Computer Aided Simulation Machining Programming In 5-Axis Nc

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Physics Procedia 25 (2012) 1457 – 1462

2012 International Conference on Solid State Devices and Materials Science

Computer Aided Simulation Machining Programming In 5-Axis Nc Milling Of Impeller Leaf Liu Huran Zhejiang university of science and technology ,Hangzhou , China

Abstract At present, cad/cam (computer-aided design and manufacture) have fine wider and wider application in mechanical industry. For the complex surfaces, the traditional machine tool can no longer satisfy the requirement of such complex task. Only by the help of cad/cam can fulfill the requirement. The machining of the vane surface of the impeller leaf has been considered as the hardest challenge. Because of their complex shape, the 5-axis cnc machine tool is needed for the machining of such parts. The material is hard to cut, the requirement for the surface finish and clearance is very high, so that the manufacture quality of impeller leaf represent the level of 5-axis machining. This paper opened a new field in machining the complicated surface, based on a relatively more rigid mathematical basis. The theory presented here is relatively more systematical. Since the lack of theoretical guidance, in the former research, people have to try in machining many times. Such case will be changed. The movement of the cutter determined by this method is definite, and the residual is the smallest while the times of travel is the fewest. The criterion is simple and the calculation is easy.

© 2012 2011 Published Published by ofof [name © by Elsevier Elsevier Ltd. B.V.Selection Selectionand/or and/orpeer-review peer-reviewunder underresponsibility responsibility Garryorganizer] Lee Open access under CC BY-NC-ND license. Keywords: milling cutter; contact; nc machining

1.Introduction At present, cad/cam (computer-aided design and manufacture) have fine wider and wider application in mechanical industry. For the complex surfaces, the traditional machine tool can no longer satisfy the requirement of such complex task. Only by the help of cad/cam can fulfill the requirement. The machining of the vane surface of the impeller leaf has been considered as the hardest challenge. Because of their complex shape, the 5-axis cnc machine tool is needed for the machining of such parts. The material is hard to cut, the requirement for the surface finish and clearance is very high, so that the manufacture quality of impeller leaf represent the level of 5-axis machining. This paper opened a new field in machining the complicated surface, based on a relatively more rigid mathematical basis. The theory presented here is relatively more systematical. Since the lack of theoretical guidance, in the former research, people have to try in machining many times. Such case will be changed. The movement of the cutter determined by this

1875-3892 © 2012 Published by Elsevier B.V. Selection and/or peer-review under responsibility of Garry Lee Open access under CC BY-NC-ND license. doi:10.1016/j.phpro.2012.03.262

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method is definite, and the residual is the smallest while the times of travel is the fewest. The criterion is simple and the calculation is easy. The method presented in this paper combined the impeller leaf design, NC machining and computer simulation together. The design and calculation is convenient, and the machining is of high efficient. 2.Side milling of the impeller leaf in 4 coordinates simultaneous controls Suppose that the equation of the impeller leaf could be expressed as:

r

r u, v

x y z

xu, v y u, v z (u, v)

n nu , v n x n x (u , v)

the normal vector

ᑇ䴶

x0

ny

n y (u, v)

nz

n z (u, v)

ᑇ䴶



yp=¢pxp

ᑇ䴶

ᑇ䴶

Fig.1 Side milling of the impeller leaf in 4 coordinates simultaneous controls

Let the impeller leaf rotate an angle of © about its axis

r

ªsin K «sin K « «¬ 0

 sin K 0º ª xu, v º sin K 0»» «« y (u , v)»» 0 1»¼ «¬ z u , v »¼

ª xu , v cosK  y u , v sin K º « xu , v sin K  y u , v cosK » « » «¬ »¼ z u , v

The normal vector rotate an angle of © as well.

n (0)

ªcosK « sin K « «¬ 0

 sin K 0º ª n x u , v º cosK 0»» ««n y u , v »» 0 1»¼ «¬ n z u , v »¼

ª n x u , v cosK  n y u, v sin K º «n u, v sin K  n u , v cosK » y « x » «¬ »¼  n z u, v

