CAD and AM-fabricated moulds for fast cranio-maxillofacial implants manufacture

2016 ◽  
Vol 22 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Leopoldo Ruiz-Huerta ◽  
Yara Cecilia Almanza-Arjona ◽  
Alberto Caballero-Ruiz ◽  
Homero Alberto Castro-Espinosa ◽  
Celia Minerva Díaz-Aguirre ◽  
...  
Keyword(s):  
Waiting Time ◽  
Lead Time ◽  
Public Hospitals ◽  
Fused Deposition Modelling ◽  
Content Type ◽  
Fused Deposition ◽  
General Terms ◽  
Injury Model ◽  
Number Of Patients ◽  
Custom Made

Purpose – The purpose of this study is to suggest the joint use of computer-aided design (CAD) and additive manufacturing (AM) technology for the fabrication of custom-made moulds, designed for the manufacture of polymethyl methacrylate (PMMA) implants for cranio-maxillofacial reconstruction to reduce their fabrication time. Even though tailor-made skull prostheses with a high technological level and state-of-the-art materials are available in the market, they are not always accessible to the general population in developing countries. Design/methodology/approach – Computed tomography data were handled to create a three-dimensional (3D) model of the injury of the patient, by reconstructing Digital Imaging and Communications in Medicine (DICOM) images into an Standard Tessellation Language (STL) file that was further used to design the corresponding implant using CAD software. Accordingly, a two-piece core and cavity moulds that replicated the implant geometry was also CAD designed. The 3D-CAD data were sent to an AM machine (fused deposition modelling) and the moulds were fabricated using polycarbonate as thermoplastic material. A reacting mixture to produce PMMA was poured directly into the fabricated moulds, and left to polymerise until cure. Finally, a clear bubble-free case of study PMMA implant was obtained. Findings – The fabrication of CAD-designed moulds with AM, replacing the production of the injury model, resulted in the reduction of the lead-time in the manufacturing of PMMA around 45 per cent. Additionally, the implant showed better fit than the one produced by conventional process. The use of AM moulds for the fabrication of PMMA implants has demonstrated the reduction in lead-time, which potentially can reduce the waiting time for patients. Social implications – Currently, the demand of cranio-maxillofacial implants at only the Hospital General de México “Dr Eduardo Liceaga” (HGM) is 4,000 implants per year, and the average waiting time for each patient is between 5 and 10 weeks, including third-party services’ delays and the time needed to obtain the economical resources by the patient. Public hospitals in Mexico lack manufacturing facilities, so patients have to make use of laboratories abroad and most of the population have no access to them. The implementation of this suggested procedure in public hospitals may improve the accuracy of the implant, increase the number of patients attended per year (up to 83 per cent) and the reduction in waiting time can also reduce mortality and infection rates. Originality/value – The authors of this paper suggest the joint use of CAD and AM technologies to significantly reduce the production time of PMMA implants by producing moulds rather than the injury model, maintaining the general terms and known steps of the process already established for PMMA implants.

Animal orthosis fabrication with additive manufacturing – a case study of custom orthosis for chicken

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wiktoria Maria Wojnarowska ◽  
Jakub Najowicz ◽  
Tomasz Piecuch ◽  
Michał Sochacki ◽  
Dawid Pijanka ◽  
...  
Keyword(s):  
Veterinary Medicine ◽  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Fused Deposition Modelling ◽  
Content Type ◽  
Fused Deposition ◽  
Secondary Objective ◽  
Traditional Manufacturing ◽  
Aided Design

Purpose Chicken orthoses that cover the ankle joint area are not commercially available. Therefore, the main purpose of this study is to fabricate a customised temporary Ankle–Foot Orthosis (AFO) for a chicken with a twisted ankle using computer-aided design (CAD) and three-dimensional (3D) printing. The secondary objective of the paper is to present the specific application of Additive Manufacturing (AM) in veterinary medicine. Design/methodology/approach The design process was based on multiple sketches, photos and measurements that were provided by the owner of the animal. The 3D model of the orthosis was made with Autodesk Fusion 360, while the prototype was fabricated using fused deposition modelling (FDM). Evaluation of the AFO was performed using the finite element method. Findings The work resulted in a functional 3D printed AFO for chicken. It was found that the orthosis made with AM provides satisfactory stiffen and a good fit. It was concluded that AM is suitable for custom bird AFO fabrication and, in some respects, is superior to traditional manufacturing methods. It was also concluded that the presented procedure can be applied in other veterinary cases and to other animal species and other parts of their body. AM provides veterinary with a powerful tool for the production of well-fitted and durable orthoses for animals. Research limitations/implications The study does not include the chicken's opinion on the comfort or fit of the manufactured AFO due to communication issues. Evaluation of the final prototype was done by the researchers and the animal owner. Originality/value No evidence was found in the literature on the use of AM for chicken orthosis, so this study is the first to describe such an application of AM. In addition, the study demonstrates the value of AM in veterinary medicine, especially in the production of devices such as orthoses.

