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Digital Material Deposition for Product Manufacturing Processes.

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Presentation on theme: "Digital Material Deposition for Product Manufacturing Processes."— Presentation transcript:

1 Digital Material Deposition for Product Manufacturing Processes

2 Material Deposition Presentation 2 Purpose of Presentation  Provide an overview of how the digital printing technologies utilized in the reprographics industry for over 50 years have been used for:  Unusual printing applications  Special material deposition applications

3 Material Deposition Presentation 3 What is Digital Material Deposition? The preparation of materials to make them suitable for digital deposition The means (process, hardware, and controls) to enable the controlled lay-down of materials onto various substrates:  Practiced in the reprographics industry for over 50 years as copying & printing  Processes and technologies have now been applied to a wide variety of non-printing applications

4 Material Deposition Presentation 4 Applications of Digital Deposition The technologies of digital printing are being used to:  Make products  Print on products  Coat products  Print on product containers  Print on packaging  Print labels

5 Material Deposition Presentation 5 Advantages of Digital Deposition Precise & controlled amounts of material lay-down  Mass  Thickness Selectively variable process  Change amounts and placement at will  Create images - monochrome to full color  Layered construction High value material capability  Little to no material wastage Readily scalable  From laboratory, to pilot, to production  Short-run to long-run  Narrow to wide format 3-Dimensional applications

6 Material Deposition Presentation 6 Potential Disadvantages of Digital Deposition Technology Some systems can be complex Sometimes material latitudes are limited May be more costly on a cost per unit basis than long-run conventional processes  Offset  Blade coating  Pad printing

7 Material Deposition Presentation 7 The Primary Forms of Deposition Materials Deposition Materials can be :  Liquid materials or  Dry powder materials or  Dry film materials

8 Material Deposition Presentation 8 Widely Practiced Reprographic Deposition (Printing) Systems Electrostatic (Dry powder and liquid)  Electrophotography  Electrography Inkjet (Liquid)  Drop on Demand  Thermal & Piezoelectric  Continuous Thermal (Dry film)  Direct & Transfer Magnetographic (Dry powder)

9 Material Deposition Presentation 9 Digital Deposition Processes Overview Digital Deposition Processes Latent Image Intermediate Direct-to- Receiver Special Process Receiver Media Electrophotography Ionography Electrography Magnetography Drop on Demand IJ Continuous IJ Thermal Transfer Toner Jet Dry Silver Thermal Paper Electrostatographic UV Light Sensitive

10 Material Deposition Presentation 10 Major Segmentation of Deposition Technologies Deposition system  Direct versus Indirect Material properties  Liquid versus Dry

11 Material Deposition Presentation 11 Major Segmentation Map Direct ProcessIndirect Process Liquid Inkjet Electrostatic  Electrophotography  Electrography Electrostatic  Electrophotography  Electrography Dry Electrostatic  Electrophotography  Electrography Thermal Transfer Electrostatic  Electrophotography  Electrography Magnetographic Solid Inkjet

12 Material Deposition Presentation 12 Liquid vs. Dry Conventional thinking for dispensing, dosing, metering:  Liquid deposition via inkjet technology  The ‘de facto approach’ However, liquid AND dry powder materials can be digitally deposited  Highly application dependent

13 Material Deposition Presentation 13 Liquid Deposition & Micro-dispensing

14 Material Deposition Presentation 14 ContinuousDrop-on-Demand Piezoelectric Edge shooter Hollow Tube Binary Deflection Multiple Deflection Hertz Mist Magnetic Deflection Multi-Jet Single Jet Printhead Roadmap Thermal ElectrostaticAcoustic Roof shooter Bending Plate Extending Member Shear Mode

15 Material Deposition Presentation 15 Inkjet Implementation: Fluid Issues Fluid physical attributes and chemistry drive the system design: Aqueous or non-aqueous Chemically reactive with print head Viscosity versus temperature Surface tension pH Volatility Fluid temperature constraints Fluid formulation modification latitude Particulate size

