Showing papers in "Rapid Prototyping Journal in 2012"

Additive manufacturing: rapid prototyping comes of age

Abstract: Purpose – The purpose of this paper is to provide a personalised view by the Editors of the Rapid Prototyping Journal.Design/methodology/approach – It collects their years of experience in a series of observations and experiences that can be considered as a snapshot of where this technology is today.Findings – Development of these technologies has progressed according to application, materials and how the designers have applied their creativity to such a unique manufacturing tool.Originality/value – The paper predicts how the future of additive manufacturing will look from the perspective of three key elements: applications, materials and design.

Integrating stereolithography and direct print technologies for 3D structural electronics fabrication

Abstract: Purpose – The purpose of this paper is to present a hybrid manufacturing system that integrates stereolithography (SL) and direct print (DP) technologies to fabricate three‐dimensional (3D) structures with embedded electronic circuits. A detailed process was developed that enables fabrication of monolithic 3D packages with electronics without removal from the hybrid SL/DP machine during the process. Successful devices are demonstrated consisting of simple 555 timer circuits designed and fabricated in 2D (single layer of routing) and 3D (multiple layers of routing and component placement).Design/methodology/approach – A hybrid SL/DP system was designed and developed using a 3D Systems SL 250/50 machine and an nScrypt micro‐dispensing pump integrated within the SL machine through orthogonally‐aligned linear translation stages. A corresponding manufacturing process was also developed using this system to fabricate 2D and 3D monolithic structures with embedded electronic circuits. The process involved part de...

Suitability of PLA/TCP for fused deposition modeling

Abstract: Purpose – Fused deposition modeling (FDM) is a layer by layer technology with the potential to create complex and individual parts from thermoplastic materials such as ABS. The use of Polylactic acid (PLA) and tricalcium phosphate (TCP) as resorbable composite is state of the art in tissue engineering and maxillofacial surgery. The purpose of this paper is to evaluate the processing conditions and the performance of parts (e.g. mechanical properties) manufactured with a FDM machine.Design/methodology/approach – In this paper, the general suitability of PLA for the processing with FDM is evaluated and material specific effects (e.g. crystallization and shrinkage) are shown. Therefore, the characterization of the semi‐crystalline biodegradable material by thermal, mechanical and microscopic analysis is carried out.Findings – Facts, which affect the functional properties of the samples, are analyzed. Among them, the processing temperature and sample size significantly affect the morphology of the final compo...

Factor analysis of selective laser melting process parameters and geometrical characteristics of synthesized single tracks

Abstract: Purpose – Properties of the parts manufactured by selective laser melting (SLM) depend strongly on the each single laser‐melted track and each single layer, as well as the strength of the connections between them. The purpose of this paper to establish links between the principal SLM parameters (laser power density, scanning speed, layer thickness), properties of the powder and geometrical characteristics of single tracks. This study will provide a theoretical and technical basis for production of parts from metal powders.Design/methodology/approach – This paper discusses the SLM parameters affecting on geometrical characteristics of the synthesized single tracks. Granulomorphometric characteristics of powders were studied in detail. A Greco‐Latin square design was used to control geometrical characteristics of the tracks. Analysis of variance (ANOVA) permitted to establish a statistically significant influence of the SLM process parameters on geometry of the single laser‐melted track.Findings – The behav...

Effect of process parameters settings and thickness on surface roughness of EBM produced Ti‐6Al‐4V

Abstract: Purpose – Ti‐6Al‐4V is one of the most attractive materials being used in aerospace, automotive and medical implant industries. Electron beam melting (EBM) is one of the direct digital manufacturing methods to produce complex geometries of fully dense and near net shape parts. The EBM system provides an opportunity to built metallic objects with different processing parameter settings like beam current, scan speed, probe size on powder, etc. The purpose of this paper is to determine and understand the effect of part's thickness and variation in process parameter settings of the EBM system on surface roughness/topography of EBM fabricated Ti‐6Al‐4V metallic parts.Design/methodology/approach – A mathematical model based upon response surface methodology (RSM) is developed to study the variation of surface roughness with changing process parameter settings. Surface roughness of the test slabs produced with different parameter settings and thickness has been studied under confocal microscope. Response surface...

