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Technical Section Phone: 516-328-3970 www.technocnc.com 21 An important addition to workshops and machines is a dust collection system. Dust collection systems make shops cleaner, safer, and extend the life of a machine. A   clean   shop   is   a   safe   shop. Uncontrolled dust can cause potentially serious health risks, contribute to messy work environment that can cause personal injury,  and  be  the  cause  of  premature machine failures. Sawdust, wood chips,  and  any  other  particles generated by cutting the wood, particle board, plywood, etc., become hazardous if they are inhaled. These products are created with the use of resins, alkaloids,  silica,  tannins, toxic  organic  and  inorganic elements. Not to mention the insecticides, formaldehydes, and  other  toxins  that  come in  contact  with  the  tree  in nature. Exposure to dust containing any of these can cause respiratory ailments, allergic reactions, skin problems, and liver, kidney, or blood diseases. Keep in mind, the fi ner dust particles can be easily inhaled and ultimately end up within the bloodstream. These are the realities as pertaining to proper dust collection in the modern workshop. DESIGNINGTHEPROPERDUSTCOLLECTIONSYSTEM FOR YOUR SHOP In  order  to  design  a  cost-effective  and  efficient  dust collection system, the ducting must be carefully planned. The simpler the system, the cheaper and more efficient it will  be.  Before  getting  started,  there  are  many  variables which should be considered, such as:  type of dust collector, type of ducting material, location, layout, and the budget for your system. Dust Collectors There are basically two types of dust collectors: single- stage, and two-stage. A single-stage unit is an inherently cheaper system which consists of an inline impeller which passes debris through the impeller and deposits the dust and debris into a filter bag. As dust and debris collects in the  bag  or  drum,  the  system  becomes  increasingly  less efficient. Precautions need to be taken with single-stage systems to prevent large objects, or any objects that can The Dust Collection System cause sparks when passing through the impeller. Objects that are too large can cause damage to the impeller, thus resulting  in  impaired  performance.  Objects  that  cause sparking exponentially increase the chance of a fi re or dust explosion. A good dust separator should be installed so that it will trap metal objects before they reach the impeller. If you suspect a spark was generated, the unit should be shut down immediately and the bag emptied into a safe airtight container. Two-stage units draw dust and debris into the system, but deposit the majority of the debris in the fi rst stage collection container before entering the impeller. At this point, only fine dust passes through the impeller. As this fi ne dust passes through the impeller, the second stage consists of a fine micron filter element which filters the fine dust as the air is exhausted from the dust collector back into the shop. Choosing Piping There are two types of piping to choose from: metal or plastic. There are several different types of metal ducting such as stove, heat, and ventilation piping, as well as piping designed specifically for dust collection systems.  Metal  piping  is  generally  more  expensive, but  has  many  advantages  over  plastic  piping.  One advantage of using metal piping is the fact that it is a conductor and does not contribute to static electrical charge build-up. Although suspended dust within the ducting still generates a static electrical charge, metal piping  is  a  conductor  that  can  be  easily  grounded, dissipating the charge. If metal piping is to be used for the system, it should be of 26 gauge material or heavier so that the ducting will not collapse from the vacuum. The ideal ducting is piping that is specifically designed for dust collection purposes because it is the most efficient;  however, this is the most expensive. The use of metal piping does make installation more difficult, and may not be airtight if it is not specifically designed for dust collection. All leaks should be sealed for optimum performance. Plastic  piping,  such  as  PVC  or  ABS,  is  the  least expensive,  readily available and easily assembled, but it has many inherent problems. Plastic piping is an insulator; thus static electricity is generated as dust particles travel through the ducting. It is very important to ground a plastic ducting system in order to dissipate the static electrical charge. This can be accomplished by running bare 16 AWG copper grounding wire, which should be stranded, braided and run inside the entire ducting system (braided antenna wire works well too). At any joints, the wire should be soldered