Treatment of casing aperture department and commonly used tooling (in)

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2, precision of treatment of casing aperture department analyses 　 (one) boring lever suffers force metabolic to affect boring lever to suffer force to be out of shape is an influence bore hole one of main reasons that machine quality. When using cantilever to bore hole with connection of main shaft tigidity when boring lever especially, of boring lever suffer force to be out of shape most serious, it is with this now exemple undertake an analysis. Cantilever boring lever is in bore hole in the process, fr of force of M of moment of force of the cutting when getting, cutting and boring lever are self-prossessed the action of G, if place of graph 8-46, 8-47 is shown, m of cutting moment of force makes boring lever produces stretch twist, the exterior essence coarse that basically affects work spends the life with cutting tool; Cutting force Fr and self-prossessed G make boring lever produces flexibility to bend (bending is out of shape) , the effect that machines precision to aperture department is serious, the effect of Fr and G is analysed below. 1. The bending that arises by place of cutting force Fr is out of shape action is in the cutting force Fr on boring lever, the whirl as boring lever ceaselessly haul, from this and the bending of the boring lever that cause is out of shape also ceaselessly haul, if graph 8-46 place is shown, make the central deviate of boring lever former ideal center. See by the graph, when cutting power volume is changeless the athletic contrail of point of a knife still is shown round, just the diameter that place boring gives opening adjusted feet to reduce 2fF than cutting tool, of the size of FF and cutting force Fr and boring lever extend length to concern, fr heals big or boring lever is extended grow more, criterion FF heals big. But should point out, those who because the change of actual mental allowance and material are qualitative,be in in actual production not divide evenly, cutting force Fr is change, because this point of a knife moves,orbit cannot be round. Manage together, be being gotten on by the axes direction of treatment aperture, pledge as a result of mental allowance and material not divide evenly, when perhaps using boring lever feed, the bending of boring lever is out of shape also is change. 2. The bending that self-prossessed G place produces boring rod is out of shape self-prossessed G is in boring lever bore hole in the process, its size and direction are changeless. Accordingly, the boring lever bending that produces by it is out of shape the direction of FG is changeless also. When high speed boring, as a result of top effect, the bending that self-prossessed place produces is out of shape very small; When boring of low speed essence, self-prossessed be equivalent to to the action of boring lever all cloth load action is on cantilever bridge, make boring lever actual centre of turning circle from beginning to end under ideal centre of turning circle a FG is worth. G heals big or boring lever is dangerous extend grow more, criterion FG heals big, if pursue,8-47 place is shown. 3. The bending that boring lever issues in joint action of self-prossessed G and cutting force Fr is out of shape in fact, the bending that boring lever produces in each instant place is out of shape, it is the bending metabolic synthesis of cutting force Fr and generation of self-prossessed G place. Visible, below the integrated action of Fr and G, the deviate of actual centre of turning circle of boring lever ideal centre of turning circle. Of dosage of the change as a result of material qualitative divide evenly, mental allowance, cutting differ, and the change that boring lever extends length, make mobbish change is made in the procedure of opening of actual centre of turning circle of boring lever, caused aperture to fasten all sorts of errors of treatment thereby; To the treatment of same hole, cause columnar difference; To coaxial aperture the department causes coaxial to spend an error; To parallel aperture the department causes parallelism alignment error of pitch sum of errors. When rough machining, be sure to cuts muscularity, this kind of effect is more distinct; When finish machining, cutting force is small, this kind of impact is less also. Analyse from above knowable: Boring lever is in self-prossessed the bending that falls with cutting strength effect is out of shape, the geometrical appearance precision to aperture and mutual degree have distinct effect. Accordingly, in bore hole must very the stiffness that notices to increase boring staff, can take following step commonly: The first add thick boring as far as possible shank diameter and decrease dangerous extend length; The 2nd, use oriented device, make the bending of boring lever is out of shape be able to restrain. In addition, also can pass reduce boring staff self-prossessed and reduce cutting force to be affected to bending metabolic will increase opening is treatment precision. To boring the (when is shank diameter bigger? 