Patient‐specific reconstruction with 3D modeling and DMLS additive manufacturing

Abstract: Purpose – The purpose of this paper is to develop a workflow for 3D modeling and additive manufacturing (AM) of patient‐specific medical implants. The comprehensive workflow consists of four steps: medical imaging; 3D modelling; additive manufacturing; and clinical application. Implants are used to reconstruct bone damage or defects caused by trauma or disease. Traditionally, implants have been manually bent and shaped, either preoperatively or intraoperatively, with the help of anatomic solid models. The proposed workflow obviates the manual procedure and may result in more accurate and cost‐effective implants.Design/methodology/approach – A patient‐specific implant was digitally designed to reconstruct a facial bone defect. Several test pieces were additive manufactured from stainless steel and titanium by direct metal laser sintering (DMLS) technology. An additive manufactured titanium EOS Titanium Ti64 ELI reconstruction plate was successfully implanted onto the patient's injured orbital wall.Findings...

Property evaluation of 304L stainless steel fabricated by selective laser melting

Abstract: Purpose – Additive manufacturing raw material cost has been recently confirmed as a significant obstacle to widespread deployment of these technologies in industry. Aiming at reducing the cost of the selective laser melting (SLM) process, the purpose of this paper is to evaluate the different properties of products fabricated by SLM using low‐cost ($10/Kg) feedstock 304L stainless steel powders. The entire process cost was also evaluated.Design/methodology/approach – Using an experimental approach, 24 samples with different shapes and sizes were fabricated with layer thickness of 30, 50 and 70 μm and laser scanning speed set at 70 and 90 mm/s. Part geometry, dimensional tolerance, surface quality, density, mechanical properties and microstructure were evaluated.Findings – Results confirmed that the SLM of low‐cost 304L powder was successful and could produce functional parts with fine details and small wall thickness. Using small layer thickness and low scanning speed improved the properties by more than ...

Effect of process parameters on the morphological and mechanical properties of 3D Bioextruded poly(ε‐caprolactone) scaffolds

Abstract: Purpose – This paper aims to report a detailed study regarding the influence of process parameters on the morphological/mechanical properties of poly(e‐caprolactone) (PCL) scaffolds manufactured by using a novel extrusion‐based system that is called BioExtruderDesign/methodology/approach – In this study the authors focused investigations on four parameters, namely the liquefier temperature (LT), screw rotation velocity (SRV), deposition velocity (DV) and slice thickness (ST) Scaffolds were fabricated by employing three different values of each parameter Through a series of trials, scaffolds were manufactured varying iteratively one parameter while maintaining constant the other ones The morphology of the structures was investigated using a scanning electron microscope (SEM), whilst the mechanical performance was assessed though compression testsFindings – Experimental results highlight a direct influence of the process parameters on the PCL scaffolds properties In particular, DV and SRV have the hig

Effects of environmental conditions, aging, and build orientations on the mechanical properties of ASTM type I specimens manufactured via stereolithography

Abstract: Purpose – The purpose of this paper is to investigate the effects of aging, pre‐conditioning, and build orientation on the mechanical properties of test samples fabricated using stereolithography (SL) and a commercially available resin.Design/methodology/approach – American Society for Testing and Materials (ASTM) Standard D638 Type I specimens were manufactured in a Viper si2 SL system using WaterShed™ 11120 resin. The specimens were manufactured in two different build setups, designed to fit batches of 18 or 24 specimens with different build orientations. The specimens were randomly tested in tension, and a design of experiments (DOE) was used to determine the effect of aging (4, 30 or 120 days), pre‐conditioning (ambient, desiccant, or ASTM recommended conditioning), and build orientation (flat, on an edge, or vertical) on the ultimate tensile stress (UTS) and elastic modulus (E) of SL fabricated samples. Additionally, the fractured samples were imaged using scanning electron microscopy (SEM) to charac...

Effect of selective laser melting layout on the quality of stainless steel parts

Abstract: Purpose – Selective laser melting (SLM) is increasingly used for the manufacture of end‐use metal tools and parts, requiring the careful identification of a range of appropriate process parameters and conditions to achieve desirable properties and quality. Process conditions such as the relation between layout of parts and internal gas flow within the SLM platform can influence the consolidation of metal powers and therefore the quality and properties of the final parts. The purpose of this paper is to investigate the effect of part layout on quality and mechanical properties of cylindrical 316L stainless steel parts manufactured by SLM.Design/methodology/approach – The cylindrical 316L stainless steel parts were manufactured in two directions, one perpendicular to the gas flow direction and one parallel to it. The investigation first focuses on visual inspection and porosity measurements to compare the quality factors such as delamination and porosity of the parts. A mechanical test procedure including t...

