2012 Moldex3D R11 European Webinar Series Application and Process Optimization Technology for Plastic Injection Compression Molding(ICM) 1
Dr. Enoch Chen»Current position: CoreTech System Technical Research Division» Education: PhD in Mechanical Engineering at University of Florida» Specialization: Experimental mechanics /Residual strain analysis in composite Research assistant in Experimental Stress Analysis Laboratory at University of Florida, specialize in the optical measurement of process-induced residual strains in composites and finite element analysis. Research assistant in Advanced Material Characterization Laboratory at University of Florida, specialize in, focus on shrinkage property study on concretes applying the optical method. In recent years, engage in plastic injection molding analysis and the solutions to molding problems. In addition, research on many special molding processes, including injection compression molding, gas-assisted injection molding, hot runner, and optical application. Moreover, experience with integration of injection molding and structural analyses in PLM. 2
Content > Why we use ICM? > What are the Issues when using ICM? > What Moldex3D can help? > How we use CAE to solve issues in practical case? - CIM versus ICM on light guide plate - Warpage issue for DVD disks in injection compression molding - Residual stress issue for optical lens in injection compression molding > What we can conclude? > Q and A 3
Why we use ICM? 4
Overview of CIM Steady Process Operation Easy Process Automation Conventional Injection Molding (CIM) High Productivity Complicated Geometrical Construction 5
Overview of CIM Filling Packing Cooling Mold open /Ejection Non-uniform packing effect Problems Non-uniform shrinkage Severe Warpage Cavity pressure Sink Mark Residual Stress /Birefringence 6
Problems in Optical Parts Using CIM > DVD disk warpage issue > Optical lens residual stress issue > Light guide plate issues Ref: http://www.cmo.com.tw 7
New Mechanism Needed > Packing and holding is always need to compensate the shrinkage Cavity pressure > But Under packing occurs if high packing pressure is required Over packing sometimes occurs, and may cause extra residual stress and molecular orientation How to pack melt into cavity through a frozen gate? > New compression mechanism appear 8
Introduction to ICM > As early as to 1960s, Japanese injection molding masters began to research on ICM. However, it was not well developed due to the limitations of machines and molds. > In the 1980, injection machine and mold technology had a very fast development which is very good for injection compression development. > Nowadays, it has become one of precision injection molding processes. The advances in CAE also help the feasibility of this special molding process. 9
Introduction to ICM Injection molding Compression molding Injection Compression Molding (ICM) Melt is compressed by the movable mold to complete the filling during the compression phase Uniform packing Cavity pressure 10
ICM Process Cycle Close mould down to the compression gap Inject and fill cavity 80 95% (equivalent to 100% or more of the ultimate volume) Sequential or simultaneous compression by clamping the mould Apply hold pressure, cool, open mold, and eject part 11
Types of ICM Short-shot compression Full-shot compression Co-injection compression 12
Benefits of ICM for Parts Reduced Sink mark and warpage Reduced molecule orientation Increase Dimension Accuracy Advantages Less material shear Reduced Residual stress Reduced birefringence 13
Benefits of ICM for process Reduced Injection Pressure Reduced cycle time Advantages Improved venting Reduced Clamping force 14
ICM Applications > Application Fields - In-Mold decoration parts - Optical parts - Finely textured surfaces 15
ICM Applications > Application Fields - Automobile parts - 3C products (PDA cover, cell phone cover, Notebook cover etc.) - Others(Fuel cell bipolar plate, SD card etc.) 16
What issues we have when using ICM? 17
Issues of ICM Extra costs for the machine and mould Flash Problem Disadvantages Parts with great depth in the injection direction are not suitable for ICM Complicated process condition control compression time, compression force, compression speed, and compression distance 18
