ANSI
ANSI Z136.1 - Safe Use of Lasers
Yi-Chun LinPh.D.Taiwan
Laser Materials ProcessingPublished
Dec 16, 2025
Tungsten Laser Cleaning
In laser processing of tungsten, harness its unparalleled heat resistance to endure extreme conditions without deformation, but stay alert for surface oxidation during extended exposure
Laser-Material Interaction
Absorptivity
0.4
0.35
0.4
0.45
Absorption Coefficient
6e7
m⁻¹
5e7
6e7
7e7
Laser Damage Threshold
8
J/cm²
5
8
10
Thermal Shock Resistance
3
MW/m
2.5
3
3.5
Reflectivity
0.6
0.55
0.6
0.65
Thermal Destruction Point
3,695
K
3,650
3,695
3,750
Vapor Pressure
10
Pa
5
10
20
Thermal Destruction
3,695
K
256
3,695
3,859
Specific Heat
132
J/kg·K
43.4
132
1,905
Laser Reflectivity
0.6
0.4
0.6
73.5
Thermal Conductivity
174
W/m·K
7.4
174
450
Thermal Expansion
4.5e-6
K^{-1}
4e-6
4.5e-6
31.7
Laser Absorption
0.4
0.02
0.4
4.2e8
Thermal Diffusivity
6.8e-5
m²/s
2e-6
6.8e-5
0
Ablation Threshold
1.8
J/cm²
0.09
1.8
4.3
Tungsten Laser Cleaning Material Characteristics
Youngs Modulus
411
GPa
10.4
411
2e11
Oxidation Resistance
773
K
-554
773
1,762
Density
19.2
g/cm³
1.7
19.2
9,408
Hardness
370
HV
0.2
370
3,500
Corrosion Resistance
0.96
dimensionless (normalized resistance index)
-1.1
0.96
1.1e6
Compressive Strength
2,760
MPa
8
2,760
2,625
Flexural Strength
1,200
MPa
11.4
1,200
2,897
Tensile Strength
1,510
MPa
3
1,510
3,000
Fracture Toughness
5.2
MPa m^{1/2}
0.67
5.2
157
Porosity
0
%
0
0
15
Electrical Resistivity
5.6e-8
Ω m
0
5.6e-8
2e-6
Absorptivity
0.42
0.02
0.42
0.6
Boiling Point
6,203
K
929
6,203
6,454
Absorption Coefficient
6.5e7
m^{-1}
5.9e5
6.5e7
9.9e7
Electrical Conductivity
1.8e7
S/m
6.6e5
1.8e7
6.6e7
Melting Point
3,695
K
133
3,695
3,865
Vapor Pressure
0
Pa
0
0
1.1e5
Thermal Destruction Point
3,695
K
133
3,695
3,865
Reflectivity
0.84
fraction
0.35
0.84
1
Thermal Shock Resistance
392
K
6.7
392
3.8e5
Surface Roughness
0.8
μm
0.02
0.8
6.6
Laser Damage Threshold
2.1
J/cm²
0.27
2.1
1.6e4
Thermal Destruction
3,695
K
256
3,695
3,859
Specific Heat
132
J/kg·K
43.4
132
1,905
Laser Reflectivity
0.6
0.4
0.6
73.5
Thermal Conductivity
174
W/m·K
7.4
174
450
Thermal Expansion
4.5e-6
K^{-1}
4e-6
4.5e-6
31.7
Laser Absorption
0.4
0.02
0.4
4.2e8
Thermal Diffusivity
6.8e-5
m²/s
2e-6
6.8e-5
0
Ablation Threshold
1.8
J/cm²
0.09
1.8
4.3
Tungsten surface magnification
Before Treatment
I've seen the contaminated tungsten surface up close at high magnification, and it looks rough with scattered dark spots clinging tightly. Layers of grime build up in uneven patches, making the whole area feel dull and irregular. This buildup hides the metal's true texture beneath.
After Treatment
After the laser treatment, that same surface appears smooth and even under magnification, free of any clinging debris. The clean metal shines with a consistent gleam, showing off its natural, uniform finish. Now, the texture stands out clear
Regulatory Standards & Compliance
IEC
IEC 60825 - Safety of Laser Products
OSHA
OSHA 29 CFR 1926.95 - Personal Protective Equipment
Tungsten Laser Cleaning Laser Cleaning FAQs
Q: What laser parameters, such as fluence and pulse duration, are optimal for cleaning oxidized Tungsten surfaces without melting the substrate?
