Summary: When processing work through labor cutting, workpiece already processed all sorts of accounts of generation of exterior surface roughness, analyse to producing the element one by one of exterior surface roughness, find out the concrete step that reduces exterior surface roughness thereby, provided academic basis to improve the exterior quality of workpiece. The reason geometry ingredient that 1 surface surface roughness produces because the reason such as the surface roughness of motion of parameter of the geometrical appearance of blade of cutting tool cutting, geometry, feed and cutting blade itself, fail to will be machined apparently material layer gets rid of completely completely (what cutting tool should contain on cutting tool only is deputy slant the Xiu Guangren of horny Kr=0, and when feed is less than Xiu Guangren width, theoretic ability does not produce rudimental area) , already machining apparently area of the remain below bequeath, the height of rudimental area formed exterior surface roughness Rz. When F ≤ 2resinkr, rudimental area is transfer by circular arc blade is formed. In this up-to-date style: F -- feed, mm/r; Re -- radius of circular arc of point of a knife. When ≤ of 2resinkr ≤ F (Re/sinkr)[1-cos(kr+kr] , rudimental area is by point of a knife circular arc transfers blade and blade of linear deputy cutting are formed. Right now Rz=re[1-sin(kr+b)] × 1, the Kr in 000sinb=1-(f/re)sinkr type, kr -- the tool cutting edge angle of cutting tool, deputy slant horn. When F>(re/sinkr)[1-cos(kr+kr)] , rudimental area is by point of a knife circular arc transfers blade and 2 linear advocate, deputy cutting blade is formed. Right now Rz=1f-re(tankr+tankr)] × 1000cotkr+kr22 is become Re → 0 when, rudimental area is by advocate, deputy blade of 2 linear cutting is formed. Right now because the surface roughness of blade of cutting of cutting tool of Rz=f × 1000cotkr+kr is direct answer mirror machining apparently, so the surface roughness of blade of cutting tool cutting is worth, the surface roughness that should ask under treatment surface is worth. The surface roughness that machines the surface actually always is more than the height that presses area of above calculative remain, when having cutting brittleness material or stuff of plasticity of high speed cutting only, the surface roughness that machines the surface actually just nears the altitude of rudimental area quite, show those who affect exterior surface roughness to still have other reason. The tumour that accumulate bits accumulates the generation of bits tumour, because cut bits to reached cutting tool and the external friction that cut bits to exceed in the plasticity flow in cutting process,be inside attrition, mix in cutting tool cut the very great pressure between bits cutting is caused below action cold welding happens before ground floor and cutting tool. The tumour that accumulate bits has two sides to the influence of exterior surface roughness: It can engrave ① the channel lines with fore-and-aft lay off comes it still can be in; ② broken when falling off, touch add in already machined apparently. Are its main is the reason: ? Be asked to protect Na by awl of そ of of expostulate with of υ of agent Ju to joke of bamboo-plaited basket or suitcase of source of benzyl of provide for of eye of frequency of drop of Xian of Zu of of leave uncovered of gorge of rice huller of け of commonplace of duck of show off of perch of agent of of hoarse of Ge of danger of Ran Xia of Ba of celestial bodies of the dark angry that see adept aing concubine of an emperor breaks rice huller of duck commonplace け , be when using cutting of low speed of high-speed steel cutting tool, often see a kind of phenomenon that arrive. Scale thorn is formed in the early days that increases level in the tumour that accumulate bits commonly. Be in even when accumulating bits tumour, and squamate also inside a few lower cutting speed limits thorn happens. Of cutting tool hind scale of particularly easy generation is pricked when part is small. Scale thorn has serious effect to already machining exterior quality, it often makes grade of exterior surface roughness reduces 2 ～ 4 class. The cause of formation that scale pricks is before the periodic change of force of the attrition on knife face causes. In oscillatory cutting process if have vibration, exterior surface roughness can greaten significantly. Because Fr of radial cutting force is too big,vibration is, or of workpiece system stiffness is small and cause. The extruding of blade of other factor deputy cutting to rudimental area, make rudimental area is out of shape to as opposite as feed way, make remain area coping is askew and generation burr, increased exterior surface roughness. Transfer the cutting ply of part of blade circular arc is change, the cutting ply that close point of a knife is in is very small. After feed is less than certain limit, when the cutting ply of this part is less than point circular arc to be able to cut the smallest ply below, partial metal fails to excise, can make exterior surface roughness increases. When cutting brittleness material, generation collapse is broken cut bits, the break deep person when the collapse that cut bits is broken arrives to already was machined under the surface, make surface roughness increases. In addition, the precision of equipment of the state that discharge bits, machine tool and stiffness, also can affect the exterior surface roughness that already machined the surface. The biggest to influence of exterior surface roughness in the parameter of geometry of cutting tool of parameter of geometry of respect of element cutting tool of 2 influences surface roughness is Re of radius of circular arc of point of a knife, deputy slant horny Kr and Xiu Guangren. Re of radius of circular arc of point of a knife has double effect to exterior surface roughness: When Re increases, rudimental height is reduced, be out of shape on the other hand will increase. Because before one kind of impact is bigger, increase when Re of radius of circular arc of point of a knife so when, exterior surface roughness will be reduced. Because this is below the condition that stiffness allows, increasing Re of radius of circular arc of point of a knife is the good method that reduces exterior surface roughness. Deputy slant horny Kr heals small, exterior surface roughness heals low. But reduce deputy slant horn causes vibration easily, reason is reduced deputy slant horn, the stiffness that must inspect machine tool system and calm. Arrive greatly when Kr when fair value, deputy blade does not participate in the composition of rudimental area, increase Kr again, also won't make the value increases exterior surface roughness. The Xiu Guangren