Yuanrui Li † , , Huachao Mao § , Pan Hu ‡ , Haneol Lim ‡ , Jongseung Yoon ‡ , Yong Chen § , Wei Wu † † Ming Hsieh Department of Electrical Engineering, University of Southern California § Daniel J. Epstein Department of Industrial and Systems Engineering, University of Southern California ‡ Mork Family Department of Chemical Engineering and Material Science , University of Southern California Variable Voxel and Shaped Beam 3D Printing Introduction CONTACT US Email: [email protected] Group Website: http://www.usc.edu/de pt/ee/wugroup/ Stereolithography • Common 3D printing resolution is about 0.1mm • Far from optical limit L V=L 3 Voxel L→ 0.1L V→ 0.001V A trade off between resolution and speed Increasing resolution 10 times will increase time consumption 10 3 times! Concept Experiment One Layer Input 3D CAD model Multi-resolution slicing Scanning paths for different resolutions: High lateral resolution and fast speed High Resolution Low Resolution Low Resolution (Red) High Resolution (blue) λ 1 λ 2 Same Filter • Switching wavelength is faster and easier • Filter selectively reflects certain wavelength • Different wavelength → Different beam shape Sub-wavelength Resonance Grating • Physics: Resonance, Re-radiation, Interference • Advantage: Optically thin. Several layers can be stacked to give multiple aperture shapes Beam Size Selection Shaped Beam Pillar Arrays Porous Woodpile Structure 200 nm We invented the technology to realize stereolithography with variable voxel sizes and shapes at higher reliability and much lower cost. The variable voxel sizes and shapes (laser beam spot sizes and shapes) are realized by simply switching the wavelength of the light source. The key component to enable this technology is an optical filter. For one wavelength, the filter is almost transparent which gives a larger spot size, while for other wavelengths, the filter works as an aperture and only part of the area is transparent, which gives a much smaller or complex shaped beam spot. The optical filter we are using is based on sub- wavelength resonance grating which is one of the best options. SEM Image of Grating Structure Setup Schematics The Need for Variable Voxel In this example, a 5 by 5 beam array is 25 times faster than a single beam.

Variable Voxel and Shaped Beam 3D Printingminghsiehece.usc.edu/wp-content/uploads/2017/08/PM-Yuanrui-Li.pdf · aperture shapes Beam Size Selection Shaped Beam Pillar Arrays Porous

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Page 1: Variable Voxel and Shaped Beam 3D Printingminghsiehece.usc.edu/wp-content/uploads/2017/08/PM-Yuanrui-Li.pdf · aperture shapes Beam Size Selection Shaped Beam Pillar Arrays Porous

Yuanrui Li†, , Huachao Mao§, Pan Hu‡, Haneol Lim‡, Jongseung Yoon‡, Yong Chen§, Wei Wu†

† Ming Hsieh Department of Electrical Engineering, University of Southern California§ Daniel J. Epstein Department of Industrial and Systems Engineering, University of Southern California

‡ Mork Family Department of Chemical Engineering and Material Science , University of Southern California

Variable Voxel and Shaped Beam 3D Printing

Introduction

Email: [email protected] Website: http://www.usc.edu/dept/ee/wugroup/

Stereolithography

• Common 3D printing resolution is about 0.1mm

• Far from optical limit

V=L3Voxel L→ 0.1L

V→ 0.001V

A trade off between resolution and speed

Increasing resolution 10 times will increase time consumption 103

times!

Concept Experiment

One Layer

Input 3D CAD model

Multi-resolution slicing

Scanning paths for different resolutions:High lateral resolution and fast speed

High Resolution

Low Resolution

Low Resolution (Red)High Resolution (blue)

λ1λ2

SameFilter

• Switching wavelength is faster andeasier

• Filter selectively reflects certainwavelength

• Different wavelength → Differentbeam shape

Sub-wavelength Resonance Grating

• Physics: Resonance, Re-radiation, Interference

• Advantage: Optically thin. Severallayers can be stacked to give multipleaperture shapes

Beam Size Selection Shaped Beam

Pillar Arrays

Porous Woodpile Structure

200 nm

We invented the technology to realize stereolithography with variable voxel sizes and shapes at higher reliability and much lower cost. The variable voxel sizes and shapes (laser beam spot sizes and shapes) are realized by simply switching the wavelength of the light source. The key component to enable this technology is an optical filter. For one wavelength, the filter is almost transparent which gives a larger spot size, while for other wavelengths, the filter works as an aperture and only part of the area is transparent, which gives a much smaller or complex shaped beam spot. The optical filter we are using is based on sub-wavelength resonance grating which is one of the best options.

SEM Image of Grating Structure

Setup Schematics

The Need for Variable Voxel

In this example, a 5 by 5 beam array is 25 times faster than a single beam.