Intermittent the experimental research that delay grinds efflux to pound heat exchange of area of aggrandizement grinding arc
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Keywords: of Jet Impinging of of of Enhancing Heat Transfer of of of Intermittent Creep Feed Grinding in recent years, intermittent grinding drops in temperature distinctly with its the attention that the effect and clear integrated craft advantage cause people. Because meantime stops cooling action, make grinding heats up accumulation to be reduced significantly, prevented the fire damage of workpiece surface layer effectively thereby, to difficult treatment the grinding of material has advantage more. Will intermittent grinding drops in temperature the low temperature that the wear-resisting character of emery wheel of advantage, CBN and delay grind is characteristic 3 person be united in wedlock, emery wheel is intermittent delay grinds craft solving delay to grind burn respect to show very great potential. The mechanism that grinds burn about delay considers to already announced, when grinding heat flux exceeds critical value, arc area happens into film to boil, grinding fluid can cut off because of enraging film can no more express surface contact with workpiece, the many grinding heat that can take away by grinding fluid vaporization originally then is forced change its course enters work, bring about workpiece surface layer thereby sharp temperature rise produces burn very quickly. Crisis of boiling heat exchange brings about workpiece burn problem to be versed in in heat early oneself traverses the field below the tall heat flux that delay grinds place to be faced with use technology of aggrandizement heat exchange to be able to solve effectively. Accordingly, article basis thought of aggrandizement heat exchange, couple leaves groovy emery wheel intermittent delay grinds craft, the grinding fluid that puts forward a kind to use high-pressured efflux to pound surface of arc area workpiece directly is added note pattern, thereby breaks through the gas film that already formed, make arc area still can produce advantage of heat exchange of nuclear boiling vaporization below tall heat flux, heat exchange efficiency raises a new standard. Pass intermittent the research of grinding function experiment that the cooling means that side direction efflux uses to pound arc area surface when delay is ground has, show efflux to pound technology of heat exchange of area of aggrandizement grinding arc to have capacious applied foreground Q. 1 experiment condition and test system open groovy emery wheel to make grinding fluid guides more easily than integral emery wheel arc area, but common and tangential feed flow kind realizes efflux very hard the immediate impact that is versed in to arc area. Accordingly, the side direction efflux that this literary grace shows 1 times with the graph pounds means directly to arc area. Because use pump of high-pressured force plunger and tailor-made experiment to use square spray head, efflux exports speed to be able to amount to 80m/s, at the same time width of grinding test specimen is less than emery wheel width. Specific experimental requirement is expressed as follows. Test specimen chooses coefficient of thermal conductivity TC4 of alloy of titanium of material of treatment of aviation accident of boat of low, easy burn has grinding function test, research is intermittent the effect of heat exchange of area of arc of aggrandizement of concussion of the efflux when grinding. Graph emery wheel of grinder of feed of delay of accurate plane of MMD7125 of grinder of watch of condition of experiment of concussion of 1 efflux side direction eletroplates groovy CBN emery wheel, granuality 80, chroma 200, open groove to count 177 grinding fluid 5% emulsion, cooling current measures 90L/min, double electrode of means of Xiu Rui of 7MPa of pressure of highest feed flow electroanalysises Xiu Rui changes to can check arc area temperature in real time, cent piece test specimen is used to place a half artificial thermocouple to measure in the experiment lukewarm, signal shows a record by 3562 signal analyzer directly, record power of grinder main shaft by X-Y recorder at the same time. 2 tests result and analysis 2.
1 arc area is common and tangential experiment of contrast of as cooling as eject of efflux side direction effect pursues 2 to be in Vs of speed of identical emery wheel, VW of workbench feed speed, different cut deep Ap, use tangential feed flow and the influence that side direction efflux pounds pair of grinding temperature. Graph 3 to be in identical grinding condition falls, below law of common feed flow and circumstance of heat exchange of concussion of side direction efflux, the curve of grinding temperature change that takes by signal analyzer, can reach by the graph efflux pounds heat exchange of aggrandizement arc area to have apparent drop in temperaturing characteristic. The graph cools two kinds 2 the comparative figure of means grinding temperature wave of temperature of grinding of 3 actual measurement pursues 4 to be in speed of identical emery wheel, workbench feed speed, different below the grinding temperature that cuts dark place correspondence, use tangential feed flow and the influence that side direction efflux pounds pair of grinding power. By Tukede, differ in grinding power below not big case, side direction eject is compared tangential the grinding temperature of feed flow correspondence is low. The J in becoming direct ratio form as a result of Q of grinding heat flux and grinding power N - mechanical equivalent of heat; R - grinding thermal current enters workpiece rate; L - contact arc length; B - workpiece width. The graph cools two kinds 4 the comparative i.e. of means grinding power shows the condition in close of grinding heat flux falls, the grinding temperature of correspondence of place of concussion of side direction efflux is low, heat exchange efficiency rises. 2.
Efflux of high speed of 2 side direction and experiment of contrast of effect of heat exchange of area of arc of low speed efflux pursue 5 to be in speed of identical emery wheel, workbench feed speed, different cut fall greatly, use efflux of side direction high speed and low speed efflux to pound the influence of pair of grinding temperature. By Tukede, efflux concussion has high speed to drop in temperature significantly advantage, although be being cut greatly,fall greatly to still did not appear burn. Graph the contrast of temperature of grinding of efflux of 5 tall, low speed 3 conclusion experiment makes clear, technology of heat exchange of efflux concussion aggrandizement is the effective method that improves efficiency of arc area heat exchange, efflux rate is higher, heat exchange effect is better. It can break through the obstacle that boils into film, although be below tall heat flux, the critical temperature that Yi Kewei of workpiece surface temperature maintains grinding fluid to happen into film to boil makes an appointment with 120 ～ 130 ℃ are the following (fluid of water radical grinding) , the material purify that burn does not produce when also showing deep-felt delay is ground leads synchronism to rise. But because accept experimental condition restriction, the side direction efflux that article place uses pounds method of surface of arc area workpiece, efficiency of its heat exchange is far still not as more perpendicular as radial of efflux edge emery wheel concussion workpiece surface, accordingly, development is developed but high-pressured efflux pounds the radial of grinding arc area of aborning application the device of feed flow of new-style grinding fluid of heat exchange, to avoiding workpiece burn effectively, raise grinding efficiency to have very great sense. CNC Milling