In situ flaw detection by IR‐imaging during electron beam melting

Abstract: Purpose – The purpose of this paper is to investigate the possibility of in situ flaw detection for powder bed, beam‐based additive manufacturing processes using a thermal imaging system.Design/methodology/approach – The authors compare infrared images (IR) which were taken during the generation of Ti‐6Al‐4V parts in a selective electron beam melting system (SEBM) with metallographic images taken from destructive material investigation.Findings – A good match is found between the IR images and the material flaws detected by metallographic techniques.Research limitations/implications – First results are presented here, mechanisms of flaw formation and transfer between build layers are not addressed in detail.Originality/value – This work has important implications for quality assurance in SEBM and rapid manufacturing in general.

Rapid manufacturing of metallic objects

Abstract: Purpose – The purpose of this paper is to review additive and/or subtractive manufacturing methods for metallic objects and their gradual evolution from prototyping tools to rapid manufacture of actual parts.Design/methodology/approach – Various existing rapid manufacturing (RM) methods have been classified into six groups, namely, CNC machining laminated manufacturing, powder‐bed technologies, deposition technologies, hybrid technologies and rapid casting technologies and discussed in detail. The RM methods have been further classified, based on criteria such as material, raw material form, energy source, etc. The process capabilities springing from these classifications are captured in the form of a table, which acts as a database.Findings – Due to the approximation in RM in exchange for total automation, a variety of multi‐faceted and hybrid approaches has to be adopted. This study helps in choosing the appropriate RM process among these myriad technologies.Originality/value – This review facilitates i...

Fabrication of a bio‐inspired beta‐Tricalcium phosphate/collagen scaffold based on ceramic stereolithography and gel casting for osteochondral tissue engineering

Abstract: Purpose – The purpose of this paper is to fabricate and characterize osteochondral beta‐tricalcium phosphate/collagen scaffold with bio‐inspired design by ceramic stereolithography (CSL) and gel casting.Design/methodology/approach – Histological analysis was applied to explore the morphological characteristics of the transitional structure between the bone and the cartilage. The acquired data were used to design biomimetic biphasic scaffolds, which include the bone phase, cartilage phase, and their transitional structure. The engineered scaffolds were fabricated from β‐TCP‐collagen by CSL and gel casting. The cartilage phase was added to the ceramic phase by gel‐casting and freeze drying.Findings – The resulting ceramic scaffolds were composed of a bone phase with the following properties: 700‐900 μm pore size, 200‐500 μm interconnected pores size, 50‐65 percent porosity, fully interconnected, ∼12 Mpa compressive strength. A suitable binding force between cartilage phase and ceramic phase was achieved by ...

First Demonstration on Direct Laser Fabrication of Lunar Regolith Parts

Abstract: Purpose – The purpose of this paper is to evaluate the feasibility of direct fabrication of lunar/Martian regolith simulant parts, in a freeform environment, using Laser Engineering Net Shaping (LENS™) – an additive manufacturing technology.Design/methodology/approach – Bulk lunar regolith simulant structures were fabricated using a LENS™‐750. Dense parts without any macroscopic defects were produced at a laser power of 50W, a scan speed of 20 mm/s, and a powder feed rate of 12.36 g/min. The laser processed parts were characterized using X‐ray diffraction, differential scanning calorimetry, scanning electron microscope and X‐ray photoelectron spectroscopy to evaluate the influence of laser processing on the microstructure, constituent phases and chemistry of lunar regolith simulant.Findings – A combination of laser parameters resulting in a 2.12 J/mm2 laser energy appeared to be ideal for generating a melt pool necessary for lunar regolith powder deposition without excessive liquid pool spreading and crac...

A comparison of the energy efficiency of selective laser sintering and injection molding of nylon parts

Abstract: Purpose – The purpose of this paper is to evaluate the energy consumed to fabricate nylon parts using selective laser sintering (SLS) and to compare it with the energy consumed for injection molding (IM) the same parts.Design/methodology/approach – Estimates of energy consumption include the energy consumed for nylon material refinement, adjusted for SLS and IM process yields. Estimates also include the energy consumed by the SLS and IM equipment for part fabrication and the energy consumed to machine the injection mold and refine the metal feedstock required to fabricate it. A representative part is used to size the injection mold and to quantify throughput for the SLS machine per build.Findings – Although SLS uses significantly more energy than IM during part fabrication, this energy consumption is partially offset by the energy consumption associated with production of the injection mold. As a result, the energy consumed per part for IM decreases with the number of parts fabricated while the energy con...

