Machine the outfit clip when large work and design of fixed position plan

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  • source:HOTA CNC Machining
Summary: The outfit mix that offerred large scale computer to add workpiece and fixed position devise plan. Reach the position getting power when using through analysis and computational workpiece treatment, gave out workpiece supports the judgement method with clamp means; Application is three-dimensional measure reach coordinate to alternate the law decided the position between workpiece and machine tool affects, achieve the goal that does not need to adjust work place to be able to allow to locate truly. 1 foreword undertakes to be used at the large work of major project to a batch nicety is machined, need devises plan of the outfit clip of workpiece and fixed position. If the graph shows) 1 times,this workpiece makes an appointment with dimension of 200(t main structure again, workpiece is pledged be ZG55 by treatment position ability, the requirement treats treatment range twice mutual parallel and as perpendicular as end face (bosseyed the biggest mental allowance is only 5mm) . Treatment facilities is CNC Milling of horizontal of two 5 axes, cutting tool is milling cutter of Ø300mm end panel. Pass anatomize operating mode, should solve above all the following two problems: Whether does ① still need clamp device to make sure workpiece is imposing a plan to so serious work 1 graph the stability in 2 industry procedure? Whether to need the special unit that prop up? ② asks to assure to machine, make workpiece waits for treatment face twice to all have mental allowance and as perpendicular as end face, need to undertake allowing to decide to workpiece. Because work is very serious, be hard to adjust through the position by groovy method search workpiece, because this needs to explore a kind of simple and quick location method, need to place the size range of pipe bent in the machine tool steadily only namely inside, without giving thought to work position position how, can achieve workpiece to decide definitely with the method such as computation through measuring purpose. The article passes analysis and computational workpiece treatment to reach the position getting power when using, put forward those who judge large work to prop up the specific means with clamp means; Application is three-dimensional measure reach coordinate commutation to decide the position between workpiece and machine tool affects, achieve the goal that need not adjust workpiece position and achieves exact location. When 2 outfit place plan design to be versed in to make workpiece is added keep consistent with the condition getting power when using, by the design the requirement undertakes was proppinged up at 4 o'clock to workpiece (if pursue,2 show) . The N1 in the graph, N2, N3, N4 gets the power that prop up for work place, the place when FZ, FX is machined for workpiece gets cutting power, workpiece weight is G. Reach ≤ of FZ of cipher out of milling means appraise according to parameter of power of machine tool main shaft, cutting 5428.

4N, FX ≤ 2285.

6N. Be contacted because of empty to prevent workpiece and strong point and affect stability, requirement N1, N2, N3, N4 all is G/4. Below afore-mentioned conditions, as a result of the action of cutting force FZ, FX, workpiece basically can generate two kinds of motion currents that affect its stability, circle Ad axis namely retroflexion reach the change inside Abcd plane to move. If be propped up only to workpiece not clamp, criterion the stability when workpiece is machined depends on workpiece relies on the capacity that resistance of self-prossessed G and attrition force F retroflexions and change uses. Because be opposite,the state getting power of the workpiece when workpiece undertakes odd side is machined is compared bilateral the state getting power when be being machined at the same time is abominable, the stability when so the article is machined to workpiece odd side only has analysis and consideration. Workpiece fights retroflexion ability: Of the rod circling Ad that produces by cutting force FZ turn over torque to turn over =FZ × for M 1.


4 × 1.


25Nm by workpiece of self-prossessed generation fight turn over torque to fight =G × for M 3.

98/2=2000000 × 1.

99=3980000Nm knowable M fights > M turns over workpiece to fight force of change kinetic energy: By the graph 2 knowable, the motivation of the biggest change that causes by cutting force is F=FZ+FX=(FZ2+FX2)½=(5428.



9N takes workpiece and the coefficient of friction between the device that prop up for 0.

3, criterion workpiece and the attrition force between the device that prop up are F=G × 0.

3=2000000 × 0.

