Elena Bassoli, Andrea Gatto, Luca Iuliano and Maria Grazia Violante
The purpose of this paper is to verify the feasibility and evaluate the dimensional accuracy of two rapid casting (RC) solutions based on 3D printing technology: investment…
Abstract
Purpose
The purpose of this paper is to verify the feasibility and evaluate the dimensional accuracy of two rapid casting (RC) solutions based on 3D printing technology: investment casting starting from 3D‐printed starch patterns and the ZCast process for the production of cavities for light‐alloys castings.
Design/methodology/approach
Starting from the identification and design of a benchmark, technological prototypes were produced with the two RC processes. Measurements on a coordinate measuring machine allowed calculating the dimensional tolerances of the proposed technological chains. The predictive performances of computer aided engineering (CAE) software were verified when applied to the ZCast process modelling.
Findings
The research proved that both the investigated RC solutions are effective in obtaining cast technological prototypes in short times and with low costs, with dimensional tolerances that are completely consistent with metal casting processes.
Practical implications
The research assessed the feasibility and dimensional performances of two RC solutions, providing data that are extremely useful for the industrial application of the considered technologies.
Originality/value
The paper deals with experimental work on innovative techniques on which data are still lacking in literature. In particular, an original contribution to the determination of dimensional tolerances and the investigation on the predictive performances of commercial CAE software is provided.
Details
Keywords
Elena Bassoli, Andrea Gatto and Luca Iuliano
Additive manufacturing is today a viable industrial solution alongside traditional processes. Techniques like selective laser sintering (SLS) address the issues of digital…
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 are integrated.
Findings
The results prove the absence of relevant anisotropy amongst specimens that are produced with the axis parallel to the plane of powder deposition. Samples whose axis is parallel to the growth direction Z, instead, reveal a significantly different response with respect to other orientations.
Originality/value
An original explanatory model is assumed and validated, based on an anisotropic distribution of the reinforcing particles during parts' production, which determines the efficacy of the strengthening mechanisms during crack propagation.
Details
Keywords
Andrea Gatto, Elena Bassoli, Lucia Denti, Luca Iuliano and Paolo Minetola
The purpose of this paper is to report an interdisciplinary, cooperative-learning project in a second-year course within the “Enzo Ferrari” Master of Science Degree in Mechanical…
Abstract
Purpose
The purpose of this paper is to report an interdisciplinary, cooperative-learning project in a second-year course within the “Enzo Ferrari” Master of Science Degree in Mechanical Engineering. The work aims to raise awareness of the educational impact of additive manufacturing and reverse engineering.
Design/methodology/approach
Students are asked to develop, concurrently, the design and the manufacturing solution for an eye-tracker head mount. A digital head model is reverse engineered from an anatomical mannequin and used as an ergonomic mock-up. The project includes prototype testing and cost analysis. The device is produced using additive manufacturing techniques for hands-on evaluation by the students.
Findings
Results of the presented case study substantiate the authors’ belief in the tremendous potential of interdisciplinary project-based learning, relying on innovative technologies to encourage collaboration, motivation and dynamism.
Originality/value
The paper confirms a spreading conviction that the soon-to-be engineers will need new practice-oriented capabilities to cope with new competitive scenarios. Engineering education must adapt to the social, rather than industrial, revolution that is being brought about by additive fabrication.
Details
Keywords
Elena Bassoli and Eleonora Atzeni
The purpose of this paper is to optimize the mechanical performances of parts produced by the ZCast Direct Metal Casting process varying the thermal treatment parameters. Adopting…
Abstract
Purpose
The purpose of this paper is to optimize the mechanical performances of parts produced by the ZCast Direct Metal Casting process varying the thermal treatment parameters. Adopting the optimized settings, a specific dimensional evaluation is planned to calculate the international tolerance (IT) grade ensured by the process.
Design/methodology/approach
Cylindrical ZCast samples are manufactured and heat treated varying time and temperature. The baked parts underwent compression tests and the rupture surfaces are observed using the scanning electron microscopy. A regression analysis is performed on the results to optimize the baking process. For the dimensional assessment, a specific benchmark is designed, built and treated. It is measured before and after baking using a coordinate measuring machine and the results are processed to obtain the IT grade.
Findings
The results proved that in the heat treatment of ZCast parts time has a negligible effect on the compressive strength, whereas temperature can be optimized for best mechanical response. The IT grade is calculated for green and baked parts; separately in all three directions in space. Tolerance is proved to be fundamentally the same in every direction and independent on the heat treatment. The considered rapid casting process can be classified in IT15 grade.
Originality/value
The paper suggests an original approach to improve knowledge of the ZCast process. The study of the building phenomena is combined with macroscopic measurements to develop a solid understanding of the expected performances, which is fundamental in order to support the industrial application of the technology.