Experimental design approach to optimize selective laser melting of martensitic 17‐4 PH powder: part I – single laser tracks and first layer

Abstract: Purpose – The purpose of this paper is to investigate the effect of main process parameters of selective laser melting (SLM) technology on single lines and single layers manufactured from 17‐4 PH martensitic powder using the experimental design approachDesign/methodology/approach – A fractional factorial approach has been applied to vary and to identify the optimal set of process parameters using three different powder particle size distributions for 17‐4 PH steel This paper assesses the impact of influence factors such as process and material parameters on objective factors such as dimension of single lines and single layers, as well as surface roughnessFindings – The influence of process parameters and materials properties on single line and single layer manufacture is shown and proved statistically The effect of each process parameter and their interactions on single layer and single line stability and quality has been investigated, and a complex objective function analyzing geometrical stability o

Accuracy and density optimization in directly fabricating customized orthodontic production by selective laser melting

Abstract: Purpose – The purpose of this paper is to investigate the research approach to optimize shape accuracy, dimensional accuracy and density of customized orthodontic production fabricated by selective laser melting (SLM).Design/methodology/approach – A series of process experiments were applied to fabricating customized brackets directly by SLM, using 316L stainless steel. Shape accuracy can be optimized through the study on fabricating characteristics of non‐support overhanging structure. A scanning strategy combining contour scanning with orthogonal scanning, which differ in scanning speed and spot compensations, was proposed to improve dimensional accuracy. Scanning laser surface re‐melting was added to enhance the SLM density.Findings – Optimized SLM parameters lead to high shape precision of customized brackets, and the average size error of bracket slot is less than 10 μm. The customized brackets density is more than 99 per cent, and the surface quality and mechanical properties meet the requirements.O...

Design, fabrication, and evaluation of negative stiffness elements using SLS

Abstract: Purpose – Recent research has shown that constrained bistable structures can display negative stiffness behavior and provide extremal vibrational and acoustical absorptive capacity. These bistable structures are therefore compelling candidates for constructing new meta‐materials for noise reduction, anechoic coatings, and backing materials for broadband imaging transducers. To date, demonstrations of these capabilities have been primarily theoretical because the geometry of bistable elements is difficult to construct and refine with conventional manufacturing methods and materials. The purpose of this paper is to leverage the geometric design freedoms provided by selective laser sintering (SLS) technology to design and construct constrained bistable structures with negative stiffness behavior.Design/methodology/approach – A meso‐scale negative stiffness system is designed and fabricated with SLS technology. The system includes a bistable structure in the form of a pre‐compressed/pre‐buckled beam. The dyna...

Isostatic pressing assisted indirect selective laser sintering of alumina components

Abstract: Purpose – The purpose of this paper is to assess a new powder metallurgy process to make alumina parts through indirect selective laser sintering (SLS). Density measurements, some geometrical assessments and scanning electron microscopy (SEM) microstructural analyses are performed after each stage of the process, allowing an objective overview to be provided of the challenges and possibilities for the processing of high density technical ceramic parts through SLS of ball milled alumina/polyamide powder agglomerates.Design/methodology/approach – The powder production by ball milling, SLS, cold isostatic pressing (CIP) or quasi isostatic pressing (QIP), debinding and sintering (FS) stages of the powder metallurgy process were sequentially investigated.Findings – Alumina parts with a density up to 94.1 per cent could be produced by a powder metallurgy process containing an SLS step. Microstructural investigation of the sintered samples reveals an alumina matrix with a grain size of ∼5 μm and two different ki...

Selective laser melting (SLM) of gold (Au)

Abstract: Purpose – Different metals have been processed using laser‐based solid freeform fabrication (SFF) processes but very little work has been published on the selective laser melting (SLM) of gold (Au). The purpose of this paper is to check the properties of gold powder and identify suitable processing parameters for SLM of 24 carat gold powder.Design/methodology/approach – A full factorial approach was used to vary the processing parameters and identify suitable processing region for gold powder. The effects of laser processing parameters on the internal porosity of the multi‐layer parts were examined.Findings – The gold powder was found to be cohesive in nature with apparent and tap densities of 9.3 and 10.36 g/cm3, respectively. The reflectance of gold powder was found to be 85 per cent in the infrared range. A very narrow good melting region was identified for gold powder. The balling phenomenon was observed at both low and high scan speeds. The size of droplets in the balling region tended to increase wi...

