Rapid Prototyping Machine Research Articles

Development of Experimental Setup of Metal Rapid Prototyping Machine using Selective Laser Sintering Technique

Unlike in the traditional manufacturing processes, additive manufacturing as rapid prototyping, allows designers to produce parts that were previously considered too complex to make economically. The shift is taking place from plastic prototype to fully functional metallic parts by direct deposition of metallic powders as produced parts can be directly used for desired purpose. This work is directed towards the development of experimental setup of metal rapid prototyping machine using selective laser sintering and studies the various parameters, which plays important role in the metal rapid prototyping using SLS technique. The machine structure in mainly divided into three main categories namely, (1) Z-movement of bed and table, (2) X–Y movement arrangement for LASER movements and (3) feeder mechanism. Z-movement of bed is controlled by using lead screw, bevel gear pair and stepper motor, which will maintain the accuracy of layer thickness. X–Y movements are controlled using timing belt and stepper motors for precise movements of LASER source. Feeder mechanism is then developed to control uniformity of layer thickness metal powder. Simultaneously, the study is carried out for selection of material. Various types of metal powders can be used for metal RP as Single metal powder, mixture of two metals powder, and combination of metal and polymer powder. Conclusion leads to use of mixture of two metals powder to minimize the problems such as, balling effect and porosity. Developed System can be validated by conducting various experiments on manufactured part to check mechanical and metallurgical properties. After studying the results of these experiments, various process parameters as LASER properties (as power, speed etc.), and material properties (as grain size and structure etc.) will be optimized. This work is mainly focused on the design and development of cost effective experimental setup of metal rapid prototyping using SLS technique which will gives the feel of metal rapid prototyping process and its important parameters.

Evolution of Cardiac Biomodels from Computational to Therapeutics.

Biomodeling the human anatomy in exact structure and size is an exciting field of medical science. Utilizing medical data from various medical imaging topography, the data of an anatomical structure can be extracted and converted into a three-dimensional virtual biomodel; thereafter a physical biomodel can be generated utilizing rapid prototyping machines. Here, we have reviewed the utilization of this technology and have provided some guidelines to develop biomodels of cardiac structures. Cardiac biomodels provide insights for cardiothoracic surgeons, cardiologists, and patients alike. Additionally, the technology may have future usability for tissue engineering, robotic surgery, or routine hospital usage as a diagnostic and therapeutic tool for cardiovascular diseases (CVD). Given the broad areas of application of cardiac biomodels, attention should be given to further research and development of their potential.

Methodologies for Development of Patient Specific Bone Models from Human Body CT Scans

This work deals with development of algorithm for physical replication of patient specific human bone and construction of corresponding implants/inserts RP models by using Reverse Engineering approach from non-invasive medical images for surgical purpose. In medical field, the volumetric data i.e. voxel and triangular facet based models are primarily used for bio-modelling and visualization, which requires huge memory space. On the other side, recent advances in Computer Aided Design (CAD) technology provides additional facilities/functions for design, prototyping and manufacturing of any object having freeform surfaces based on boundary representation techniques. This work presents a process to physical replication of 3D rapid prototyping (RP) physical models of human bone from various CAD modeling techniques developed by using 3D point cloud data which is obtained from non-invasive CT/MRI scans in DICOM 3.0 format. This point cloud data is used for construction of 3D CAD model by fitting B-spline curves through these points and then fitting surface between these curve networks by using swept blend techniques. This process also can be achieved by generating the triangular mesh directly from 3D point cloud data without developing any surface model using any commercial CAD software. The generated STL file from 3D point cloud data is used as a basic input for RP process. The Delaunay tetrahedralization approach is used to process the 3D point cloud data to obtain STL file. CT scan data of Metacarpus (human bone) is used as the case study for the generation of the 3D RP model. A 3D physical model of the human bone is generated on rapid prototyping machine and its virtual reality model is presented for visualization. The generated CAD model by different techniques is compared for the accuracy and reliability. The results of this research work are assessed for clinical reliability in replication of human bone in medical field.

Fabrication and characterization of open cell porous regular interconnected metallic structure with solid core

Metallic parts having open cell porous regular interconnected metallic structure of predetermined unit cell are being fabricated using metal powder–based rapid prototyping machines. These machines are capital intensive. All porous structures including open cell porous regular interconnected metallic structure have less density, so they lack in strength problems as compared to the solid structure. The strength of open cell porous regular interconnected metallic structure can be enhanced by providing solid inner core. In this study, a cost-effective technique has been developed to fabricate open cell porous regular interconnected metallic structure with solid core using ceramic powder–based three-dimensional printing machine and pressureless sintering. In this work, two approaches of fabrication were developed. In the first approach, only spherical metal powder was used, while in the second approach, a solid metallic rod along with spherical metal powder was utilized. Interconnected porosity and sinter density of the fabricated specimens were measured using Archimedes’ principle. The characterization was done using microstructure analysis, energy dispersive analysis, scanning electron microscopy and X-ray diffraction analysis. Mechanical properties of developed structures were determined using tensile, compressive and impact tests.