16 Material Deposition Presentation 16 Inkjet Implementation: Head Issues All inkjet head types are possible candidates Head matched to the fluid and application: Ejected volume and nozzle count requirements Jetting frequency requirement Throw distance and direction Number of unique fluid types required Head maintenance algorithms and hardware Ambient environment Reliability and operator interaction constraints

17 Material Deposition Presentation 17 Inkjet Implementation: Substrate Issues Like the fluid, the substrate is typically a given and influences the integration: x and y motion requirements Speed, step size, and precision Mounting and alignment Topography considerations Substrate - Fluid interactions

18 Material Deposition Presentation 18 Inkjet Implementation: Other Challenges Head-drive electronics and algorithms Data source and manipulation requirements Environmental concerns Temperature and humidity Outside contaminants Process effluents Drying

19 Example: Polymer Electronics - Displays Ejection of electro-luminescent polymer onto glass substrate for monochrome or color displays ADVANTAGE Inexpensive Automated Repeatable “Displays-on- Demand”

20 Example: Polymer Electronics - Sensors Ejection of “environmentally sensitive” polymer onto silicon or advanced PCB substrate ADVANTAGE Inexpensive Automated Repeatable “Sensors-on- Demand”

21 Material Deposition Presentation 21 Layer-upon-layer fluid ejection to build computer-generated, three- dimensional parts and prototypes. Example: Rapid Prototyping – SLA Substitute ADVANTAGE Inexpensive Automated Repeatable “Parts-on-Demand”

22 Material Deposition Presentation 22 Manufacturing Dispensing Examples Flexible adhesive placement, coating, soldering, and precise patterning for in-line and off-line production ADVANTAGE Automated Repeatable Quantity-controlled dispensing

23 Material Deposition Presentation 23 Example: Manufacturing – Dispensing Solder 25µm bumps of 63/37 solder deposited on 35µm pitch using “Solder Jet” technology

24 Example: Pharmaceutical – Dispense Active Agent Advanced drug-dispensing system Active agent(s) stored in carrier wells that are filled on demand by specialized inkjet heads ADVANTAGE Increased medical control over drug application Drugs tailored to individual’s medical requirements

25 Example: Biotechnology – DNA Testing HP partnership with Affymetrix Gene Chip Dispensing of “tiny DNA segments, housed inside picoliter-size droplets of liquid … onto an array of integrated circuit-like chips…” Source: Upside, Sept. 23, 1998 ( ADVANTAGE Automated procedures Repeatable results

26 Example: Medical - Containment Hydrophobic material forms barrier to contain biological fluids or other fluids for tissue preparation ADVANTAGE Automated Pattern retention Repeatable processes

27 Material Deposition Presentation 27 A Case Study – Liquid Deposition  Precision coating of a medical device for drug loading  Project performed by Xactiv Inc, (formerly Torrey Pines Research)  The development activity was carried out on behalf of a client

28 Material Deposition Presentation 28 Case Study – Stent Coating Stent – small, lattice-shaped, metal tube that is inserted permanently into an artery. The stent helps hold open an artery so that blood can flow through it.

29 Material Deposition Presentation 29 Case Study – Stent Coating Requirements Drug eluting stent is coated with polymer that incorporates a drug that helps prevent plaque build- up Drug elutes very slowly over a period of years Coating must be applied uniformly on inside and outside of stent Coating thickness must be very uniform (+/- 5%) Coating weight stent to stent must be well controlled (+/- 5%) Stents of various diameters and lengths

30 Material Deposition Presentation 30 Case Study – Stent Coating Challenges Coating materials pre-defined by client  Polymer has few viable solvents Stent must be coated all over while handling Precision requirement Minimize wastage Speed

31 Material Deposition Presentation 31 Case Study – Stent Coating Solution Piezo industrial drop on demand system selected Dimatix S-series print head  Resistant to solvents  Precision jetting system TPR modified the print head  Replaced seals

