Design of thermoformable three dimensional-printed PLA cast for fractured wrist

Patient specific plastic cast for broken limbs has been developed recently in pharmaceutical field through three-dimensional (3D) printing method. However, the production of a 3D printed cast through normal 3D printing method is time consuming compared to conventional plaster casting. In this study, a design of ventilated structured thermoformable 3D-printed polylactic acid (PLA) cast was produced as an alternative for the 3D printed cast production method. This design was initially printed in a flat shape and then transformed into a cast which can be fitted to the user’s arm by using heat and external force. Finite Element Analysis (FEA) method was used to assess the mechanical properties of the proposed cast. In this analysis, thethermoformable design was exerted with a distributed force of 400 N, which is larger than the loading conditions encountered by human in their daily life. The mechanical properties of the thermoformable PLA cast such as local displacement under a specific load, maximum load, and stress were evaluated. Results were compared with the mechanical properties of Plaster of Paris cast. The results obtained from the FEA indicates that at the same layer thickness, the thermoformable 3D-printed PLA cast is stronger than the Plaster of Paris cast.

FABRICATION CYCLES COMPARISON OF ASSEMBLIES AND MONOLITHIC PARTS MADE BY 3D PRINTING METHOD

The article presents an analysis of the time-consuming, energy-consuming, and cost-consuming nature of 3D printing a three-dimensional polymer components made in two separate approaches: assembly and monolith structure of various materials (automatic filament change required). The introduction includes the definition of 3D printing, its advantages and examples of practical applications, as well as the reason for undertaking the researches described in the article. The justification of the form of 3D sample models was discussed in detail, as well as the methodology adopted by the authors for comparing the print characteristics and the steps of the printing cycles (print preparation, the course of the printing process and post-processing). A comparison of the materials consumption in the phasess of manual and automatic filament change in the mixer were also described. The test printout was made on the Prusa i3 MK3S printer for filament deposition (FDM or FFF methods). For automatic filament mixing, the Palette 2 Pro device was used. The conclusions also include guidelines for the design and production of models made in one continuous printing cycle (using automatic filament feeding devices). Monolithic elements are less accurate, while elements with replaceable filaments are cheaper, less energy-consuming and the material consumption is lower.

Effect of High-Pressure Hot Airflow On Interlayer Adhesion Strength of 3D Printed Parts

The characteristics of FDM 3D printed parts depend largely on the process used to make them. This paper demonstrates the design of an FDM 3D printing gas-assisted molding printing head, which is used to eliminate the effect of swelling away from the mold and improve the dimensional accuracy. Meanwhile, the high-pressure hot airflow instantly heats and pressurizes the printing surface layer to enhance the interlayer adhesion strength and its mechanical properties. A stable gas lubrication layer can be formed on the inner wall of gas-assisted nozzle to smoothly deposit filaments when the gas flow (Qgas) is set to 1.75 L/min and the gas pressure (Pgas) is set to 0.4 MPa. The interlayer adhesion strength of the printed parts is enhanced by more than 50% compared with that without gas assistance, and the volumetric shrinkage rate of the optimal group is only 0.13%. The proposed printing method can significantly improve the performance of thermoplastic parts and provide new capabilities for biomedical printing, automotive, aerospace and functional device printing in the future.

Project and Software of a Robotic Welding Station Using Virtual Reality Technology

The use of VR technology in various industries, including in the industry is constantly growing. ABB is one of the first companies to introduce programming using virtual reality to its offer. This system greatly facilitates the work of an engineer, allowing the user to interact with 3D models through virtual reality goggles. The article presents the design and software of a robotic station that enables the creation of movement instructions using virtual reality technology. The review of the existing industrial solutions using VR technology in welding simulators and other industries. A project of a welding station in the RobotStudio environment was presented and built. Software was written using virtual reality and a model of the real tool was made using the 3D printing method. The designed welding station was tested.

A movable type bioelectronics printing technology for modular fabrication of biosensors

Biosensors have been widely used in various fields such as food industry, environmental testing and medical testing for their high sensitivity. However, current fabrication methods of biosensors, such as screen printing, micro fabrication and 3D printing suffer from complex procedures, requirement of cleanroom facility and limited fabrication materials, which significantly restrict the development and utilization of biosensors. Here, we propose a movable type bioelectronics printing method for the fabrication of biosensors by directly transferring bioelectronic materials onto various substrates using pre-fabricated molds. This simple, low-cost, yet robust method facilitates on-demand printing of master molds of partial or complete circuits on both rigid or flexible substrates. With this method, bioactive materials such as enzymes can be directly transferred onto substrates together with other electronic components, without complex modification after electrode fabrication using conventional methods. For demonstration, a dual-channel flexible electrochemical biosensor was fabricated by the movable type bioelectronics printing method for continuous monitoring of glucose and lactate. The movable type bioelectronics printing technology holds advantages of repeatability, flexibility and low cost for fabrication of biosensors on rigid and flexible substrates, as well as direct transfer printing of bioactive materials, which greatly promotes small-scale production of biosensors.

3D Printing of Aramid Nanofiber Composites by Stereolithography

Vat photopolymerization is a versatile 3D printing method that produces parts using polymeric materials with uniform mechanical properties, high quality surface finish and high-resolution features. However, it is challenging to make composite materials with vat photopolymerization mainly due to the imperfect filler dispersion in the photo resin. Herein, we describe a methodology to incorporate aramid nanofibers (ANFs) into a 3D printable photoresin as a dispersion, followed by a solvent exchange process that limits anisotropic shrinkage and cracking of the printed polymer. By incorporating 0.60 wt.% of ANFs, both the tensile strength and toughness increased by 264 % and 219 % respectively, while the Young’s modulus had a 406 % increase compared to the control photoresin.

Parameters Influencing the Emission of Ultrafine Particles during 3D Printing

This paper presents a complex and extensive experimental evaluation of fine particle emissions released by an FDM 3D printer for four of the most common printing materials (ABS, PLA, PET-G, and TPU). These thermoplastic filaments were examined at three printing temperatures within their recommended range. In addition, these measurements were extended using various types of printing nozzles, which influenced the emissions considerably. This research is based on more than a hundred individual measurements for which a standardized printing method was developed. The study presents information about differences between particular printing conditions in terms of the amount of fine particles emitted as well as the particle size distributions during printing periods. This expands existing knowledge about the emission of ultrafine particles during 3D printing, and it can help reduce the emissions of these devices to achieve cleaner and safer 3D printer operations.

Second-harmonic generation from green printed selenium structures

Plenary large-scale efficient second-harmonic generation sources remains a challenge in micro-/nanoscale research. In this work, we demonstrate the strong second-harmonic generation in arrays of selenium particles fabricated by green printing method at the pumping wavelength of 1047 nm. Second-harmonic generation mapping shows the strong signal over the whole area of selenium particle. We propose, that such structures can be a perspective platform for efficient frequency conversion systems and nonlinear sensing applications.