Injection moulding and modelling on a micro scale

Transcription

1 Injection moulding and modelling on a micro scale Technology Update Injection moulding and welding of plastics 11 November 2014 Research Projects (National / European) Micro/Nano/Multimaterial Manufacturing POLYMETAL DK ( ) Metallization of polymers for micro manufacturing MASMICRO EU FP6 ( ) Micro assembly techniques for micro products 4M EU FP6 ( ) Multi Material Micro Manufacture NANOCMM EU FP6 ( ) Coordinate Metrology for Micro Components Production COTECH EU FP7 ( ) Converging Technologies for Micro Manufacture PolyNano DK ( ) for Micro/Nano Fluidic Manufacturing Platform Innomold DK ( ) Innovative Moulding Technologies Hi Micro EU FP7 ( ) High Precision Technology for Micro Manufacture HINMICO EU FP7 ( ) High Throughput Integrated Technologies for Multi material Functional Micro Components 2 DTU Mechanical Engineering, Technical University of Denmark 1

2 Now: Associate professor on Micro/Nano Polymer Processing PhD project at DTU Mechanical Engineering on Micro Injection Moulding (µim) 3 DTU Mechanical Engineering, Technical University of Denmark Section of Manufacturing Engineering Injection Moulding (IM), Micro Injection Moulding (µim), Injection Compression Moulding (ICM) RESEARCH: Process development Process simulation Design & Tooling 4 DTU Mechanical Engineering, Technical University of Denmark 2

3 Section of Manufacturing Engineering Laboratory of Geometrical Metrology 5 DTU Mechanical Engineering, Technical University of Denmark Precision injection moulding of polymer micro/nano geometries 1,0E 03 CURRENT STATE OF THE ART Replication studies Calibration of µ n geometries Mould Polymer Process Investigation Optimization Simulation Vertical dimension [m] 1,0E 04 1,0E 05 1,0E 06 1,0E 07 1,0E 08 Hot Embossing Injection Compression Moulding Injection Moulding µ Injection Moulding Soft Lithography 1,0E 09 1,0E 09 1,0E 08 1,0E 07 1,0E 06 1,0E 05 1,0E 04 1,0E 03 Lateral dimension [m] [Hansen, Hocken, Tosello, Replication of micro and nano surface geometries, CIRP Key Note STC S, 2011] 6 DTU Mechanical Engineering, Technical University of Denmark 3

4 7 DTU Mechanical Engineering, Technical University of Denmark mm µm nm SIZE FEATURES TOLE RANCES 8 DTU Mechanical Engineering, Technical University of Denmark 4

5 Outline (1) Injection moulding of surface micro nano structures (2) Injection moulding of surface micro nano structures (3) Injection moulding of optical micro components (4) Injection moulding of micro components (5) Injection moulding and simulation of thin wall moulded parts (6) Injection moulding of micro components with micro features (7) Injection moulding and simulation of miniaturized precision parts (8) Multi material micro injection moulding simulation 9 DTU Mechanical Engineering, Technical University of Denmark no. 1 mm µm nm SIZE FEATURES TOLE RANCES 10 DTU Mechanical Engineering, Technical University of Denmark 5

6 Precision injection molding of surface micro nano structures Full electric injection molding machine: Screw diameter of 18mm Clamping force 600 kn Repeatability (std deviation) 0,8 mg Cylclic Olefin Copolymer (COC): Cyclic Olefin Copolymer, COC TOPAS 6013 High heat deflection, chemical resistance possible parts sterilization 11 DTU Mechanical Engineering, Technical University of Denmark Dimensional measurements and Tolerance Verification Product compliance with specification Quality control Process chain capability (Uncertainty) Tolerance limits Etched silicon master geometries Nickel electroplated geometries Injection moulding replica AFM measurements (magnification: X 1x, Y 1x, Z 5x) 12 DTU Mechanical Engineering, Technical University of Denmark 6

7 Dimensional measurements and Tolerance Verification Crosses channels depth [nm] Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 Sample 8 Silicon Wafer Nickel Shim Polymer Samples Sample 9 Largest depth deviation among the different polymer sample is equal to 7nm Average polymer channel depth replication fidelity equal to 94% 13 DTU Mechanical Engineering, Technical University of Denmark Process monitoring Injection pressure (based on machine measurements) Injection pressure - Repeatability test Injection pressure [bar] Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7 Test 8 Test 9 Test Injection time [ms] 14 DTU Mechanical Engineering, Technical University of Denmark 7

8 no. 2 mm µm nm SIZE FEATURES TOLE RANCES 15 DTU Mechanical Engineering, Technical University of Denmark Methodology SEM image processing & AFM measurements CD 16 DTU Mechanical Engineering, Technical University of Denmark 8

9 Methodology SEM image processing & AFM measurements DVD 17 DTU Mechanical Engineering, Technical University of Denmark Methodology SEM image processing & AFM measurements HD DVD 18 DTU Mechanical Engineering, Technical University of Denmark 9