32 Material Deposition Presentation 32 Case Study – Stent Coating Solution Piezo drop on demand industrial print head  Modified seals to withstand solvent Custom designed stent handling system Custom designed precision inkjet coating system Special maintenance algorithms and maintenance system  Eliminate nozzle blockage due to drying Solvent resistant fluid handling Solvent chemistry Ink development

33 Material Deposition Presentation 33 Case Study – Stent Coating Precision stent handling system

34 Material Deposition Presentation 34 Case Study – Stent Coating Precision inkjet coating system

35 Material Deposition Presentation 35 Case Study – Stent Coating System

36 Material Deposition Presentation 36 Dry Powder Deposition

37 Material Deposition Presentation 37 Electrostatic Dry Powder Deposition Typical Application Requirements Dry powder materials From ~ 5 to 75 microns in size Solvent-less process High area coverage - usually Large volumes of material Precise metering/thickness control Uniform coating Static or variable information Contact or non-contact process Direct or indirect process 2D or 3D deposition

38 Material Deposition Presentation 38 Conventional Powder Coating Charging air gun Typical powder spray system

39 Material Deposition Presentation 39 Conventional Powder Coating Problems/Limitations  Corona or tribo charging with air transport  Poor powder charging  Poor directional control  Air overwhelms electric field and wastes material Requires substantial post “clean-up”  Uniformity not assured  Masking difficult  Images with information impossible

40 Material Deposition Presentation 40 The Challenges of Electrostatic Powder Development Using/modifying or creating the materials for:  Functional requirements of application  Charging  Transport Identifying a suitable powder Development Sub-system technology  Direct versus Indirect architecture Dealing with Substrate properties  Often a given

41 Material Deposition Presentation 41 Important Powder Properties Dielectric properties  Insulative versus conductive Magnetic properties Powder size and size distribution Electrostatic charging characteristics Rheological (melt) properties Flow properties Functional characteristics  Color  Application dependent functionality

42 Material Deposition Presentation 42 Important Substrate Properties Dielectric properties  Insulative versus conductive Flat or 3D  If flat  Sheet vs. roll stock  Flatness tolerance  If 3D  Shape and 3D depth Layered construction characteristics Hard vs. soft characteristics

43 Material Deposition Presentation 43 Dry Powder Deposition System Considerations Conductive Insulative Magnetic Non-magnetic Powder Properties Conductive Insulative Substrate Properties Triboelectrification Induction Charging Method Direct Transfer Deposition Method

44 Material Deposition Presentation 44 What are Conductive Materials It depends on time for current to flow:  With copper – not very long  With fused quartz - sit down because you’re going to be there a while Conductivity represents a continuum

45 Material Deposition Presentation 45 Conductivity is a Continuum In conductors, electric charges are free to move In an insulator, charges are less free to move There’s no such thing as a perfect insulator  However, insulating ability of fused quartz is 10 25 times that of copper Conductivity is characterized by a physical property - Resistivity Conductive Materials Insulative Materials Semi-conductive Materials

46 Material Deposition Presentation 46 Resistivity of a ‘Conductive’ Material A conductive material for many electrostatic processes may have a resistivity of 7.5(10 8 ) ohm-cm or less. 0 – 10 -8 Most Metals 10 810 10 18 Fused Quartz Conductive Materials Insulative Materials ?? Resistivity Scale (ohm-cm)

47 Material Deposition Presentation 47 The Significant Properties that Drive the Electrostatic Deposition Process Powder charging  Determined by the material being Conductive versus Insulative Powder transport  Determined by the material being Magnetic versus Non-magnetic

48 Material Deposition Presentation 48 Charging of Insulative Powders Insulative Material Charging  Most commonly charged by triboelectrification  Mechanical contact/rubbing causes charges to exchange - - - - - + + + + + + + + + + + + + + + + - - - - - - - - - - - - - - - - - - - - - - - - - Functional Powder Carrier

