Industrial Workshop Programme Hi-Micro_High precision... · 2015. 10. 8. · 30 September 2015, Leuven, Belgium Industrial Workshop Programme 13:30 Welcome Dominiek Reynaerts (KULeuven)

1Revolutionary Technologies in Micro Injection Moulding

30 September 2015, Leuven, Belgium

Industrial Workshop Programme

13:30 WelcomeDominiek Reynaerts

(KULeuven)

13:35 - 13:45Introduction by EC project officer of the European project Hi-Micro

Erastos Filos

(European Commission)

13:45 - 14:00 Introduction Hi Micro and Change2Micro

Jun Qian

(KULeuven) |

Hilde Krikor

(SIRRIS)

14:00 - 14:30High precision technologies for micro manufacturing

Jun Qian (KULeuven) |

Henning Zeidler (TUChemnitz)

14:30 - 15:00 Change2microHilde Krikor

(SIRRIS)

15:00 - 15:30Micro-machining, moulding and printing solutions for polymers at SIRRIS SMALL-Lab

Denis Vandormael | Laurent Seronveaux (SIRRIS)

15:30 - 15:45 Break

15:45 - 16:15 Simulation of precision micro injection mouldingGuido Tosello

(DTU)

16:15 - 16:45Enabling AM & CT technologies for micro injection moulding

Wouter Vanderauwera

(3DS- Layerwise) |

Andrew Ramsey

(NIKON)

16:45 - 17:15Micro injection moulding with integrated in-process quality control

Björn Dormann

(DESMA)

17.15 – 19:00 Closing remarks and networking reception (visit to KULeuven facilities)

© EU-FP7 HI-MICRO

Revolutionary Technologies in Micro Injection Moulding


High precision technologies for

micro manufacturing

Jun Qian, KU Leuven

Henning Zeidler (TUChemnitz)

© EU-FP7 HI-MICRO



KULeuven

Micro-EDM and wire-EDM



3D MICRO-EDM MILLING

4

3D Micro-EDM machine with access to certain parameters

Layer by layer 3D milling



CHALLENGES IN MICRO-EDM MILLING

• Non-linear process (material

removal vs sparking energy)

• Unstable process (stochastic

process)

• Low material removal rate

• Tool wear compensation

– Tool wear measurement/prediction

– Tool wear compensation &

implementation



LINEAR TOOL WEAR COMPENSATION

WorkpieceTool

Without wear compensation With wear compensationIn-process variable tan δ

PULSE MONITORING/COUNTING BASED

LINEAR WEAR COMPENSATION

Pulse no. = 1208

𝑾𝒆 = 𝟎

𝒕𝒆

𝒖𝒆 𝒕 ∙ 𝒊𝒆(𝒕) ∙ 𝒅𝒕Spark energy:

Pulse monitoring

Processed current waveforms



MICRO INJECTION MOLDING OF 3D PARTS

Wire-EDM on Cut 300mS



MICRO-EDM MILLING

Position measured value drawing value difference

b1-x -0.002 0 0.002

b1-y 0.002 0 -0.002

radi B1 0.437 0.39 -0.047

b2-x -2.214 -2.17 0.044

b2-y 2.981 2.98 -0.001

Radi B2 1.382 1.37 -0.012

b3-x -3.396 -3.32 0.076

b3-y 7.231 7.32 0.089

Radi B3 0.166 0.13 -0.036

b4-x -6.938 -6.86 0.078

b4-y 8.175 8.26 0.085

Radi B4 0.981 0.97 -0.011

C5-x -6.987 -6.91 0.077

C5-y 7.532 7.61 0.078

Radius +/- 22 micron(10 micron required)

© EU-FP7 HI-MICRO



TUChemnitz

PECM, Jet-ECM, Multiphysics Simulation



Principle of anodic metal dissolution:

Electrical voltage source: Workpiece = Anode (+), Tool = Cathode (-)