Efficient volumetric error compensation technique for additive manufacturing machines

Purpose – This paper aims to present a methodology for volumetric error compensation. This technique is applied to an Objet Eden350V 3D printer and involves a custom measurement strategy. Design/methodology/approach – The kinematic model of the printer is explained, and its error model is simplified to 18 independent error functions. Each error function is defined by a cubic Legendre polynomial. The coefficients of the polynomials are obtained through a Levenberg–Marquardt optimization process. This optimization process compares, in an iterative algorithm, nominal coordinates with actual values of the cloud of points. The points are built in the faces of a gauge artefact as conical sockets defining one unique point for each socket. These points are measured by a coordinate measuring machine self-centring measurement process. Findings – Most of the errors of the 3D printer are systematic. It is possible to obtain an improvement of 70 per cent in terms of global mean error reduction in single points within a volume of 120 × 120 × 40 mm. The forecast of the final error compensation fully matches the actual final error. Practical implications – This methodology can be used for accuracy improvement in additive manufacturing machines. Originality/value – Unlike the calculation of geometric errors, the proposed parametric determination through optimization of the error model allows global error reduction, which decreases all sort of systematic errors concurrently. The proposed measurement strategy allows high reliability, high speed and operator independence in the measurement process, which increases efficiency and reduces the cost. The proposed methodology is easily translated to other rapid prototyping machines and allows scalability when replicating artefacts covering any working volume.

Simulation of osteotomy and support for surgery using VR haptic device

A novel computer-assisted 3-D simulation for osteotomy and CAD/CAM fabrication of surgical splints consider the relative inter-bone interference and space after bone translation were developed. CT image of a patient for osteotomy was operated and simulation of surgery for deformation, segmentation, displacement of the bone was processed effectively by virtual reality haptic device PHANTOM. CAD of a bite splint before surgery and after bone displacement was done in the process of simulation. CAM of resin bite splints was done by precise Rapid Prototyping CAM machine. All fabricated splint were sufficiently functioned to determine the position of jaws.

Comparison of Two Different Rapid Prototyping System Based on Dimensional Performance Using Grey Relational Grade Method

In this research, an attempt has been made to find out the influence of the process parameter along with their interactions on the dimensional accuracy of part fabricated using two different rapid prototyping machines namely fused deposition modelling machine, and a low cost open source 3D printer. 3D open source printer (3D-OSP) is one of the newly developed rapid prototyping (RP) process for part fabrication. It has been observed from previous research that the contribution of parameters such as raster width, slice height, and path speed are the most significant to the dimensional accuracy of 3D open source product while raster width, slice height, and tip dimension are the most influencing factors for fused deposition modelling machine. Taguchi parameter design of experiment method has been used to find out the optimum parameters level to minimize percentage change in length (L1), length (L2) and height (H) of test specimens fabricated by each of these two rapid prototyping machines. Experimental result revels that there is different optimal parameters level setting for each dimensional characteristics namely change in length (L1), length (L2) and height (H). Therefore, grey relational method is used to obtain optimum factor level of each dimensional characteristic simultaneously. Dimensional accuracy of parts fabricated by two different technique namely 3D open source printer and fused deposition modelling machine is within a desired range. Appropriate controls of machine process parameters improve the dimensional accuracy of parts. It is concluded that a low cost 3D open source printer gave sufficient amount of part accuracy when it is compared with the industrial based fused deposition modelling machine.

Parametric Design and Rapid Prototyping of Installation Box for Vehicle Terminal PCB

Installation box for vehicle terminal PCB (Printed Circuit Board) was took as research object, which is encountered in the process of project developing. Vehicle terminal PCB in actual development process was set as an example, point cloud data were acquired by three coordinate measuring method; Imageware software was used to reconstruct the vehicle terminal PCB model, basic size parameters of vehicle terminal PCB can be got and then design parameters of installation box for vehicle terminal PCB can be determined. Design of the installation box for vehicle terminal PCB was completed based on Solidworks software, then 3D modeling and 2D drawing of installation box for vehicle terminal PCB was gained. Up Plus 2 rapid prototype machine was used to manufacture installation box for vehicle terminal PCB rapidly based on 3D printing technology, then prototype of installation box for vehicle terminal PCB was obtained. It is of certain engineering significant for single (small amount) manufacturing of installation box for general PCB.