10 Injection moulding at µm nm scale 19 DTU Mechanical Engineering, Technical University of Denmark Replication assessment and tolerance verification at nm scale pit height Pit height [nm] CD Replication 80% Height DVD Replication 88% Nickel stamper Polycarbonate disc Specification (tolerance) HD-DVD Replication 100% CD DVD HD DVD 20 DTU Mechanical Engineering, Technical University of Denmark 10

11 Replication assessment and tolerance verification at nm scale track pitch CD Replication 94% Track pitch Nickel stamper Track pitch [nm] DVD Replication 100% Polycarbonate disc Specification (tolerance) HD-DVD Replication 100% CD DVD HD DVD 21 DTU Mechanical Engineering, Technical University of Denmark no. 3 mm µm nm SIZE FEATURES TOLE RANCES 22 DTU Mechanical Engineering, Technical University of Denmark 11

12 Precision moulding of optical polymer micro geometries Micro structured optical component Ni mould PMMA part 23 DTU Mechanical Engineering, Technical University of Denmark Injection compression moulding PMMA part: made by injection compression moulding 1) INJECTION mould cavity partially open facilitate flow of plastic inside 2) COMPRESSION mould cavity reduction to real thickness of the component uniform distribution of the pressure into the mould cavity 24 DTU Mechanical Engineering, Technical University of Denmark 12

13 Injection compression moulded component B C I F E L A D H G 25 DTU Mechanical Engineering, Technical University of Denmark Pitch measurements SEM (Scanning Electron Microscope) analysis 1-2: vertical pitch 2-3: diagonal pitch 3-4: horizontal pitch Measurements on: Ni mould PMMA part 26 DTU Mechanical Engineering, Technical University of Denmark 13

14 Manufacturing Process Control Vertical pitch 255 Pitch 1-2 Ni PMMA [µm] A B C D E F G H I L 27 DTU Mechanical Engineering, Technical University of Denmark Manufacturing Process Control Diagonal pitch 225 Pitch 2-3 Ni PMMA [µm] A B C D E F G H I L 28 DTU Mechanical Engineering, Technical University of Denmark 14

15 Manufacturing Process Control Horizontal pitch 185 Pitch 3-4 Ni PMMA [µm] A B C D E F G H I L 29 DTU Mechanical Engineering, Technical University of Denmark Deviation [µm] Pitch measurement Absolute deviations Ni PMMA B C I F E L A D H G 5-14 µm deviation Deviations depend on: Location Deviations decreasing With pitch length A B C D E F G H I L Pitch 1-2 Pitch 2-3 Pitch DTU Mechanical Engineering, Technical University of Denmark 15

16 Pitch measurement Relative deviations Ni PMMA B C I F E L A D H G 2%-6% deviation Deviations independent from: Pitch direction Deviation [%] Shrinkage locally isotropic Shrinkage anisotropic at component level A B C D E F G H I L Pitch 1-2 Pitch 2-3 Pitch DTU Mechanical Engineering, Technical University of Denmark no. 4 mm µm nm SIZE FEATURES TOLE RANCES 32 DTU Mechanical Engineering, Technical University of Denmark 16

17 Case study Toggle for hearing aid application Heights 0.38 to 2.08 mm (T mm) Diameters mm; mm Concentricity 0.02 mm Material POM Weight 35 mg Batch production > unit/year 33 DTU Mechanical Engineering, Technical University of Denmark Quality control Coordinate Measuring Machine 34 DTU Mechanical Engineering, Technical University of Denmark 17

18 Outer diameter D = µm U caltcmm (D) = 1.5µm Outer diameter [µm] Sample number 35 DTU Mechanical Engineering, Technical University of Denmark Inner diameter d = µm U caltcmm (d) = 3.4µm Inner diameter [µm] Sample number 36 DTU Mechanical Engineering, Technical University of Denmark 18

19 Concentricity C = (0, 20) µm U caltcmm (C) = 1.7µm Outer diameter [µm] Sample number 37 DTU Mechanical Engineering, Technical University of Denmark Height H = µm U caltcmm (H) = 4.7µm Height [µm] Sample number 38 DTU Mechanical Engineering, Technical University of Denmark 19

20 no. 5 mm µm nm SIZE FEATURES TOLE RANCES 39 DTU Mechanical Engineering, Technical University of Denmark Injection moulding of precision thin wall parts Polymer: POM 40 DTU Mechanical Engineering, Technical University of Denmark 20

21 41 DTU Mechanical Engineering, Technical University of Denmark Warpage measurements No relaxation No deviations larger than std. dev. after: 24 hours 48 hours 7 days 7d 48h 24h POM Geo. a: Measurements L3 L2 0,80 0,70 0,60 0,50 0,40 0,30 0,20 0,10 0,00 Deviation [mm] 42 DTU Mechanical Engineering, Technical University of Denmark L1 H 21

