Machining magnesium is risky business, as the chips and dust generated are flammable. Powder or dust from grinding or other operations can present an explosion hazard. Magnesium is classified as an alkaline earth metal and has 2 hydration shells. At this stage, a tradeoff of productivity to machinability is estimated. Linear heat detection wire protectowire in the mist extractor ducts and chip tray extractor. However, auxiliary collection devices hamper both tool changes and machine high speed movements. Siliconbased liquids do not have any of the disadvantages identified with the chlorinated biphenyls. Magnesium is considered to be in the class d fire category. The use of oilbased coolants reduces, but doesnt eliminate, the fire risk. Magnesium machining practices and precautions magnaloy. It does not rely on sulfur, chlorine or nitritecontaining additives, that known to be harmful to the. Development of a lightweight forged magnesium aircraft.
This fluid was specifically formulated to solve the issues of instability, short fluid life, and separation associated with machining magnesium. Coolants containing water should not be used because of the fire danger when magnesium chips react with water. Common dietary sources of magnesium include nuts cashews, peanuts, almonds, beans, bananas, apples, carrots, broccoli, and leafy greens. We are looking into an automatic fire detection and suppression system to install in the cnc machine. Fine powder, oil or turnings are easily ignited and burn with intense heat and brilliant white flame. We recently had quite a bit of magnesium in the shop we had to machine parts from, and it almost resulted in a fire while in the milling machine. Metalworking fluid is designed for magnesium machining.
Magnesium is the third most commonly use structural metal after iron and aluminium and historically has been used in applications including german aircraft during world war 1. Highspeed tools or carbide tipped tools are preferred for the machining of magnesium. When magnesium is in its metal form, it burns very easily in air. Fine finishingcuts,however,produce fine chips that can be ignited by a spark. Roughing cuts and medium finishing cuts produce chips too large to be readily ignited during machining.
Covers machining and fabrication, scrap handling, and storage. The element can be found in abundance in the hydrosphere and in mineral salts such as dolomite and magnesium carbonate. Never use water based coolant because of the risk of any reaction with the chips during storage. The oil functions primarily as a coolant, reducing the risk of fire, which is common to magnesium machining.
Long term storage of magnesium shavingspowder safety. Watercontaining metalworking fluids such as soluble oil emulsions should never be used for machining operations on magnesium or magnesiumcontaining alloys as a fire or explosion hazard may exist. If when necessary to use coolant, a light mineral oil will suffice. Since magnesium will ignite and burn fiercely when heated to a point near its melting temperature, certain precautions should be taken during working of it. Magnesium usually does not react with water, but oil based coolants would probably be better, because magnesium can react with very hot water, ie steam, and very small magnesium powder is more reactive than big magnesium chips. For transformer windings immersed in oil, hydrocarbon oil is the most widely used, whereas in areas where fire risk is a problem, then aircooled transformers an or synthetic siliconbased liquid cooling sn can be specified. The main concern in machining magnesium alloy is the danger of fire ignition. Should a fire occur, dry turnings will burn slow and evenly. Nfpa 480 applies to the storage, handling, and processing of magnesium at magnesium foundries, processing plants, and commercial storage facilities.
Machining, magnesium, hydrogen abstract in machining of. Fire may occur when the melting point of the alloy 400600 degrees celsius is exceeded during machining. Pieces 3 mm thick difficult to ignite but possible when sufficient heat is applied. Hot magnesium is a fire hazard when it contacts water. This makes the machining of magnesium alloy even more. The small chips and fine dust generated during cutting are also highly flammable and pose a serious fire risk if not properly handled. I work at a factory that uses a cnc to make magnesium parts. Fires in edm machines frequently result from a drop in oil level. I am pretty sure a magnesium fire is a class d for extinguishers and it will be sodium chloride based dry chemical that will make a crust or shell over what is burning and let it burn out contained. Some pistons have magnesium in them and for that reason i dont melt pistons except in a non metallic crucible. The main concern in machining magnesium alloy is the danger of fire ignition when dry cutting. In machining of magnesium alloys, waterbase cutting fluids can be effectively used to eliminate the buildup formation and. Magnesium machining is normally done without any coolant.
Chapter 25, oil burner flammability test for magnesium alloy seat structure. Where coolants are desired, only mineral oil based cutting fluids should. I have read msds sheetsarticles warnings and other research items that say obviously no water contact. Suri me scholar1, production engineering department, pec university of technology, chandigarh, india. Powders form explosive mixtures with air which may be ignited by a spark. How to avoid easy burning and explosion when cnc machining magnesium alloys. Metallurgical considerations for machining magnesium alloys jstor. You may make both very fine magnesium particles and hot water machining with water based coolant. Fire may occur when the melting point of the alloy. If magnesium fines or dust catches fire, do not use water as hydrogen gas will be generated along with extreme heat. I remember spending hours in boyscouts trying to shave off.