Issues for ICM > Issues from CIM to ICM Very complicated process parameter control, Smaller process window, The injection pressure, temperature, clamping force and their histories become very different, The physical mechanism and the detailed internal information cannot be fully understood by the experiments, Different materials have different viscosity, compressibility etc. It is a much more complicated process A scientific tool is in great demand: CAE 19
What Moldex3D can help? 20
Numerical Theory-Basic Governing Equation > Full 3D theory > Mass Conservation ρ + t ( ρv ) = 0 > Momentum Conservation ( ρu ) + ( ρuu τ ) = p + ρg t > Energy Conservation > Moving Grid Approach 21
Numerical Theory-Constitutive Equations > Generalized Newtonian Fluid Modified-Cross model τ = η γ η ( T, & γ ) T ( T, & )( u + u ) ( ) η o = T 1 & b η ( T ) = BExp 1 + * ( η & γ τ ) n o η o T T > Viscoelastic fluid Constitutive equation (ex White Metzner Model) τ t T T τ + λ + V τ V τ τ V = η ( V + V ) Add elastic characteristic term 22
Compression Surface Setting in Moldex3D-Mesh Compression region setting in Moldex3D-Mesh 23
Process Parameter Setting in Moldex3D- Project Process settings in Moldex3D-Project Nozzle can be shut off before the beginning of compression 24 24
ICM Analysis in Moldex3D-Project Mesh Deformation to generate a gap before filling Compression ratio and compression force information during compression 25
ICM Analysis in Moldex3D-Project Filling completes prior to compression finish 26
Injection Compression Simulation - Key points and features > The compression gap, compression speed, delay time and other settings for ICM are all available in process wizard. > Support injection and compression processing at the same time > Support new meshing method: compression gap solid mesh > Support animation of compression action on melt > Support to calculate flow residual stress and thermallyinduced stress. > Support connection with optical analysis. > Support multiple-component parts. > Support multiple-time output. 27
How we use CAE to solve issues in practical case? 28
Case Study (1): light guide plate Two different geometry designs and their effects on process and product quality 29
Two Type LGP Model > Wedge LGP 176mm 99mm rectangular with wedge-shape, which the thickness varies from 1.5mm at one end to 0.5mm at the other end > Flat LGP 176mm 99mm rectangular with constant thickness 1.0mm 1 mm SN 10 SN 9 SN 8 SN 7 SN 6 1 mm 30
Material and Process Condition Information 31
Flat LGP with CIM > During the packing stage of CIM, the pressure decreases smoothly as packing starts 32
Wedge LGP with CIM > During the packing stage of CIM, the pressure decreases smoothly as packing starts 33
Wedge LGP with ICM Gate is shut-off movable mold starts to compress 34
Flat LGP with ICM Gate is shut-off movable mold starts to compress 35
Wedge LGP > ICM (46~55 MPa) process has more uniform pressure distribution than CIM (35~71 MPa) Conventional injection molding (CIM) Injection compression molding (ICM) 36
Flat LGP > ICM (48~50 MPa) process has more uniform pressure distribution than CIM (12~53 MPa) Conventional injection molding (CIM) Injection compression molding (ICM) 37
Wedge LGP - Part Shrinkage > ICM (-2.3 ~ -0.5 %) has smaller shrinkage variation than CIM (-3.4 ~ -0.3 %) (more uniform pressure distribution) Conventional injection molding (CIM) Injection compression molding (ICM) 38
Flat LGP - Part Shrinkage > ICM (-2.0 ~ -1.6 %) has smaller shrinkage variation than CIM (-2.1 ~ 0.9 %) (more uniform pressure distribution) Conventional injection molding (CIM) Injection compression molding (ICM) 39
Case Study (2): DVD Disk Compression force profile design for warpage issue 40
Process Conditions Design Experimental Process Conditions Melt temperature ( o C) 295 Core side ( o C) 109 Cavity side ( o C) 117 Filling Time (sec) 0.1 Compression Time (sec) 4.19 Cycle time (sec) 4.29 Compression gap (mm) 0.3 Compression force control Delay time, switch time, compression force magnitude 41
Design Compression Force Profile > Compression force profile 2. Delay time 1. Force magnitude 3. Switch time 42
Numerical Model Information > Elements were constructed by hexahedron and average 12 layers in thickness direction. > Cooling Channel are designed in six circles. 43