Correction of nasal deformity in infants with unilateral cleft lip and palate using multiple digital techniques

Presurgical correction of severe nasal deformities before cheiloplasty is often recommended for infants with cleft lip and palate. This article describes an approach for the computer-aided design and fabrication of a nasal molding stent. A 3-dimensional photogrammetric system was used to obtain the shape information of the nosewing that was then built as the nostril support for the nasal molding stent. The stent was fabricated automatically with a rapid prototyping machine. This technique may be an alternative approach to presurgical nasal molding in the clinic. Moreover, the patient’s nasal morphology can be saved as clinical data for future study.

New Design for Rapid Prototyping of Digital Master Casts for Multiple Dental Implant Restorations.

AimThis study proposes the replacement of all the physical devices used in the manufacturing of conventional prostheses through the use of digital tools, such as 3D scanners, CAD design software, 3D implants files, rapid prototyping machines or reverse engineering software, in order to develop laboratory work models from which to finish coatings for dental prostheses. Different types of dental prosthetic structures are used, which were adjusted by a non-rotatory threaded fixing system.MethodFrom a digital process, the relative positions of dental implants, soft tissue and adjacent teeth of edentulous or partially edentulous patients has been captured, and a maser working model which accurately replicates data relating to the patients oral cavity has been through treatment of three-dimensional digital data.ResultsCompared with the conventional master cast, the results show a significant cost savings in attachments, as well as an increase in the quality of reproduction and accuracy of the master cast, with the consequent reduction in the number of patient consultation visits. The combination of software and hardware three-dimensional tools allows the optimization of the planning of dental implant-supported rehabilitations protocol, improving the predictability of clinical treatments and the production cost savings of master casts for restorations upon implants.

Global adaptive slicing of NURBS based sculptured surface for minimum texture error in rapid prototyping

Purpose – This paper aims to propose a global adaptive direct slicing technique of Non-Uniform Rational B-Spline (NURBS)-based sculptured surface for rapid prototyping where the NURBS representation is directly extracted from the computer-aided design (CAD) model. The imported NURBS surface is directly sliced to avoid inaccuracies due to tessellation methods used in common practice. The major objective is to globally optimize texture error function based on the available range of layer thicknesses of the utilized rapid prototyping machine. The total texture error is computed with the defined error function to verify slicing efficiency of this global adaptive slicing algorithm and to find the optimum number of slices. A variety of experiments are conducted to study the accuracy of the developed procedure, and the results are compared with previously developed algorithms. Design/methodology/approach – This paper proposes a new adaptive algorithm which globally optimizes a texture error function produced by staircase effect for a user-defined number of layers. The adaptive slicing algorithm dynamically calculates optimized slicing thicknesses based on the rapid prototyping machine’s specifications to minimize the texture error function. This paper also compares the results of implementing the developed methodology with the results of previously developed algorithms and presents cost-effective optimum slicing layer thicknesses. Findings – A new methodology for global adaptive direct slicing algorithm of CAD models, based on a texture error function for the final product and the possible layer thicknesses in rapid prototyping, has been developed and implemented. Comparing the results of implementation with the common practice for several case studies shows that the proposed approach has greater slicing efficiency. Typically, by utilizing this approach, the number of prototyping layers can be reduced by 20-50 per cent compared to the slicing with other algorithms, while maintaining or improving the accuracy of the final manufactured surfaces. Therefore, the developed slicing method provides a better solution to trade-off between the rapid prototyping time and the rapid prototyping accuracy. For the many advantages of global direct slicing, it can be seen as the future solution to the slicing process in rapid prototyping systems. Originality/value – This paper presents an innovative approach in direct global adaptive slicing of the additive manufacturing parts. The novel definition of an error function which comprehensively addresses the resulting manufactured surface quality of the entire product allows presenting an objective function to solve and to find the optimum selection of all the layer thicknesses during the slicing process.

Implementation of Computer Aided Engineering for Francis Turbine Development in Nepal

The expansion of the existing industries involved in the production of components of hydropower to the Francis turbine manufacturer up to 5 MW unit size has been recognized as one of the most promising business models in Nepal. Given the current fact that the development of Francis turbines with the manufacturers of Nepal has not been done yet, due to lack of designing expertise and limitations in the available technology, this paper presents the use of different available manufacturing technologies, which is suitable in the Nepalese hydropower market. This is an experience based paper, in which the advanced manufacturing process implementing Computer Aided Simulation (CAS), Computer Aided Design (CAD), and Computer Aided Manufacturing (CAM) is introduced for turbine manufacturing. Moreover, CAD from Solidworks, 3D printing from Rapid Prototyping Machine (RPM), and manufacturing of three designs by three different methods, dye casting, lost wax casting, and forging in a local workshop, have been described. The outcome of this work is the identification of suitable Francis turbine development methodologies in context of Nepal, incorporating industrial revolution through research based products.

