MECHANICAL PROPERTIES OF THE WOVEN NATURAL FIBER REINFORCED SHEET STOCKS USED FOR THE LAMINATED OBJECT MANUFACTURING (LOM) RAPID PROTOTYPING PROCESS

This paper investigates the mechanical properties of potential sheet stocks of a Laminated Object Manufacturing (LOM) 3D printer made using woven jute fabrics infused with two types of bioresin. The combinations of bioresins and the reinforcements would make green sheet stocks that are expected to be environmentally friendly comparing to traditional synthetic fibers infused with regular resins. Pure resin samples are also involved for comparison purposes. Both tensile and flexural properties are measured following ASTM D638 and D3039 standards (for tensile tests) as well as ASTM D790 and D7264 standards (for flexural tests). Detailed processes of specimen preparation followed by test procedures are introduced. Tensile strengths and moduli as well as flexural strengths and moduli are obtained for comparison. Based on the study of the mechanical properties of both types of pure resin and woven jute fiber-reinforced composites, the research team concluded a few important findings that could be used as guidelines in the sheet stock selection and preparation for the LOM 3D printer that is currently under the building process.

Individual layer fabrication (ILF): a novel approach to additive manufacturing by the use of wood

A novel process named ‘individual layer fabrication (ILF)’ is presented, in which objects are built up by laminating individually contoured wood-based panels. However, contrary to the well-known process of ‘laminated object manufacturing (LOM)’, in ILF, the individual panels are not shaped by a subtractive process but additively by selective binding of wooden particles. The particles are spread as a thin layer onto a built platform. A liquid adhesive is then applied only to those areas where the contoured panel is to be generated. As each layer is fabricated individually, the ILF process allows the application of mechanical pressure. Thereby, compared to other additive manufacturing techniques, the necessary amount of binder can be significantly reduced and mechanical properties comparable to particle boards can be achieved.

Z-axis limit switch 3D printer

Not much time has passed since the appearance of the first 3D printer. Today there are many different printers. They differ in various 3D printing technologies, namely: Stereolithography – SL, Selective Laser Sintering, Fused Deposition Modeling – FDM, Laminated Object Manufacturing – LOM, Polyjet and Ployjet Matrix. In recent years, the spread of 3D printing technology has become and continues to be used more and more today. Of course, in the future we will see a large-scale spread of additive methods, but the practical application of 3D printing today is available to everyone. Melting deposition modeling technologies have become widespread and available. The authors in this article consider possible options for upgrading the mounting of the end sensor of the Z Axis and automating the process of calibration of the zero gap of the extruder nozzle relative to the working surface of the printer. This calibration is important. This affects the accuracy and printing process of the future plastic model. During the operation of the 3D printer, it is often necessary to service the extruder, which forces the process of calibrating the zero gap of the printer nozzle. Optimally correct selected nozzle clearance affects the accuracy, geometry of the model and printing as a whole. It also allows you to get rid of peeling off the model from the desktop surface and the destruction of the model during printing.

An Additive Manufacturing Method Using Large-Scale Wood Inspired by Laminated Object Manufacturing and Plywood Technology

Wood-based materials in current additive manufacturing (AM) feedstocks are primarily restricted to the micron scale. Utilizing large-scale wood in existing AM techniques remains a challenge. This paper proposes an AM method—laser-cut veneer lamination (LcVL)—for wood-based product fabrication. Inspired by laminated object manufacturing (LOM) and plywood technology, LcVL bonds wood veneers in a layer-upon-layer manner. As demonstrated by printed samples, LcVL was able to retain the advantageous qualities of AM, specifically, the ability to manufacture products with complex geometries which would otherwise be impossible using subtractive manufacturing techniques. Furthermore, LcVL-product structures designed through adjusting internal voids and wood-texture directionality could serve as material templates or matrices for functional wood-based materials. Numerical analyses established relations between the processing resolution of LcVL and proportional veneer thickness (layer height). LcVL could serve as a basis for the further development of large-scale wood usage in AM.

Surface Quality Improvement of 3D Microstructures Fabricated by Micro-EDM with a Composite 3D Microelectrode

Three-dimensional (3D) microelectrodes used for processing 3D microstructures in micro-electrical discharge machining (micro-EDM) can be readily prepared by laminated object manufacturing (LOM). However, the microelectrode surface always appears with steps due to the theoretical error of LOM, significantly reducing the surface quality of 3D microstructures machined by micro-EDM with the microelectrode. To address the problem above, this paper proposes a filling method to fabricate a composite 3D microelectrode and applies it in micro-EDM for processing 3D microstructures without steps. The effect of bonding temperature and Sn film thickness on the steps is investigated in detail. Meanwhile, the distribution of Cu and Sn elements in the matrix and the steps is analyzed by the energy dispersive X-ray spectrometer. Experimental results show that when the Sn layer thickness on the interface is 8 μm, 15 h after heat preservation under 950 °C, the composite 3D microelectrodes without the steps on the surface were successfully fabricated, while Sn and Cu elements were evenly distributed in the microelectrodes. Finally, the composite 3D microelectrodes were applied in micro-EDM. Furthermore, 3D microstructures without steps on the surface were obtained. This study verifies the feasibility of machining 3D microstructures without steps by micro-EDM with a composite 3D microelectrode fabricated via the proposed method.

Advances in Orthotic and Prosthetic Manufacturing: A Technology Review

In this work, the recent advances for rapid prototyping in the orthoprosthetic industry are presented. Specifically, the manufacturing process of orthoprosthetic aids are analysed, as thier use is widely extended in orthopedic surgery. These devices are devoted to either correct posture or movement (orthosis) or to substitute a body segment (prosthesis) while maintaining functionality. The manufacturing process is traditionally mainly hand-crafted: The subject’s morphology is taken by means of plaster molds, and the manufacture is performed individually, by adjusting the prototype over the subject. This industry has incorporated computer aided design (CAD), computed aided engineering (CAE) and computed aided manufacturing (CAM) tools; however, the true revolution is the result of the application of rapid prototyping technologies (RPT). Techniques such as fused deposition modelling (FDM), selective laser sintering (SLS), laminated object manufacturing (LOM), and 3D printing (3DP) are some examples of the available methodologies in the manufacturing industry that, step by step, are being included in the rehabilitation engineering market—an engineering field with growth and prospects in the coming years. In this work we analyse different methodologies for additive manufacturing along with the principal methods for collecting 3D body shapes and their application in the manufacturing of functional devices for rehabilitation purposes such as splints, ankle-foot orthoses, or arm prostheses.