Electrochemical Additive Manufacturing

Transcription

1 Electrochemical Additive Manufacturing Murali Sundaram Associate Professor of Mechanical Engineering Secondary Faculty, Materials Program Director, Micro and Nano Manufacturing Laboratory Department of Mechanical and Materials Engineering University of Cincinnati, Cincinnati, OH SmartManufacturingSeries.com

2 What is ECAM? Electrochemical Additive Manufacturing (ECAM) is the combination of localized electrodeposition and additive manufacturing principles to produce a novel additive manufacturing process with many advantages over conventional AM. Localized Electrochemical Deposition Additive Manufacturing 100 μm CAD File Manufactured Part 2 mm [U.S. Patent App. No. 15/235,460]

3 Localized Electrochemical Deposition Similar to electroplating A micro tool is used to create a localized deposit Aqueous metal is reduced to solid deposit Example: + + ( ) Publication Sundaram, M., A. B. Kamaraj, and V. S. Kumar. "Mask-less electrochemical additive manufacturing: a feasibility study." Journal of Manufacturing Science and Engineering (2015):

4 CAD-CAM Integration The entire system was designed and built in-house at UCMAN Lab

5 Process Control The current passing through the cell is monitored A short circuit indicates that the deposit has grown to the tool When this feedback is combined with 3-axis motion, deposition of 3D parts is achieved Tool Electrolyte Tank Substrate Supporting Plate Y Z X Applied Tool Voltage 3D Stepper Motor Stage Current Feedback 100 Ω Tool Tool (+) (+) Cathode ( )

6 Why ECAM? 3-D Printing (3DP) : Powder or liquid resin, deposited in layers. Cured with UV or heat. Fused Deposition Modeling (FDM) : Nozzle layers molten polymer onto a support structure. Stereolithography (SLA): Convert liquid plastic resin/composites into solids using light Selective Laser Sintering/Melting (SLS): Fuses powdered material using energy beam Electrochemical Additive Manufacturing (ECAM): Electrochemically deposits 3D metal shapes layer-by-layer or voxel-byvoxel at room temperature ECAM can make solid metal parts at room temperature ECAM can make parts from liquid, solid, or powder source. ECAM can make solid parts at macro, micro, or nano scales. ECAM can built in any direction! Feature/Process 3DP FDM SLA SLS ECAM Metal printing Support Structure Stress Post processing <1 Micron Resolution

7 Ongoing ECAM Studies Macro to Nano Scale Micro Repair Engineered porosity Size Scalability Multi Material Deposition ECAM Modeling and Simulation Multimaterial deposition ECAM No support Micro structures Repair Engineered High Porosity strength parts Low residual stress Residual Stress Strength and Hardness

8 Support Structureless Manufacturing Support structures in AM pose many cons: extra material cost time, labor, and risk of damage to the part Additionally, at the small scale, support stuctures may not even be feasible Therefore, we have established a method of determining the correct tool path for ECAM using an example voxelized part

9 Support Structureless Manufacturing Step 1:Detection of supported vs. unsupported voxels Scanning for unsupported voxels 2D projection of unsupported voxels and detection of separate bodies Detection of build orientation Scan Direction (Normal to Plane) Reference Plane

10 Support Structureless Manufacturing Step 2:The plane manufacturing order is sequenced according to the build direction Level Sublevel Build Order Build Direction p 1 p 2 p 3 p 4 p n Segment Planes In build direction

11 Support Structureless Manufacturing Step 3:The row manufacturing order is sequenced in alternating directions from row-to-row and plane-to-plane Level Sublevel Build Order Plane r 1 r 2 r 3 r n Rows r 1 r 2 r 3 r n r n r 3 r 2 r 1 Alternates by plane r 1 r 2 r 3 r n

12 Support Structureless Manufacturing Step 4:The voxels are sequenced in alternating order by row Level Sublevel Build Order Row Voxels Alternates by row

13 Support Structureless Manufacturing The allowable field of voxels for tool motion was found The transition path from one segment to another was made 1 to 2 2 to 3 3 to 4 4 to 5 P r (,, ) Retract from last point on current segment View Y Z X Y 3D,, Approach to first point on next segment X Z

14 Support Structureless Manufacturing Sequence of resulting tool paths from segment to segment Legend Built voxels Retract path Approach path Transition path Segment 1 to 2 Segment 2 to 3 Segment 3 to 4 Segment 4 to 5

15 Support Structureless Manufacturing Final Tool Path ECAM Conventional AM No support structures! Support structures Publication Brant, Anne, and Murali Sundaram. "A Novel Electrochemical Micro Additive Manufacturing Method of Overhanging Metal Parts without Reliance on Support Structures."Procedia Manufacturing (2016): Vol 5, pp DOI: /j.promfg

16 Engineered Porosity ECAM allows for controlled porosity of output parts Advantages include Increased surface area Lower weight Higher strength to weight ratio Applications include: Chemical Catalyst and reaction substrates Biomedical Cell adhesion; implants Energy Batteries and Solar cell Porous part Porous Electrodes for Micro Batteries [Pikul, J. H, 2013] Porous Implant for Hip Replacement [Hong, Cai, 2016] Pore

17 Engineered Porosity Two types of porosity, and their causes, in the ECAM process Macro porosity: irregularities in part Micro porosity: hydride and bubble generation during the electrochemical process Animation of porosity generation in pillar deposition : 2 2 ( ) 2 ( ) ( ) + 4 Dissolved Nickel Salt Bath, Ni 2+ Ni (Solid Nodules with Pores) Platinum Electrode (+) Oxygen Bubbles Brass Plate ( ) Cathode: + + ( )