Laser sintering of blended Al‐Si powders

Abstract: Purpose – The purpose of this paper is to study the effects of particle size distribution, component ratio, particle packing arrangement, and chemical constitution on the laser sintering behaviour of blended hypoeutectic Al‐Si powders.Design/methodology/approach – A range of bimodal and trimodal powder blends were created through mixing Al‐12Si and pure aluminium powder. The powder blends were then processed using selective laser sintering to investigate the effect of alloy composition, powder particle size and bed density on densification and microstructural evolution.Findings – For all of the powder blends the sintered density increases with the specific laser energy input until a saturation level is reached. Beyond this saturation level no further increase in sintered density is obtained for an increase in specific laser energy input. However, the peak density achieved for a given blend varied significantly with the chemical constitution of the alloy, peaking at approximately 9 wt% Si. The tap density ...

The effects and interactions of fabrication parameters on the properties of selective laser sintered hydroxyapatite polyamide composite biomaterials

Abstract: Purpose – Hydroxyapatite‐polymer composite materials are being researched for the development of low‐load bearing implants because of their bioactive and osteoconductive properties, while avoiding modulus mismatch found in homogenous materials. For the direct production of hydroxyapatite‐polymer composite implants, selective laser sintering (SLS) has been used and various parameters and their effects on the physical properties (micro and macro morphologies) have been investigated. The purpose of this paper is to identify the most influential parameters on the micro and macro pore morphologies of sintered hydroxyapatite‐polymer composites.Design/methodology/approach – A two‐level full factorial experiment was designed to evaluate the effects of the various processing parameters and their effects on the physical properties, including open porosity, average pore width and the percentage of pores which could enable potential bone regeneration and ingrowth of the sintered parts. The density of the sintered par...

Influence of printing parameters on the transformation efficiency of 3D‐printed plaster of paris to hydroxyapatite and its properties

Abstract: Purpose – The purpose of this paper is to study the influence of changing printing parameters (powder layer thickness and binder saturation) in a three dimensional printing machine (3DP) on the transformation of 3DP printed plaster of paris to hydroxyapatite by low temperature phosphorization.Design/methodology/approach – Plaster of paris‐based powder mixture was used to print specimens using different powder layer thickness (0.080, 0.10 and 0.20 mm) and saturation ratio (1 and 2). Subsequently, density, microstructure, mechanical properties, transformation rate and phase composition were analyzed to compare the influence of such printing parameters on properties.Findings – It was found that printing parameters strongly affect the transformation efficiency and properties of the samples. The sample printed at layer thickness of 0.10 mm and saturation ratio of 1 yielded the highest transformation rate, density and greatest flexural modulus and strength after conversion. This was related to the sufficiently ...

A study on the fabrication method of removable partial denture framework by computer‐aided design and rapid prototyping

Abstract: Purpose – The purpose of this paper is to explore an application of computer‐aided design and manufacture (CAD/CAM) to a process of electronically surveying a scanned dental cast as a prior stage to producing a sacrificial pattern for a removable partial denture (RPD) metal alloy framework.Design/methodology/approach – With the introduction of laser scan technology and commercial reverse engineering software, a standard plaster maxillary dental cast with dentition defect was successfully scanned and created as a STL‐formatted digital cast. With the software, the unwanted undercuts were eliminated based on the desired path of insertion. Parts of the RPD framework were then successfully custom‐designed and combined as a whole.Findings – A sacrificial pattern was produced by rapid prototyping (RP) method and finally casted with chromium cobalt alloy. With suitable finishing process, both the sacrificial pattern and the casted framework fitted the cast well.Originality/value – The research indicated the feasi...

Influence of surface characteristics on fatigue behaviour of laser sintered plastics

Abstract: Purpose – The purpose of this paper is to provide macromechanical insight into the fatigue behaviour of laser sintered parts and to understand the influence of the laser sintered surface structure on this behaviour.Design/methodology/approach – A background on the technological maturity of manufacturing processes and the demand for structural and aesthetic properties of laser sintered plastic products is given. As the contribution of surface structure on part quality was the focus, laser sintered specimens with and without surface finishes, as well as injection moulded specimens were used. The latter simply served as a comparison and was not intended to qualify injection moulding. The study comprises the determination of short‐term tensile properties, the load increase method for investigating fracture and deformation behaviours, and fatigue crack propagation analysis.Findings – According to the test results, the contribution of laser sintered surface structures to relevant mechanical properties can be ne...

