Northwestern University Robert R. McCormick School of Engineering and Applied Science

Advanced Manufacturing Processes Laboratory

EPµAM / Micro Self Assembly


Current product and component miniaturization trends in many high-added-value industries (e.g. aerospace, biomedical, electronic) have shown and demonstrated the need for versatile and multi-material production techniques where manipulation of micron-sized objects during the assembly phase is a common occurrence. Our goal is to develop a micro-additive manufacturing (μAM) process with multi-material processability in such a way that the machine can double-down as a manipulator for micron-sized objects.



Electrophoretically-guided Micro Additive Manufacturing (EPμAM) is a μAM process currently under development at the AMPL. In EPμAM, modulated electric fields exert forces on particles and micron-sized objects and govern where they are to be deposited or placed. Underlying principles for this contact-less manipulation method are electrophoresis and dielectrophoresis. Electrophoresis is a phenomenon where electric fields exert forces on charged particles and cause them to move. Electrophoresis is the backbone of the electrophoretic deposition process, an industry scale coating process. Dielectrophoresis is another phenomenon where non uniform (spatial or temporal) electric fields exert forces on a dielectric particle via induced dipole moments. Dielectrophoretic forces do not require particles to be charged and they are predominantly used in biomedical and microfluidic systems for sorting, manipulation and characterization of biological and nonbiological specimens. The electric fields necessary for electrophoretic and dielectrophoretic manipulation are applied via 2D array of micro-electrodes.


Current development of EPμAM includes:

    1. Numerical and theoretical modeling of the governing physics,

    2. Design and fabrication of the process test bed,

    3. Preliminary characterization of particle mobilities under applied electric fields, and

    4. Demonstration of a localized deposition of particles.

Preliminary work includes multiphysics modeling of the EPμAM process, theoretical derivation of the process control algorithm and characterization of particle group mobilities under applied electric waveforms.


NSF CMMI award No. 1463411.