3=600000N knowable F>F can see as a result by above analysis: In milling this are large when workpiece, although not clamp, rely on workpiece only self-prossessed the stability in also can making sure with attrition force workpiece is machining a process reliably, need not consider clamp orgnaization when tool is designed so. To assure workpiece the force propping up of 4 strong point is equal, the CNC synchronism that we used American ENERPAC company to produce carries litre of system on the head, the system rises system of pumping station of component, hydraulic pressure, control and join by hydraulic pressure top the composition such as cable of the hydraulic pressure pipeline of each unit, signal, power supply cord, the load that the system can rise component place to suffer with hydraulic pressure top already has power as feedback signal synchro control, the displacement that also can raise a part with the top undertakes supporting rising as feedback signal or drop synchro control. The use move of hydraulic pressure system is as follows: Support beforehand. The top that start promotes a system, make hydraulic pressure carries litre of component and workpiece bottom surface contact on the head, suffer force to regard feedback as signal with each at the same time, all stop a top to rise when each suffer force to achieve 20t, but the system holds working position. Synchronous top rises. With the top that prop up the top rises displacement to control each to carry synchronous top on the head to rise as feedback signal (maintain a top to rise what place of the work in the process suffers to supported power at 4 o'clock equal) , work the top leaves the stage that prop up, after reaching proper place, lock up device to the lock supports a position surely and shut the system oneself with machinery, in order to assure the stability of position of position of the work in treatment process. Synchronous fall after a rise. After treatment ends, the system that start loosens the system locks up device oneself, control sustains very synchronous fall after a rise, put work on the stage that prop up gently. When design of plan of 3 fixed position uses machine tool of 5 axes numerical control to machine, because workpiece is self-prossessed,reach structural dimension to all be compared big, the adjustment that uses a convention hard the method of work place will locate. Need not adjust workpiece position to achieve and come true to decide definitely purpose, through three-dimensional measure reach coordinate commutation to decide the position between workpiece and machine tool affects. Particular program is as follows: If the graph notifies workpiece coordinate department 3 times,set measurement point is built, on workpiece set A, B, C, D locates 4 times in all measurement point, the requirement is apart from end face at each o'clock equidistant; E is nodded and F dot connects line and Cd to connect the midpoint of the line for Ab respectively, workpiece coordinate fastens origin and E dot coincide, workpiece coordinate fastens X axis and Ef to connect line coincide, y axis and planar Cde are perpendicular, in order to make sure workpiece coordinate fastens positional validity. Graph 3 measure measure a pair of A, B, C, D each a little bit to undertake metrical with 3 coordinate, attainable the value of machine tool coordinate that nods each, the machine tool coordinate that the value of machine tool coordinate that E, F nods can pass A, B, C, D each a little bit is worth computation to get. The measured value in setting A, B, C, D each a little bit to be fastened in machine tool coordinate is A=(xa respectively, ya, za) , b=(xb, yb, zb) , c=(xc, yc, zc) , d=(xd, yd, the value of machine tool coordinate that Zd) criterion E, F nods is E=(A+B)/2=((xa+xb)/2 respectively, (Ya+yb)/2, (Za+zb)/2) F=(C+D)/2=((xc+xd)/2, (Yc+yd)/2, (Vector is Ec=C-E Ed=D-A H=F-E=(Hx related Zc+zd)/2) , hy, ed=(Vx of Hz) V=ec × , vy, h=(Kx of Vz) K=V × , ky, the changeover basis that Kz) coordinate fastens the relevant theory of dimensional geometry, machine of W of department of machine tool coordinate and existence of work of W of workpiece coordinate department alternate as follows relation: W machine =W is versed in TtTzTxTy among them Tt, Tz, Tx and Ty are coordinate commutation matrix, its geometry meaning reachs the method that seek solution to be as follows: Tt: Translation workpiece coordinate fastens W labour to make its origin and machine tool coordinate fasten coincide of W machine origin, and in type (Ex, ey, ez) nods the coordinate in department of machine tool coordinate to be worth E for E. Tz: The Z axis that circles the W labour after passing Tt translation department of machine tool coordinate rotates G horn, make Y and Yz planar coincide, criterion the G=arccos[in type | Vy | / (V2x+V2y)½] , the sign of the sign of G and Vx is identical. Ty: the W after be being changed through Tt, Tz labour circles machine tool coordinate to fasten X axis to rotate B horn, make Y and Y coincide, the B=arccos in type [| Vy | / (V2x+V2y+V2z)½] , the sign of the sign of B and Vz is contrary. Ty: The W labour after the course Tt, Tz, Tx is changed circles machine tool coordinate to fasten Y axis to rotate A horn, make X and X coincide, after be being changed through Tz, Tx as a result of vector H namely as planar as Xz already coincide, can write down the vector after changeover so for M=(Mx, 0, mz) , criterion (Mx, 0, mz, 1)=(Hx, hy, hz, 1)TzTxa=arccos[| Mx | / (M2x+M2z)½] , the sign of the sign of A and Mz is identical. Need a feature to order construction with place of the process designing on workpiece 4 matrix of one N × Z labour, the before 3 in labelling each a little bit to fasten W to be versed in in workpiece coordinate coordinate that Z is versed in are worth, the 4th is completely 1; With similar method reframe 4 matrix of one N × Z machine, the before its 3 coordinate in labelling each correspondence dot to fasten W machine in machine tool coordinate are worth. Criterion: Main shaft of machine tool of computation of TtTyTx of labour of Z machine =Z places part from the graph 3 can see, main shaft of the machine tool when processing work must agree with the direction of vector K, we assume to X axis circles main shaft to rotate first when treatment A horn, circle Y axis to rotate again B horn can make the direction of main shaft and vector K consistent, criterion A=arccos[(K2y+K2z)½(/K2x+K2y+K2z)½] , the sign of A and Ky are identical. B=arccos[| Kz | (/ K2x+K2z)½] , the sign of B and Kx are identical. So far, the changeover computation that we finished workpiece to fasten machine tool coordinate from workpiece coordinate and machine tool main shaft place horny computation. This is the problem of treatment fixed position in solving random to place workpiece to be fastened in machine tool coordinate with a kind of new thinking actually, next treatment of numerical control process designing can undertake by groovy method. We are placed according to afore-mentioned outfit and fixed position plan machined 4 executive effects 900 large work, achieve design requirement entirely not only, and in shorten construction preparation cycle, reduce tool cost and the result that improve the aspect such as manufacturing efficiency very remarkable also. Through this treatment example the outfit clip to large work, fixed position is mixed the design that machines plan undertook beneficial exploration, hope to benefit somewhat to the person of the same trade. CNC Milling CNC Machining