The equation of the cylindrical cutter:

x

[, y

R cosT , z

R sin T

The normal vector of the cutter:

ncx

0, ncy

cosT , ncz

sin T

If the cutter and the work to be machined is in contact with each other, they must satisfy the following requirements:

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Liu Huran / Physics Procedia 25 (2012) 1457 – 1462

ncy

ncx n x( 0 )

n

ncz n z( 0 )

(0) y

Solve the above equation, we can get:

n x( 0)

0

n x u , v cosK  n y u , v sin K

0

>n u, v sin K  n u, v cosK @sin T

n z u , v cos T

x

y

˄1˅ ˄2˅

K , and from equation (2), we can get the solution of T ,

From equation (1), we can get the solution of

©

Fig.2. The relate position between the cutter and the work to be machined

Let

xc , y c , z c to be the coordinates of the cutter center x [  xc y R cos T  y c z R cos T  z c

Since that on the contact point, the coordinates of the cutter and the work should be the same

x cosK  y sin K

[  xc

˄3˅

x sin K  y sin K

R cos T  y c

˄4˅

z From equation (4)(5) we can determine

R sin T  z C

˄5˅

yC , zC .

3.The computer simulation for the side milling of the impeller leaf With the soft ware of Mastercam, we can do same computer simulation for the side milling of the impeller leaf. The change of the angle Ș can be substituted with the drilling of the hole.

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Fig.3. the fetch of the point on the blank

On the convex side , we fetch 4 points: x

y

z

Ș

Xc

ș

Zc

32.3573, 210, 113, -20.20, -61.54 -51.6764

132.431

-20.966, 210, 80, -4.252, -51.84 -48.8356

97.298

-34.864, 210, 68, 0.123, -46.17 -48.2635

83.871

-61.349, 210, 30, 8.415, -20.33 -48.7108

37.643

First of all, establish a blank for the work. Mark the points on the surface of the work By the Mastercam we cannot simulate the revolution of the work, the revolution is substituted by the angular displacement of the cutter. In every places all the feed line of the cutter have an angular displacement of Ș relative to the work. From above figure we can find that, with different coordinate, the angular displacement of Ș is different as well.

Fig.4 the milling of the work by the milling tool

Liu Huran / Physics Procedia 25 (2012) 1457 – 1462

Fig.5 the simulated work to be machined

Fig.6 the simulation of the work to be machined

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Fig.7 the result

Conclusions This paper opened a new field in machining the complicated surface, based on a relatively more rigid mathematical basis. The theory presented here is relatively more systematical. Since the lack of theoretical guidance, in the former research, people have to try in machining many times. Such case will be changed. The movement of the cutter determined by this method is definite, and the residual is the smallest while the times of travel is the fewest. The criterion is simple and the calculation is easy. Acknowledgment This project is supposed by the natural scientific foundation of China, No.2006-50675235. and the natural scientific foundation of Zhejiang province, China, No. Y106047 and Y1080093.3 References [1]

Miyazawa,S and Takada,K ‘Micro milling of three-dimensional surface’ Trans.Jap.Soc.Precission Eng.Vol.47. No.2

(1981 )pp94-99(in Japanese) [2]

Kishinami,T and Suzuki,H ‘A theoretical analysis of cutting speed components on the rake face of circular cutting

edge ball and mill’ Trans.Jap.Soc.Precission Eng.Vol.46. No.10 (1980 )pp115-122(in Japanese) [3]

Fujii,Y and Iwabe, H

‘ Relation between cutting force curve and working accuracy with ball-nose end mills’

Trans.Jap.Soc. Precission Eng.Vol. 48 No.5 (1982 )pp105-110 (in Japanese) [4]

Vickers,GW,Bedi, S and Haw,R ‘ The definition and manufacture of compound curvature surfaces using G-surf”

Comput.Indust.Vol 6 No 2(1985)pp173-183