80mm above) , should machine voidance heart, in order to reduce weight; Logical choice fixed position is standard, make mental allowance even; Lesser cutting dosage is used when finish machining, the cutting dosage that makes machine each aperture place to use agrees basically, in order to reduce cutting power influence. (2) boring lever and when directing covered precision and the influence that cooperate clearance use oriented device or boring model to bore hole, boring lever by guide-post bushing bearing, the stiffness of boring lever relatively rise greatly when cantilever boring. Right now, cooperate clearance with the geometrical appearance precision of guide-post bushing and its each other, will becoming influence hole is one of main factors that machine precision, analyse as follows now. Because existing to cooperate clearance certainly between boring lever and guide-post bushing, in bore hole in the process, when cutting force Fr is more than self-prossessed G, no matter cutting tool lies any cutting positions, cutting force can drive boring lever to lean closely in the surface inside as contrary as cutting position guide-post bushing such, as the whirl of boring lever, boring lever surface with guide-post bushing of edge of one fixed place whole inside round face is slip. Accordingly, the error will cause the circularity of guide-post bushing to be machined the circularity error of aperture, and the error is opposite the circularity of boring lever to be done not have to affect by the circularity of treatment aperture. When boring of essence of life, cutting force is very small, normally Fr<G, cutting force Fr cannot raise boring lever. As the whirl of boring lever, boring lever journal swings with the lower part of the aperture inside guide-post bushing of different position edge, if pursue,8-48 place is shown. Apparent, contrail of motion of point of a knife is the blame of a the centre of a circle under guide-post bushing center round, caused directly by the circularity error of treatment aperture; Right now, the circularity error of boring lever and guide-post bushing also goes to report to go up and be caused by treatment aperture circularity error. Pledge when mental allowance and material not divide evenly or cutting dosage are chosen different when, make cutting force produces change, cause boring lever to also change ceaselessly in the amplitude of lower part of the aperture inside guide-post bushing. The treatment of this kind of change to same hole, the likelihood causes cylinder to spend an error, to the treatment of different aperture, the likelihood causes the error of pitch of sum of errors of mutual position. Of the size of these errors that cause and guide-post bushing and boring lever cooperate clearance to concern: Cooperate clearance to heal big, below cutting strength effect, of boring lever swing the error that limits causes greatly more also heals big. The place on put together is narrated, bore hole in what have oriented unit in, machine quality to make sure aperture is fastened, besides wanting to make sure boring lever and guide-post bushing itself must have taller geometrical appearance precision, should notice to choose to direct means is mixed reasonably especially maintain boring lever and guide-post bushing to cooperate clearance reasonably, using from beginning to end when double oriented bearing, should make around cooperates clearance orientedly to agree. In addition, because this kind of influence returns the size with cutting force and change to concern, because this answers on craft,the place before be like is narrated, notice logical choice fixed position is standard with cutting dosage, when finish machining, answer to increase knife number appropriately, in order to maintain the stability of cutting force and the effect that reduce cutting force as far as possible. (3) the influence 　 of way of movement of machine tool feed bores hole to have kind of two kinds of feed constantly: By boring lever direct feed; Enter on machine tool slideway by workbench to. The influence that feed means is treatment precision to aperture and bore hole means is concerned, use boring when boring lever and connection of float of machine tool main shaft when the model bores hole, feed means machines precision not to have apparent effect to aperture department; And when using boring lever and cantilever of connection of main shaft tigidity to bore hole, feed means machines precision to have bigger effect to aperture department. When cantilever bores hole, if with boring lever direct feed, if graph 8-49a place is shown, in bore hole in the process as boring lever ceaseless and stretchy, the bending deflection that point of a knife is in is bigger and bigger, make be machined hole is smaller and smaller, cause cylinder to spend an error; Manage together, if use boring rod,direct feed machines coaxial on-line each aperture, cause coaxial to spend an error. Conversely, the lever that be like boring extends length changeless, and with workbench feed, if graph 8-49b place is shown, in bore hole in the process, the deflection cost that point of a knife manages is fixed (assume cutting force is changeless) . Accordingly, the mutual position precision that the bending of boring lever is out of shape to be being machined the geometrical appearance precision of aperture and aperture are all does not have an influence. But, when using workbench feed, the linearity error of machine tool slideway can make be produced by treatment aperture cylinder spends an error, make with axial on-line aperture produces coaxial to spend an error. The parallelism alignment error of machine tool slideway and main shaft axes, make be produced by treatment aperture circularity error, if pursue,8-50 place is shown. Be in perpendicular at boring lever the sectional A of axis of rotation, inside A, be machined aperture is round; And be in perpendicular the sectional B at feed direction, inside B, by ellipse of treatment Kong Wei. Nevertheless error of place generation circularity is extremely tiny usually, negligible not plan. Grow to tilt in 100mm when machine tool slideway and main shaft axes for example 1 Mm, be machined to what the diameter is 100 Mm aperture, the circularity error that produces is only 0.