Current transport through an electrically conductive fluid (electrolyte)

Anode: donation of electrons generation of metallic ions pass into the electrolyte

removal of material

Electrolyte: precipitation reactions, enable a filtration of removal products

Cathode: no removal

Possibility of oxidation at the anode and

reduction at the cathode

Application areas:

Automotive- and aviation engine design

Tool making

Micro machining

ELECTROCHEMICAL MACHINING WITH EXTERNAL

VOLTAGE SOURCE

Scheme of anodic metal dissolution

Hydrous electrolyte

e.g.: NaNO3 - Dissolution

Kathodic

reduction

Anodic metal

dissolution

2H2O + 2e-

H2↑ + 2OH-

NO3 + H2O + 2e-

NO2- + 2OH-

Following reactions, e.g.:

Men+ + nOH- → Me(OH)n ↓

Me → Men+ + n e-

Anode Cathode



Process: No mechanical contact between tool and workpiece No process inherent tool wear Low processing temperature No burring Process parallelisation only limited by current supply, not by

removal mechanism

Shape: Difficult to access geometries (undercuts) Complex shapes in hollow, geared or slotted profile parts Thin-walled, fragile and complex workpieces

Material Super alloys and powder metallurgic steels No change of microstructure in the workpiece

potential technique for machining of complex parts,

using additive manufactured alloys

ADVANTAGES OF ELECTROCHEMICAL MACHINING

Selective Jet-ECM removal

PECM removal



Principle:

Localisation of electrical current density in

a closed electrolytic free jet

Shaping by movement of the nozzle and control ofelectric current

Characteristics:

Electrical current density up to 2000 A/cm² (DC)

Feed up to 150 mm/min

Very good electrolyte flushing (vJet > 70 km/h)

High geometric flexibility

Variants: Milling, cutting, drilling, turning

Applications:

Microfluidics, Miniaturisation of parts

Creating microstructured surfaces

Cutting of foils (also material selective)

JET-ECM –

ELECTROCHEMICAL MACHINING WITH ELECTROLYTE JET

Schematic setup

Jet-ECM ablation progress

electrolyte supply

nozzle

working gap

workpiece

closed

free jet

_

+



Video of Jet-EC cutting metal-plastic laminates

for photovoltaic applications

Selective removal of an Aluminium coating from a Polyester-substrate,Trench width: 1 mmDepth: 50 µmNozzle speed: 500 µm/s

Jet-EC drilling of selective laser

melted 18Ni-300 and AlSi10Mg

Bore-Ø: (170…300) µmDepth: (5…130) µm depending on material and machining time

JET-ECM EXAMPLES



SEM-Image of a micro mixer in stainless steel 1.4541 (channel width: 200 µm, depth: 60 µm)

Measurement results of Jet-EC milled micro structures for measurement calibration

Video of Jet-EC milling

Jet-EC milling of a micro reactor in stainless steel nozzle diameter: 100 µmvf = 30 mm/min

JET-ECM EXAMPLES



Stainless steel 1.4301

SEM-images of machined areas

Video of Jet-EC turning

Jet-EC turning, Machining sequence: 4, 5, 6

JET-ECM EXAMPLES



Average grain size: g = 1 µm

Voltage: U = 20 V

Nozzle speed:

1. cycle: v1 = 200 µm/s

2. cycle: v2 = 1000 µm/s

Machining is possible when using

combined electrolytes

SEM-image of Jet-EC milled trenches

Video of Jet-EC milling of WC-Co6 cemented carbide

JET-ECM EXAMPLES

v=

10

00

µm

/s

v=

20

0 µ

m/s



Principle:

Anodic metal dissolution using pulsed current

Localisation of removal area by minimising working

gap

Often combination with oscillating working gap

Advantages:

Roughing/Finishing in one machining

step possible

High reproduction accuracy

Surface quality up to Ra = 0,03 μm

Applications:

Tool- and mould making, dies,

punches etc.