Printing with mechanically interlocked extrudates using a custom bi-extruder for fused deposition modelling

2018 ◽  
Vol 24 (6) ◽  
pp. 921-934 ◽  
Author(s):  
Mohammad Abu Hasan Khondoker ◽  
Asad Asad ◽  
Dan Sameoto
Keyword(s):  
Cross Sections ◽  
Acrylonitrile Butadiene Styrene ◽  
Easy Access ◽  
Fused Deposition Modelling ◽  
Content Type ◽  
Immiscible Polymers ◽  
Fused Deposition ◽  
Functionally Gradient ◽  
Different Sources ◽  
Butadiene Styrene

Purpose This paper aims to target to print functionally gradient materials (FGM) devices made of immiscible polymers in multi-material fused deposition modelling (FDM) systems. The design is intended to improve adhesion of dissimilar thermoplastics without the need for chemical compatibilization so that filaments from many different sources can be used effectively. Therefore, there is a need to invent an alternative solution for printing multiple immiscible polymers in an FDM system with the desired adhesion. Design/methodology/approach In this study, the authors have developed a bi-extruder for FDM systems which can print two thermoplastics through a single nozzle with a static intermixer to enhance bonding between input materials. The system can also change the composition of extrudates continuously. Findings The uniqueness of this extruder is in its easy access to the internal channel so that a static intermixer can be inserted, enabling deposition of mechanically interlocked extrudates composed of two immiscible polymers. Without this intermixer, the bi-extruder extrudes with simple side-by-side co-extrusion having no mechanical interlocking. The bi-extruder was characterized by printing objects using pairs of materials including polylactic acid, acrylonitrile butadiene styrene and high impact polystyrene. Microscope images of the cross-sections of the extrudates confirm the ability of this bi-extruder to control the composition as desired. It was also found that the mechanically interlocked extrudates composed of two immiscible polymers substantially reduces adhesion failures within and between filaments. Originality/value In this study, the first-ever FDM extruder with a mechanical blending feature next to the nozzle has been designed and used to successfully print FGM objects with improved mechanical properties.

scholarly journals Waiting time in public hospitals: case study of total joint replacement in Hong Kong

2018 ◽  
Vol 21 (2) ◽  
pp. 120-133 ◽  
Author(s):  
Yee-man Tsui ◽  
Ben Y.F. Fong
Keyword(s):  
Hong Kong ◽  
Waiting Time ◽  
Joint Replacement ◽  
Process Management ◽  
Emergency Services ◽  
Total Joint Replacement ◽  
Care Quality ◽  
Public Hospitals ◽  
Content Type

Purpose The purpose of this paper is to review the causes of long waiting time in Hong Kong public hospitals and to suggest solutions in the service, organisational, systems, financial and policy perspectives. Design/methodology/approach The paper is a review of waiting time of public hospital services. Total joint replacement, which is one of the elective surgeries in public hospitals, is presented as a case study. Findings The average waiting time of semi-urgent and non-urgent patients in the accident and emergency departments of public hospitals is two hours, and that of specialist outpatient (SOP) clinics is from 1 to 144 weeks. For total joint replacement, it is from 36 to 110 months. Measures like Government subsidisation programme for the replacement surgery and employing adequate physiotherapists, Chinese medicine practitioners, clinical psychologists and nurses to reduce the waiting time are suggested. Issues concerning the healthcare system of Hong Kong, such as structural reform, service delivery model, primary care, quality and process management, and policy reviews, are also discussed. Originality/value The ‬over-reliance of public services has resulted in long waiting time in public hospitals in Hong Kong, particularly in the emergency services and SOP clinics. However, the consequences of long waiting period for surgical operations, though much less discussed by the media and public, can be potentially detrimental to the patients and families, and may result in more burdens to the already stretched public hospitals‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬.