Analysis Results Parameters 1 st 2 nd 3 rd 4 th C1 Compression force (tonne) 0 21 9 10 44
Experimental & Analysis Result: Group A A1 A2 A3 Parameters 1 st 2 nd 3 rd 4 th Switch time (sec) Switch time (sec) Switch time (sec) 0.08 0.05 0.08 0.11 0.08 0.08 0.02 0.02 0.02 0.05 0.08 0.08 0.08 0.02 0.02 0.02 0.05 0.08 45
Experimental & Analysis Result: Group B Parameters 1 st 2 nd 3 rd 4 th B1 Delay time (sec) 0.1 0.1 0.3 0.7 3.27 3.07 B2 Delay time (sec) 0.1 0.1 0.4 0.7 1 3.57 3.27 2.97 46
Experimental & Analysis Result: Group C C1 C2 C3 Parameters 1 st 2 nd 3 rd 4 th Compression force (tonne) Compression force (tonne) Compression force (tonne) 0.3 19 21 0.3 21 9 10 7 9 11 0.3 21 9 10 8 10 12 47
Case Study (3): Plastic Optical Lens ICM compression parameter optimization for Residual Stress Issue 48
CIM Experimental Results Part1 Part2 Parts from real mold trials CIM Experimental Fringe Patterns 49
Numerical Simulation Information -Meshed Model Meshed Model 30mm 1mm 2.12mm Mesh Type Mixed (Prism and Hexa) Part dimension 30.00 x 2.12 x 94.00 (mm) Mold dimension 180.00 x 108.75 x 180.00 (mm) Cavity(Part) volume 1.9521 (cc) Cold runner volume 1.86602 (cc) Element number 158720 Part elements 158720 Node number 92829 50
Numerical Simulation Information-Cooling Channel and Compression Surface Cooling channel design Compression region 51
Numerical Simulation Information- Material Viscosity PVT Heat Capacity Thermal Conductivity 52
CIM Numerical Simulation Information - Process Parameter Process Parameters Settings Filling Time 1.9730 (sec) Melt Temperature 300.0 ( C) Mold Temperature 90.0 ( C) Max. Injection Pressure Injection Volume (including runner) 220.00 (MPa) 3.81812 (cc) VP Switch by volume(%) filled 98.00 (%) Packing Time Packing Pressure Cooling Time Mold Opening Time 5 (sec) Refer to the end of filling pressure 40.0 (sec) 5.00 (sec) Ejection temperature 144.0 ( C) Coolant (oil) 90.0 ( C) Air Temperature 25.0 ( C) 53
CIM Experimental and Simulation Results Flow-induced Fringe Pattern Thermal-induced Fringe Pattern CIM Total Fringe Pattern & Fringe Order 54
Numerical Simulation Information - Process Parameter Process Parameters Settings Filling Time 1.9730 (sec) Melt Temperature 300.0 ( C) Mold Temperature 90.0 ( C) Injection Pressure Injection Volume 220.00 (MPa) 3.81812 (cc) VP Switch by volume(%) filled 98.00 (%) Compression gap Delay time Compression time Start compressed by Filling stage compression velocity Maximum compression force Variable 0s 5s Variable (Change with compression gap) Variable 1500 (tf) Nozzle is Shut off Yes Cooling Time 40.0 (sec) Coolant (oil) 90.0 ( C) Mold Opening Time 5.00 (sec) Ejection temperature 144.0 ( C) 55
Simulation Results Compression gap=0.5mm, compression speed=1mm/s, Compression time=5s 56
ICM Simulating and Experimental Results: Compression Gap Effect 0.1mm (5mm/s) 0.5mm (5mm/s) 1mm (5mm/s) 57
ICM Simulating and Experimental Results: Compression Speed Effect 2mm/s (0.5mm) 5mm/s (0.5mm) 10mm/s (0.5mm) 58
Simulation Results: Compression Gap Effect 59
Simulation Results: Compression Speed Effect 60
What we can conclude? 61
Conclusions > We have introduced Injection compression and its current industrial applications. > We have pointed out the issues in design and development for injection compression products. > We have proposed a useful tool: An innovative 3D injection compression simulation technology-moldex3d. > We have learned the benefits from using Moldex3D on practical studies. > Moldex3D can help us to reduce real mold trials and product development time to save money and time. 62
If you need help or have questions, please type into the chat box. 63
Contact Information Dr. Chen enochchen@moldex3d.com Vincent vincenthung@moldex3d.com 64
Next Webinar Topic In-depth Study of Hot Runner Technology and Industrial Applications Goals Time Hot runner system and its current industrial applications The issues in design and development of hot runner system The bottlenecks for traditional product development cycle The breakthrough with CAE in hot runner system development An advanced hot runner analysis technology and application The benefits to practical cases from using advanced hot runner CAE 9:00AM UTC -19 January,2012 65