Gao Ge's cast-iron cutting dosage optimizes computation

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Summary: In trends of consideration cutting tool the condition of intensity falls, use finite the cutting dosage with yuan of cast-iron to machining Gao Ge with cutting tool of compound pottery and porcelain law had consideration, machine Gao Ge effectively for economy cast-iron provided academic basis. Tall chromic white mouth is cast-iron it is stuff of a kind of the wear-resisting that fight corrupt that has very tall hardness and strength, its tensile strength is 650 ~ 850MPa, casting condition hardness is HRC48 ~ 55, quench hardness is HRC55 ~ 62. But this kind of material hard fragile, cutting position is extremely rough firm, if cannot solve cutting to machine a problem well, its application will get very big limitation. The experiment makes clear, machine Gao Ge with hard alloy cutting tool cast-iron, cutting tool wears away splitting, cutting forms collapse fragile cutting easily, exterior surface roughness is big, can use at general rough machining only. To Gao Ge's cast-iron finish machining, with pottery and porcelain cutting tool can obtain inferior surface roughness. But of cutting tool of pottery and porcelain fight concussion ability is weaker, tall to cutting chromium is cast-iron material of this kind of brittleness is pounded more easily, cause the destruction of the cutting tool such as collapse blade. Because price of cutting tool of pottery and porcelain is more expensive, answer to avoid to be destroyed as far as possible, because this chooses cutting dosage correctly reasonably,be the efficient way that avoids cutting tool happening to pound collapse blade to destroy. The article is considering condition of socioeconomic of intensity of cutting tool trends to fall, tall chromium of turning of cutting tool of compound to using pottery and porcelain is cast-iron a powerful person of broken bits oar the cutting dosage of the circle outside spare parts of board of a powerful person undertook the door optimize computation. The influence cutting temperature of dynamic to cutting tool of compound pottery and porcelain function adjusts 1 cutting temperature the influence of performance of cutting tool trends, main show is in the influence of mechanical to cutting tool material function and the additional thermal stress that cutting temperature field produces. Temperature is compound to the influence of function of machine of tool of compound pottery and porcelain function is in the physical machinery of pottery and porcelain usually, what follow cutting temperature is elevatory and reduce. The experiment makes clear, inside certain limits, when machining steely spare parts, the index of each mechanical function of cutting tool of compound pottery and porcelain and temperature have following experience formula in Sbt=sbo(1-bt)(1)sst=ssoexp(1-ct)(2)Et=Eoexp(-dt)(3)Ht=Ho(1-kt)(4) type: Sbt, sst, et, the tensile strength when Ht is cutting tool of compound pottery and porcelain to be T in temperature respectively, succumb quantity of the limit, stretch model and hardness: Sbo, sso, eo, the tensile strength that Ho issues for normal temperature respectively, succumb quantity of the limit, stretch model and hardness: B, C, K, D is the constant with affirmatory experiment. The additional thermal stress that cutting temperature field produces is in successive turning treatment, when cutting dosage and external ambient conditions are changeless, can think on face of knife of cutting tool around action has stable state heat source, what the cutting temperature field on cutting tool can use three-dimensional heat to conduct is finite yuan of law computation. Because cutting tool is,work inside stretch limits, in be St=at(t-t0)E (9) type by the additional thermal stress that temperature causes accordingly: T0 is the temperature when stress-free: At is the linear expansion coefficient of compound pottery and porcelain. The dynamic stress of 2 compound pottery and porcelain and dynamic intensity are right the dynamic stress of cutting tool of compound pottery and porcelain, use three-dimensional and finite yuan of law computation, if the model pursues 1. Action of cutting force Fz is in cutting blade is mid, unit uses 8 node three-dimensional a body yuan, cutting tool and edge of cutter hub contact are stretch tie, the others is free edge. Computation the method seeking solution with the greatest stress below this condition and general mechanical solid is identical, but the impact that considers temperature, to every unit has (10) forms flexibility with this group of equation blast, undertake finite yuan seek solution, can get cutting tool the Smax of the greatest dynamic stress that in cutting force and temperature field joint action issues, if cutting tool of pottery and porcelain is advanced,the intensity when knife face temperature is T is [St] , criterion condition of its trends strength is Smax ≤ [St] (11) pursues graph of 1 stress equivalence pursues 2 computation block diagram of dosage of cutting of material of cutting tool of 3 compound pottery and porcelain optimize dosage of cutting of computational target function optimizing computation is it is target function with finished cost, generate a spare parts to basically include following charge: Cost of raw materials uses (the charge that Cc) makes semifinished product of a part: Machine tool charge (charge of man-hour of unit of Cj) machine tool, the depreciation cost that includes a machine tool: Tool charge (Cg) production worker and management and the unit man-hour salary that assist personnel: Change a knife to reach the charge that grind a knife (the total cost that Cd) produces a part is Cw=Cc+(Cj+Cg)(tz+tj)+Cdtj/T (12) type in: Tz is preparative time: Tj is effective cutting time: T is cutting tool durability, the unit all is Min. By Taylor basic cutting time is formulary computation T=CV+V-1/mf-1/nap-1/p (13) in on Tj=kV(Vfap) (14) two type: CV is constant: Ap is surplus. type (13) , type (14) generation enters type (12) gets Cw=Cc+tzCm+kvCm/(Vfap)+kvCd/[CVf(-1/n)+V(1-1/m)ap(1-1/p)] (15) form in: Cm=Cj+Cg. Type (15) optimizes function of calculative cost target for dosage of cutting tool cutting namely. Dosage of tie function cutting optimizes calculative to restrain function to basically have the following sides: Cutting dosage takes value obligation. Be like the cutting speed of the machine tool, the extraction of feed is worth limits to be (Vmax, vmin) , (Fmax, fmin) , have the tie function G1(f below, v)=V-Vmax ≤ 0 (16)G2(f, v)=Vmin-f ≤ 0 (17)G3(f, v)=fmax-f ≤ 0 (18)G4(f, precision of V)=f-fmax ≤ 0 (19) is restrained. If given exterior surface roughness is Ra, have tie function G5(f, power of machine tool of V)=f-(8Rar)½ ≤ 0 (20) is restrained. Those who be like a machine tool is allowable power is P, have the tie G6(f below, durability of cutting tool of V)=VFz1+zfFzy-p/CFzaKFz ≤ 0 (21) restrains G7(f, above V)=V1/mf1/nap1/p-CV/T0 ≤ 0 (22) various in, XFz, YFz, KFz, CFz is experiment constant. Intensity of cutting tool trends restrains function G8(f, v)=smax-st ≤ 0 Smax is passed for cutting dosage finite yuan of calculative is the biggest dynamic stress. Because the greatest dynamic stress of cutting tool is to use,optimize computation finite yuan of calculative, without mensurable analytic function. Tie function G8 cannot introduce in optimizing computation, in be being calculated accordingly, we take no account of G8 first, optimize a dosage of a group of cutting, optimize cutting dosage according to this group again, with finite the greatest dynamic stress of yuan of law computation cutting tool. If satisfy dynamic intensity, criterion this cutting dosage is best, if be not satisfied, reduce cutting dosage till contented trends till intensity, parameter is the cutting dosage that gets right now the most reasonable cutting dosage. If computational block diagram pursues 2. Graph dimension of geometry of 3 cutting tool 4 computation result and trial are original parameter machine tool: CA6140, rotate speed limits, n=12 ~ 1200r/min, feed limits F=0.