Details
Keywords
Paolo Minetola, Luca Iuliano, Elena Bassoli and Andrea Gatto
The purpose of this paper is to evaluate how the direct access to additive manufacturing (AM) systems impacts on education of future mechanical engineers, within a Master’s…
Abstract
Purpose
The purpose of this paper is to evaluate how the direct access to additive manufacturing (AM) systems impacts on education of future mechanical engineers, within a Master’s program at a top Italian University.
Design/methodology/approach
A survey is specifically designed to assess the relevance of entry-level AM within the learning environment, as a tool for project development. The survey is distributed anonymously to three consecutive cohorts of students who attended the course of “computer-aided production (CAP)”, within the Master of Science Degree in Mechanical Engineering at Politecnico di Torino. The course includes a practical project, consisting in the design of a polymeric product with multiple components and ending with the production of an assembled prototype. The working assembly is fabricated by the students themselves, who operate a fused deposition modelling (FDM) machine, finish the parts and evaluate assemblability and functionality. The post-course survey covers diverse aspects of the learning process, such as: motivation, knowledge acquisition, new abilities and team-working skills. Responses are analyzed to evaluate students’ perception of the usefulness of additive technologies in learning product design and development. Among the projects, one representative case study is selected and discussed.
Findings
Results of the research affirm a positive relationship of access to AM devices to perceived interest, motivation and ease of learning of mechanical engineering. Entry-level additive technologies offer a hands-on experience within academia, fostering the acquisition of technical knowledge.
Research limitations/implications
The survey is distributed to more than 200 students to cover the full population of the CAP course over three academic years. The year the students participated in the CAP course is not tracked because the instructor was the same and there were no administrative differences. For this reason, the survey administration might be a limitation of the current study. In addition to this, no gender distinction is made because historically, the percentage of female students in Mechanical Engineering courses is about 10 per cent or lower. Although the answers to the survey are anonymous, only 37 per cent of the students gave a feedback. Thus, on the one hand, impact assessment is limited to a sample of about one-third of the complete population, but, on the other hand, the anonymity ensures randomization in the sample selection.
Practical implications
Early exposure of forthcoming designers to AM tools can turn into a “think-additive” approach to product design, that is a groundbreaking conception of geometries and product functionalities, leading to the full exploitation of the possibilities offered by additive technologies.
Social implications
Shared knowledge can act as a springboard for mass adoption of AM processes.
Originality/value
The advantages of adopting AM technologies at different levels of education, for diverse educational purposes and disciplines, are well assessed in the literature. The innovative aspect of this paper is that the impact of AM is evaluated through a feedback coming directly from mechanical engineering students.
Details
Keywords
Elena Bassoli, Agar Brugiavini and Giacomo Pasini
We exploit the international comparability and the longitudinal dimension of the Survey of Health, Ageing and Retirement in Europe to look at regional and cohort differences in…
Abstract
We exploit the international comparability and the longitudinal dimension of the Survey of Health, Ageing and Retirement in Europe to look at regional and cohort differences in disease prevalence across European regions. We find a significantly higher probability of reporting cardiovascular diseases among older Eastern European women than among other Europeans. Moreover, we observe a worsening in health conditions for younger cohorts.
Details
Keywords
Jerzy Bochnia and Slawomir Blasiak
The purpose of this paper was to verify the possibility of applying differential calculus of incomplete order to describe relaxation of the material obtained using selective laser…
Abstract
Purpose
The purpose of this paper was to verify the possibility of applying differential calculus of incomplete order to describe relaxation of the material obtained using selective laser sintering (SLS) technology.
Design/methodology/approach
The samples were made using the incremental technology for three print directions. Relaxation tests were conducted. The theoretical curves, which are the solution of the equation describing the five-parameter Maxwell-Wiechert model for derivatives in relation to the total time of complete order and fractional order, were adjusted to the obtained experimental curves.
Findings
The SLS technology creates new possibilities regarding modelling polymeric elements which might be applied as functional models (products). Therefore, it is necessary to conduct an in-depth study of their properties, including relaxation properties, which is associated with the necessity to use proper mathematical tools to describe those properties. The differential calculus of incomplete order was applied herein to describe the anisotropy of relaxation properties because of the print direction in relation to the relaxation curves adjusted with the five-parameter Maxwell-Wiechert model.
Research limitations/implications
As a result of the conducted considerations, the authors obtained the dependencies describing the anisotropy of relaxation properties with the use of coefficients alpha and beta, which stand for the derivative order of the differential equation, whereas coefficient kappa stands for the translation coefficient which is an innovative application of this type of mathematical apparatus.
Practical implications
The developed method might be applied to describe the anisotropy of a broader group of materials manufactured with the use of incremental technologies.
Originality/value
The application of the differential calculus of incomplete order to describe the anisotropy of the materials manufactured from polyamide powder using the SLS technology is a distinctive feature of this paper. A crucial cognitive element of the conducted research is the fact which confirms that the dynamic viscosity coefficients have the greatest impact on the anisotropy of material properties depending on the print directions.