A review of the mechanical properties of 17-4PH stainless steel produced by bound powder extrusion

17-4PH Stainless Steel is a mechanically high-performing alloy that is widely used across chemical and mechanical processing industries. The alloy is conventionally fabricated by cast methods, but emerging additive manufacturing techniques are presently offering an economic, efficient, and environmentally friendly alternative. Bound Powder Extrusion (BPE) is a relatively new additive manufacturing technique that is used to fabricate three-dimensional, free-form components. Investigation into the mechanical properties and behavior of 17-4PH stainless steel fabricated by BPE is vital to understanding whether this technique proposes a competitive substitute to the cast alloy within industry. Published literature has investigated the as-fabricated mechanical properties, microstructure, porosity, and post-processing heat treatment of the BPE alloy, with limited comparison evident among the papers. This paper, therefore, aims to review published findings on the mechanical properties of 17-4PH stainless steel produced by additive manufacturing techniques, with a key focus on BPE. It is important to highlight that this review study focuses on the MetalXTM 3D printer, manufactured by Markforged. This printer is among the widely utilized BPE 3D printers available in the market. The key results, together with the impact of post-heat treatments, were discussed and compared to provide a more comprehensive picture of the patterns that this alloy presents in terms of its microstructure and mechanical properties. This enables the manufacture of components relative to desired material performance, improving overall functionality. A comparison of yield strength, ultimate tensile strength (UTS), Young’s modulus, ductility, and hardness was made relative to microstructure, porosity, and density of published literature for the as-fabricated and post-heat-treated states, identifying areas for further research

Evaluation of the effect of product demand uncertainty on manufacturing system selection

The use of advanced manufacturing systems is widespread; however, manufacturers frequently face difficult decisions when it comes to selecting the most appropriate system. Uncertainty regarding product demand makes this process more difficult, as many factors are influencing simultaneously. This paper focuses on analyzing the demand uncertainty on the performance of modular drilling manufacturing systems versus other alternatives and evaluating the uncertainty’s impacts on the final decision. To do so, a model is suggested and the effect of demand uncertainty on the output is investigated. Three automotive components of varying complexity are used to examine the approach for making reliable decision

New cost model for feasibility analysis of utilising special purpose machine tools

Special purpose machine tools (SPMs) have been widely used to perform drilling-related operations in high volume production including within automotive component industries. The first step in designing and manufacturing a SPM is a feasibility analysis. Since SPMs have relatively higher investment cost than other machine tools, this task must be performed before any investment on the preparation of detailed design. The present paper explores an economic feasibility analysis strategy which aims to make logical decision by assessing the strengths and limitations of an SPM in comparison with other machine tools. The mathematical product cost model for SPMs is proposed for estimating important economic factors and then financial indicators are calculated to evaluate the SPM’s economic performance. A case study is used to examine the proposed model and results are compared with other machine tools. The proposed model provides a decision support approach for selecting an SPM for manufacturing a given part from an economic perspective

Sensitivity analysis for justification of utilising special purpose machine tools in the presence of uncertain parameters

Decision-makers in manufacturing area frequently face machine tool selection problem under uncertainty due to competitive market changes. Special purpose machines (SPMs), a relatively new class of reconfigurable machine tools, are used to react quickly to changes. Justification of utilising these machines vs. other machine tools requires a technique to investigate the sources of uncertainties. In this work, sensitivity analysis is utilised to investigate the sources of these uncertainties and errors which may reveal new insights for evaluating a machine tool. An illustrative example is provided to show the sensitivity of parameters on the economic performance of SPMs compared to the other alternatives. The results show that this analysis provides additional information and moves the decision closer to the optimum alternative

An integrated model to use drilling modular machine tools

Modular machine tools provide a platform for drilling-related operations within automotive companies. The use of these machine tools is widespread; however, manufacturers wishing to use this technology frequently face the challenge of selecting the most appropriate manufacturing system. Accordingly, a comprehensive feasibility analysis procedure is required to assist decision-makers before any investment is made on the preparation of detailed machine design or purchase one. This paper presents a model, which collects the previous works of the authors. To do this, an integrated framework for decision-making of using machine tools is developed. The aim of this model is to enable users to make a logical decision by assessing the strengths and limitations of machine tools. To do this, the parameters which have a key influence on the decision-making process and relevant procedures are identified and integrated into a model. A case study is presented to illustrate the application of proposed model, and results are discussed. The results show that the proposed model is useful in assisting manufacturers in evaluating the performance of a modular machine tool in comparison with other alternatives

Advances in metal additive manufacturing: A review of common processes, industrial applications, and current challenges

