Digital Material Deposition for Product Manufacturing Processes

Digital Material Deposition for Product Manufacturing Processes

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

What is Digital Material Deposition? n n 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: u u 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 Material Deposition Presentation 3

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

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

Potential Disadvantages of Digital Deposition Technology n n n 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 u u u Offset Blade coating Pad printing Material Deposition Presentation 6

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

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

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

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

Major Segmentation Map Direct Process Inkjet n Electrostatic n Liquid Indirect Process n Electrostatic u. Electrophotography u. Electrography n Electrostatic u. Electrophotography Dry u. Electrography n u. Electrophotography u. Electrography Thermal Transfer Magnetographic n Solid Inkjet n Material Deposition Presentation 11

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

Liquid Deposition & Micro-dispensing Material Deposition Presentation 13

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

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 p. H Volatility Fluid temperature constraints Fluid formulation modification latitude Particulate size Material Deposition Presentation 15

Inkjet Implementation: Head Issues n n All inkjet head types are possible candidates Head matched to the fluid and application: n n n n 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 Material Deposition Presentation 16

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

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

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

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

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

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

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

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

Example: Biotechnology – DNA Testing n n 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 (www. upside. com) n n ADVANTAGE Automated procedures Repeatable results

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

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

Case Study – Stent Coating n 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. Material Deposition Presentation 28

Case Study – Stent Coating Requirements n n n Drug eluting stent is coated with polymer that incorporates a drug that helps prevent plaque buildup 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 Material Deposition Presentation 29

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

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

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

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

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

Case Study – Stent Coating System Material Deposition Presentation 35

Dry Powder Deposition Material Deposition Presentation 36

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

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

Conventional Powder Coating Problems/Limitations u 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 u Masking difficult u Images with information impossible u Material Deposition Presentation 39

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

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

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

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

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

Conductivity is a Continuum Conductive Materials n n Semi-conductive Materials Insulative Materials 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 25 u However, insulating ability of fused quartz is 10 times that of copper Conductivity is characterized by a physical property - Resistivity Material Deposition Presentation 45

Resistivity of a ‘Conductive’ Material A conductive material for many electrostatic processes may have a resistivity of 7. 5(108) ohm-cm or less. 0 – 10 -8 Most Metals Resistivity Scale (ohm-cm) 108 Conductive Materials 1010 ? ? 1018 Fused Quartz Insulative Materials Material Deposition Presentation 46

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

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

Increasingly Positive Triboelectric Series Air Human Hands Asbestos Rabbit Fur Glass Mica Human Hair Nylon Wool Fur Lead Silk Aluminum Paper Increasingly Negative COTTON – The Dividing Point 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 Material Deposition Presentation 49

VOLUME (Number) Powder Charge Distribution -5 5 10 15 20 25 30 Charge - C/gm Wrong Sign Low Charge Target High Charge Material Deposition Presentation 50

Charging of Conductive Powders n Conductive Materials u 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 Material Deposition Presentation 51

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

What about the Substrate? n The substrate is the material upon which the powder is being deposited. u n It ultimately refers to the final working material for the given application. Examples might include: u Electronic materials « « u u n n 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 Material Deposition Presentation 53

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

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 Material Deposition Presentation 55

Summary n The challenges of Electrostatic Deposition of Dry Powder include: u u n n 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: u u Dry powder applications Speed Scalable to wide format No solvents Material Deposition Presentation 56

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

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

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

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

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

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

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

Pharmaceutical EDPD Housing Elements Licensed from Heidelberg Material Deposition Presentation 64

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

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

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

Coating Uniformity Issues Weak field Strong field Weak field n n n 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 Material Deposition Presentation 68

Field Collapse Process E = maximum 1 E 2 Time = 0 E E=0 3 4 Time = Completion Material Deposition Presentation 69

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

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

The Finished Product Material Deposition Presentation 72

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

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

Electrostatic Deposition Problems (Intermediate Dielectric Substrate) n n 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 Material Deposition Presentation 75

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

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

Magnetic Brush Unit Material Deposition Presentation 78

Magnetic Brush Structure Material Deposition Presentation 79

Magnetic Brush Forces Carbon Paper VA N Material Deposition Presentation 80

Non Contact Magnetic Brush Deposition Carbon Paper Electric field intensified for induction charging & detachment of Pt. C/PTFE blend VA N Material Deposition Presentation 81

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

“Tribo” Fixture Material Deposition Presentation 83

Pt. C/PTFE on Carbon Paper Material Deposition Presentation 84

Deposited Powder Characteristics n n Pt. C/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 Material Deposition Presentation 85

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

Q/M & Percent Powder Detachment Material Deposition Presentation 87

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

What This Means n n n 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 Material Deposition Presentation 89

Electrode Fabrication Process Transport Belt with Electrostatic Grip Powder Radiant Heat Consolidation Sintering Developer unit Carbon Paper Feed • 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 3/15/2018 Torrey Pines Research, Inc. 90

Linear Plate Translator & Magnetic Brush Material Deposition Presentation 91

Powder Blend Deposition on Carbon Paper n n n n 10 cm square carbon paper attached to holder with porous plate for vacuum assist Developer with 60% Pt. C (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 2 mm/s Carbon paper biased at +2000 volts across 5 mm gap Deposit 4. 2 mg/cm 2 of powder blend after 2 passes Production system would use 2 rolls in a single pass Material Deposition Presentation 92

Powder Blend Consolidation n n n 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 Material Deposition Presentation 93

Powder Blend Sintering n n 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 u u Resistive heating of carbon paper in inert atmosphere Flash radiant heating Material Deposition Presentation 94

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

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

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

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

Any Questions? ? ? Material Deposition Presentation 99