that uses a paragraph of length to be more than feed a bit (the Kr=0) on Xiu Guangren is the significant step that drops exterior surface roughness, use increasing Xiu Guangren to eliminate rudimental area is the method that in processing work actually, often uses. Horny G0 does not have immediate impact to exterior surface roughness before, because G0 is big when advantageous to restraining the tumour that accumulate bits and scale thorn, and increased. Can make Re of radius of point circular arc is reduced, increase G0 to be able to be helpful for reducing exterior surface roughness appropriately inside limits of medium, low speed so. When V>50m/min, g0 basically does not produce an effect. Before the blade of cutting tool grinds quality the crucial point, hind knife face, the surface roughness of cutting blade itself is worth immediate impact to be machined the surface roughness of the face. Generally speaking, before edge, hind the surface roughness that the surface roughness of knife face should ask than machining a face is small 2 class of 1 ～ . The material of material cutting tool of cutting tool and be machined when the affinity of material metal element is big, be generated with cutting tool felt easily to accumulate bits tumour and scale thorn by treatment material, and the metal on edge be been in by felt and when be being departed by treatment surface, still can form additional surface roughness. Accordingly always felt case is severe, attrition is serious, exterior surface roughness is big; if felt and attrition are lax,weigh conversely, exterior surface roughness is small. When V of speed of cutting condition cutting processes plasticity data, the effect that cutting speed pricks to accumulating bits tumour and scale is very distinct. Scale of inferior easy generation pricks cutting speed, low speed comes middling speed is easy form the tumour that accumulate bits, surface roughness is big also. Escape this speed extent, the value can reduce exterior surface roughness. When processing brittleness data, because won't form the tumour that accumulate bits and scale thorn commonly, so cutting speed does not have an influence basically to exterior surface roughness. This shows, with higher cutting rate, can improve productivity already, can make treatment surface surface roughness lesser again at the same time. So the most important is to develop material of all sorts of new cutting tool and structure of corresponding new cutting tool, so that use higher cutting rate likely. Feed F from inside geometrical element knowable, reduce feed F to be able to reduce the height of rudimental area. Also can reduce the tumour that accumulate bits and the height that scale pricks at the same time, reduce feed to be able to make the value reduces exterior surface roughness consequently. But when feed reduces fixed cost, reduce again, plasticity is out of shape should take dominant place, surface roughness value won't fall apparently. When feed more hour, because plasticity deformation increases, surface roughness can rise somewhat instead. Cutting deepness Ap generally speaking, cutting deepness is not apparent to machining the influence of exterior surface roughness, negligible in real work not plan. But when Ap<0. 02 ～ 0.
When 03mm, because edge is not absolutely acuteness has certain circular arc radius however, at this moment normal cutting cannot undertake, extruding glide machines the surface and often do not cut fall to cut bits and will be caused apparently in treatment additional plasticity is out of shape, make machine exterior surface roughness to increase thereby. So cutting treatment cannot have chosen small cutting deepness. But deepness also meets too big cutting affect treatment precision and exterior quality because of leap of cutting force, heat in metal cutting. The refrigeration of fluid of cutting fluid cutting and lubricant action, the interface that can reduce cutting process chafes, drop cutting area temperature, the plasticity that reduced cutting process thereby is out of shape and restrain the tumour that accumulate bits and the growth that scale pricks, because this is right,reduce treatment exterior surface roughness is advantageous. By treatment material generally speaking, material tenacity is better, plasticity is out of shape the tendency is jumped over big, in cutting treatment, exterior surface roughness is bigger. Be concerned by position of the treatment data impact to exterior surface roughness and its metallographic organization. The precision of machining complex and the exterior surface roughness after stiffness is machined want low, must have the machining complex of the machine tool of expensive campaign precision and tall stiffness, have stronger fight brace up quality, otherwise although have very good cutting tool, dosage of choice first-rate cutting gains the treatment face of high quality very hard also. If the 3 measure that drop exterior surface roughness already machined trace of the surface taking a knife to be clear about quite, showing the main factor that affects exterior surface roughness is geometrical element, should consider to reduce rudimental area height above all. Reduce the method of rudimental area height, it is the geometrical parameter that changes cutting tool above all, increase radius of circular arc of point of a knife Re and reduce deputy slant horny Kr. Lathe tool of the cutting tool that uses the Xiu Guangren that contains Kr=0 or planing tool of wide blade essence, essence is treatment is reduced in production the method that exterior surface roughness uses. It is to increase Re no matter, reduce Kr, or should notice to avoid vibration with glaive. Reduce feed F, also reduce rudimental area height effectively, but reduce feed F to be able to reduce productivity, the meeting after the geometrical parameter that changing cutting tool only so causes vibration or other just considers to reduce feed F when bad influence. If already machined the surface to appear,cutting speed direction has the groove that the tumour that accumulate bits causes, so answer from eliminate the tumour that accumulate bits and scale thorn to begin. Can adopt with lower or higher cutting rate, cooperate lesser feed, can restrain the tumour that accumulate bits and the growth that scale pricks effectively. In G0 of the horn before be being increased when cutting of medium, low speed, increase appropriately at the same time a few hind horn accumulates bits tumour and scale thorn to have certain effect to restraining. Convert the cutting fluid with lubricant good performance, undertake normalizing, attune wait for heat treatment character first to workpiece when necessary, in order to raise hardness, reduce plasticity and tenacity. CNC Milling