Printing and Laser Curing of Ag and Cu Paste - Prospects and Challenges in Additive Manufacturing

This study depicts substantial characteristics of copper and silver pastes, dispensed and cured by oven processing. Different analyses, such as second electron microscopy (SEM), rheometry, thermogravimetric analysis (TGA), UV-VIS-NIR-spectroscopy and 4-point measurement were used. This work also will illustrate some results of computational design of experiment (DOE) and regression analyses for jet and mechanical printing processes.

Microhardness of Two Composite Resins with Different Curing Sources

Background This study evaluated the influence of two light sources on the microhardness of two recent composite resins.Methods A total of one hundred and twenty specimens were prepared and divided into two groups according to the composite resin restoration used (Tetric EvoCeram Bulkfill) and (Universal Nanohybrid Mosaic). Each group was subdivided into four subgroups according to the light source used with different curing intervals: laser curing system (SIROLaser) for 10,15, and 20 seconds and conventional blue light system (LED) for 20 seconds. Microhardness testing machine was used to assess the microhardness. Two-way ANOVA was done for comparing resin composite and curing energy effect on different variable studied. One-way ANOVA followed by pair-wise Tukey’s post-hoc tests were performed to detect significance between each composite subgroups and t-test for subgroups. P values ≤ 0.05 are considered statistically significant in all tests.Results LED cured Tetric EvoCeram Bulkfill composite resin recorded higher B/T ratio than laser cured one and the difference in B/T ratio between both energies was statistically non-significant. LED cured Mosaic composite resin recorded higher B/T ratio than laser cured one. The difference in B/T ratio between both energies was statistically significant.Conclusion SIROLaser Blue laser device has been promoted for composite resin curing with different curing intervals, but the high cost and technique sensitivity result in their limited use. Clinical Significance: Different types of curing systems are present in the dental practice. The use of SIROLaser Blue laser to photopolymerize composite resin will offers proper polymerization properties.

Additive manufacturing by material extrusion with medical grade silicone elastomers and IR laser curing

Purpose Techniques of extrude and cure additive manufacturing for thermally cured, high viscosity and medical-grade silicone are investigated by using a small ram extruder and a near-infrared (IR) laser. The purpose of this study is to evaluate the process parameter effects on the stiffness of the final products. Design/methodology/approach Process parameter effects on axial stiffness values and durometer are explored. Parameters such as extrusion layer height, laser speed, laser current, laser raster spacing and multiple laser passes were investigated and compared to traditional cast and cure methods. Dimensional changes were also recorded and compared. Findings Tensile and durometer tests show that certain curing parameters give tensile stress and durometers within 10 per cent of bulk material specifications at 200 per cent strain. Parameters that had the highest impact on tensile stress at 200 per cent strain were layer height (0.73 per cent) followed by laser power (0.69 per cent), and then laser raster spacing (0.45 per cent). Parameters that had the highest impact on durometer were laser power (1.00 per cent), followed by layer height, (0.34 per cent) and then laser raster speed (0.32 per cent). Three-dimensional printed samples had about 11.2 per cent more shrinkage than the bulk cast samples in the longest dimension. Originality/value This paper is one of the first that demonstrates near IR laser curing parameter effects on three-dimensional printed, commercial off-the-shelf, medical-grade and viscous silicone. The ability to cure very viscous thermosets locally enables interesting technologies such as wire encapsulation, high voltage actuators and drug delivery devices.

Fabrication of Soft Sensor Using Laser Processing Techniques: For the Alternative 3D Printing Process

Recently, the rapid prototyping process was actively studied in industry and academia. The rapid prototyping process has various advantages such as a rapid processing speed, high processing freedom, high efficiency, and eco-friendly process compared to the conventional etching process. However, in general, it is difficult to directly apply to the fabrication of electric devices, as the molding made by the rapid prototyping process is usually a nonconductive polymer. Even when a conductive material is used for the rapid prototyping process, the molding is made by a single material; thus, its application is limited. In this study, we introduce a simple alternative process for the fabrication of a soft sensor using laser processing techniques. The UV laser curing of polymer resin and laser welding of nanowires are conducted and analyzed. Through the laser processing techniques, we can easily fabricate soft sensors, which is considered an alternative 3D printing process for the fabrication of soft sensors.

Polymer selective laser curing for integrated optical switches

A simple in-layer electro optical switch has been prepared by selectively curing a photocurable optical polymer with a UV laser. The core of the device is a NOA-81 multimode waveguide grown by selective laser curing. The cladding is a positive calamitic liquid crystal, which allows tunability and switching of the waveguide by external driving electric signals. The effective refractive index in the guide changes upon switching the liquid crystal. Depending on the geometry, this setup leads to an electrooptical modulator or a switch between two levels of transmitted light. Full Text: PDF ReferencesT. Ako, A. Hope, T. Nguyen, A. Mitchell, W. Bogaerts, K. Neyts, and J. Beeckman, "Electrically tuneable lateral leakage loss in liquid crystal clad shallow-etched silicon waveguides", Opt. Express 23, 2846 (2015). CrossRef K. Kruse, C. Middlebrook, "Laser-direct writing of single mode and multi-mode polymer step index waveguide structures for optical backplanes and interconnection assemblies", Photon. Nanostruct. - Fundamentals and Appl. 13, 66 (2015). CrossRef A. Günther, A.B. Petermann, M. Rezem, M. Rahlves, M. Wollweber, and B. Roth, European Conf. Lasers and Electro-Optics - European Quantum Electronics Conference, Munich, Germany (2015).C. Florian, S. Piazza, A. Diaspro, P. Serra, M. Duocastella, "Direct Laser Printing of Tailored Polymeric Microlenses", ACS Appl. Mater. Interfaces, 8(27), 17028 (2016). CrossRef F. Costache, M. Blasl, "Optical switching with isotropic liquid crystals", Opt. Photonik 6, 29 (2011). CrossRef M. Cano-Garcia, R. Delgado, T. Zuo, M.A. Geday, X. Quintana, Jose M. Otón, 16th OLC Topical Meeting on the Optics of Liquid Crystals, Sopot, Poland (2015).S. Ishihara, H. Wakemoto, K. Nakazima, Y. Matsuo, "The effect of rubbed polymer films on the liquid crystal alignment", Liq. Cryst. 4(6), 669 (1989). DirectLink