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This work aims to present the design of a new continuous tool-path strategy for open-source low-cost fused deposition modeling (FDM) machines, such as Fab@Home or RepRap; and the development of an innovative integrated tool to design and fabricate customized tracheal stents with any FDM machine and six patient parameters. Both contributions were validated and implemented by obtaining a customized medical-grade silicone tracheal stent.

For the design of the new deposition strategy, a Python programming language was used. The new tool-path strategy was proposed as a continuous path to avoid drops and gaps and to improve the accuracy of the final model. Meanwhile, patient parameters were obtained by medical doctors and introduced into the innovative integrated system. On the one hand, one mold generated automatically, and viewed with Matlab® software, was fabricated with a Fab@Home machine, optimized with the continuous tool-path strategy. On the other hand, the same generated mold was viewed in SolidWorks/Excel software and was fabricated using a commercial FDM machine. Finally, the mold was filled with medical grade silicone, and a silicone tracheal stent was obtained.

Path planning for extrusion technologies is still a major concern, especially for open-source FDM machines. The results obtained in this work show the benefits of applying the newly developed continuous tool-path strategy to optimize the performance and efficiency of these machines. In addition, the proposed innovative integrated system allows the fabrication of customized tracheal stents rapidly and affordably.

The possibility of obtaining customized tracheal stents is a worthy challenge. Medical doctors could play a more active role and interact during the design process, helping to obtain more suitable stents. The method proposed herein would provide the opportunity to obtain real values from the trachea of a patient in the operating room and quickly fabricate a customized stent that would fit the patient's trachea perfectly.

The results obtained in this work are relevant and have future applications in both the medical and the additive manufacturing fields. The optimized tool-path strategy can help to improve and enhance the use of low-cost FDM machines. Moreover, the innovative automatic design approach to fabricate tracheal stents may open new market opportunities in the medical device field.

The purpose of this paper is to focus on tracheal stent production with the aim of investigating the available devices and improving their performances. The biomedical field is a continuously growing area of the market always in search of the most innovative and competitive solutions for healthcare. Beside the actual critical period of the world economy, it shows continuous improvements in research and innovation.

Within a market analysis and the collaboration between engineering and biomedical research fields, it was outlined a new product concept able to satisfy the patient’s and physician’s requirements with the focus on the enhancement of the stent anchorage. As a result, the concept of a custom- or tailor-made stent was identified as a potential solution. Moreover, additive technologies were identified as the economically sustainable processes for manufacturing these innovative stents. In the present paper, different types of stents were derived from the proposed concept, they were designed, manufactured and their anchorage capability was tested. In particular, the procedures adopted for their design are described and discussed. Moreover, silicone fused deposition modelling was adopted and two types of deposition method, namely, layer-by-layer and continuous, were used to manufacture the devices identifying their pro, cons and limits. Finally, the stents were tested against migration and results were compared with one of the most widely used today.

The results show how additive manufacturing allowed to manufacture more efficient and migration resistant stents.

It is expected that this new stent design will reduce the risk of complications in stenting, as granulation, thanks to a more uniform stress distribution on the trachea tissues. These improved characteristics will allow to enhance the quality of both the product and the patient’s healthcare.

Tracheobronchial stents are commonly used in airway management as a form of palliation for obstruction. This form of therapy immediately relieves the patients from life‐threatening conditions and significantly improves their quality of life. In the cases of complex tracheobronchial obstruction, customised airway stents are required for effective palliation. In this work, an Airway Stent Customisation Protocol (ASCP) is introduced.

It describes two variant routes that use a combination of rapid prototyping (RP) and rapid tooling (RT) techniques to fabricate customised airway stents in short lead times. The ASCP allows the stents to be tailored in terms of geometry, and distending strength. A brief comparison between the ASCP and other RP/RT manufacturing routes is also carried out.

The ability to customise airway stents in short lead times is important as it allows surgeons to swiftly treat life‐threatening conditions arising from tracheobronchial obstructions. It is shown that the ASCP is capable of providing relief to patients quickly. The application of RP and RT in the ASCP has not only allowed shorter response time to patients, but has also allowed the stents to be produced at a relatively low cost.

Tracheobronchial stents are commonly used in patients facing advanced stages of cancer. Focuses on a time and cost‐effective solution that is provided to improve their quality of life.