An overview of fused deposition modelling (FDM): research, development and process optimisation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohammadreza Lalegani Dezaki ◽  
Mohd Khairol Anuar Mohd Ariffin ◽  
Saghi Hatami
Keyword(s):  
Metal Alloys ◽  
Future Research ◽  
Fused Deposition Modelling ◽  
Process Optimisation ◽  
Content Type ◽  
Novel Materials ◽  
Fused Deposition ◽  
Bed Temperature ◽  
Vast Range ◽  
Research Studies

Purpose The purpose of this paper is to review research studies on process optimisation and machine development that lead to the enhancement of final products in various aspects of the fused deposition modelling (FDM) process. Design/methodology/approach An overview of the literature, focussing on process parameters, machine developments and material characterisations. This study investigates recent research studies that studied FDM capabilities in printing a vast range of materials from thermoplastics to metal alloys. Findings FDM is one of the most common techniques in additive manufacturing (AM) processes. Many parameters in this technology have effects on three-dimensional printed products. Therefore, it is necessary to obtain the optimum elements, for example, build orientation, layer thickness, nozzle diameter, infill pattern and bed temperature. By selecting a proper variable range of parameters, the layers adhere strongly and building end-use products of high quality are achievable. A vast range of materials and their properties from polymers to composite-based polymers are presented. Novel techniques to print metal alloys and composites are examined to increase the productivity of the FDM process. Additionally, defects such as shrinkage and warpage are discussed to eliminate the system’s limitations and improve the quality of final products. Multi-axis and mobile machines brought enhancements throughout the process to eliminate obstacles such as staircase defects in the conventional FDM process. In brief, recent developments were identified and a summary of major improvements was discussed in this study for future research. Originality/value This paper is an overview that provides information about research and developments in FDM. This review focusses on process optimisation and obstacles in printing polymers, composites, geopolymers and novel materials. Therefore, machine characteristics were examined to find out the accessibility of printing novel materials for different applications.

3D printing of clay paste enhanced by scrap polymer from powder bed processes

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mattia Mele ◽  
Michele Ricciarelli ◽  
Giampaolo Campana
Keyword(s):  
Additive Manufacturing ◽  
Volumetric Flow Rate ◽  
The Body ◽  
Fused Deposition Modelling ◽  
Powder Bed Fusion ◽  
Dimensional Error ◽  
Content Type ◽  
Powder Bed ◽  
Fused Deposition ◽  
Polymer Fraction

Purpose Powder bed additive manufacturing processes are widespread due to their many technical and economic advantages. Nevertheless, the disposal of leftover powder poses a problem in terms of process sustainability. The purpose of this paper is to provide an alternative solution to recycle waste PA12 powder from HP multi jet fusion. In particular, the opportunity to use this material as a dispersion in three-dimensional (3D) printed clay is investigated. Design/methodology/approach A commercial fused deposition modelling printer was re-adapted to extrude a viscous paste composed of clay, PA12 and water. Once printed, parts were dried and then put in an oven to melt the polymer fraction. Four compositions with different PA12 concentration were studied. First, the extrudability of the paste was observed by testing different extrusion lengths. Then, the surface porosities were evaluated through microscopical observations of the manufactured parts. Finally, benchmarks with different geometries were digitalised via 3D scanning to analyse the dimensional alterations arising at each stage of the process. Findings Overall, the feasibility of the process is demonstrated. Extrusion tests revealed that the composition of the paste has a minor influence on the volumetric flow rate, exhibiting a better consistency in the case of long extrusions. The percentage of surface cavities was proportional to the polymer fraction contained in the mix. From dimensional analyses, it was possible to conclude that PA12 reduced the degree of shrinkage during the drying phase, while it increased dimensional alterations occurring in the melting phase. The results showed that the dimensional error measured on the z-axis was always higher than that of the XY plane. Practical implications The method proposed in this paper provides an alternative approach to reuse leftover powders from powder bed fusion processes via another additive manufacturing process. This offers an affordable and open-source solution to companies dealing with polymer powder bed fusion, allowing them to reduce their environmental impacts while expanding their production. Originality/value The paper presents an innovative additive manufacturing solution for powder reuse. Unlike the recycling methods in the body of literature, this solution does not require any intermediate transformation process, such as filament fabrication. Also, the cold material deposition enables the adoption of very inexpensive extrusion equipment. This preliminary study demonstrates the feasibility and the benefits of this process, paving the way for numerous future studies.