A Study on Generic Representation of Skeletal Remains Replication of Prehistoric Burial

Abstract. Generic representation of skeletal remains from burials consists of three dimensions which include physical anthropologists, replication technicians, and promotional educators. For the reason that archaeological excavation is irreversible and disruptive, detail documentation and replication technologies are surely needed for many purposes. Unearthed bones during the process of 3D digital scanning need to go through reverse procedure, 3D scanning, digital model superimposition, rapid prototyping, mould making, and the integrated errors generated from the presentation of colours and textures are important issues for the presentation of replicate skeleton remains among professional decisions conducted by physical anthropologists, subjective determination of makers, and the expectations of viewers. This study presents several cases and examines current issues on display and replication technologies for human skeletal remains of prehistoric burials. This study documented detail colour changes of human skeleton over time for the reference of reproduction. The tolerance errors of quantification and required technical qualification is acquired according to the precision of 3D scanning, the specification requirement of rapid prototyping machine, and the mould making process should following the professional requirement for physical anthropological study. Additionally, the colorimeter is adopted to record and analyse the “colour change” of the human skeletal remains from wet to dry condition. Then, the “colure change” is used to evaluate the “real” surface texture and colour presentation of human skeletal remains, and to limit the artistic presentation among the human skeletal remains reproduction. The“Lingdao man No.1”, is a well preserved burial of early Neolithic period (8300 B.P.) excavated from Liangdao-Daowei site, Matsu, Taiwan , as the replicating object for this study. In this study, we examined the reproduction procedures step by step for ensuring the surface texture and colour of the replica matches the real human skeletal remains when discovered. The “colour change” of the skeleton documented and quantified in this study could be the reference for the future study and educational exhibition of human skeletal remain reproduction.

Does Access to Rapid Prototyping Enhance Student Vision-ization?

At its core, engineering technical design is the process of taking a concept to creation. In order to achievesuccessful technical design a student must combine their idea or vision of a solution (function) with a visualization of thepart/assembly (form) -- referred to henceforth as vision-ization. Teaching technical design to a large first-year class ofengineering students presents a number of challenges, but perhaps the most significant is the rapid change of the toolsused in engineering technical design. To be clear, the tools themselves are not the challenge, as the students generallyhave no trouble mastering the tools. The challenge lies in the teaching and ultimately the learning objectives; at aUniversity level the fundamental question is what pedagogical benefit does a tool provide without the knowledge to applyit? As the tools have advanced, the students (and the instructors) find themselves further from the design process resultingin course topics perceived as disconnected or without relevance. In 2006 McMaster University's first-year engineeringprogram departed from the traditional method of teaching engineering design, which was heavily focussed on form, toestablish design function as the primary objective of the course. With a yearly enrolment near 1000 students, thescalability of teaching and evaluating design function was implemented using a customized simulation and visualizationtool. The simulation was extended to the logical use of rapid prototyping machines (3D-printers) for physical creation andtesting. This paper will present the author's initial analysis of the link between pure visualization, applied visualization,and success in functional design via rapid prototyping..

COMPUTER AIDED DESIGN AND FABRICATION OF A CUSTOM ARTICULATED ANKLE FOOT ORTHOSIS

Traditional design and manufacturing methods of ankle foot orthosis (AFO) involve manual techniques e.g., casting and molding of the limbs and often depend on trial and error. Three-dimensional scanning allows computer aided design (CAD) tools to be incorporated, however, both approaches rely on the external model of the limb. To design AFO with articulated joint, precise alignment of mechanical and anatomical joint axes is imperative. It is difficult to infer joint axis from external model as it is partially specified by the skeletal structure. In this article, a computer integrated design approach of an articulated AFO has been demonstrated. CAD model of the AFO was developed for a healthy subject's left leg based on the 3D models of skeleton and soft tissue of the limb. Components of the AFO were fabricated by rapid prototyping and CNC machining. The design approach is faster than the traditional techniques and also facilitates exact positioning of articulated ankle joint. The gait analysis indicates that the subject's ankle had to overcome lesser resistance with the custom made AFO compared to a pre-fabricated AFO. Simultaneous viewing of exterior and skeletal geometry might help the clinicians modify the design to enhance performance of the orthotic.