The purpose of the paper was to present a specific case study of how 3D printing was introduced in the chest wall construction process of a specific patient with unique medical condition. A life-size 3D model of the patient’s chest wall was 3D printed for pre-surgical planning. The intent was to eliminate the need for operative exposure to map the pathological area. The model was used for preoperative visualization and formation of a 1-mm thick titanium plate implant, which was placed in the patient during chest wall reconstructive surgery. The purpose of the surgery was to relive debilitating chronic pain due to right scapular entrapment.

The patient was born with a twisted spine. Over time, it progressed to severe and debilitating scoliosis, which required the use of a thoracic brace. Computerized tomography (CT) data were converted to a 3D printed model. The model was used to size and form a 1-mm thick titanium plate implant. It was also used to determine the ideal location for placement of the plate during thoracotomy preoperatively.

The surgery, aided by the model, was successful and resulted in a significantly smaller incision. The techniques reduced invasiveness and enabled the doctors to conduct the procedure efficiently and decreased surgery time. The patient experienced relief of the chronic debilitating pain and no longer need the thoracic brace.

The 3D model facilitated pre-operative planning and modeling of the implant. It also enabled accurate incision locations of the thoracotomy site and placement of the implant. Although chest wall reconstruction surgeries have been undertaken, this paper documents a specific case study of chest wall construction fora specific patient with unique pathological conditions.

The purpose of this study is to highlight the direct fabrication of rapid tooling (RT) with desired mechanical, tribological and thermal properties using fused deposition modelling (FDM) process. Further, the review paper demonstrated development procedure of alternative feedstock filament of low-cost composite material for FDM to extend the range of RT applications.

The alternative materials for FDM and their processing requirements for fabrication in filament form as reported by various researchers have been summarized. The literature demonstrates the role of various post-processing techniques on surface finish of FDM prints. Further, low-cost materials for feedstock filament have been investigated experimentally to check their adaptability/suitability for commercial FDM setup. The approach was to realize the requirements of FDM (melt flow rate, flexibility, stiffness, glass transition temperature and mechanical strength), necessary for the successful run of an alternative filament. The effect of constituents (additives, plasticizers, surfactants and fillers) in polymeric matrix on mechanical, tribological and thermal properties has been investigated.

It is possible to develop composite material feedstock as filament for commercial FDM setup without changing its hardware and software. Surface finish of the parts can further be improved by applying various post-processing techniques. Most of the composite parts have high mechanical strength, hardness, thermal stability, wear resistant and better bond formation than standard material parts.

Future research may be focused on improving the surface quality of parts fabricated with composite feedstock, solving issues related to the uniform distribution of filled materials during the fabrication of feedstock filament which in turns further increases mechanical strength, high dimensional stability of composite filament and transferring the technology from laboratory scale to various industrial applications.

Potential applications of direct fabrication with RT includes rapid manufacturing (RM) of metal-filled parts and ceramic-filled parts (which have complex shape and cannot be rapidly made by any other manufacturing techniques) in the field of biomedical and dentistry.

This new manufacturing methodology is based on the proper selection and processing of various materials and additives to form high-performance, low-cost composite material feedstock filament (which fulfil the necessary requirements of FDM process). Finally, newly developed feedstock filament material has both quantitative and qualitative advantage in RT and RM applications as compared to standard material filament.

The staircase effect and support structure under overhanging geometry are two inherent weaknesses that reduces the surface quality and induces material waste. This paper aims to design a five-axis fused deposition modeling system with interference-free nozzle to solve the problems.

To facilitate the application of five-axis printing machine, three new printing methods are proposed according to different geometries and application requirements, which include tangential direction printing, normal sculpture printing and compatible printing.

The static flow beading characteristic is researched to establish the criterion for switching the mode between three-axis printing and five-axis printing. Experiment proves the critical point existing and 51° is the critical point at the given parameters. The concept of dynamic flow beading is proposed. The relationship between equivalent volume and roughness is established based on elaborate experiments, which helps to figure out the boundary between safe area and beading area under different parameters of layer thickness and nozzle diameter.

Three new printing methods are proposed according to different geometries and application requirements, which include tangential direction printing, normal sculpture printing and compatible printing. Considering the special movement situation during five-axis printing process, the dynamic flow beading issue is proposed. The relationship between equivalent volume and roughness is established based on elaborate experiments, which helps to figure out the boundary between safe area and beading area under different parameters of layer thickness and nozzle diameter.