49 Material Deposition Presentation 49 Triboelectric Series Steel, Wood Amber, Sealing Wax Hard Rubber, Nickel, Copper Grass, Silver, Gold Platinum Sulfur, Acetate, Rayon Polyester, Celluloid Orlon, Saran Polyurethane, Polyethylene Polypropylene, PVC (Vinyl) Kel-F (CTFE) Silicon Teflon Increasingly Positive Increasingly Negative COTTON – The Dividing Point Air Human Hands Asbestos Rabbit Fur Glass Mica Human Hair Nylon Wool Fur Lead Silk Aluminum Paper

50 Material Deposition Presentation 50 Powder Charge Distribution 5 10 1520 25 30 Charge -  C/gm VOLUME (Number) -5 Wrong Sign Low Charge Target High Charge

51 Material Deposition Presentation 51 Charging of Conductive Powders Conductive Materials  Most commonly charged by Induction  An applied voltage causes electrons to migrate to the tip of the material in the presence of an electric field (E) V _ - - - - +

52 Material Deposition Presentation 52 Powder Transport Magnetically permeable powders are most commonly transported via magnetic forces  Powder can be magnetically permeable or  Can incorporate a magnetic Carrier NSNS NSNS NSNS NSNS Development Zone Substrate

53 Material Deposition Presentation 53 What about the Substrate? The substrate is the material upon which the powder is being deposited.  It ultimately refers to the final working material for the given application. Examples might include:  Electronic materials  Flexible circuits  PCB materials  Pharmaceutical tablet  Consumer products  Product packaging  Food products The substrate can be conductive or insulative Its properties will dictate the powder and transfer method

54 Material Deposition Presentation 54 Electrostatic Deposition Material Choices Powders Insul Cond Insul Yes Yes Substrate Cond Yes Yes The physics to follow

55 Material Deposition Presentation 55 Dry Powder Development Purpose Apply powder particles to the electrostatic latent image on the photoreceptor or electrostatically charged receiver Functions Charge the powder Transport powder into the “development zone” Fully develop the image, not the background

56 Material Deposition Presentation 56 Summary The challenges of Electrostatic Deposition of Dry Powder include:  Material formulation (Powder and Substrate)  Charge methodology  Transport means  Transfer mechanism Many deposition technologies exist from the fields of Electrophotography and Electrography The advantages of electrostatic dry powder deposition include:  Dry powder applications  Speed  Scalable to wide format  No solvents

57 Material Deposition Presentation 57 A Case Study – Powder Deposition Dry powder coating of pharmaceutical tablets for coating and/or drug loading  Project performed by Xactiv, Inc, (formerly Torrey Pines Research)  The development activity was carried out on behalf of Phoqus Limited,

58 Material Deposition Presentation 58 Tablet Coating Most tablets are coated to:  Protect the tablet  Seal the tablet  From environment  Taste masking  Control drug release  Create brand identification  Create desirable appearance

59 Material Deposition Presentation 59 Tablet Coating Process Today Batch process Solvent based Tumble dried

60 Material Deposition Presentation 60 Problems with the Current Process Liquids and solvents  Compatibility problems with certain drug actives  Environmental problems  Drying costs Quality  Tablet damage due to aggressive tumbling  Variation in coating thickness Batch process  Minimum lot size very large  No individual tablet customization  Expensive wastage if problems occur Not suitable for certain tablets, such as fast dissolving dosage forms

61 Material Deposition Presentation 61 The Technical Challenges The challenges over those normally encountered in Reprographics Industry:  3-D Tablet Surface  Most printing done on flat surfaces  Use of many different powders and tablets  In printing, there is typically one set of materials for a given machine  Precision  +/- 10% typical in printing  +/- 2% required for this application

62 Material Deposition Presentation 62 The Solution Improve, Customize, and Optimize “Electrostatic Dry- Powder Development” (EDPD)  As practiced in the Reprographics Industry for over 50 years