The Data Combining Method and the Forming Control Algorithm from the 3D Scanning Machine and Processing in the SLS Machine

This paper presents the data structure combining from 3D laser scanners direction, for processing rapid prototyping by SLS machine. Formed data will have special structure for combining with the rapid prototyping machine and processing will be more directly and easily. Control algorithm automatically identifies the images from the scanning data.

Computer-Aided Design and Computer-Aided Manufacturing Hydroxyapatite/Epoxide Acrylate Maleic Compound Construction for Craniomaxillofacial Bone Defects

The aim of this study was to investigate the use of computer-aided design and computer-aided manufacturing hydroxyapatite (HA)/epoxide acrylate maleic (EAM) compound construction artificial implants for craniomaxillofacial bone defects. Computed tomography, computer-aided design/computer-aided manufacturing and three-dimensional reconstruction, as well as rapid prototyping were performed in 12 patients between 2008 and 2013. The customized HA/EAM compound artificial implants were manufactured through selective laser sintering using a rapid prototyping machine into the exact geometric shapes of the defect. The HA/EAM compound artificial implants were then implanted during surgical reconstruction. Color-coded superimpositions demonstrated the discrepancy between the virtual plan and achieved results using Geomagic Studio. As a result, the HA/EAM compound artificial bone implants were perfectly matched with the facial areas that needed reconstruction. The postoperative aesthetic and functional results were satisfactory. The color-coded superimpositions demonstrated good consistency between the virtual plan and achieved results. The three-dimensional maximum deviation is 2.12 ± 0.65 mm and the three-dimensional mean deviation is 0.27 ± 0.07 mm. No facial nerve weakness or pain was observed at the follow-up examinations. Only 1 implant had to be removed 2 months after the surgery owing to severe local infection. No other complication was noted during the follow-up period. In conclusion, computer-aided, individually fabricated HA/EAM compound construction artificial implant was a good craniomaxillofacial surgical technique that yielded improved aesthetic results and functional recovery after reconstruction.

Feasibility Study: Investigation of Polymer Nano-Composites (PNC) Material for Biomedical Application via Fused Deposition Modelling (FDM) Routes

Polymer nanocomposites (PNC) have emerged as new materials which can show significantly enhanced mechanical properties over other polymer based materials through the addition of relatively small amounts of nanoscale additives. Rapid prototyping is impacting biomedical in several important ways. This research aims to investigate the potential of using new polymer nanocomposites (PNC) as a raw material for fused deposition modelling machine (FDM). Here, PNCs materials containing a polyamide (PA) and nanoparticles (<5wt%) will be synthesis by mechanical blending using twin extruder compounder to produce 0.85mm diameter of PNC. Dispersion analysis of the nanoparticles in the polymer matrix will be analyzed during the preparation and synthesis process. Futhermore, molecular binding and mixture structure will be investigated by using XPS analysis & Laser Raman Spectroscopy. Material will be characterized for their thermal properties using DSC and processed using FDM, the commercial rapid prototyping (RP) machine. The RP processing parameters will be established and used to produce test specimens to evaluate the mechanical properties of the PNC.

Mechanical and thermal properties of photopolymer/CB (carbon black) nanocomposite for rapid prototyping

Purpose – The purpose of this paper is to evaluate the mechanical properties of photopolymer/CB (carbon black) nanocomposite when applied in a visible-light rapid prototyping (RP) machine. Design/methodology/approach – The mechanical properties of the samples such as hardness and tensile strength along with thermal stability were analyzed. The curing time behavior of the photopolymer/CB nanocomposites was tested by using a rigid-body pendulum rheometer. The shrinkage property and dimensional stability were also analyzed using the technique according to ASTM D2566 and ASTM D1204, respectively. Findings – The results showed that the prototype fabricated from pristine photopolymer tended to exhibit poor mechanical properties and low thermal stability. However, after adding the photopolymer with various concentrations of nano-CB and dispersant in appropriate composition, the photopolymer/CB nanocomposite prototype not only reduced its curing time but also enhanced its mechanical properties, thermal stability and dimensional stability. Practical implications – The presented results can be used in a visible-light RP machine. Originality/value – The mechanical and thermal properties of photopolymer are improved with nano-CB additives for a RP system.

Modeling Design of Plastic Bottles Based on Laser Scanner and Rapid Prototyping Technology

Accurate surface modeling of washing liquid bottle is to get through RP technology. Point cloud data of washing liquid bottle is obtained by hand-held laser scanner and processed by Imageware software, 3D model is got by Pro/E. Rapid prototyping machine is used to print solid model. High precision model built by ABS is easily got without complex processes.