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wiki:tools:laserfilter [2026/02/21 17:36] – Added Wayback Machine permalinks for the PDF references, fixed some spelling mistakes, and deleted some conflicting info about the filters ddqwiki:tools:laserfilter [2026/02/28 18:51] (current) – Updated filter spec ddq
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 ====== Laser Filtration System ====== ====== Laser Filtration System ======
-It is well understood that depending on the material being "lased" that the fumes from a laser cutter can be detrimental to human health, either through the release of particulates, or volatile organic compounds (VOCs). (reference: [[https://web.archive.org/web/20250405083356/https://assets.pubpub.org/11oas02j/22%20Herrick%20Klein%20Emerging%20Health%20and%20Safety%20Issues%20in%20Makerspaces-31691084105595.pdf|Download PDF]]) In particular, wood creates a significant amount of small particulate matter, while most plastics create various VOCs that must be removed from the exhaust stream before it is ducted either inside or outside the space.+It is well understood that depending on the material being "lased" that the fumes from a laser cutter can be detrimental to human health, either through the release of particulates, or volatile organic compounds (VOCs) (reference: [[https://web.archive.org/web/20250405083356/https://assets.pubpub.org/11oas02j/22%20Herrick%20Klein%20Emerging%20Health%20and%20Safety%20Issues%20in%20Makerspaces-31691084105595.pdf|Download PDF]]). In particular, wood creates a significant amount of small particulate matter, while most plastics create various VOCs that must be removed from the exhaust stream before it is ducted either inside or outside the space.
  
 Many commercial systems exist in order to address these concerns, and in general follow the same design principles: Many commercial systems exist in order to address these concerns, and in general follow the same design principles:
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 ===== Filter Setup ===== ===== Filter Setup =====
-In most cases, a prefilter, bagfilter, HEPA filter is the preferred option. This provides the longest lasting filter media for this application of the systems reviewed. However VHS has a modular setup that is arranged to accept standard 20"x25" furnace filters. Therefore the arrangement above was created using: +The VHS laser filter system is designed to use standard 20" x 25" furnace filters in two identical parallel stacks (see photo below). Each stack comprises, from bottom to top: 
-  - 2x reusable/washable plastic prefilters to capture large particles entrained in the flow from the laser +  - Bottom plenum (i.e., empty space); coarse particulates get deposited here 
-  - 4x Filtrete 1900 MPR 1900 "Maximum Allergen Filtrete Furnace Filters" (Can be replaced by a single deep pleat MERV 14 or higher commercial filter as necessary). +  - MERV 6 / MPR300 Pre-filter (x3 layers) 
-  - 6x trays of 1" Jacobi Ecosorb GXB granular activated carbon (or equivalent), 4 or 5 mm particle size+  - MERV8 / MPR 600 Furnace filters (one 2" layer or two 1" layers) 
 +  - MERV11 / MPR 1000 Furnace filters (one 2" layer or two 1" layers) 
 +  - MERV13 / MPR 1900 Furnace filters (one 2" layer or two 1" layers) 
 +  - Jacobi Ecosorb GXB or equivalent granular activated carbon, 4mm or 5 mm particle size (x3 layers) 
 + 
 +{{ :wiki:tools:laser_filter_stack.jpg?direct&400 |}}
  
 This system is designed to: a) reduce particulate entrapment in the fine particulate phase, b) ensure removal of particulate matter which is roughly similar to tobacco smoke as per literature on laser exhaust, and c) have sufficient residence time of the air in the carbon bed, while not increasing the overall dP of the filter system. This system is designed to: a) reduce particulate entrapment in the fine particulate phase, b) ensure removal of particulate matter which is roughly similar to tobacco smoke as per literature on laser exhaust, and c) have sufficient residence time of the air in the carbon bed, while not increasing the overall dP of the filter system.
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 While there are no specific change intervals, once a filter becomes clogged with debris it should be replaced. Current experience is that the filter media shouldn’t need to be replaced any more frequently than once every 3-6 months, but this will be highly dependent on usage. While there are no specific change intervals, once a filter becomes clogged with debris it should be replaced. Current experience is that the filter media shouldn’t need to be replaced any more frequently than once every 3-6 months, but this will be highly dependent on usage.
 In each set of filters, it is recommended to replace the lower filter first, and add the new filter to the top of the stack. In each set of filters, it is recommended to replace the lower filter first, and add the new filter to the top of the stack.
-Repeat for each bank of MERV 8, 10 & 13 filters.+Repeat for each bank of MERV 8, 11 & 13 filters.
 Activated carbon trays (top three) are not a part of this basic maintenance procedure and can be left alone. Activated carbon trays (top three) are not a part of this basic maintenance procedure and can be left alone.