It is becoming much more common that cast and fabricated magnesium alloy parts will undergo cnc machining. Well i was grinding and the barrel caught on fire,before i could say anything the boss threw a bucket of water on it. Various mineral oil cutting fluids are used on magnesium, and mineral seal oil and. Traditionally a low viscosity oil has been the recommended cutting fluid for magnesium machining. Sansol ma806 is a superior microemulsion specially designed for machining magnesium and sensitive aluminum alloys. Fast, efficient, dry machining of a magnesium alloy safely demonstrated. In addition, the magnesium particles mixed in oil cant be recycled, and the machined parts would require extensive cleaning to remove oil residue. Blaser swisslube launches new fluid for magnesium machining goshen, n. Magnaloycouplingcompany technicalproductinformation couplings thepossibilityoffirewhenmachiningmagnesiumisalwaysarealconcern. Discover the best magnesium metal raw materials in best sellers. Magnesiumbased sheet metal processing in the precision parts processing. Using co2 gas, we may try to cut off the oxygen supply. As i mentioned, magnesium is a very important mineral for the body.
Recommended cutting fluid for various materials smithy. The study of machining of magnesium is very important for researchers and industries. Furthermore, the machining of mg comes with a very limited choice of coolant, as it reacts with water as well as several oilbased coolants. We recently had quite a bit of magnesium in the shop we had to machine parts from, and it almost resulted in a fire while in the milling. Putting out a magnesium fire using water doesnt seem a good idea as lowering the temperature would require a lot of it. It has a melting point of 1,202 f and a boiling point of 2,024 f. The possibility of fire when machining magnesium is always a real concern. Magnesium chips will burn, very hot, very bright blinding and i think it is hard to put out a magnesium fire. Watersoluble oils, oilwater emulsions or water solutions of any kind should not be used on magnesium. In this paper the main topic on machining of magnesium is introduced. Chips must be heated close to thier melting point before ignition can occur. Sansol ma806 is carefully formulated with high performance lubricity additives to enhance tool life and surface finishing. Cnc fire protection firetrace fire suppression systems. Magnesium has very good machining abilities like sawing, punching, drilling, milling, turning compared to other.
In the previous fire it burned through 1 of refractory and almost all the way through 1 of kaowool before it suficated out. A research consortium has developed a novel way to extract magnesium particles out of the machine by vacuuming them through a hollow tool and spindle during machining. Development of a lightweight forged magnesium aircraft seat component. Ok, i picked up the skylighter deal of the day last week.
Water soluble coolant is not recommended, as magnesium and water are highly reactive. The possibilty of chips or turnings catching fire must be considered when machining magnesium. The preferred recommendation is chevron utility oil lvi iso 22. Water reducess the scrap value of magnesium turnings and introduces potential fire hazards during shipment and storage of machine shop scrap. When magnesium is alloyed with aluminum, the resultant material is very light and strong, and easily machinable.
Since 1968, specmaster has been an industry leader in machining a variety of complex parts from magnesium. Much larger than will be seen in a oil coolant or mist fire. Has anyone had problems porting magnesium manifolds. Safety measures related to machining, handling of chips and fines, and fire. Ive always been curious to what happens if you light one of these whole blocks of magnesium on fire. Emulsions of soluble metalworking fluids and water may become contaminated with harmful microorganisms such as bacteria and fungus, which can cause illness and infection. Long term storage of magnesium shavingspowder posted in safety. The source of the magnesium in that fire was a connecting rod from an outboard. The ocean is still a wonderful source of magnesium and trace minerals, but for those of us who dont have daily access to a beach, transdermal magnesium oil can be the easiest and most effective way to increase magnesium levels. Always have dry sand, flux such as m310, or a class d fire extinguisher available when machining magnesium. When this occurs, the large supply of coolant oil and oil vapor can burst into a major fire in moments, destroying an expensive machine and threatening lives and property.
The use of animal or vegetable oil exacerbates any potential fire risk, since these oils can spontaneously ignite. For over 15 years weve specialized in complex surface machining and are capable of reproducing even the most challenging geometries. Small chip fires are not entirely avoidable in dry machining of magnesium. Standard for the storage, handling and processing of magnesium solids and powders. As im sure you all know magnesium fires can be pretty serious especially when shavings are involved. When machining with water soluble coolants one can expect. Our skilled machinists have years of experience and an extensive knowledge of various machining strategies to produce your magnesium components. Machining of magnesium and magnesium alloys asm digital library. In addition, lubricating oil, hydraulic oil, guide oil, and spindle oil used in machine tools are mostly flammable liquids, and the general oil storage. Heat detector senses the fire and activates the system without any built in delay. The recommended product for machining these metals is caltex almag oil all trademarks are property owned by chevron intellectual property llc.
1547 30 910 582 396 1499 605 604 396 190 377 1344 1198 1444 1117 255 1201 757 258 606 369 422 779 536 45 1190 102 1355 1371 976