Axial Control Of Two-Photon Polymerization With Femtosecond Bessel Beam

Keywords

Additive manufacturing; Bessel beam; Spatial beam shaping; Stereolithography; Two-photon polymerization

Abstract

Stereolithography of three-dimensional, arbitrarily-shaped objects is achieved by successively curing photopolymer on multiple 2D planes and then stacking these 2D slices into 3D objects. Often as a bottleneck for speeding up the fabrication process, this layer-by-layer approach originates from the lack of axial control of photopolymerization. In this paper, we present a novel stereolithography technology with which two-photon polymerization can be dynamically controlled in the axial direction using Bessel beam generated from a spatial light modulator (SLM) and an axicon. First, we use unmodulated Bessel beam to fabricate micro-wires with an average diameter of 100 μm and a length exceeding 10 mm, resulting in an aspect ratio > 100:1. A study on the polymerization process shows that a fabrication speed of 2 mm/s can be achieved. Defect and deformation are observed, and the micro-wires consist of multiple narrow fibers which indicate the existence of the selfwriting effect. A test case is presented to demonstrate fast 3D printing of a hollow tube within one second. Next, we modulate the Bessel beam with an SLM and demonstrate the simultaneous generation of multiple focal spots along the laser propagation direction. These spots can be dynamically controlled by loading an image sequence on the SLM. The theoretical foundation of this technology is outlined, and computer simulation is conducted to verify the experimental results. The presented technology extends current stereolithography into the third dimension, and has the potential to significantly increase 3D printing speed.

Publication Date

1-1-2017

Publication Title

ASME 2017 12th International Manufacturing Science and Engineering Conference, MSEC 2017 collocated with the JSME/ASME 2017 6th International Conference on Materials and Processing

Volume

2

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.1115/MSEC2017-2788

Socpus ID

85027705722 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85027705722

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