22 Injection and cavity pressure Simulation vs. Experiments Pressure [bar] POM Geo. a simulation P0 P1 P2 P3 0 0,00 0,50 1,00 1,50 2,00 Time [s] Pressure [bar] 1200 Experimental ,00 0,50 1,00 1,50 2,00 Time [s] 43 DTU Mechanical Engineering, Technical University of Denmark no. 6 mm µm nm SIZE FEATURES TOLE RANCES 44 DTU Mechanical Engineering, Technical University of Denmark 22

23 Precision Moulding of polymer microcomponents with micro features 2 cavities with micro structures Pressure sensor at injection location sample rate 25 khz one pressure sampling every 0.04 ms 50 mm 45 DTU Mechanical Engineering, Technical University of Denmark Pressure sensor mark 46 DTU Mechanical Engineering, Technical University of Denmark 23

24 Gate 47 DTU Mechanical Engineering, Technical University of Denmark 47 Micro features 48 DTU Mechanical Engineering, Technical University of Denmark 48 24

25 Micro injection moulding Cycle analysis and cavity filling time Pressure at injection location [bar] PRESSURE 130mm3 - exp1 PRESSURE 130mm3 - exp2 PRESSURE 130mm3 - exp3-50 0,400 0,420 0,440 0,460 0,480 0,500 0,520 0,540 0,560 0,580 0,600 Time [s] Cavity injection time 49 DTU Mechanical Engineering, Technical University of Denmark 0.060s no. 7 mm µm nm SIZE FEATURES TOLE RANCES 50 DTU Mechanical Engineering, Technical University of Denmark 25

26 Effect of process parameters on injection pressure Mean of Piston Injection Pressure [bar] Tmelt Inj.Vel Tmould Stroke length ,0 1,0 2,0 3,0 5,0 10,0 12,0 12,7 51 DTU Mechanical Engineering, Technical University of Denmark Injection pressure Coefficient of variation (COV%) of piston injection pressure 8 different process settings 14 different piston stroke lengths Sample for each discrete point = 20 measurements Piston injection pressure Coefficient of Variation (COV) [%] Piston Injection Pressure Variation 190 C 55 C 100mm/s 220 C 55 C 100mm/s 190 C 90 C 100mm/s 220 C 90 C 100mm/s 190 C 55 C 200mm/s 220 C 55 C 200mm/s 190 C 90 C 200mm/s 220 C 90 C 200mm/s Piston stroke length [mm] 52 DTU Mechanical Engineering, Technical University of Denmark 26

27 Part length Effect of process parameters 11,68 Tmelt [ C] Tmold [ C] 11,67 11,66 Mean of LENGTH [mm] 11,65 11,64 11,68 11, InjVel [mm/s] PackTime [s] 90 11,66 11,65 11, ,0 0,4 53 DTU Mechanical Engineering, Technical University of Denmark Part length STD DEV Effect of process parameters 0,016 Tmelt [ C] Tmold [ C] Mean of Std dev Length [mm] 0,014 0,012 0,010 0,016 0, InjVel [mm/s] PackTime [s] 90 0,012 0, ,0 0,4 54 DTU Mechanical Engineering, Technical University of Denmark 27

28 Short shots & injection pressure 55 DTU Mechanical Engineering, Technical University of Denmark Injection Pressure Comparison Simulation vs. Experiments Pressure [MPa] SIMULATION vs. EXPERIMENTAL SPRUE TIP INJ. PRESSURE Simulation Experimental Injection Time [ms] 56 DTU Mechanical Engineering, Technical University of Denmark 28

29 no. 8 mm µm nm SIZE FEATURES TOLE RANCES 57 DTU Mechanical Engineering, Technical University of Denmark Multi material Micro Injection Moulding Simulation 2k 58 DTU Mechanical Engineering, Technical University of Denmark 29

30 Multi material Micro Injection Moulding Simulation 2k Flow pattern validation Shot 1 POM (white) 100% shot Shot 2 ABS (blue) short shots Experiments Simulation 59 DTU Mechanical Engineering, Technical University of Denmark s/o = 7.2 mm 5 mm 60 DTU Mechanical Engineering, Technical University of Denmark 60 30

31 5 mm 61 DTU Mechanical Engineering, Technical University of Denmark 61 s/o = 7.2 mm 62 DTU Mechanical Engineering, Technical University of Denmark 31

32 Flow pattern and micro features replication possible to be predicted by simulation 63 DTU Mechanical Engineering, Technical University of Denmark Key learnings Message to take home Injection moulding can produce features at micrometre level Injection moulding can produce features at 100 nm level Tolerances at micro/nano level can be obtained by injection moulding Simulation resolution can be achieved at 10 µm level Injection pressure and flow can be simulated with good accuracy Calibration is KEY PROCESS PRODUCTS MATERIALS MOULDS 64 DTU Mechanical Engineering, Technical University of Denmark 32

33 Thank you for your attention 65 DTU Mechanical Engineering, Technical University of Denmark 33