This paper aims to propose a functional methodology to produce cranial prostheses in polymeric sheet. Within the scope of rapid prototyping technologies, the single-point incremental forming (SPIF) process is used to demonstrate its capabilities to perform customized medical parts.

The methodology starts processing a patient’s computerized axial tomography (CAT) and follows with a computer-aided design and manufacture (CAD/CAM) procedure, which finally permits the successful manufacturing of a customized prosthesis for a specific cranial area.

The formability of a series of polymeric sheets is determined and the most restrictive material among them is selected for the fabrication of a specific partial cranial prosthesis following the required geometry. The final strain state at the outer surface of the prosthesis is analysed, showing the high potential of SPIF in manufacturing individualized cranial prostheses from polymeric sheet.

This paper proposes a complete methodology to design and manufacture polymer customized cranial prostheses from patients’ CATs using the novel SPIF technology. This is an application of a new class of materials to the manufacturing of medical prostheses by SPIF, which to this purpose has been mainly making use of metallic materials so far. Despite the use of polymers to this application is still to be validated from a medical point of view, transparent prostheses can already be of great interest in medical or engineering schools for teaching and research purposes.

This paper aims to achieve rapid design and manufacturing of personalized total knee femoral component.

On the basis of a patient’s bone model, a matching personalized knee femoral component was rapidly designed with the help of computer-aided design method, then manufactured directly and rapidly by selective laser melting (SLM). Considered SLM as manufacturing technology, CoCrMo-alloyed powder that meets ASTM F75 standard is made of femoral component under optimal processing parameters. The feasibility of SLM forming through conducting experimental test of mechanical properties, surface roughness, biological corrosion resistance was analyzed.

The result showed that the tensile strength, yield strength, hardness and biological corrosion resistance of CoCrMo-alloyed personalized femoral component fulfill knee joint prosthesis standard through post-processing.

Traditional standardized prosthesis implantation manufacturing approach was changed by computer-aided design and personalized SLM direct manufacturing, and provided a new way for personalized implanted prosthesis to response manufacturing rapidly.

The purpose of this paper is to describe a novel design workflow for the digital fabrication of custom-made orthoses (CMIO). It is intended to provide an easier process for clinical practitioners and orthotic technicians alike. It further functions to reduce the dependency of the operators’ abilities and skills.

The technical assessment covers low-cost three-dimensional (3D) scanning, free computer-aided design (CAD) software, and desktop 3D printing and acetone vapour finishing. To analyse its viability, a cost comparison was carried out between the proposed workflow and the traditional CMIO manufacture method.

The results show that the proposed workflow is a technically feasible and cost-effective solution to improve upon the traditional process of design and manufacture of custom-made static trapeziometacarpal (TMC) orthoses. Further studies are needed for ensuring a clinically feasible approach and for estimating the efficacy of the method for the recovery process in patients.

The feasibility of the process increases the impact of the study, as the great accessibility to this type of 3D printers makes the digital fabrication method easier to be adopted by operators.

Although some research has been conducted on digital fabrication of CMIO, few studies have investigated the use of desktop 3D printing in any systematic way. This study provides a first step in the exploration of a new design workflow using low-cost digital fabrication tools combined with non-manual finishing.

Bioprinting is a promising technology, which has gained a recent attention, for application in all aspects of human life and has specific advantages in different areas of medicines, especially in ophthalmology. The three-dimensional (3D) printing tools have been widely used in different applications, from surgical planning procedures to 3D models for certain highly delicate organs (such as: eye and heart). The purpose of this paper is to review the dedicated research efforts that so far have been made to highlight applications of 3D printing in the field of ophthalmology.

In this paper, the state-of-the-art review has been summarized for bioprinters, biomaterials and methodologies adopted to cure eye diseases. This paper starts with fundamental discussions and gradually leads toward the summary and future trends by covering almost all the research insights. For better understanding of the readers, various tables and figures have also been incorporated.

The usages of bioprinted surgical models have shown to be helpful in shortening the time of operation and decreasing the risk of donor, and hence, it could boost certain surgical effects. This demonstrates the wide use of bioprinting to design more precise biological research models for research in broader range of applications such as in generating blood vessels and cardiac tissue. Although bioprinting has not created a significant impact in ophthalmology, in recent times, these technologies could be helpful in treating several ocular disorders in the near future.

This review work emphasizes the understanding of 3D printing technologies, in the light of which these can be applied in ophthalmology to achieve successful treatment of eye diseases.