Rapid prototyping of porcelain products by layer‐wise slurry deposition (LSD) and direct laser sintering

Abstract: Purpose – The purpose of this paper is to study the rapid prototyping of porcelain products by using layer‐wise slurry deposition (LSD), in order to reduce the time to market of new or customized porcelain products or artworks.Design/methodology/approach – The properties such as phase composition, microstructure, shrinkage, density, and mechanical strength, of laser sintered (LS) and biscuit fired (BF) samples, before and after post sintering in a furnace, were studied and compared with each other.Findings – The laser sintered sample was comparable with the biscuit fired sample in porosity, but had just half the mechanical strength of the latter due to the layer‐wise fabrication process. The feasibility of rapid prototyping of porcelain products was validated by the successful fabrication of some porcelain samples, which showed that the relatively low mechanical strength of the laser sintered sample was still high enough for the following handling processes, such as surface glazing and glost firing.Origin...

Metallic part fabrication using selective inhibition sintering (SIS)

Abstract: Purpose – The purpose of this paper is to investigate the fundamentals of the selective inhibition sintering (SIS) process for fabricating dense metallic parts.Design/methodology/approach – A SIS‐Metal process based on the microscopic mechanical inhibition is developed. In the process, salt solution is printed in the selected area of each powder layer; the salt re‐crystallizes when water evaporates; salt crystals decompose and grow rapidly prior to sintering; the generated salt particles spread between metal powder particles and prevent the fusing of these particles together, hence inhibiting the sintering process in the affected regions.Findings – The SIS‐Metal process has numerous advantages. An inhibition of sintering mechanism is established for the future development of the technology. Through chemical and visual analysis using STM the mechanism for the inhibition phenomenon has been identified.Research limitations/implications – Only bronze powder has been used in the research. Accordingly, the inhi...

Joining mechanisms and mechanical properties of PA composites obtained by selective laser sintering

Abstract: Purpose – Additive manufacturing is today a viable industrial solution alongside traditional processes. Techniques like selective laser sintering (SLS) address the issues of digital production and mass customization in a variety of materials. Composite parts can be obtained with specific functional and mechanical properties. Building orientation during additive manufacturing often causes anisotropy of parts' properties that is still unspecified in technical information. The purpose of this paper is to investigate the mechanical performances and failure mechanisms of an aluminium‐filled polyamide and of a new alumina‐polyamide composite produced by SLS, in comparison with unfilled PA.Design/methodology/approach – A specific focus is set on the evaluation of primary and secondary anisotropy in the case of metal or ceramic filler, as well as on the specific contribution of powder distribution modes and joining phenomena. Macroscopic mechanical tests and the observation of joining and failure micro‐mechanisms...

Obtaining desired surface roughness of castings produced using ZCast direct metal casting process through Taguchi's experimental approach

Abstract: Purpose – The purpose of this paper is to investigate experimentally the effect of volume of casting, pouring temperature of different materials and shell mould wall thickness on the surface roughness of the castings obtained by using ZCast direct metal casting process.Design/methodology/approach – Taguchi's design of experiment approach was used for this investigation. An L9 orthogonal array (OA) of Taguchi design which involves nine experiments for three factors with three levels was used. Analysis of variance (ANOVA) was then performed on S/N (signal‐to‐noise) ratios to determine the statistical significance and contribution of each factor on the surface roughness of the castings. The castings were obtained using the shell moulds fabricated with the ZCast process and the surface roughness of castings was measured by using the surface roughness tester.Findings – Taguchi's analysis results showed that pouring temperature of materials was the most significant factor in deciding the surface roughness of th...

An improved methodology for design of custom‐made hip prostheses to be fabricated using additive manufacturing technologies

Abstract: Purpose – The purpose of this paper is to present an improved methodology for design of custom‐made hip prostheses, through integration of advanced image processing, computer aided design (CAD) and additive manufacturing (AM) technologies.Design/methodology/approach – The proposed methodology for design of custom‐made hip prostheses is based on an independent design criterion for each of the intra‐medullary and extra‐medullary portions of the prosthesis. The intra‐medullar part of the prosthesis is designed using a more accurate and detailed description of the 3D geometry of the femoral intra‐medullary cavity, including the septum calcar ridge, so that an improved fill and fit performance is achieved. The extra‐medullary portion of the prosthesis is designed based on the anatomical features of the femoral neck, in order to restore the original biomechanical characteristics of the hip joint. The whole design procedure is implemented in a systematic framework to provide a fast, repeatable and non‐subjective...