The article basically discusses: Stainless steel why so difficult abrade and how to solve this problem. Dr. Badger, in Irish Dublin 31 institutes obtain emperor mechanical engineering doctor's degree, go up in mill magazine column with " mill doctor " name is well-known, serve as independent adviser now, annual circumnavigation serves for much home company, the mill craft that devotes oneself to to raise them reachs his to be opposite the understanding of mill flow. Stainless steel why difficult abrade? About this problem, must involve two big fields: Jam and heat up telex conductance. Can appear in abrade process two kinds jam type: Machinery jams and chemistry jams. The following material produces machinery to jam easily: Have the stuff that delays malleability high; Have the stuff of high strenth; "Stickiness " material; Stainless steel; Nickel radical alloy; Can form the full-length film that has stickiness (the lump with short and rather than) material; Altogether, weaker data (or sclerotic steel is familial) . Jam about chemistry, because regular meeting of rolled steel surface forms a thin FeO,basically be, fe2O3, feAl2O4 layer, and surface of stainless steel material has a thin Cr2O3 layer, when Al2O3 emery wheel is abrade, these chemical elements can produce chemical reaction. Somebody may ask: Can you jam according to the exterior judgement of emery wheel circumstance? Is emery wheel blacker jam more serious? My answer is: Not certain. We use naked eye normally or be in times lower the observation below microscope is globose the circumstance that jam. Through many survey, our scale goes out below this chart: Chart shows: Most the emery wheel with right the blackest exterior, jam the case is not severe, and the emery wheel with very light color, jam very serious however. That is to say, whether does surface color blacken, and jam circumstance, did not concern directly. "Do not want the outside color according to emery wheel forever, and should be judged according to the stain circumstance above jam circumstance! " below it is a few more commonly used solutions that reduce machinery to jam: With softer emery wheel, before jamming slowly, emery wheel is changed from acute and wear away. With open the emery wheel with larger angle, for instance constituent name counts larger groovy abrasive emery wheel, or n is spent centrally inferior (for instance 75, of 100) of and rather than exceed hard abrasive emery wheel. With pottery and porcelain union replaces colophony felt (colophony felt emery wheel is very few aperture) when using CBN emery wheel especially, with the high-pressured cleanness nozzle that exceeds 100bar. Move with low stuff except rate is abrade (to load regular meeting has a critical value, for instance 4 Mm3/mm/s, after exceeding this critical value, jam the circumstance can become austere. Use the water with higher concentration base refrigerant emulsion, in thick arenaceous and a protective screen is formed between workpiece. The refrigerant that use oil replaces water radical refrigerant (form better protective screen) and the more commonly used solution that reduces chemistry to jam has the following 3 kinds: With softer emery wheel, before jamming slowly, emery wheel is changed from acute and wear away. Use the water with higher concentration base refrigerant emulsion, in thick arenaceous and a protective screen is formed between workpiece. The refrigerant that use oil replaces water radical refrigerant (the protective screen) with be formed better. I think: These solutions can be careless only, there is a better solution now -- cooling! -- heat up again when these stinging fragment flies from workpiece, if use microtherm refrigerant to quench them instantly, it is to be able to decrease sticky go up to emery wheel or each other are sticky together. It is better to there is oil between abrasive grain and workpiece, can conduce to prevent its to produce chemical reaction. Pursue as follows: And low pyroelectricity conductance is stainless steel difficult place of abrade another big question: The low pyroelectricity conductivity of stainless steel, make emery wheel and abrade surface temperature extremely high, can feed makings speed to drop temperature through reducing only. The yield that the limitation that overcomes mill facility wants to improve abrade facility can efficiency, above all a few big restriction that we want to understand it to often must be faced. Nextpage restricts one: Bad cooling system is abrade the cooling system on equipment, be normally how the design comes out? A lot of stylist can be after development of machine tool success, get through hastily to cooling system: "Everybody works well. You had cost the past two years time design, framework this character admirable, value the machine of 1 1 million U.S. dollors. Let us throw a few old copper pipe now cooling system, go out its lading carry this afternoon! " so, make much time, we need to learn cooling knowledge, oneself develop a system. Before the cooling system that develops oneself, want first when understanding is abrade " heat " area -- the ground with can elevatory temperature. Going up in the graph, we can see the surface exceeds 2000F(to make an appointment with 1093 ℃ clearly) heat place. When our infuse cooling fluid when, must carry cooling rate and emery wheel rate identical, such refrigerant can slip between the Kong Zhi in emery wheel, heat area is sent again later. Ask everybody to must remember this formula: Wheel of emery wheel of V refrigerant Coolant = V -- the success of 90% is based on refrigeration to go up. Do not mind discharge, speed just is crucial! About infuse cooling fluid, big the daily life of a family has a wrong idea, think nozzle is bigger namely, cooling fluid infuse is more, produce burn not easily more. Actually, too big nozzle, can cause great pressure to drop. We must know need how old pressure. This is common common sense only actually, but in using a process actually, often search forbid pressure, bring about burn. Want to keep correct and proper pressure, need appropriate nozzle design. See the nozzle design of next graphs please: The not some petty gain, coarse, beautiful, nozzle that owes high-tech is designed, run rise fruit of its actual effect not common. I ever had seen the metal that used a squash only is in charge of, improved the cooling condition of whole abrade equipment, still decreased to jam even problem. The method is: It is ply 0. 5-1.
0 Mm(effect is best) metallic canal crimp is on the spacer in vice, reoccupy jimmy levers a few, in pivot on around roll is exporting a place to make a taper, enter extreme jab next vice again squash. Now, we got the compressed nozzle with a very small area. Hook up this metal canal after machinery, our meeting discovery jams appeared no longer. What is the key? The key is to make start to talk pettily in order to keep back pressure! Restrict 2: Bad emery wheel chooses most the mistake that often makes often was to choose too good-sized thick arenaceous. The emery wheel that issues a graph to be able to help our basis differ, different face casts luminosity, choose proper rough arenaceous measure. If choose to use too big thick arenaceous or emery wheel nap the excessive, word that wears too dully, the likelihood is caused of a lot of quiver shake and burn. Restrict 3: The error with bad nap common parameter is: The direction of rotation of the nap lead of emery wheel and corundum, different situation or show retrorse. This will be caused emery wheel becomes very quickly blunt and burn. Restrict 4: Bad abrade parameter we can want to find proper abrade parameter according to laying a plan: CNC Milling
CNC Machining