame rate [FPS] | 488 | 1360 |
Table 4.
Overview of the optimized cutting speed and cut edge quality for static beam shaping and longitudinal, linear beam oscillation. Improvements or degradations compared to static beam shaping have been indicated symbolically and in percentiles.
Table 5.
Overview of cutting speed, melt pool size, absorptivity, and interaction time for static beam shaping and longitudinal, linear beam oscillation.
Table 5.
Overview of cutting speed, melt pool size, absorptivity, and interaction time for static beam shaping and longitudinal, linear beam oscillation.
Parameter | Set #1 | Set #2 | Set # 3 | Set #4 |
---|
beam shaping | static | longitudinal, linear |
amplitude [µm] | 0 | 300 | 550 | 300 |
frequency [Hz] | 0 | 500 | 500 | 2000 |
focal plane [mm] | −10.5 | −3.2 | 3.2 | −2.8 |
cutting speed vc [m/min] | 0.5 | 0.85 | 0.7 | 0.7 |
melt pool size [mm2] in Figure 19 | 0.65 | 0.37 | 0.48 | 0.36 |
averaged absorptivity [-] in Figure 12 | 0.27 | 0.39 | 0.43 | 0.39 |
interaction time [ms] in Figure 20 | 132 | 70 | 132 | 84 |
Table 6.
Overview of burr height, maximum, and average temperatures and temperature volatility for static beam shaping and longitudinal, linear beam oscillation (calculated with e = 1).
Table 6.
Overview of burr height, maximum, and average temperatures and temperature volatility for static beam shaping and longitudinal, linear beam oscillation (calculated with e = 1).
Parameter | Set #1 | Set #2 | Set # 3 | Set #4 |
---|
beam shaping | static | longitudinal, linear |
burr height Ø zburr [m/min] | 1.1 | 0.65 | 0.78 | 1.37 |
surface roughness Ø Rz [µm] | 79 | 75 | 116 | 125 |
highest temperature of [°C] in Figure 16 | 2250 | 2665 | 2600 | 2910 |
average temperature of [°C] in Figure 18 | 1890 | 1970 | 1930 | 1670 |
volatility ΔT of °C] in Figure 18 | 575 | 1230 | 1420 | 1700 |