005 Mm. In addition, of workbench and lathe bed slideway cooperate clearance to fasten treatment precision to also have certain effect to aperture, because be made when workbench, when back feed, contact with different position and slideway normally, such, workbench can happen as the change of feed direction slant place, clearance heals big, workbench is weighed more, its slant place a quantity to heal big. Accordingly, when aperture fastens boring coaxial, meeting generation coaxial spends an error; When aperture of boring photograph adjacent is fastened, can produce parallelism alignment error of pitch sum of errors. Compare above means of two kinds of feed, bore hole in cantilever in, the bending of boring lever is out of shape more difficult control, and the workbench feed of the machine tool, use reasonable mode of operation, the treatment quality that makes sure aperture is fastened more easily than boring lever feed. Accordingly, bore hole in general cantilever in, be more than 200mm when hole depth especially when, use workbench feed mostly, but when should machining large casing, the stiffness of boring lever is good, and with workbench feed very heavy, easy generation is creeping, not as direct as boring lever instead feed is faster, this what is appropriate to the occasion uses boring lever feed; Additional, when hole depth is less than 200mm, boring lever is dangerous extend short, also can use boring lever feed directly. 3, clamping apparatus of boring machine of boring clamping apparatus calls boring the model again, it is a kind of rigid clamping apparatus, basically use treatment casing, pedestal kind the narrow opening on the spare parts or aperture are. Boring model and jig photograph want than the structure complex much, production precision also should be gotten high much. Boring model applies extensively on of all kinds boring machine not only, and still can use on lathe, radial drilling machine and modular machine tool. (one) the design point 　 of boring clamping apparatus 1.