Use of polymer concrete for large-scale 3D printing

2021 ◽  
Vol 27 (3) ◽  
pp. 465-474
Author(s):  
Martin Krčma ◽  
David Škaroupka ◽  
Petr Vosynek ◽  
Tomáš Zikmund ◽  
Jozef Kaiser ◽  
...  
Keyword(s):  
3D Printing ◽  
Large Scale ◽  
Mechanical Performance ◽  
Construction Material ◽  
Polymer Concrete ◽  
Fused Deposition Modelling ◽  
Cast State ◽  
Content Type ◽  
Fused Deposition ◽  
3D Printed

Purpose This paper aims to focus on the evaluation of a polymer concrete as a three-dimensional (3D) printing material. An associated company has developed plastic concrete made from reused unrecyclable plastic waste. Its intended use is as a construction material. Design/methodology/approach The concrete mix, called PolyBet, composed of polypropylene and glass sand, is printed by the fused deposition modelling process. The process of material and parameter selection is described. The mechanical properties of the filled material were compared to its cast state. Samples were made from castings and two different orientations of 3D-printed parts. Three-point flex tests were carried out, and the area of the break was examined. Computed tomography of the samples was carried out. Findings The influence of the 3D printing process on the material was evaluated. The mechanical performance of the longitudinal samples was close to the cast state. There was a difference in the failure mode between the states, with cast parts exhibiting a tougher behaviour, with fractures propagating in a stair-like manner. The 3D-printed samples exhibited high degrees of porosity. Originality/value The results suggest that the novel material is a good fit for 3D printing, with little to no degradation caused by the process. Layer adhesion was shown to be excellent, with negligible effect on the finished part for the longitudinal orientation. That means, if large-scale testing of buildability is successful, the material is a good fit for additive manufacturing of building components and other large-scale structures.

A review on advancements in applications of fused deposition modelling process

2020 ◽  
Vol 26 (4) ◽  
pp. 669-687 ◽  
Author(s):  
Sathies T. ◽  
Senthil P. ◽  
Anoop M.S.
Keyword(s):  
Additive Manufacturing ◽  
Research Work ◽  
Rapid Tooling ◽  
Future Research ◽  
Fused Deposition Modelling ◽  
Content Type ◽  
Fused Deposition ◽  
Low Volume ◽  
Customized Products

Purpose Fabrication of customized products in low volume through conventional manufacturing incurs a high cost, longer processing time and huge material waste. Hence, the concept of additive manufacturing (AM) comes into existence and fused deposition modelling (FDM), is at the forefront of researches related to polymer-based additive manufacturing. The purpose of this paper is to summarize the research works carried on the applications of FDM. Design/methodology/approach In the present paper, an extensive review has been performed related to major application areas (such as a sensor, shielding, scaffolding, drug delivery devices, microfluidic devices, rapid tooling, four-dimensional printing, automotive and aerospace, prosthetics and orthosis, fashion and architecture) where FDM has been tested. Finally, a roadmap for future research work in the FDM application has been discussed. As an example for future research scope, a case study on the usage of FDM printed ABS-carbon black composite for solvent sensing is demonstrated. Findings The printability of composite filament through FDM enhanced its application range. Sensors developed using FDM incurs a low cost and produces a result comparable to those conventional techniques. EMI shielding manufactured by FDM is light and non-oxidative. Biodegradable and biocompatible scaffolds of complex shapes are possible to manufacture by FDM. Further, FDM enables the fabrication of on-demand and customized prosthetics and orthosis. Tooling time and cost involved in the manufacturing of low volume customized products are reduced by FDM based rapid tooling technique. Results of the solvent sensing case study indicate that three-dimensional printed conductive polymer composites can sense different solvents. The sensors with a lower thickness (0.6 mm) exhibit better sensitivity. Originality/value This paper outlines the capabilities of FDM and provides information to the user about the different applications possible with FDM.

Photonic curing of silver paths on 3D printed polymer substrate

Circuit World ◽  
2019 ◽  
Vol 45 (1) ◽  
pp. 9-14
Author(s):  
Jakub Krzeminski ◽  
Bartosz Blicharz ◽  
Andrzej Skalski ◽  
Grzegorz Wroblewski ◽  
Małgorzata Jakubowska ◽  
...  
Keyword(s):  
Polymer Substrate ◽  
Fused Deposition Modelling ◽  
Content Type ◽  
Fused Deposition ◽  
Photonic Curing ◽  
Structural Electronics ◽  
Jet Printing ◽  
3D Printed ◽  
Aerosol Jet Printing ◽  
Photonic Sintering