63 Material Deposition Presentation 63 Deposition Applicator of Choice Rotating magnet DCD system Permanently magnetized carrier Both provide vigorous mixing in development zone

64 Material Deposition Presentation 64 Pharmaceutical EDPD Housing Elements Licensed from Heidelberg

65 Material Deposition Presentation 65 Critical Coating Materials DCD Carrier materials  Strontium and manganese ferrite powder, 40  – 80   Silicone, Acrylic or Fluoro-Silicone coated Coating powders  Many formulations  Various proprietary resins  Water soluble  Low glass transition temperatures

66 Material Deposition Presentation 66 Tablet Holding Requirements Securely hold individual tablets Make electrical contact to body of tablet Create an electrical shield:  To prevent contamination of holder  Shut-down development of powder on tablet

67 Material Deposition Presentation 67 Tablet Holder Ejector/Electrode Conductive Flexible Cup Shield (reverse biased) Vacuum Connection

68 Material Deposition Presentation 68 Coating Uniformity Issues Electric Field is a function of voltage difference and dielectric distance In conventional coating practice, coating thickness varies with field In copiers/printers, field is uniform because coated surface is flat. Tablet is not flat, so field varies and coating thickness will vary Strong field Weak field

69 Material Deposition Presentation 69 Field Collapse Process 1 2 34 Time = 0 Time = Completion E = maximum E = 0E E

70 Material Deposition Presentation 70 Coating Uniformity Results Section through the corner of an EDPD coated tablet showing uniformity of coating on top and around the edge

71 Material Deposition Presentation 71 Continuous Process Section of coating drum with tablets

72 Material Deposition Presentation 72 The Finished Product

73 Material Deposition Presentation 73 A Case Study – Powder Deposition Dry powder coating to make fuel cell electrodes  Activity performed by Xactiv, (formerly Torrey Pines Research)  Independent activity resulting in significant IP  US Patent now issued  Prepares Xactiv for position in renewable energy markets

74 Material Deposition Presentation 74 Electrostatic Deposition (Intermediate Dielectric Substrate) 60% PtC and 40% PTFE mixture is conducting Apply voltage between conducting mixture and dielectric coated electrode Monolayer of PtC/PTFE particles is induction charged and electrostatically attracted to dielectric VAVA

75 Material Deposition Presentation 75 Electrostatic Deposition Problems (Intermediate Dielectric Substrate) Some non-uniformity of deposited layer requires conditioning Monolayer is only ~0.5 mg/cm 2 Multiple transfix steps would be required to achieve target Pt loadings Need to repeatedly clean and neutralize intermediate dielectric substrate

76 Material Deposition Presentation 76 Xactiv Conductive-Conductive Deposition Particle Induction Charging & Detachment via Field Intensification VAVA Electric Field Intensification for Induction Charging & Detachment Weak Electric Field for Deposition Electrode structures

77 Material Deposition Presentation 77 Xactiv Cond-Cond Implementation Magnetic Brush Deposition Carbon Paper N S N S N S N S N S N S N S N S Paddle Wheel Elevator & Metering Cross Mixer Magnetic Brush Rotating Magnets Stationary Sleeve Air Gap

78 Material Deposition Presentation 78 Magnetic Brush Unit

79 Material Deposition Presentation 79 Magnetic Brush Structure

80 Material Deposition Presentation 80 Magnetic Brush Forces Carbon Paper N VAVA

81 Material Deposition Presentation 81 Non Contact Magnetic Brush Deposition Carbon Paper N VAVA Electric field intensified for induction charging & detachment of PtC/PTFE blend

82 Material Deposition Presentation 82 Surrogate “Tribo” Fixture Theory N SN S S Motor VAVA Enables rapid evaluation of materials, concentrations, blend and mixing conditions.