Boring covers 　 (1) the model of structural choice boring that boring covers and jig are same, it is to rely on oriented component -- boring is covered will guide boring lever (also can guide bring reamer or reamer) assure to be machined thereby the positional precision of aperture. The positional precision that bore hole can not suffer machine tool precision to affect (boring lever and machine tool main shaft use float connection) , and basically depend on the rationality of the positional precision that boring covers and structure. At the same time boring covers a construction influential to the appearance precision that is bored hole, dimension precision and exterior surface roughness. Commonly used boring covers a structure to have stationary and circumgyrate type two kinds. Logical choice adopts the different treatment requirement that designs Shi Kegen to occupy workpiece and treatment requirement. If graph 8-51 place is shown,① stationary boring is covered, the over all dimension that this kind of boring covers is small, the structure is compact, make simple, easy obtain tall positional precision, be in commonly so reaming, bore hole or apply in aperture of bore with a reamer more. Be being covered as a result of boring is fixed go up in boring model bracket, do not turn along with boring lever and move, and boring lever is covered in boring in already opposite roll has opposite shift again, boring is covered wear away easily, reason appropriate leaves the job at the circumstance of low speed, and should take significant lubricant step. What stationary boring covers material to often use bronze, big diameter is usable also and cast-iron. Stationary boring covered a structure to already was standardized, can consult when the design GB " clamping apparatus spare parts and component " medium GB2266, 91. Boring of ② circumgyrate type covers circumgyrate type boring to cover the lever that follow boring to turn together, comfortable work below higher rate condition at boring lever. Because boring lever is covered in boring inside make opposite shift only (rotational part uses bearing) , because chafe,can avoid to give out heat consequently and arise " card is dead " phenomenon. The position that arranges according to circumgyrate part is different, type boring covers circumgyrate to be divided again " outside roll type " and " inside roll type " . Graph 8-52 place is shown is boring of type of a few kinds of circumgyrate is covered, pursue among them 8-52a, B is " outside boring rolling type is covered " ; Graph C, D is " inside boring rolling type is covered " . Of sliding bearing inside boring rolling type is covered (graph 8-52c) , it is better to be had below good lubricant condition fight brace up quality, commonly used bore hole at half essence boring and essence, press slip cover the copper inside inside Kong Ying and arbor deserve to grind, in order to make sure taller precision asks. (2) boring covers decorate what formal boring covers to decorate a form main basis is mixed by the ratio L/D of the diametical D of treatment aperture and Kong Changyu aperture precision asks and decide. Have commonly the following 4 kinds of forms. Guide after ① odd bearing when D<60mm, often cover boring decorate what machine place in cutting tool is rear (namely between machine tool main shaft and workpiece) . When the blind aperture of the via that machines L<D or small-sized casing, should use what show like graph 8-53b place to decorate means (D>D) , tigidity of arbor of this kind of means is very big, treatment precision is tall, and when using Yu Li boring, do not have cut bits to fall into boring to cover; Should machine L>(1 ～ 1.

When the via of 25)D and blind aperture, should use what show like graph 8-53c place to decorate means (D<D) , the vertical distance H that this kind of means makes cutting tool and boring are covered decreases greatly, raised the stiffness of cutting tool. The length that boring covers (be equivalent to getting a height) lever of boring of H appropriate basis directs diametical D of the part will choose, take H ＝ commonly (2 ～ 3)d. Boring covers the distance H that is apart from workpiece aperture to want a basis to change to cutting tool and platoon bits ask to wait and be decided. If be on vertical boring machine as similar as jig, h value can consult the circumstance of jig decides. When be used on horizontal boring machine, modular machine tool, often take H ＝ 60~100mm. Guide before ② odd bearing when boring diameter D>60mm, and on the via of L/D<1 or small-sized casing one-way when permutation coaxial line via, often cover boring (reach its bracket) decorate the ahead that machines place in cutting tool, if pursue,8-53a place is shown. This kind of means facilitates in be being machined, undertake observe and be metricaled, suit Huo plane or the process that attack whorl particularly, its defect is in cutting bits to take boring easily to cover. Discharge bits to facilitate, take H ＝ commonly (0.

5~1)D, but H should not be less than 20mm. Boring covers length H choose with " guide after odd bearing " with. If graph 8-54a place is shown,around of ③ double bearing guides, oriented bracket is installed respectively in workpiece two side. When boring length L>1.

The via of 5D, and treatment aperture is bigger, or form a few hole on same axes, and its position precision also asks taller when, appropriate is used " double bearing around guides " . The defect of this kind of means is boring lever longer, rigid difference, change cutting tool is no-go. In the graph hind guiding is to use inside boring rolling type is covered, guide before those who use is outside boring rolling type is covered. The length that the circumgyrate type boring that place of bearing of these two kinds of scroll forms covers, can press H ＝ 0.

The relation of 75d and structural case are chosen. When if use stationary boring,be being covered, can press H ＝ (1.

