Papers by Keyword: CAD/CAM

Abstract: The general term of CAD/CAM technology (i.e., Computer-Aided Design/Compute-Aided Manufacturing) comprises several aspects, such as subtractive manufacturing processes, like milling (soft and hard milling), and additive manufacturing processes, like Selective Laser Melting (SLM), which refers to metallic materials, or Selective Laser Sintering (SLS), which refers to glasses/glass-ceramics/ceramic, or polymeric, or related composite materials produced via powder metallurgy technique. In biomaterials fabrications, the first step in SLM or SLS technology is the digital design of the prosthetic restoration, whereby the patient's individual anatomical and morphological features are precisely described. Afterwards laser-aided melting or sintering is repeated (layer-by-layer) until the complete restoration item is fabricated. A wide range of dental materials can be produced by SLM or SLS technology, e.g., metals and alloys, thermoplastic polymers, glasses/ceramics, waxes, and thermoplastic composites. Thus, it is a promising technology for producing a variety of dental restorations, such as metal-ceramic restorations, all-ceramic restorations, maxillofacial prostheses, functional skeletons, individual scaffolds for tissue engineering, etc. SLM technology is already widely applied for fabricating metal objects for dental (e.g., Co-Cr alloy) and orthopedic prostheses. As a subsequence, in the last decade, researchers' interest has been shifted to SLS of ceramic powders, such as SiO₂, Al₂O₃, SiO₂/Al₂O₃, and ZrO₂/Y₂O₃. This article comprehensively reviews the SLS process and its prospects for producing glasses/glass-ceramic/ceramic materials for biomedical/dental applications. The experimental results clearly show that this very modern additive manufacturing technology does not jeopardize the properties of the ceramic biomaterials' properties.

Abstract: Inside Direct Energy Deposition (DED) processes is the Laser Metal Deposition (LMD) technology. Industries that can implement this technology approach are from automotive to energy sectors where critical parts suffer due to operation cycles, weather or hazardous environments etc. LMD process can be applied for coating, repair and build near net shape geometries. One of the main problems of LMD applied in the coating or in the repair is the dealing with these different types of geometries, to achieve an adherent and homogeneous coating. The current calculation of toolpaths in LMD software is based on a mathematical algorithm that relies on subtractive processes such as machining. The main drawback of using this type of toolpaths is that in this case they do not take into account the overlap between adjacent machining toolpaths. While for machining this parameter is not relevant, in the LMD process, the overlap between two contiguous laser tracks is a critical point to have an adequate process with the required quality. Talens Systems has developed a new Software, Azala software is able to calculate these strategy toolpaths for advanced repairs and coatings in any type of geometry. Beside taking into account the overlapped between contiguous laser clads, the calculated toolpaths have integrated the main laser process in LMD (laser power, process speed, powder flow). The objective of this work is to validate the Azala software developed using a piece with complex geometry on a laboratory scale. The developed software brings the possibility to automate repair and coating, where the LMD process provides a value-added opportunity to reduce production costs due to the repair of value-added components.

Abstract: There is a growing demand for more efficient and economic manufacturing process to improve product quality, reduce production cost, reduce lead time and increase productivity. The application of computer aided design and manufacturing (CAD/CAM) techniques to forging is becoming increasingly popular as the resulting improvements in yield and productivity. Modeling and simulation have become a major concern in recent and advanced research. In this paper die design for forging of an automobile component “Stub Axle” is presented. In die forging process, complex shape component cannot be made in one stage and therefore, the use of preform die becomes essential. The initial preform design was carried out by conventional method. The simulation has been carried out using software DEFORM-3D. The main goal of this study is to design an optimal preform shape resulting an optimal initial billet selection. Keywords:CAD/CAM, Preform, DEFORM-3D, Simulation, Forging

Abstract: Over the course of the last decade 3D printing has become a more established technology in terms of prototype development (rapid prototyping). The current effort is focused on transferring this knowhow into a product driven approach in order to manufacture even small batch sizes more economic. In terms of this work, this idea is adapted for the development of injection molds (rapid manufacturing). Hereby, a hardened polymer is used to create a forming cavity instead of tool-steel. In order to fulfil the mechanical process requirements of micro injection molding such as form stability under temperature and pressure this cavity is nevertheless integrated into a metal housing. A first set of experiments has been carried out using this develop mold to verify the capabilities of the developed prototype as well as molding process. Based on these first results, an optimization is carried out to improve the next iteration of this molding tool.

