Multiscale analysis of micro-cavity filling during injection molding

한국정밀공학회 2008년도 춘계학술대회논문집

1. Introduction

, , ,

㎛ nm .

(micro-injection molding)

.

, , ,

.

.

.(1)

.

(Moldflow) 6.1 (Fluent) 6.3

(Slip Velocity) .

2. Simulation Procedure

Micro Macro

(Slip Velocity) , Capillary force

.(2) Continuity equation

_

_

 ∇ ∙    (1)

Momentum equation

__{  }

  __{ ∙ }



_

^{  }

_

(2)

_ _^^_ _ 

 _

_

 _

_

 (3)

_ __^



(4) Energy equation

_ 



  



  



  





  ^

^

 ^

^

 ^

^

  ^ 

∆

(5)

The Cross-WLF model viscosity

__{  }

  __{ ∙ }



_

^{  }

_

 _{}

_ ^

_^



(6)

Local slip velocity model

_ 

   _

_

^

 _^ (7)

Continuity

Navier-stokes non-isothermal

energy .

Free surface

VOF method (3) rheological

Cross-WLF .(4) Micro

(Slip Velocity)

Power-law Local slip velocity model(5) . 3. Macro Domain Analysis

. multi-scale

(6) Fig.1 Macro Micro

. 1 Macro

Moldflow6.1 30mm*30mm 1mm

Table 3 Filling control . Table. 1 Constants for the Cross-WLF equation

0.2751 26.12

51.6 4.66e+12

263.15 24200

Table. 2 Constants for Slip velocity model 1.2

3 0.12

Table. 3 Analysis Condition (Macro)

298k,343k,393k

미세 형상 사출성형의 멀티스케일 충전 해석

Multiscale analysis of micro-cavity filling during injection molding

*최성주¹

,

,

*S.J.Choi¹, ^#S.K.Kim¹(sunkkim@snut.ac.kr), Y.E.Yoo²

1서울산업대학교 나노아이티 공학과, ²한국기계연구원 나노공정기계연구본부

Key words : Injection molding, micro-cavity, flow simulation, slip velocity, volume of fluid method

625

한국정밀공학회 2008년도 춘계학술대회논문집

Table. 4 Material Properties of Polypropylene

2740 0.164

 728.28

 891.63

Table.4 Polypropylene

Packing Cooling

Filling . Fig 2

A, B, C, D .

Packing 0.0298sec Fill time

. 4. Micro Domain Analysis

Macro Domain 1

2

. Macro Domain Moldflow

4 (Fig. 2)

coding Converter Fluent

. Pre-Processor Fluent Gambit

Modeling . 100㎛,

30㎛

Slip , Cross-WLF , , Viscous heat

. 4 298k, 343k,

393k 12 .

.Fig.3

. A, D

Filling

. 298k 393k

.

Fig. 1 Simulation Method

Fig. 2 Macro Analysis Coordinates and Results

Fig. 3 Micro Analysis -Contours of Phases Polypropylene

5. Conclusion

.

Macro Micro

.

(Slip Velocity)

.

, ,

. ,

.

참고문헌

1. Jehuda Greener, Reinhold Wimberger-Friedl ,"Precision Injection Molding", HANSER, 2006

2. William B. Black, Michael D. Graham, "Effect of wall slip on the stability of viscoelastic plane shear flow" Phys. Fluids, Vol.11, No.7,1999

3. Hirt C W and Nichols B D, "Voume of fluid(VOF)method for the dynamics of free boundaries", Journal of comutational Physics, Vol. 39, pp. 201-225, 1981

4. Sung Yong Kang, Sun Kyoung Kim and Woo ll Lee, "Penalty for- mulation for postfilling analysis during injection molding", Wiley Interscience, 2007

5. Eugene E. Rosenbaum and Savvas G. Hatzikiriakos, "Wall Slip in the Capillary Flow of Molten Polymers Subject to Viscous Heating", AIChE Journal, Vol. 43, No. 3,1997

6. S. M. Kim, S. H. Park, W. I. Lee, "Mulit-Scale Simulation of Molding Process to Achieve Micro Features on the Large Surfaces", KSPE Journal, 2007

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