All over the world, governmental organizations like OSHA have established safety standards to ensure health and safety in the workplace. To make sure laser technology is perfectly safe in manufacturing environments, it must be implemented properly to prevent health risks. One of the important laser safety considerations is the extraction and the filtration of fumes.
Laser processes like laser cleaning, laser engraving, laser cutting and laser welding all release contaminants into the air. These contaminants include dust and fumes that must first be extracted and then filtered.
3 Important Tips for Laser Fume Extraction
Tip #1: Perform Source Capture to Improve Efficiency
Fume capture is most effective when a fume extraction nozzle is positioned next to the source of fumes. If you can’t position a nozzle in that area because you have mechanical constraints, fume extraction should be as close as possible. If the laser moves during the operation, the nozzle should follow the laser beam to maintain the efficiency of fume extraction.
If multiple processes generate fumes, a single fume and dust collector can be used. For example, manufacturers who perform laser cleaning at the same time as welding can have a single welding fume extractor.
Tip #2: Automate Safety Measures Through PLC Communication
Filtration systems need to be connected to the machine PLC so that if a problem occurs with fume filtration, the laser is shut down immediately.
Here are examples of filtration problems that can occur and how they can be prevented to avoid exposing employees to hazardous fumes:
- Filter life: Filters become saturated over time and need to be changed. To detect saturation, pressure differences between the air input and the air output need to be monitored in the filtration systems. When the pressure difference indicates that filters are almost saturated, maintenance reminders should be displayed. When the saturation threshold is reached, the machine must stop automatically.
- Airflow leaks: The fume extraction system is useless if it is leaked. To detect leaks, the extraction unit’s pressure needs to be monitored near the extraction point to ensure that the airflow is adequate.
Tip #3: Identify Contaminants That Need to be Extracted
Knowing which contaminants are released into the air is essential to choosing the right filter and extraction units. This will also make you aware of the potential health risks. For example, paint and oil can release quite hazardous substances into the air. The same applies for rust micro particles.
Contaminants that need to be extracted may come from two sources: the removed materials and, in some cases, gases used by the laser.
Here’s how you can identify which contaminants you’re dealing with:
- Removed materials: All removed materials are transformed into dust and fumes. To identify which byproducts are released into the air, you need to use the Material Safety Data Sheet (MSDS) provided by your materials supplier. This document contains information on the properties and potential hazards of the material you’re working with.
- Assist and shield gases: Many laser cutters and welders use assist or shield gases. These gases may include nitrogen, oxygen, helium and argon. The resulting byproducts need to be removed from the work environment. Laser marking and laser cleaning systems do not use gases.
Frequently Asked Questions (FAQ)
How Much Airflow Is Needed?
The volume of airflow needed is directly related to the amount of material removed. While laser marking removes little to no material, other processes like laser cutting and laser cleaning remove important quantities of material and require a high airflow. When buying a laser, an expert should be able to guide you toward the volume of airflow you need.
How Are Contaminants Filtered?
Air can be filtered using two main methods. Either you connect the laser fume extraction system to your in-house duct system, or you buy a filtration system.
Whether air filtration is done through ducting or in a standalone unit, there are typically three main types of filters. The resulting air quality is 100% safe for employees. Once filters are saturated, they need to be changed to maintain their efficiency and ensure a clean air.
- Pre-filters: Pre-filters capture large particles that are visible to the human eye.
- HEPA filters: High Efficiency Particulate Air filters capture small particles such as fine dust through layers of fibers. These filters can remove at least 99.97% of particles with a size of 0.3 microns.
- Activated carbon filters: Carbon filters capture and neutralize odors, smoke, fumes and chemicals (such as VOCs). When these contaminants pass through, they are trapped in the small pores of the activated carbon.
Do You Need Additional Safety Measures?
Additional safety measures need to be followed when changing filters.
- Eye protection: Wear safety eyewear if there is a risk of exposure.
- Skin protection: Wear gloves and avoid prolonged contact with your skin. Apply a barrier cream before handling dust to protect exposed skin areas (but never after).
- Respiratory protection: Use a NIOSH-approved respirator that has been selected based on known or anticipated dust exposure levels.
- Personal hygiene: Wash your hands before eating, drinking, using the bathroom, and at the end of the filter maintenance. Wash your contaminated clothes independently before reusing them.
How Much Sound is Too Loud?
Fume extractor product sheets often include dBA units (weighted decibels) to indicate sound levels produced by the unit. In the US, the OSHA governmental organization recommends that employees wear ear protection when sound levels exceed 85 dBA. Since most fume extractors generate noise between 20 and 80 dBA, they rarely require ear protection.
To better understand the amount of noise generated by a laser fume extractor, refer to the following chart provided by the OSHA.
Image courtesy of the U.S. Occupational Safety and Health Administration (OSHA).
Keep Lasers Safe and Efficient
With a proper laser fume extraction system, dust and fumes are rendered harmless. If you perform source capture, change saturated filters, and implement automated safety measures, you should not encounter any safety problems.
You might encounter another type of problem, however.
Dust can affect the effectiveness of the laser process. When it accumulates on the laser’s lens, the laser beam becomes less efficient. Lens cleaning maintenance needs to be performed at a frequency that varies according to the amount of dust generated. To diminish the frequency of this operation, you can install a blower (such as an air-knife) to prevent dust accumulation on the lens.
If you need a laser for marking, cleaning or texturing and are worried about dust and fumes, contact our laser experts. They are regularly in touch with fume extraction experts and know what is needed for specific applications.