Purpose Despite almost limitless possibilities of rapid prototyping, the idea of 3D printed fully functional electronic device still has not been fulfilled – the missing point is a highly conductive material suitable for this technique. The purpose of this paper is to present the usage of the photonic curing process for sintering highly conductive paths printed on the polymer substrate. Design/methodology/approach This paper evaluates two photonic curing processes for the conductive network formulation during the additive manufacturing process. Along with the xenon flash sintering for aerosol jet-printed paths, this paper examines rapid infrared sintering for thick-film and direct write techniques. Findings This paper proves that the combination of fused deposition modeling, aerosol jet printing or paste deposition, along with photonic sintering, is suitable to obtain elements with low resistivity of 3,75·10−8 Ωm. Presented outcomes suggest the solution for fabrication of the structural electronics systems for daily-use applications. Originality/value The combination of fused deposition modelling (FDM) and aerosol jet printing or paste deposition used with photonic sintering process can fill the missing point for highly conductive materials for structural electronics.

Effect of cold vapour treatment on geometric accuracy of fused deposition modelling parts

2017 ◽  
Vol 23 (6) ◽  
pp. 1226-1236 ◽  
Author(s):  
Ashu Garg ◽  
Anirban Bhattacharya ◽  
Ajay Batish
Keyword(s):  
Surface Roughness ◽  
Surface Finish ◽  
Fused Deposition Modelling ◽  
Curved Surfaces ◽  
Geometric Accuracy ◽  
Content Type ◽  
Fused Deposition ◽  
Cold Vapour ◽  
Side Face ◽  
Functional Components

Purpose The purpose of this paper is to investigate the influence of low-cost chemical vapour treatment process on geometric accuracy and surface roughness of different curved and freeform surfaces of fused deposition modelling (FDM) specimens build at different part building orientations. Design/methodology/approach Parts with different primitive and curved surfaces are designed and modelled to build at three different part orientations along X orientation (vertical position resting on side face), Y orientation (horizontal position resting on base) and Z orientation (upright position). Later, the parts are post-processed by cold vapours of acetone. Geometric accuracy and surface roughness are measured both before and after the chemical treatment to investigate the change in geometric accuracy, surface roughness of FDM parts. Findings The results indicate that surface roughness is reduced immensely after cold vapour treatment with minimum variation in geometric accuracy of parts. Parts build vertically over its side face (X orientation) provides the overall better surface finish and geometric accuracy. Originality/value The present study provides an approach of post-built treatment for FDM parts and observes a significant improvement in surface finish of the components. The present approach of post-built treatment can be adopted to enhance the surface quality as well as to achieve desired geometric accuracy for different primitive, freeform/curved surfaces of FDM samples suitable for functional components as well as prototypes.

Fused deposition modelling based rapid patterns for investment casting applications: a review

2016 ◽  
Vol 22 (1) ◽  
pp. 123-143 ◽  
Author(s):  
Sunpreet Singh ◽  
Rupinder Singh
Keyword(s):  
Investment Casting ◽  
Biomedical Applications ◽  
Design Methodology ◽  
State Of The Art ◽  
Fused Deposition Modelling ◽  
Content Type ◽  
Biomedical Implant ◽  
Fused Deposition ◽  
Manufacturing Organizations ◽  
Machine Parts

Purpose – This paper aims to review the industrial and biomedical applications of state-of-the-art fused deposition modelling (FDM)-assisted investment casting (FDMAIC). Brief literature survey of methodologies, ideas, techniques and approaches used by various researchers is highlighted and use of hybrid feedstock filament-based pattern to produce metal matrix composite is duly discussed. Design/methodology/approach – Pattern replica required for investment casting (IC) of biomedical implant, machine parts, dentistry and other industrial components can be directly produced by using FDM process is presented. Relevant studies and examples explaining the suitability of FDMAIC for various applications are also presented. Findings – Researches to optimize the conventional IC with FDM solutions and develop new hybrid feedstock filament of FDM done by researchers worldwide are also discussed. The review highlights the benefit of FDMAIC to surgeons, engineers and manufacturing organizations. Research limitations/implications – The research related to this survey is limited to the suitability and applicability of FDMAIC. Originality/value – This review presents the information regarding potential IC application, which facilitates the society, engineers and manufacturing organizations by providing variety of components for assisting FDM. The information reported in this paper will serve doctors, researchers, organizations and academicians to explore the new options in the field of FDMAIC.

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