Abstract: The engineering production is currently characterized by frequent changes. These changes are caused because the life cycle of products is shortened. Producers must introduced the upgraded products in a shorter interval. In this article we will focus on identifying the possibilities of production innovation in the flexible manufacturing system. An analysis of the production possibilities of one of the production machines in the flexible production system will be carried out. This production machine is a lathe that produces one basic part of the finished product. We will determine what variants of this component can be manufactured without changing the physical configuration of the machine.

Abstract: Bioreactor systems for cultivating cells in Life Sciences have been widely used for decades. Recently, there is a trend towards miniaturization, disposables and even micro platforms that fulfill increasing demands strongly aiming for production and testing of novel pharmaceutical products. Miniaturized bioreactors allow low power consumption, portability and reduced space requirements and utilize smaller volumes of reagents and samples [1,2]. A recursive strategy is necessary for optimizing the design and the manufacture of such miniaturized bioreactors. For the fabrication of these prototypes utilized micro-milling. Micro milling is a mechanical process which is commonly applied to create micro-structures in metals, e.g. aluminum and steel, or polymers, e.g. poly carbonate substrates. The structures and geometries are generated by utilizing computer aided design. By means of computer-aided manufacturing, the machining operations are implemented and then transferred to the machine tool. The machine tool moves the cutting tools with certain speeds, feeds and traverse ranges to the substrate. Micro milling has the advantage that the materials are generally not degraded by chemical substances, heating procedures or electromagnetic radiation.

Abstract: Dental applications like crowns, veneers or bridges require high accuracy to be fitted on the patient’s stump. Stereolithography is an additive manufacturing method, which offers high precision by using light exposure as the layer generating mechanism. In the LCM process, this precision is combined with a thermal post-processing step to achieve full ceramic restorations. The overall production of such ceramic parts in a reproducible way is a highly complex procedure. The first requirement is to find a slurry formulation, which is stable against sedimentation and segregation, that is also processable in a stereolithographic system. Such a formulation has been found by us, which could be shown by rheology measurements. During experiments with this formulation, it could be observed that there is a correlation between wet film thickness and resolution. Several adjustments to the machine have been made, to fully control this parameter. Namely, changes to the vat, the doctor blade and the building platform have been made. The improvement of the process and the quality of the final parts are validated by fabricating Siemens stars and by biaxial bending tests.

Abstract: The article focuses on the design, construction and manufacture of an inspection vehicle intended to access difficult-to-reach places. The vehicle is able to monitor piping system failures at the view angle of 180° in deep depths and adverse environments. The individual components of the inspection vehicle, more detailed their programming and production on CNC machines are discussed. The vehicle is supposed to easily run into the piping systems and can be safely pulled out. A control system was created for motion and video signal transmission to the operator from above the ground. Aluminum alloy (EN AW 2024) is the predominant material of the manufactured components and at the same time has ideal processing and operating properties. Proposed inspection vehicle is a robust and functional solution with minimal maintenance.

Abstract: In order to solve the problem of openness, intelligence and low integration in the current machining robot control system, STEP-NC standard is introduced into the field of robot machining, and defines the STEP-NC data model of industrial robots. The 6R industrial robots are used to build the machining platform and the connection between the machining robot and the CAD / CAM system and the integrated data stream structure are discussed. The key issues involved in the post processing of the machining robot are studied. Taking the 6R robot as an example, the robot prototype system is established, and the kinematics solution in the post-processing process is studied and deduced. The cutting and post-processing system platform of cutting robot was established and the sample art machining was completed. The experimental and simulation results show that the system can complete the machining process of the cutting robot and generate executable robot machining instructions.

Abstract: A patient with severe head trauma must was scheduled for cranioplasty. Due to the large defect with complex profile, the surgeons decided to ask for help from engineers who designed the cranioplasty plate using Mimics© and 3-matic© (software produced by Materialise NV) and 3D printed the prototype of the skull and the cranioplasty plate using a ZPrinter 310 machine (patented by MIT). The cranioplasty plate was manufactured following the prototype using Polyether Ether Ketone (PEEK). The surgery was a success as the first intervention using a complex research team for the Central Military Hospital from Bucharest. The paper presents the case evolution and the engineering processing steps (design and manufacturing) of the cranioplasty plate obtaining.