18 Engineered Porosity SEM images were used to quantify volume and porosity for calculations Volume Porosity

19 Engineered Porosity Porosity was estimated using the following equation: VP Porosity( P) 100 V V S P P = Porosity percentage V P = Volume of Pores calculated as the difference between the total part volume estimated from CAD model of the part and the V S V S = Volume of Solid calculated from the mass of the part and density of nickel

20 Engineered Porosity Findings: Porosity between 20% 75% achieved Voltage and duty cycle are the primary input parameters that influence porosity Effect of voltage and duty cycle on porosity Pore size distribution Part Integrity (regular vs. irregular) Surface Texture (rough vs. smooth) Publication:A. B. Kamaraj, H. Shrestha, E.Speck and Sundaram, M. (2017). Experimental study on the porosity of electrochemical nickel deposits. ProcediaManufacturing ProcediaManufacturing 10C pp DOI: / j.promfg

21 Strength and Hardness The electrochemical deposition procedure was modified to incorporate a copper powder with nickel binder Binding strength of the sample influences the yield strength of the electrochemically bound part. A CSM Nanoindentation tester (NHT) was used to carry out the tests. The tester gave a hardness value in the form of a Vickers Hardness number (HV). The HV number was correlated to get approximated yield strength values At Tool M (s) M + (aq) +e ELECTROLYTE At Layer in progress M + (aq) +e M Binder Material Completed Layers Horizontal Feed INSULATION A A A METAL SUBSTRATE ( ) TOOL ELECTRODE (M) (+) M + M + M + M + M + M+ M M M M M M M M Vertica Feed Inter Electrode Gap A METAL POWDER CSM Nanoindentation tester

22 Strength and Hardness The interelectrode gap, voltage, duty cycle, and on-time were varied Hardness value range: kg/mm 2 Yield strength range: MPa Comparison of Vickers hardness values Comparison of yield strength values Publication: Kumar, V.S., and Sundaram, M.M (2016). A mathematical model for the estimation of hardness of electrochemical deposits. Journal of Process Mechanical Engineering. DOI: / Kumar, V.S. and M.M. Sundaram, Experimental study of binding copper powders by electrochemical deposition.proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, (8): p

23 Residual Stress A full-factorial experiment of the influence of input process parameters on the output residual stress of the part was conducted. Applied Voltage 3 V 4 V 5 V Pulse Period 100 ns 200 ns ECAM Process Duty Cycle 50% 75% Termination Criteria Constant time Constant height Residual Stress

24 Residual Stress The residual stress of ECAM fell in the kpa range This contrasts to conventional AM methods, which have a residual stress in the Mpa range Publication: Brant, A., Kamaraj, A., and Sundaram, M.(2014). Experimental Study of Residual Stresses Induced in Nickel Micro Structures Made by Electrochemical Deposition. ASME International Manufacturing Science and Engineering Conference, MSEC2014.

25 Micro Repair Liquid marble method: Encasing electrolyte in a liquid marble using copper powder Pick-and-place technique Can be used for localized repair, difficult-to-reach areas, and areas where immersing the part in an electrolyte tank is not feasible or economical Cu Powder LIQUID MARBLE Target Substrate + Platinum Anode Micro deposit

26 Micro Repair Results of experimental and mathematical modeling work Publications Shailendar, Shiv, and Murali M. Sundaram. "A Feasibility Study of Localized Electrochemical Deposition Using Liquid Marbles." Materials and Manufacturing Processes 31.1 (2016): Shailendar, Shiv, and Murali Sundaram. "Modeling of Deposition Height in Localized Electrochemical Deposition Using Liquid Marbles." Procedia Manufacturing 5 (2016):

27 Modeling and Simulation To understand the mechanisms involved in the deposition and to study the effect of process parameters on deposition rate and part quality mathematical modeling and finite element simulations of the process was performed. Finite Element Simulation Mathematical Model Surface concentration plot at 5V and 100 µm gap for a 100 µm tool width µm Tool IEG for 250 µm tool = 15 µm Limiting Current Potential = 2 V Rate of deposition = 1 5 µm/s Current Dens ity (A/cm 2 ) Output Current Density vs. Input Potential 1540 mol/cm mol/cm mol/cm mol/cm Applied Electric Potential (V) Output Concentration vs. Distance from Substrate Concentration (m ol/cm 3 ) x Distance from substrate (cm) Substrate µm Ion Depletion Region Publication Kamaraj, Abishek, Spenser Lewis, and Murali Sundaram. "Numerical study of localized electrochemical deposition for micro electrochemical additive manufacturing." Procedia CIRP 42 (2016): DOI: /j.procir

28 What is next? Ongoing work involves involves deposition at the macro scale and nano scale The nano scale poses many new challenges compared to the micro scale Simulation of ECAM Process Legend Anode Nucleus Cathode Nucleus Electron Newly-added Electron Aqueous Cation Nano-Scale Deposition may not occur at intended spot due to atomic-scale processes Our ECAM research has been featured in the latest issue of MForesight's "Manufacturing Ideas to Watch" ( Publication Brant, Anne M., and Murali Sundaram. "A fundamental study of nano electrodeposition using a combined molecular dynamics and quantum mechanical electron force field approach."procedia Manufacturing 10 (2017):

29 Acknowledgments Financial support provided by the National Science Foundation (NSF) under grant numbers CMMI and CMMI is acknowledged. Thank You! For Enquiries, Questions and Comments: