Air-Diffusion-Channel Constrained Surface Based Stereolithography for Three-Dimensional Printing of Objects With Wide Solid Cross Sections

He, Haiyang; Pan, Yayue; Feinerman, Alan; Xu, Jie

doi:10.1115/1.4039440

Cited by 14 publications

(4 citation statements)

References 36 publications

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“…1. Compared to free surface process, the constrained surface process has several advantages including less material waste, higher resolution, and faster speed, and is being used increasingly recently [2][3][4][5][6][7][8][9]. Despite the advantages, the separation of a newly cured layer from the constrained surface is a historical technical barrier and still greatly limits the printable size, process reliability, and print speed [10].…”

Section: Introductionmentioning

confidence: 99%

Effect of Constrained Surface Texturing on Separation Force in Projection Stereolithography

et al. 2018

Journal of Manufacturing Science and Engineering

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In projection stereolithography (SL) processes, the separation of a newly cured layer from the constrained surface is a historical technical barrier and still greatly limits its printable size, process reliability, and print speed. This paper presents an approach to reduce the separation force in projection SL processes by texturing the constrained surface with radial microgroove patterns. Separation forces with conventional smooth constrained surface and textured surface are both modeled. The analytical model suggests that a proper design of micropatterns of the constrained surface is capable of reducing separation forces greatly. Furthermore, a projection SL testbed with online separation force monitoring unit is developed for experimental study. Experimental results verified the effectiveness of microsurface textures in reducing separation forces. Test cases also show that with the help of the proposed textured constrained surface, parts with wide solid cross sections that could not be printed using conventional methods were manufactured successfully. The influence of the textured constrained surface on the printed parts' surface roughness is studied, a gray scale projection approach is proposed to eliminate the influence and improve the surface quality of printed parts. Hence, the presented methods can help to improve the manufacturing capability of Projection SL processes.

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Section: Introductionmentioning

confidence: 99%

Effect of Constrained Surface Texturing on Separation Force in Projection Stereolithography

et al. 2018

Journal of Manufacturing Science and Engineering

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“…Full understanding of the separation process is a prerequisite for optimizing the separation process. Experimental methods (Zhou et al, 2013;Huang and Jiang, 2005;He et al, 2018;YU-SHENG LIN, 2019) have been used to investigate the separation force. The force sensors record the separation force during separation for comparing different parameters such as exposure shape, area and separation speed (Zhou et al, 2013;Venketeswaran, 2019).…”

Section: Introductionmentioning

confidence: 99%

Tilting separation simulation and theory verification of mask projection stereolithography process

Zhang

et al. 2021

RPJ

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Purpose This study aims to accurately simulate the tilting separation process of mask projection stereolithography (MPSL) and verify the tilting theory. Design/methodology/approach The finite element separation models of MPSL 3D printing process were established. The established models simulated both tilting and pulling-up separation process by changing the constraints and boundary conditions. The bilinear cohesive curves were used to define the separation interface. The stress distribution of the cured part and FEP film at different times during the whole separation process was extracted. Different orientations of pulling-up and tilting were also compared for stress distribution. The stress change was analyzed for the center and edge points of the upper surface of cured part. Findings The results showed that the stress increased with the separation speed, and the stress at the edge position of exposure area was greater than the internal position. The tilting traction stress distribution was affected by the exposure area function and the velocity distribution. Alternation of the exposure area function changed the cohesive stiffness. The non-coincidence of the calculated traction stress with the input bilinear cohesive curve reflected the influence of the material properties and the separation methods. The high-speed side of tilting had fast separation and high traction stress. Originality/value This study proposes a technical method for simulation tilting separation and verified the tilting theory. The cohesive zone model was proved applicable to the tilting traction stress calculation.

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“…Researchers have also investigated patterned surface designs by creating microscale patterns on the vat for air diffusion in the layer-by-layer SL process. 31 The printed structure might suffer from undesired textures caused by the microscale patterns and off-centered light reflection.…”

Section: Introductionmentioning

confidence: 99%

Constrained Window Design in Projection Stereolithography for Continuous Three-Dimensional Printing

Jiang

Wang

et al. 2020

3D Printing and Additive Manufacturing

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Although continuous projection Stereolithography (SL) printing is one of the next-generation ultra-fast additive manufacturing (AM) processes, its current constrained window design of the resin vat is suffering from many challenges, such as the complex control mechanism and limited hardware lifetime. In this article, we investigate a novel constrained window design, namely Island Window (IW), for the continuous three-dimensional (3D) printing by using the projection SL process. The proposed IW window has a highly oxygen-permeable polydimethylsiloxane membrane onto the laser-machined acrylic vat frame, which allows the formation of an effective liquid interface (>200 lm oxygen inhibition layer) to enable the continuous projection SL process. Experimental results verified the feasibility of the window design for extending the maximum printing time (increased by up to 73%) due to the enhanced oxygen concentration. It was also found that the maximum printing speed for producing parts with a smooth surface (Rz <30 lm) can be as high as 90 mm/h, which is comparable to the speeds in recently reported continuous SL processes. In addition, a variety of parts were successfully fabricated through continuous 3D printing by using the proposed IW design, implying tremendous promise for future low-cost, high-resolution, easy-controlled, and ultra-fast AM processes.

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Air-Diffusion-Channel Constrained Surface Based Stereolithography for Three-Dimensional Printing of Objects With Wide Solid Cross Sections

Cited by 14 publications

References 36 publications

Effect of Constrained Surface Texturing on Separation Force in Projection Stereolithography

Effect of Constrained Surface Texturing on Separation Force in Projection Stereolithography

Tilting separation simulation and theory verification of mask projection stereolithography process

Constrained Window Design in Projection Stereolithography for Continuous Three-Dimensional Printing

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