Search

The ever-growing demand for reducing costs and decreasing the time to market in today's plastics industry makes rapid tooling and rapid prototyping highly researched areas. Stereolithography (SLA)-manufactured injection mold inserts make it possible to produce prototype parts rapidly and cost-effectively. To utilize SLA in the injection molding industry, two steps have to be considered. The first is to identify suitable SLA process and post-thermal curing process parameters to enhance the mechanical and thermal characteristics. The second is to verify the applicability of SLA-manufactured molds for use in the injection molding industry. IA comprehensive study was performed to find the optimum process parameters for an SLA mold with excellent mechanical and thermal properties and to verify the applicability of the mold. First of all, the mechanical and thermal properties of samples manufactured based on various laser powers and heat treatment at different temperatures were analyzed with a tensile test, DSC, and TMA according to the degree of cure. On the basis of the results from those tests, an SLA mold was designed and fabricated with the optimum mechanical and thermal properties. In addition, the SLA mold was assembled into an injection machine, and an injection molding test was conducted. The SLA mold endured during the injection cycle, and 500 shots were successfully injected without damaging the mold, which resulted in reaching the quick-delivery mold standard. Finally, we demonstrate that SLA is an effective technology to produce molds for use in the injection molding industry. [ABSTRACT FROM AUTHOR]

Hydrogel precursor photoresists (HPR) are being studied widely due to the close similarities between HPR cured microstructures and biological materials. A vast majority of such resists are formulated in water and suffer from swelling-related inhomogeneities during microfabrication. Hence formulation HPRs in non-aqueous media are being studied as an alternative. This approach enables controlled swelling of fabricated structures. In this work, we demonstrate that controlled swelling of hydrogel microstructures fabricated by two-photon lithography (TPL) can be used to drive 2D to 2.5D transitions in flat microstructures. Through fabrication experiments, mechanical analysis and finite element method (FEM) simulations we have shown that swelling delamination leads to bend microstructures, and the height of the resulting bend structure depends on the designed thickness of the structure.

Structural coloration is closely related to the progress of innovative optoelectronic applications, but the absence of direct, on‐demand, and rewritable coloration schemes has impeded advances in the relevant area, particularly including the development of customized, reprogrammable optoelectronic devices. To overcome these limitations, a digital laser micropainting technique, based on controlled thin‐film interference, is proposed through direct growth of the absorbing metal oxide layer on a metallic reflector in the solution environment via a laser. A continuous‐wave laser simultaneously performs two functions—a photothermal reaction for site‐selective metal oxide layer growth and in situ real‐time monitoring of its thickness—while the reflection spectrum is tuned in a broad visible spectrum according to the laser fluence. The scalability and controllability of the proposed scheme is verified by laser‐printed painting, while altering the thickness via supplementary irradiation of the identical laser in the homogeneous and heterogeneous solutions facilitates the modification of the original coloration. Finally, the proof‐of‐concept bolometer device verifies that specific wavelength‐dependent photoresponsivity can be assigned, erased, and reassigned by the successive application of the proposed digital laser micropainting technique, which substantiates its potential to offer a new route for reprogrammable optoelectronic applications. [ABSTRACT FROM AUTHOR]

In this topical review of two-photon stereolithography (TPS), we discuss novel materials and demonstrate applications of this technology. Two-photon-initiated chemical processes are used to fabricate arbitrary three-dimensional structures in TPS. In the first part of this article, the development of novel photoactive materials to fabricate pure inorganic or organic–inorganic hybrid microstructures is discussed. The second part discusses the fabrication of functional microstructures for highly specific applications to demonstrate the importance of TPS in different fields of science. [ABSTRACT FROM AUTHOR]