SmartManufacturingSeries.com
Electrochemical Additive Manufacturing
Murali SundaramAssociate Professor of Mechanical Engineering
Secondary Faculty, Materials ProgramDirector, Micro and Nano Manufacturing LaboratoryDepartment of Mechanical and Materials Engineering
University of Cincinnati, Cincinnati, OH
Localized Electrochemical DepositionAdditive Manufacturing
CAD File Manufactured Part
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.
[U.S. Patent App. No. 15/235,460]
100 μm
2 mm
Localized Electrochemical Deposition• Similar to electroplating• A micro tool is used to create a
localized deposit• Aqueous metal is reduced to
solid deposit • Example:
++ −→ ( )
PublicationSundaram, M., A. B. Kamaraj, and V. S. Kumar. "Mask-less electrochemical additive manufacturing: a feasibility study." Journal of Manufacturing Science and Engineering 137.2 (2015): 021006.
CAD-CAM Integration• The entire system was designed and built in-house at UCMAN Lab
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
Cathode (‐)
(+)
Tool
Z
XY
Supporting Plate
3D Stepper Motor Stage
Substrate
Applied Tool Voltage
Current Feedback
Tool
Electrolyte Tank
100 Ω
• 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-by-voxel at room temperature
Feature/Process 3DP FDM SLA SLS ECAM
Metal printing Support Structure Stress Post processing <1 Micron Resolution
Feature/Process 3DP FDM SLA SLS
Metal printing Support Structure Stress Post processing <1 Micron Resolution
Why ECAM? ECAM can make parts from
liquid, solid, or powder source. ECAM can make solid parts at
macro, micro, or nano scales.
ECAM can make solid metal parts at room temperature
ECAM can built in any direction!
Ongoing ECAM Studies
Size Scalability
Micro Repair
Engineered Porosity
Strength and
Hardness
Residual Stress
Multi Material
DepositionECAM
Modeling and
Simulation
ECAM
Engineered porosity
High strength
parts
Low residual stress
No support structures
Multi‐material deposition
Micro Repair
Macro to Nano Scale
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
1
24 3
5
Support Structureless ManufacturingStep 1:Detection of supported vs. unsupported voxels
Reference Plane
Scan Direction (Normal to Plane)
Scanning for unsupported voxels
2D projection of unsupported voxels and detection of separate bodies
Detection of build orientation
Support Structureless ManufacturingStep 2:The plane manufacturing order is sequenced according to the build direction
Segment
Build Direction
Level Build Order
In build directionPlanes
p1 …
Sublevel
p2 p3 p4 pn
Support Structureless ManufacturingStep 3:The row manufacturing order is sequenced in alternating directions from row-to-row and plane-to-plane
Rows
Sublevel
…r3
rn
r2r1
Level
Plane
Build Order
Alternates by plane
…r3
rn
r2r1
r2r3
r1
…rn
…r3
rn
r2r1
Support Structureless ManufacturingStep 4:The voxels are sequenced in alternating order by row
Level
Row Voxels
Sublevel Build Order
Alternates by row
Support Structureless Manufacturing• The allowable field of voxels for tool motion was found• The transition path from one segment to another was
madePr ( , , )
, ,
Retract from last point on current
segment
Approach to first point on next segment
1 to 2 2 to 3 3 to 4 4 to 5
3DX‐Y
Y‐Z
X‐Z
View
Support Structureless Manufacturing• Sequence of resulting tool
paths from segment to segment
Segment 1 to 2 Segment 2 to 3 Segment 3 to 4 Segment 4 to 5
Retract pathApproach path
Legend
Built voxels
Transition path
Final Tool Path
Support Structureless Manufacturing
PublicationBrant, 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 928-943. DOI: 10.1016/j.promfg.2016.08.081
ECAM
No support structures!