83 Material Deposition Presentation 83 “Tribo” Fixture

84 Material Deposition Presentation 84 PtC/PTFE on Carbon Paper

85 Material Deposition Presentation 85 Deposited Powder Characteristics PtC/PTFE powder layer has electrostatic adhesion/cohesion but is low The magnetic brush must be gapped from the carbon paper to enable multilayer powder deposition Q/M of powder blend depends on applied voltage but magnitude independent of polarity Since magnetic brush architectures prefer underside deposition on a receiver, a minimum vacuum can be provided for increasing the powder adhesion during the electrostatic deposition process

86 Material Deposition Presentation 86 PtC/PTFE Density vs Depositions with “Tribo” Fixture (Fixed field, Blend of 60% 15%PtC & 40% Teflon mixed with carrier) Require ~5 & ~10 mg/cm 2 for anode and cathode, respectively

87 Material Deposition Presentation 87 Q/M & Percent Powder Detachment

88 Material Deposition Presentation 88 Vacuum Assisted Magnetic Brush Deposition N S N S N S N S N S N S N S N S Carbon Paper Porous/Conducting Support Vacuum Plenum VAVA

89 Material Deposition Presentation 89 What This Means Ability to electrostatically deposit conductive &/or insulative powder blends Ability to deposit thin or thick layers of powder blend onto conductive substrate Control of layer thickness by electrostatic field strength (voltage and distance) and dwell time (process speed) Enables low cost continuous manufacturing process Dry deposition method can enable improved fuel cell performance by circumventing possible platinum catalyst contamination by current wet methods

90 5/4/2015Torrey Pines Research, Inc.90 Transport Belt with Electrostatic Grip Developer unit Carbon Paper Feed Powder Consolidation Radiant Heat Sintering Electrode Fabrication Process Sheet fed architecture shown, may also be configured as a web fed system Multiple Developer units can be used for multiple layers or multiple depositions

91 Material Deposition Presentation 91 Linear Plate Translator & Magnetic Brush

92 Material Deposition Presentation 92 Powder Blend Deposition on Carbon Paper 10 cm square carbon paper attached to holder with porous plate for vacuum assist Developer with 60% PtC (10% Pt) and 40% Teflon blend mixed with permanently magnetized ferrite carrier beads at concentration of 4% 500 g of mixture loaded in developer unit sump of 12 cm width Magnet assembly rotated at 50 rpm, and carbon paper translated at speed of 2mm/s Carbon paper biased at +2000 volts across 5mm gap Deposit 4.2 mg/cm 2 of powder blend after 2 passes Production system would use 2 rolls in a single pass

93 Material Deposition Presentation 93 Powder Blend Consolidation Particle-to-particle contact of Teflon required prior to heating Achieved by compacting the powder layer with pressure 10 cm square samples consolidated with pressure (200 psi) from hydraulic press Rubber sheet (3 mm thick) attached to one of the two pressure plates Release layer (paper) in contact with powder Roll pressure likely feasible for production environment

94 Material Deposition Presentation 94 Powder Blend Sintering Nitrogen purged oven at 355 o C used to sinter consolidated powder on carbon paper for 4 min. Alternative sintering methods are likely feasible for production environment  Resistive heating of carbon paper in inert atmosphere  Flash radiant heating

95 Material Deposition Presentation 95 Sintering via Flash Radiant Heating Carbon Paper Transport Belt PtC/PTFE N 2 ? Flash Lamp Cavity

96 Material Deposition Presentation 96 Results – Surface Morphology 25x 500x

97 Material Deposition Presentation 97 Results - Dispersion Uniformity SEM from Deposited Layer Platinum Carbon Fluorine

98 Material Deposition Presentation 98 Results - Functionality Deposited ~ 5 mg/cm 2 on 4”x4” carbon paper Consolidated and sintered layer Measured 75% of ‘normal’ platinum Assembled as electrode into fuel cell test module Exceeded ‘normal’ cell output at 200mA/cm 2 No degradation after 6 months of operation

99 Material Deposition Presentation 99 Any Questions???

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