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. In recent years, Additive Manufacturing (AM), also called 3D printing, has been expanding into several industrial sectors due to the technology providing opportunities in terms of improved functionality, productivity, and competitiveness. While metal AM technologies have almost unlimited potential, and the range of applications has increased in recent years, industries have faced challenges in the adoption of these technologies and coping with a turbulent market. Despite the extensive work that has been completed on the properties of metal AM materials, there is still a need of a robust understanding of processes, challenges, application‐specific needs, and considerations associated with these technologies. Therefore, the goal of this study is to present a comprehen-sive review of the most common metal AM technologies, an exploration of metal AM advancements, and industrial applications for the different AM technologies across various industry sectors. This study also outlines current limitations and challenges, which prevent industries to fully benefit from the metal AM opportunities, including production volume, standards compliance, post processing, product quality, maintenance, and materials range. Overall, this paper provides a survey as the benchmark for future industrial applications and research and development projects, in order to assist industries in selecting a suitable AM technology for their application

Drilling reconfigurable machine tool selection and process parameters optimization as a function of product demand

Special purpose machines (SPMs) are customized machine tools that perform specific machining operations in a variety of production contexts, including drilling-related operations. This research investigates the effect of optimal process parameters and SPM configuration on the machine tool selection problem versus product demand changes. A review of previous studies suggests that the application of optimization in the feasibility analysis stage of machine tool selection has received less attention by researchers. In this study, a simulated model using genetic algorithm is proposed to find the optimal process parameters and machine tool configuration. During the decision-making phase of machine tool selection, unit profit is targeted as high as possible and is given by the value of the following variables: SPM configuration selection, machining unit assignment to each operation group, and feed and cutting speed of all operations. The newly developed model generates any random chromosome characterized by feasible values for process parameters. Having shown how the problem is formulated, the research presents a case study which exemplifies the operation of the proposed model. The results show that the optimization results can provide critical information for making logical, accurate, and reliable decisions when selecting SPMs

A review: drilling performance and hole quality of aluminium alloys for aerospace applications

Despite the growth of composites and other lightweight materials, aluminium alloys remain an attractive choice of the aerospace industry due to their mature manufacturing processes, good resistance to fatigue crack growth and superior damage tolerance. In the aerospace industry, the drilling process is the most challenging among all the other machining process as millions of holes are required for producing riveted and bolted joints in the assembly operation of the aircraft\u27s structures. The major challenges which arise from the drilling of these alloys are characterized by the poor hole quality which might initiate cracks within the airframe structure and reduces their reliability. This results in the rejection of parts at the assembly stage which directly impacts the manufacturing cost. Hence, appropriate selection of tool geometry, tool material and coatings, optimal cutting speed and feed rate, as well as drilling machines, is required to meet the requirement of machined parts. This motivates both academia and industries to further research on the application of drilling operations in the aircraft industry. This review aims to document details on drilling forces, drilling parameters, drill tool geometry, drill materials and coatings, chips formation, analysis of tool wear and hole metrics such as the hole size and circularity error, surface roughness, and burrs formation during the drilling of different aluminium alloys used in the aerospace industry. The focus will be mainly on Al2024 and Al7075 alloys since they are most commonly used and reported in the open literature

Technical feasibility analysis of utilizing special purpose machine tools

Special purpose machine tools (SPMs) are primarily used for performing drilling-related operations and are widely used in mass production including automotive component manufacturing. Utilization of SPM is considerably widespread; however, this technology is relatively new and expensive. The important problems facing manufacturing industries wishing to utilize this technology is feasibility analysis to decide whether a SPM can be utilised for production of the given part and if it is feasible which SPM components would be appropriate. Since the cost of utilizing SPM is high, feasibility analysis must be performed before any investment on detailed design. This paper proposes a technical feasibility analysis method which assists in deciding whether SPM is applicable for machining a given part to achieve the highest productivity. The method is based on the framework which consists of relations between the desired part properties to the characteristics of the SPM components. These relations are captured as rules and constraints in an intelligent system which is implemented in Visual Basic. Applying the proposed method to a number of industrial parts shows that it is a very useful tool in deciding when SPMs should be utilized

Impacts of traverse speed and material thickness on abrasive waterjet contour cutting of austenitic stainless steel AISI 304L

Abrasive water jet machining is a proficient alternative for cutting difficult-to-machine materials with complex geometries, such as austenitic stainless steel 304L (AISI304L). However, due to differences in machining responses for varied material conditions, the abrasive waterjet machining experiences challenges including kerf geometric inaccuracy and low material removal rate. In this study, an abrasive waterjet machining is employed to perform contour cutting of different profiles to investigate the impacts of traverse speed and material thickness in achieving lower kerf taper angle and higher material removal rate. Based on experimental investigation, a trend of decreasing the level of traverse speed and material thickness that results in minimum kerf taper angle values of 0.825° for machining curvature profile and 0.916° for line profiles has been observed. In addition, higher traverse speed and material thickness achieved higher material removal rate in cutting different curvature radii and lengths in line profiles with obtained values of 769.50 mm3/min and 751.5 mm3/min, accordingly. The analysis of variance revealed that material thickness had a significant impact on kerf taper angle and material removal rate, contributing within the range of 69–91% and 62–69%, respectively. In contrast, traverse speed was the least factor measuring within the range of 5–18% for kerf taper angle and 27–36% for material removal rate