Volume 16, No. 9, September 2016, Pages 2216-2226 PDF(640 KB)
Characterization and Exposure Assessment of Odor Emissions from Laser Cutting of Plastics in the Optical Film Industry
Yun-Jung Chan1, Tzu-Hsuen Yuan2, Hui-Chu Sun1, Ta-Chang Lin1
1 Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan
2 Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University, Taipei 10055, Taiwan
- First study investigating odorous gas from laser cutting process in high-tech site.
- The amount of air pollutants increased when laser cutting power increased.
- Thirteen carbonyls and three phenols identified as the major odor sources.
- Laser cutter workers had higher carbonyls and phenols exposure than other workers.
- Formaldehyde exposure for laser cutter workers exceeded PEL-STEL.
The introduction of lasers as a cutting tool has become an important step in achieving further cost reductions in the multi-functional optical film industry. However, the fumes produced during laser cutting causes an annoying and often unbearable odor in the working environment. To date, little research has been reported in terms of the worker exposure assessment and odorous substances generated in the process of cutting plastics with lasers. This study firstly investigated the worker exposure assessment and the protection efficiency of the carbonyls and phenols when a laser is used to cut polycarbonate (PC) and polyethylene terephthalate (PET), the primary base materials used in optical film industry. Results indicate that the concentrations of these substances increased with the power of the laser. Due to differences in the monomer structures of these materials, a 240 W laser produced a high concentration of phenols (1.56 mg m–3) from PC and a high concentration of carbonyls (20.3 mg m–3) from PET. Without adequate protection and within a one-meter distance, laser cutting PET at the 240 W power level would expose machine operators to 2.74 mg m–3 of formaldehyde, which exceeds the regulatory standard of 2.4 mg m–3. An N95 valved active carbon respirator can effectively reduce this concentration to 0.07 mg m–3. However, the result of the masks studies could only reduce concentrations to between 1.88 mg m–3 and 2.2 mg m–3, which barely meet the related regulatory standards. In contrast, the installation of local ventilation alone can effectively remove as much as 99% of the gaseous substances produced in the laser cutting of plastics.
Laser cutting; Plastic; Carbonyls; Phenols; Protections.