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Article
Publication date: 18 April 2017

Ashfaq Mohammad, Abdurahman Mushabab Al-Ahmari, Abdullah AlFaify and Muneer Khan Mohammed

Electron beam melting (EBM) is one of the potential additive manufacturing technologies to fabricate aero-engine components from gamma titanium aluminide (γ-TiAl) alloys. When a…

659

Abstract

Purpose

Electron beam melting (EBM) is one of the potential additive manufacturing technologies to fabricate aero-engine components from gamma titanium aluminide (γ-TiAl) alloys. When a new material system has to be taken in to the fold of EBM, which is a highly complex process, it is essential to understand the effect of process parameters on the final quality of parts. This paper aims to understand the effect of melting parameters on top surface quality and density of EBM manufactured parts. This investigation would accelerate EBM process development for newer alloys.

Design/methodology/approach

Central composite design approach was used to design the experiments. In total, 50 specimens were built in EBM with different melt theme settings. The parameters varied were surface temperature, beam current, beam focus offset, line offset and beam speed. Density and surface roughness were selected as responses in the qualifying step of the parts. After identifying the parameters which were statistically significant, possible reasons were analyzed from the perspective of the EBM process.

Findings

The internal porosity and surface roughness were correlated to the process settings. Important ones among the parameters are beam focus offset, line offset and beam speed. By jointly deciding the total amount of energy input for each layer, these three parameters played a critical role in internal flaw generation and surface evolution.

Research limitations/implications

The range selected for each parameter is applicable, in particular, to γ-TiAl alloy. For any other alloy, the settings range has to be suitably adapted depending on physical properties such as melting point, thermal conductivity and thermal expansion co-efficient.

Practical implications

This paper demonstrates how melt theme parameters have to be understood in the EBM process. By adopting a similar strategy, an optimum window of settings that give best consolidation of powder and better surface characteristics can be identified whenever a new material is being investigated for EBM. This work gives researchers insights into EBM process and speeds up EBM adoption by aerospace industry to produce critical engine parts from γ-TiAl alloy.

Originality/value

This work is one of the first attempts to systematically carry out a number of experiments and to evaluate the effect of melt parameters for producing γ-TiAl parts by the EBM process. Its conclusions would be of value to additive manufacturing researchers working on γ-TiAl by EBM process.

Details

Rapid Prototyping Journal, vol. 23 no. 3
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 14 May 2018

Abdurahman Mushabab Al-Ahmari, Osama Abdulhameed and Awais Ahmad Khan

In additive manufacturing processes such as stereolithography and fused deposition modeling, optimal part orientation is pivotal in improving the quality of the part. This paper…

542

Abstract

Purpose

In additive manufacturing processes such as stereolithography and fused deposition modeling, optimal part orientation is pivotal in improving the quality of the part. This paper aims to propose an automatic and optimal part orientation system to improve part quality/accuracy in additive manufacturing, which minimizes the production time and hence reduces the cost of product.

Design/methodology/approach

The developed system reads STEP AP 203 E2 file from CATIA V5 and generates data extraction output file by extracting the relevant geometrical and topological data using an object-oriented approach. Afterwards, the algorithms and rules are developed to extract and recognize feature faces along with their geometric properties such as face type, face area, parallelism and perpendicularity. The feature data obtained that are used to develop feasible part orientations depend on the maximization of G&DT for all part faces. The automatic slicing is then achieved by creating slicing file using CATVBA editor inside CATIA V5.

Findings

After slicing, output data are exported in Excel data sheet to calculate the total additive volume of the part. The building time of the part is then calculated on the basis of machine parameters, part geometry, part height, layer thickness and amount of support volume needed to build the part. The optimal orientation of the part is achieved by maximization of G&DT value and minimization of production time. The proposed methodology is tested using an illustrative example.

Originality/value

Although lot of approaches have been discussed in the literature, automation of setup planning/orientation of the part in additive manufacturing is not fully attained. Therefore, the article focuses on the automation of setup planning by adding automatic feature extraction and recognition module along with the automatic slicing during setup planning. Moreover, the significance of adding feature extraction and recognition module is to achieve best accuracy for form feature faces and hence reduction in post processing machining/finishing operations.

Details

Rapid Prototyping Journal, vol. 24 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 16 January 2017

Emad Abouel Nasr, Abdurahman Mushabab Al-Ahmari, Khaja Moiduddin, Mohammed Al Kindi and Ali K. Kamrani

The purpose of this paper is to demonstrate the route to digitize the customized mandible implants consisting of image acquisition, processing, implant design, fitting rehearsal…

490

Abstract

Purpose

The purpose of this paper is to demonstrate the route to digitize the customized mandible implants consisting of image acquisition, processing, implant design, fitting rehearsal and fabrication using fused deposition modeling and electron beam melting methodologies.

Design/methodology/approach

Recent advances in the field of rapid prototyping, reverse engineering, medical imaging and image processing have led to new heights in the medical applications of additive manufacturing (AM). AM has gained a lot of attention and interest during recent years because of its high potential in medical fields.

Findings

Produced mandible implants using casting, milling and machining are of standard sizes and shapes. As each person’s physique and anatomical bone structure are unique, these commercially produced standard implants are manually bent before surgery using trial and error methodology to custom fit the patient’s jaw. Any mismatch between the actual bone and the implant results in implant failure and psychological stress and pain to the patient.