Microsystem technology

PECM – PULSED ELECTROCHEMICAL MACHINING

Principle of Precise Electrochemical Machining

s ,I

t

s(t)

I II III

Ca

tho

de

Ca

tho

de

Ele

crto

lyte

Ele

crto

lyte

Ele

ctro

lyte

Anode

Ca

tho

de

Ca

tho

de

Ele

ctro

lyte

Anode

I(t) I(t)∆s

∆z

IV

t1 t2 t3 t4

PEM-Center 8000, PEMTec



Electrolyte processing:

Conductivity

Temperature

pH-Values

Kinematics:

Feed motion

Oscillation

Control:

Control software and hardware

Operation

Generator:

Process current

Process voltage

PECM – MACHINE TOOL SETUP

Schematic View of a PECM machine tool

Degassing of oxygen and

hydrogenPulsed current

Electrolyte

Sensor system and control



Machining of micro-structures

PECM – EXAMPLES

SEM image of the micro-milled cathode

SEM image of PECM machining result:

cavity for injection molding, feed rate: 35 µm/min

tool holder

flushing chamber

work piece

work piece holder

Photograph of the PECM tool setup



PECM – EXAMPLES

Blank (left) and PECMed forming tool (right), feed speed 0.2 mm/min, HSS, Ra 0.18 µm

Machining of micro-structures with high aspect

ratio

Structure for brain imlants;4000 spikes per cm²,height: 500 µm, Ø 70 µm,machining time: 20 min

Cavity in stainless steel1.4301,depth 1.8 mm, width 0.2 mm, aspect ratio: 9

Surface roughness detection on forming tool

http://www.electrochemicalmachining.com/wp-content/uploads/micropinstructure.jpg

http://www.electrochemicalmachining.com/wp-content/uploads/micropinstructure.jpg



Multitude of physical parameters:

Experimental parameters

Data acquisition

Implementation

Coupling

Approaches:

Sequential simulation of parameters

Definition of target values, examination of

relevance of parameters

Reduction to simulation of relevant

parameters

PROCESS DESIGN BY MULTIPHYSICS SIMULATIONS

Influence and of physical parameters Einflussgrößen on FEM-simulation of electrochemical prozesses



FEM-Simulation of PECM

Simulation of the removal process

Feed speed 30µm/min

Sequiential simulation of the removal

and the feed of the cathode

Increasing precision and decreasing

roundings by using an undercut and

by a side insulated on the cathode

PROCESS DESIGN BY MULTIPHYSICS SIMULATIONS

Geometrical model for Jet-ECM simulation withdynamic electrolyte jet

FEM-simulation of the PECM removal

FEM-simulation of the PECM removal with insulatedelectrode (left) and with undercut electrode (right)



Challenges in the beginning of the Hi-Micro project:

Unknown process parameters for electrochemical machining of additive manufactured materials

Missing knowledge about removal behaviour of AMed steel 18Ni-300 and aluminium AlSi10Mg

No knowledge about electrode design for PECM fabrication of micro injection moulds

CHALLENGES

Jet-ECM machinability studyon SLMed 18Ni-300

Jet-ECM machinability studyon SLMed AlSi10Mg



Outcome of the Hi-Micro project in terms of ECM:

Machinability studies for the determination of process parameters for PECM and Jet-ECM of additive

manufactured materials were carried out

Electrochemical removal of additive manufactured and molten metallurgical steel were analysed and compared to each other paths of the SLM process are revealed

Several experiments and FEM-simulations of PECM for manufacturing of IM cavities were performed increasing accuracy due to undercut and insulated cathode was analysed

Novel tool setup for PECM of injection molding cavities was designed and realised

OUTCOME



THANK YOU!



Documents

Industrial Workshop Programme Hi-Micro_High precision... · 2015. 10. 8. · 30 September 2015, Leuven, Belgium Industrial Workshop Programme 13:30 Welcome Dominiek Reynaerts (KULeuven)