金屬射出成型模擬之表面光澤瑕疵預測林舜天國立台灣科技大學機械工程系阮朝宗新日興股份有限公司曾煥錩 *

Transcription

1 金屬射出成型模擬之表面光澤瑕疵預測林舜天國立台灣科技大學機械工程系阮朝宗新日興股份有限公司曾煥錩 * 科盛科技股份有限公司 曾煥錩 Ivor Tseng 研究發展部 R&D Division 專案經理,ivortseng@moldex3d.com 2015/04/17

2 Marketing, Manufacture, and Complex Material

3 A dynamic $1.5 billion-plus global industry > Powder Injection Molding (PIM), which encompasses Metal Injection Molding (MIM) and Ceramic Injection Molding (CIM) is a major manufacturing technology > MIM market has grown from $ 382 million USD in 2004 to $985 million USD in Further the market is estimated to be about $1.5 billion USD in 2012 by BCC Research, with continued double digit growth expected through See more at: metal_injection_molding_mim_pim#sthash.1w8sn8d2.dpuf

4 Apple gives Metal Injection Molding (MIM) a boost with its new Lightning connector > Apple s new Lightning connector system, featured on the recently launched iphone 5 and ipad mini, has given the international Metal Injection Molding (MIM) industry a substantial boost thanks to its use of this advanced manufacturing process. - See more at: 4

5 Introduction to MIM processing > MIM process consists of the following steps: Feedstock preparation Injection molding Debinding Sintering Feedstock preparation 5

6 Complex Composites > SEM Images of powder-binder mixture 6

7 Complex Flow Behavior (1) Effect of Powder Concentration > Shear viscosity as a function of powder concentration For high concentration, as shear rate increases, the particles are trying to move more rapidly and the effect becomes more pronounced. 7

8 Complex Flow Behavior (2) Effect of Powder Size > A higher number of smaller particles results in more particle-particle interactions and an increased resistance to flow. 8

9 9 Complex Flow Behavior (3) Particle Size Distribution

10 Complex Flow Behavior (4) Different Particle Shape > Smoother particles have a lower low shear viscosity than those which are sharp/non-smooth 10

11 Big Issue: Black Lines/Powder-Binder Separation

12 Focus: Surface Defect > Listen to industry, the so-called Black Lines are frequently observed in the surface inspection of attractive MIM articles. Namely, grey color is found on the surface shine Grey (black line) 12

13 Powder-Binder Separation > 陶瓷粉末 : 粉膠分離出現在齒輪的尖端 (tip) 粉膠分離結果 13

14 What Black Line s microscopic view?

15 Black Line s SEM micrographs Black lines Black lines Uniform surface Void or Crack 15

16 Key Cause of Black-Line Defect: Powder-Binder Phase Separation > Phase separation is a term commonly used for an adhesion failure of powder and binder during injection molding step in PIM. Phase separation between powder and binder is a significant phenomenon for quality issue of the green part > Phase separation is also called Shear-induced Particle Migration Due to the maximum shear rate, particles disperse along the mold wall, known as low powder concentration; on the other hand, Particles concentrate highly in the central area for the minimum shear rate 16

17 Non-Brownian Motion Shear-induced Particle Migration The central area has highest particles concentration 50 μm The size of particle diameter is 1.5 μm. The average volume concentration is 34%. 17

18 Validation of Powder Concentration Prediction

19 Suspension Balance Model (via Moldex3D) > A governing equation for volume fractions of particles is based on the conservations of mass and momentum for both particle phase and suspension phase. Nott and Brady (1994); Morris and Brady(1997); D Dt j u t 2 2a 9 s f ( ) sedimention hindrancefuction j particle migration flux p(, max ) particle stress f ( ) (1 max )(1 ) 1 19

20 Validation of Powder Concentration Prediction > Shear Induced Variation in Powder Concentration Near stationary outer-cylinder, the high concentration is due to maximum shear rate, but close to rotating inner-cylinder, the low concentration for minimum shear rate 20 rotating inner-cylinder radius stationary outer-cylinder radius

21 Validation of Fiber Concentration Prediction > The excellent predictions are very close to experimental points Using Landa_2 = Ref.: X.-J. Fan, N. Phan-Thien, and R. Zheng, Simulation of Fibre Suspension Flow with Shear- Induced Migration, J. Non-Newtonian Fluid Mech. 90, 47 (2000).

22 Fiber Concentration Prediction for Injection Molding > Moldex3D Fiber Concentration Predictions almost pass through experimental data. low shear rate of inner center relatively has high concentration distribution 22 Vélez-García, G. M., P. Wapperom, D. G. Baird, A. O. Aning, and V. Kunc, "Unambiguous orientation in short fiber composites over small sampling area in a center-gated disk ". Compos. Pt. A-Appl. Sci. Manuf (2012).

23 Moldex3D PIM: Black Line Prediction

24 實際專案 ( 新日興股份有限公司 ) 案例背景資料 材料 長度 : 72 mm 寬度 : 104 mm 高度 : 27 mm 單穴產品體積 : 4.05 c.c. 材質 : MIM 型號 : Catamold 316LA 製造商 : BASF 固化溫度 : 140 加工條件 充填時間 : sec 保壓時間 : 2.3 sec 熔膠溫度 : 200 模具溫度 :100 24

25 Powder Injection Molding Project > Using Moldex3D-Power Injection Molding 25

26 Moldex3D Powder Injection Molding > From plastics to Metals/Ceramics, injection molding business continues to expand Moldex3D supports injection molding stage in Powder Injection Molding process simulation 26 Ref:

27 Independent Material Laboratory Rheograph RG25 Capillary viscosity and thermal conductivity with counter pressure equipped CR-6000 Capillary viscosity at different temperature and shear rates pvt-6000 pvt change at different temperature and pressure MCR 502 Rotation and oscillation tests for viscoelastic properties DSC 8500 Transition temperatures and crystallization kinetics Instron 5966 Mechanical properties 27

28 Material Characterization Viscosity PVT Heat capacity Thermal conductivity 28

29 Powder Information > For BASF MIM compound (316LA, steel powder) 29

30 Moldex3D PIM > Concentration Computational Setting Particle diameter, average concentration, and maximum concentration can be determined by experiment Default values is suited for the general MIM feedstock Particle friction index is NOT measured at present, namely, that its value (suggested between 10 and 20) might be tried to get a convergent result with respect to real case. 30

31 31 Filling Animation

32 Filling Percentage 85% 90% 94% 98% 32

33 Welding Line 80% 84% 95% 99.9% 33

34 Powder Concentration (1) > Low powder concentration is most possible to be black lines. 34

35 Powder Concentration (1) > A Comparison with practical MIM part Low powder concentration is most possible to be black lines. 35

36 Moldex3D Powder Injection Molding > Provides the full spectrum of meticulous metal/ceramic injection molding process for mixture conditions of polymer and binder evaluation > Helps users easily grasp phase separation phenomenon and examine the powder concentration distribution based on the fluid flow behavior of green part > Efficiently minimize the effects of volumetric shrinkage, warpage, and black lines, achieving the need of high sintered product quality standard Ref: Ref: 36

37 Future Work > 考慮粒子重力效應對粉末濃度分佈的影響 > 燒結後產品的強度, 收縮性, 以及內部孔隙度的可行性 37