5 ～ 2)d will choose. Guide after ④ double bearing should fall in certain circumstance, when because conditional limitation cannot use from beginning to end double guiding, can be in cutting tool is rear decorate two boring to cover, if pursue,8-54b place is shown. This kind decorates means to assemble and unassemble workpiece is convenient, change boring pole is light, facilitating observation and measure, more in applying at large quantities of production. Because boring lever submits cantilever form when getting cutting power, to raise the stiffness of cutting tool, duan Yingman sufficient L1<5d is extended outside general boring lever. No matter bosseyed double bearing or double-faced odd bearing, the two boring that decorate are covered must coaxial, and float connection should be used between boring lever and machine tool main shaft. The form of boring model and connection of machine tool float is very much, graph 8-55 is a kind of commonly used form. Float couplet reinforce can be self-adjusting measure in order to compensate angle deviation and displacement, lose floating effect otherwise, the influence machines precision. The covers interior with boring bearing hammer that axial cutting force carries a department by boring lever comes bearing, circumferential force is sold by boring lever join and boring covers horizontal chamfer to deliver. 2.

The boring staff that 8-56 of boring lever graph covers to be used at stationary boring is oriented partial structure. Direct when boring lever when partial diameter D<50mm, boring lever often uses integral formula. When diametical D>50mm, often use what 8-56d place shows to set a type structure, set should introduce coefficient of friction small and the material of wear-resisting, be like copper or steel. Set after wearing away, spacer can be added in bottom, repair afresh grind use. Graph 8-57 place is shown to be used at outside the boring staff that boring of circumgyrate rolling type covers introduces a structure. Graph 8-57a place shows front of the lever that it is boring to install smooth key, key remove theatrical makeup and costume has compress bedspring, the forehead of key has inclined plane, apply to a boring that has keyway to cover. No matter boring lever with why the position enters guide-post bushing, ping Jianjun can enter be good at chamfer automatically, drive boring to cover circumgyrate. Graph 8-57b place shows boring lever to go up to have keyway, helix of its head make it guides a structure, should its helix angle is less than 45? , so that boring lever is introduced hind make key enters groove smoothly inside. When affirmatory boring shank diameter, the stiffness of lever of boring of Lv of take an examination and the due space holding bit when boring hole. General and desirable 　 D=(0.

6~0.

The D in 8)D 　 type -- boring shank diameter (Mm) , d -- diameter be boringed hole (Mm) . When designing boring staff, bore hole diametical D, the relation between sectional BxB presses D of boring shank diameter, boring cutter commonly consideration, or consult watch 8-4 is chosen. What D of shank diameter of watch 8-4 boring, boring cutter lists the range of boring shank diameter in the watch of relation D(mm)110~4040~5050~7070~9090~110d(mm)20~3030~4040~5050~6565~90BxB(mm)1010101012~1216x1616x162020 　 of sectional BxB and D of diameter be boringed hole, big cost is taken when machining alveolus, machining big Kong Shi, if had directed, cutting negative charge is small desirable little value; Take intermediate cost commonly, if direct undesirable, when cutting negative charge is big desirable great value. The axial dimension of boring lever, should press bore hole the concerned measure on systematic graph is certain. The hardness of surface of lever of material requirement boring of boring lever is tall and core has better tenacity, because this uses 20 steel, 20Cr steel, cementite quenchs hardness is 61~63HRC; Usable also nitrogen changes steel 38CrMoAlA; The boring lever of big diameter, still can use 45 steel, 40Cr steel or 65Mn steel. The main technique condition of boring lever asks general provision is: ① boring lever directs partial circularity and taper allow difference control the 1/2 less than in diametical public errand. Does ② boring lever direct belt of partial public errand is: ? of kill scoop up with a dust pan 6, boring of essence of life is G5. Exterior surface roughness is worth Ra0.

8~0.

4 μ M. ③ boring lever is differred in the linearity allow inside 500mm length for 0.

01~0.

1mm. Surface roughness of tool bore surface is Ra1 commonly.

6 μ M, outfit tool bore does not quench. CNC Milling