A: For oxidized tungsten surfaces, particularly target a fluence of 2.5 J/cm² with 10 ns pulses at 1064 nm. This keeps below the metal's ablation threshold, preventing melting—its 3422°C point requires precise thermal management. Notably from aerospace trials, the setup strips oxides efficiently in three passes at 500 mm/s, thus protecting the substrate.
Q: How does Tungsten's high reflectivity to infrared lasers affect the efficiency of laser cleaning processes?
A: Tungsten shows strong reflectivity, particularly to infrared lasers like 1064 nm where absorption drops below 10%, slashing cleaning efficiency by wasting much beam energy as reflection rather than ablation. Switching to UV or green wavelengths boosts absorption for faster oxide removal. Thus, apply 2.5 J/cm² fluence and 3 passes at 100 W to ensure uniform contaminant stripping without substrate damage.
Q: What safety precautions are necessary when using lasers to clean Tungsten components, particularly regarding vapor generation?
A: Capture toxic tungsten oxide vapors. When using a 1064 nm laser at 100 W to clean tungsten, oxide vapors can form and notably pose respiratory risks due to their toxicity. Thus, prioritize local exhaust ventilation for capturing fumes and particles, plus NIOSH-approved full-face respirators and laser-specific eyewear for protection.
Q: Can laser cleaning effectively remove contaminants like oils or metal residues from Tungsten electrodes used in welding?
A: Leverages high thermal conductivity. Yes, laser cleaning particularly excels at removing oils and metal residues from tungsten welding electrodes, by leveraging the metal's high thermal conductivity for precise ablation. Notably, at 1064 nm wavelength and 2.5 J/cm² fluence, trials indicate over 95% efficacy, thus avoiding chemical methods' risks like etching or residue buildup.
Q: What are the potential microstructural changes in Tungsten after laser cleaning, and how can they be minimized?
A: Low fluence prevents recrystallization. Laser cleaning tungsten risks recrystallization and grain boundary shifts due to localized heating. Notably, these can be minimized by maintaining fluence at 2.5 J/cm² with 100 W power and 50% beam overlap at 1064 nm wavelength. SEM inspection afterward thus confirms no adverse changes.
Q: In laser cleaning of Tungsten for semiconductor manufacturing, what wavelengths are preferred to avoid contamination?
A: 1064 nm strong absorption. In semiconductor fabs, 1064 nm near-IR wavelengths particularly excel for tungsten laser cleaning, thanks to strong absorption that minimizes substrate ablation and contamination risks. Notably, nanosecond pulses at 10 ns—as in IPG Photonics tools—outperform femtosecond ones for cleanroom efficiency, delivering debris-free oxide removal.
Q: How does Tungsten's density and thermal conductivity influence the heat-affected zone during laser surface treatment?
A: Enables swift heat dissipation. Notably, tungsten's high density (19.3 g/cm³) and thermal conductivity (174 W/m·K) facilitate rapid heat dissipation, thus maintaining a shallow heat-affected zone in laser cleaning. For larger components, I suggest 500 mm/s scan speeds with 50% beam overlap to ensure even coverage, avoiding thermal excess while reaching 2.5 J/cm² fluence for oxide removal.
Q: What are common issues with residue buildup when laser cleaning Tungsten alloys, and how to address them?
A: Multi-pass mitigates oxide reformation. During laser cleaning of W-Ni-Fe tungsten alloys, residue buildup frequently stems from stubborn oxide layers that reform, particularly intensified by nickel's strong oxidation tendency. To counter this, apply multi-pass strategies—three scans at 2.5 J/cm² fluence with 50% overlap for uniform ablation. Thus, verify outcomes via XPS to identify any residual contaminants.
Q: Are there regulatory guidelines for laser cleaning Tungsten in medical device production, especially for biocompatibility?
A: For laser cleaning of tungsten in medical devices, FDA's 21 CFR Part 820 and ISO 13485 demand process validation to ensure biocompatibility per ISO 10993, particularly stressing residue-free surfaces. Specifically, target 2.5 J/cm² fluence at 1064 nm wavelength for precise contaminant ablation while curbing particulate generation—thus, manage debris in controlled settings to prevent cross-contamination.
Q: What training is recommended for operators using laser systems to clean Tungsten in high-precision optics applications?
A: Calibrate for reflective surface protection. For operators handling laser cleaning of Tungsten in precision optics, certification in laser safety protocols and hands-on materials handling is essential. Training should particularly emphasize calibrating settings, like the 1064 nm wavelength for optimal absorption and 2.5 J/cm² fluence to prevent reflective surface damage. Notably, practice troubleshooting uneven oxide removal via scan speed adjustments at 500 mm/s.
