The factor that affects metallic cutting to machine exterior quality and improve measure

The element 　 that affects machining surface quality 1.

The influence wearability to machining surface quality is opposite 1 machine performance characteristics the influence of exterior quality just had machined rub sassafras between deputy two contacts surface, first phase is touched in the peak ministry with rough surface, actual contact area is far be less than academic interface to accumulate, there is very great unit stress in the ministry of mutual contact, make actual interface accumulates place generation plasticity to be out of shape, flexibility is out of shape and the shear failure between peak ministry, cause wear away badly. Fatigue intensity is being handed in to the influence of exterior quality change load action, the sunken cereal place of exterior surface roughness causes stress concentration easily, produce fatigue grain. Exterior surface roughness is worth more big, grain mark of the surface heals deep, grain bottom radius heals, the ability that fights exhaustion to destroy is differred more. Leftover stress is very great to the influence of intensity of spare parts exhaustion. Exterior layer remains pulls stress to will make fatigue crackle expands, what exhaustion destroys; and express facing remains stress to be able to prevent fatigue crackle quickly is patulous, defer the generation that exhaustion destroys. Be able to bear or endure the corrode sex influence to exterior quality of the spare parts be able to bear or endure corrode sex depends on greatly exterior surface roughness. Exterior surface roughness is worth more big, sunken Gu Zhongju accumulates caustic material to heal much. The sex that fight corrode is differred more. The remains of exterior layer pulls stress to be able to produce stress to corrode craze, reduce the wearability of the spare parts, and remains pressing stress can prevent stress to corrode craze. 1.

The reflective cutting tool of the appearance of geometry of cutting tool of element 　 ① of the surface roughness of surface of influence of element cutting treatment of surface roughness of 2 influences surface makes feed at workpiece relatively when motion, in treatment the surface left cut remain area, its appearance is the report of appearance of cutting tool geometry. When the property of ② workpiece material processes plasticity data, produced plasticity to be out of shape to metallic extruding by cutting tool, together with cutting tool forces those who cut bits and workpiece depart to tear off action, make the value increases exterior surface roughness. When ③ cutting dosage processes brittleness data, when cutting speed affects not big; to process plasticity data to surface roughness, the tumour that accumulate bits is very big to surface roughness influence. The element of surface roughness of surface of grinding treatment influence affects the main factor with grinding rough surface to have: Radial of speed of the nap of the hardness of the granuality of emery wheel, emery wheel, emery wheel, grinding, grinding, feed and light grind frequency, workpiece circumferential feed speed and axial feed, cooling lubricating fluid. 1.

The element surface layer of function of machinery of physics of layer of surface of 3 influences treatment is cold the plasticity that in making sclerotic machining process, arises because of cutting strength effect is out of shape, make twist of character and morals, distortion, the generation between grain cuts slippage, taste bead to be spun to mix fiber is changed, broken even, these metropolises make the hardness of exterior layer metal and intensity rise, this kind of phenomenon is called cold make sclerosis (or call aggrandizement) . The influence is cold the main factor that makes sclerosis has: Blunt round radius increases cutting sword, increase to the extruding action of surface layer metal, plasticity is out of shape aggravate, bring about cold hard increase. Face of the knife after cutting tool wears away increase, hind knife face and by the attrition aggravate of treatment surface, plasticity is out of shape increase, bring about cold hard increase. Cutting rate increases, the effect time of cutting tool and workpiece shortens, make plasticity is out of shape patulous deepness is reduced, deepness of cold hard layer is reduced. After cutting rate increases, heat in metal cutting expresses the effect time on facing to also shorten in workpiece, will make cold strong pitch increases. Feed increases, cutting force also increases, the plasticity of surface layer metal is out of shape aggravate, cold strong action is strengthened. The plasticity of workpiece material heals big, cold good appearance heals serious. Change of organization of metallographic of material of layer of Nextpage 　 surface makes be changed more than by the temperature of treatment surface when heat in metal cutting after temperature, the metallographic organization of surface layer metal will produce change. Baked wheaten cake is hurt and basically grinding burn, temper by dipping in water retreats baked wheaten cake to hurt 3 kinds. Improve grinding burn to have two ways: It is the generation; that reduces grinding heat as far as possible 2 it is to improve cooling condition, make the quantity of heat of generation sends person work less as far as possible. Choose emery wheel correctly, dosage of logical choice cutting improves cooling condition. The account that stress produces remains of surface of stress of exterior layer remains: It is leftover stress arose in exterior metal layer when cutting, and be in li of generation in layer metal is leftover pull stress. 2 it is cutting in treatment, cutting area can have generation of many heat in metal cutting. 3 it is the change that metal of layer of surface of different metallographic organization produced metallographic to organize, the change of specific volume of surface layer metal wants the set back of the base metal that is linked together to it necessarily, have leftover stress generation consequently. 2.

The measure 　 that improves quality of machining work surface 2.

The procedure with 1 formulate reasonable science is the methodological basis that the procedure with the reasonable background science that assures workpiece surface quality is treatment workpiece. Have formulate only scientific and reasonable procedure, ability satisfies a requirement to provide scientific and rational method basis to machine workpiece surface quality, make machine workpiece surface quality to satisfy a requirement to become a possibility. The requirement of reasonable to science procedure is technological process wants short, fixed position wants accurate, make fixed position standard as far as possible when option fixed position is standard as fiducial as the design coincide. 2.

2 reasonable choice cutting parameter are the formation that the cutting parameter that makes sure the crucial choice that machines quality is logical can restrain the tumour that accumulate bits effectively, reduce the height that machines rudimental area theoretically, assure to machine the exterior quality of workpiece. The choice of the chooses to basically include point of view of cutting cutting tool option of cutting parameter, choice of cutting speed and cutting deepness and feed speed. The experiment proves, the cutting tool that is like the horn before the selection is bigger when processing plasticity data can restrain those who accumulate bits tumour effectively form, because the horn before cutting tool increases,this is when, cutting force is reduced, cutting is out of shape small, cutting tool and the osculatory length that cut bits shorten, reduced the basis that the tumour that accumulate bits forms. 2.

3 reasonable choice cutting fluid are to make sure the requirement that machines workpiece surface quality chooses reasonable cutting fluid to be able to improve the coefficient of friction between workpiece and cutting tool, can drop cutting force and cutting temperature, reduce cutting tool thereby wear away, in order to assure the treatment quality of workpiece. 2.

4 workpiece basically work the choice that expresses final process to machine a method is crucial workpiece basically is versed in final process machines tabulation face methodological choice is crucial, the leftover stress that because final process is in,cover of this labour tabulation remains will affect the performance characteristics of machine spare parts directly. Choice spare parts basically is versed in final process machines tabulation face method, must consider this spare parts to basically be versed in the specific work requirement of tabulation face is mixed destroy a form possibly. Closely related the exterior quality of workpiece and its performance characteristics, the performance characteristics of workpiece is the design requirement that serves as premise with making sure the machine is versed in normally, because this is in treatment workpiece process, we still should wait for many sided consideration from economic benefits, ability assures the treatment quality of workpiece surface already, avoid to increase the production cost of the spare parts again, cause needless loss. Have understanding and the factor that master quality of influence machining surface only, ability is in manufacturing practice, take corresponding craft step, reduce the treatment quality problem that the spare parts poses because of exterior quality blemish, raise the performance characteristics of mechanical product, life and dependability thereby.

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