Originality/value

The novelty in this paper is the construction of the customized mandibular implant from the computed tomography (CT) scan which includes surface reconstruction, implant design with validation and simulation of the mechanical behavior of the design implant using finite element analysis (FEA). There has been few research studies on the design and customization of the implants before surgery, but there had been hardly any study related to customized design implant and evaluating the biomechanical response on the newly designed implant using FEA. Though few studies are related to FEA on the reconstruction plates, but their paper lacks the implant design model and the reconstruction model. In this research study, an integrated framework is developed for the implant design, right from the CT scan of the patient including the softwares involved through out in the study and then performing the biomechanical study on the customized design implant to prove that the designed implant can withstand the biting and loading conditions. The proposed research methodology which includes the interactions between medical practitioners and the implant design engineers can be incorporated to any other reconstruction bone surgeries.

Details

Rapid Prototyping Journal, vol. 23 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 28 September 2018

Osama Abdulhameed, Abdurahman Mushabab Al-Ahmari, Wadea Ameen and Syed Hammad Mian

Hybrid manufacturing technologies combining individual processes can be recognized as one of the most cogent developments in recent times. As a result of integrating additive…

408

Abstract

Purpose

Hybrid manufacturing technologies combining individual processes can be recognized as one of the most cogent developments in recent times. As a result of integrating additive, subtractive and inspection processes within a single system, the relative benefits of each process can be exploited. This collaboration uses the strength of the individual processes, while decreasing the shortcomings and broadening the application areas. Notwithstanding its numerous advantages, the implementation of hybrid technology is typically affected by the limited process planning methods. The process planning methods proficient at effectively using manufacturing sources for hybridization are notably restrictive. Hence, this paper aims to propose a computer-aided process planning system for hybrid additive, subtractive and inspection processes. A dynamic process plan has been developed, wherein an online process control with intelligent and autonomous characteristics, as well as the feedback from the inspection, is utilized.

Design/methodology/approach

In this research, a computer-aided process planning system for hybrid additive, subtractive and inspection process has been proposed. A framework based on the integration of three phases has been designed and implemented. The first phase has been developed for the generation of alternative plans or different scenarios depending on machining parameters, the amount of material to be added and removed in additive and subtractive manufacturing, etc. The primary objective in this phase has been to conduct set-up planning, process selection, process sequencing, selection of machine parameters, etc. The second phase is aimed at the identification of the optimum scenario or plan.

Findings

To accomplish this goal, economic models for additive and subtractive manufacturing were used. The objective of the third phase was to generate a dynamic process plan depending on the inspection feedback. For this purpose, a multi-agent system has been used. The multi-agent system has been used to achieve intelligence and autonomy of different phases.

Practical implications

A case study has been developed to test and validate the proposed algorithm and establish the performance of the proposed system.

Originality/value

The major contribution of this work is the novel dynamic computer-aided process planning system for the hybrid process. This hybrid process is not limited by the shortcomings of the constituent processes in terms of tool accessibility and support volume. It has been established that the hybrid process together with an appropriate computer-aided process plan provides an effective solution to accurately fabricate a variety of complex parts.

Details

Rapid Prototyping Journal, vol. 24 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 15 June 2015

Emad Abouel Nasr, Abdurahman Mushabab Al-Ahmari, Hazem Alkhawashki, Abdulsalam Altamimi and Mohammed Alkhuraisi

The purpose of this paper is to design and analyze four proximal interphalangeal joint (PIP) prosthesis thorough finite element analysis (FEA) and fabricate them using rapid…

415

Abstract

Purpose

The purpose of this paper is to design and analyze four proximal interphalangeal joint (PIP) prosthesis thorough finite element analysis (FEA) and fabricate them using rapid prototyping (RP) technique. Arthritis of the finger joints is an important pathology of the hand. Major complaints in arthritis are stiffness, deformity and severe pain. The pain is due to the inflammatory process that occurs due to pathology, which involves joint degeneration, synovial swelling and ligament and muscle stiffness. Among the surgical treatment of arthritis is Arthroplasty which involves replacing the diseased joint with an artificial joint.

Design/methodology/approach

In this paper, four proximal interphalangeal joint (PIP) prostheses are designed, analyzed using FEA and fabricated using rapid prototyping technique. Four different prostheses “BM”, “IMP”, “IMP2” and “FINS” are designed using CATIA software and tested by normal daily functions such as grasp, key pinch and tip pinch tests using FEA to analyze the results based on their stress and deformation. Finally, the prostheses are fabricated using electron beam melting technology.

Findings

This paper examined and analyzed the relative motion of PIP designs using FEA by applying varying loads to check the stability and range of motion of the PIP implant. The ANSYS summary results were analyzed depending on the minimal results of equivalent stress and deformation from the taken tests that have happened on the designed prosthesis. The results conclude that, in the grasp test, the minimal equivalent stress and deformation have happened on the “BM” and “IMP2” implants. Furthermore, in the key pinch test, minimal equivalent stress and deformation occurred on the “FINS” implant, and finally, in the tip pinch, minimal equivalent stress occurred on the “FINS” and minimal deformation has happened on the “IMP2” implant.

Research limitations/implications

These results conclude that both “IMP2” and “FINS” share the minimum results in the taken tests, and this shows that these implants may be further studied brainstormed upon to aid innovation of a better implant design that shares both of these implants’ features and shape. Nevertheless, testing in an in vivo or in vitro model to prove more of the effectiveness of these implants should be taken into consideration, and to test how the prostheses will function in an actual environment, a simulated hand can be designed and made to discover the true forces and mechanics of the fingers and the hands with the prosthesis that is implanted, as well as to know if the hand works properly.

Originality/value

This paper examined and analyzed the relative motion of PIP designs using FEA by applying varying loads to check the stability and range of motion of the PIP implant.

Details

Rapid Prototyping Journal, vol. 21 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

Available. Open Access. Open Access

Abstract

Details

Journal of Intelligent Manufacturing and Special Equipment, vol. 4 no. 1
Type: Research Article
ISSN: 2633-6596

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