08 ~ 1.

59mm/r, power P=7.

5kW. Cutting tool: AG2 compound pottery and porcelain, mechanical parameter: E=4550kg/m2, coefficient of thermal conductivity is 22.

93W/m · K, ℃ of 10-6(of × of A=8 of hot coefficient of expansion) - 1, bending strength Sb=800MPa, stretch model measures E=420GPa, bai Song compares µ=0.

24, hardness HV2400. Geometrical parameter: G0=-5 ° , a0=12 ° , ls=-6 ° , lose edge 30 ° , wide for 1mm, r=1mm of radius of point of a knife, dimension is shown 3 times like the graph. Workpiece: A powerful person of broken bits oar, ra=1 of exterior surface roughness.

6, material is new-style chromic Gao Bai the mouth is cast-iron, intensity 680 ~ 800MPa, diametical 300mm, ply 40mm, unilateral surplus 3mm. Economic parameter: Machine tool charge, cm=Cj+Cg=42 yuan / Min, change knife and Cd=4 of the charge that grind a knife.

8 yuan. Prepare time Tz=1.

5 minutes, cc=130. (Above parameter offers) for machinery plant of Wuhan sea couplet. Other parameter: M=0.

23, n=0.

57, p=1.

33 durability T0=60min, h=0.

75, ZFz=0.

15, CFy=244, CFz=436, CV=2.

28 × 103, XFy=0.

9, YFy=0.

55, ZFy=0.

3(above parameter is A.

K.

Cnattopadnyay place is written " cutting tool of pottery and porcelain is in cutting is cast-iron when the makings that reach steel wear away characteristic " with experiment earning) . Optimize computation to enter afore-mentioned parameter era target function and tie function to be able to get cost target function to be CW=136.

3+332.

506V-1f-1+2.

229V × 4f0.

75 (23) restrains function to be G1(f each, v)=V-565 ≤ 0 (24)G2(f, v)=0.

565-V ≤ 0 (25)G3(f, v)=0.

08-f ≤ 0 (26)G4(f, v)=f-1.

59 ≤ 0 (27)G5(f, v)=f-0.

113 ≤ 0 (28)G6(f, v)=V0.

85f0.

75-49.

5 ≤ 0 (29)G7(f, v)=V5f1.

75ap0.

75-2.

1011 ≤ 0 (30) uses 27 × Monte-Cono algorithm computation can obtain dosage of cutting of the smallest cost to be V=109.

8m/min, f=0.

1mm/r. Use below this cutting dosage finite yuan of computational temperature field see a picture 1, by experience formula knowable, right now action is Fz=436 × in the concentrated force on cutting tool 2 × 0.

10.

75 × 109.

8-0.

15=92.

016kgFy=244 × 20.

9 × 0.

10.

6 × 109.

8-0.

3=29.

28kg is used finite if the stress that joint action leaves Fz of yuan of force of law computation cutting, Fy and temperature field pursues 2 are shown. From computation the result can see intensity of cutting tool trends satisfies a requirement. Cutting speed V=109.

8m/min, feed F=0.

8mm/r is optimization dosage. Test result uses V=109 on CA6140 lathe.

8m/min, f=0.

8mm/r turning tall chromium is white the circle outside board of a powerful person does not have an a powerful person of oar of cast-iron broken bits collapse blade attaint, durability (VB=0.

When 1mm) amount to 65 minutes. And use V=142m/min formerly, f=0.

Collapse blade produces when 2mm/r. 5 last words are used finite yuan of way is right it is feasible that the temperature field that in cutting temperature field and cutting force joint action leaves calculates cutting tool. Consider the stress impact to cutting tool intensity, the cutting dosage with tall to cutting of cutting tool of pottery and porcelain chromic white cast-iron mouth undertakes optimizing assuring lowest of cutting finished cost namely, won't produce collapse blade to destroy again, be economy undoubtedly. CNC Milling CNC Machining