Conventional AM
Support structures
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
Pore
Porous Implant for Hip
Replacement [Hong, Cai, 2016]
[Pikul, J. H, 2013]
Porous Electrodes for Micro‐Batteries
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
Platinum Electrode (+)
Brass Plate (‐)
Ni (Solid Nodules with Pores)
: 2 2 ( ) 2( ) + 4 +( ) + 4 −
Cathode: ++ −→ ( )
Oxygen Bubbles
Dissolved Nickel Salt Bath, Ni2+
Animation of porosity generation in pillar deposition
Engineered Porosity• SEM images were used to quantify volume and porosity for calculations
Porosity
Volume
Engineered Porosity
• P = Porosity percentage• VP = Volume of Pores
• calculated as the difference between the total part volume estimated from CAD model of the part and the VS
• VS = Volume of Solid• calculated from the mass of the part
and density of nickel
100)(
PS
P
VVVPPorosity
• Porosity was estimated using the following equation:
Engineered Porosity• Findings:
• Porosity between 20% – 75% achieved• Voltage and duty cycle are the primary input
parameters that influence porosity
Pore size distributionEffect of voltage and
duty cycle on porosity
Part Integrity (regular vs. irregular)
Surface Texture (rough vs. smooth)
Publication:A. B. Kamaraj, H. Shrestha, E.Speckand Sundaram, M. (2017). “Experimental study on the porosity of electrochemical nickel deposits.” ProcediaManufacturing ProcediaManufacturing 10C pp.478-485 DOI: 10.1016/ j.promfg.2017.07.032.
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
M+
A‐A‐
TOOL ELECTRODE (M) (+)
METAL SUBSTRATE (‐)
At Tool M (s) →M+ (aq) +e‐
Horizontal Feed
VerticaFeed
ELECTROLYTE
INSULATION
M+
M+ M+
M+M+
A ‐
A ‐
Inter‐Electrode Gap
M M M M M M M M
At Layer‐in‐progress M+ (aq) +e ‐→ M↓
Completed Layers
METAL POWDER
Binder Material
CSM Nanoindentation tester
Strength and Hardness• The interelectrode gap, voltage, duty cycle,
and on-time were varied• Hardness value range: 10-100 kg/mm2
• Yield strength range: 50 – 350 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: 10.1177/0954408916671973
• Kumar, V.S. and M.M. Sundaram, Experimental study of b inding copper powders by electrochemical deposition. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 2015. 231(8): p. 1309-1318.
Residual Stress
ECAM Process
Applied Voltage
Pulse Period Duty Cycle
Termination Criteria
3 V
4 V
5 V
100 ns
200 ns
50%
75%
Constant time
Constant height
Residual Stress
• A full-factorial experiment of the influence of input process parameters on the output residual stress of the part was conducted.
Residual Stress• The residual
stress of ECAM fell in the kParange
• This contrasts to conventional AM methods, which have a residual stress in the Mparange
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.
Micro Repair
‐
+
Target Substrate
Platinum Anode
LIQUID MARBLE
Micro deposit
Cu Powder
• 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
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): 81-86.
• Shailendar, Shiv, and Murali Sundaram. "Modeling of Deposition Height in Localized Electrochemical Deposition Using Liquid Marbles." Procedia Manufacturing 5 (2016): 132-143.
Modeling and SimulationTo 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.
0 1 2 3 4 5 60
10
20
30
40
50
60
Applied E lec tric Potential (V)
Cur
rent
Den
sity
(A/c
m2 )
1540 mol/cm3
1000 mol/cm3
2000 mol/cm3
2500 mol/cm3
0 0.005 0.01 0.015 0.020
0.5
1
1.5
2x 10-3
Distance from subs trate ( cm)
Con
cent
ratio
n (m
ol/c
m3 )
Mathematical Model
Output Current Density vs. Input Potential
Output Concentration vs. Distance from Substrate
Finite Element Simulation
Substrate
Toolµm
µm
Surface concentration plot at 5V and 100 µm gap for a 100 µm tool width
Ion Depletion Region
IEG for 250 µm tool = 15 µmLimiting Current Potential = 2 VRate of deposition = 1 – 5 µm/s
PublicationKamaraj, Abishek, Spenser Lewis, and Murali Sundaram. "Numerical study of localized electrochemical deposition for micro electrochemical additive manufacturing." Procedia CIRP 42 (2016): 788-792.DOI:10.1016/j.procir.2016.02.320
Nano-ScaleDeposition may not occur at intended spot due to atomic-scale processes
Simulation of ECAM ProcessLegendAnode NucleusCathode NucleusElectronNewly-added ElectronAqueous Cation
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
PublicationBrant, 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): 253-264.
Our ECAM research has been featured in the latest issue of MForesight's "Manufacturing Ideas to Watch" ( http://mforesight.org/2017/07/31/manufacturing-ideas-to-
watch-issue-3-july-2017/).
AcknowledgmentsFinancial support provided by the National Science
Foundation (NSF) under grant numbers CMMI –1400800 and CMMI – 1454181 is acknowledged.
Thank You!For Enquiries, Questions and Comments:
[email protected] 513-556-2791