Search results

The purpose of this paper is to present a solution for the levelling plate of fused deposition modelling (FDM) additive manufacturing (AM) systems. This automatic levelling system is presented as an evolution of actual systems, which uses a new ultrasound sensing system.

After obtaining a prototype, different tests were conducted for getting a system which solves the level plate problem and can be mounted in any FDM AM machine. Several benchmark models were obtained and compared with current equipment concepts for the validity of the product.

All tests were performed with high accuracy, enabling the production of geometries that could not have been achieved without this novel system.

This development will enable experienced users to set aside the problems of calibration and focus on the purpose of this type of machines, making prototypes.

A system architecture has been developed and integrated into an open hardware AM system, allowing real-time adjustment of the plate during each layer, thus eliminating the need of levelling the plate, allowing to achieve easier printing, and without increasing the cost significantly.

The purpose of this study is to propose an automatic leveling method for a printing platform based on a three-point coordinate feedback. The proposed method is used in fused deposition modeling additive manufacturing systems. The coordinate error of the leveled plane is constrained to within  ± 0.2 mm, which is less than the printed layer thickness.

First, the model of the forward and inverse solutions of the parallel arm is obtained based on the principles of vector algebra. Second, the automatic leveling mechanism for collecting the z-coordinate is designed. The best position of the virtual origin plane is obtained by comparing the z-coordinates of the test points. Finally, after making multiple adjustments through a closed-loop z-coordinate feedback, the parallelism of the printing plane and the virtual origin plane is limited to an effective range.

The experimental results show that after three leveling attempts, the z-coordinate of the test points can be constrained to within  ± 0.2 mm, which shows that this method can effectively achieve automatic leveling in a delta three-dimensional (3D) printer.

This study presents a novel and distinctive delta 3D printer leveling system by designing a leveling mechanism and a leveling algorithm. The method uses a closed-loop feedback mode to make the leveling process simple, convenient and efficient without requiring major changes to the printer. The error after leveling is less than the printed layer thickness, which fully guarantees the accuracy of the leveling process.

A three-dimensional (3D) printing error simulation approach is proposed to analyze the influence of tilted vertical beams on the 3D printing accuracy. The purpose of this study is to analyze the influence of such errors on printing accuracy and printing quality for delta-robot 3D printer.

First, the kinematic model of a delta-robot 3D printer with an ideal geometric structure is proposed by using vector analysis. Then, the normal kinematic model of a nonideal delta-robot 3D robot with tilted vertical beams is derived based on the above ideal kinematic model. Finally, a 3D printing error simulation approach is proposed to analyze the influence of tilted vertical beams on the 3D printing accuracy.

The results show that tilted vertical beams can indeed cause 3D printing errors and further influence the 3D printing quality of the final products and that the 3D printing errors of tilted vertical beams are related to the rotation angles of the tilted vertical beams. The larger the rotation angles of the tilted vertical beams are, the greater the geometric deformations of the printed structures.

Three vertical beams and six horizontal beams constitute the supporting parts of the frame of a delta-robot 3D printer. In this paper, the orientations of tilted vertical beams are shown to have a significant influence on 3D printing accuracy. However, the effect of tilted vertical beams on 3D printing accuracy is difficult to capture by instruments. To reveal the 3D printing error mechanisms under the condition of tilted vertical beams, the error generation mechanism and the quantitative influence of tilted vertical beams on 3D printing accuracy are studied by simulating the parallel motion mechanism of a delta-robot 3D printer with tilted vertical beams.

In this work, the production of ceramic moulds for aluminium casting using a stereolithographic apparatus (SLA) is presented.

Suspensions of silica powders in a photoreactive resin were used in a standard SLA equipment in order to build green parts. SLA, SLA‐250 (3D System, Valencia, CA) was modified in order to fabricate a ceramic green parts.

A characterization of mechanical properties of the material samples was performed. Finally, moulds for aluminium casting were obtained either using the stereolithographic part as a green mould, either by pyrolisis of the organic binder and subsequent sintering at high temperature.

Future investigations will be devoted to optimise the process and the mechanical performances of the sintered parts, improving the rheological properties of suspensions and reducing the building time.

This is a novel work on the production of ceramic moulds for aluminium casting using a SLA.

In order to minimize the impact of variability on performance of the process, proper understanding of factors interdependencies and their impact on process variability (PV) is required. However, with insufficient/incomplete numerical data, it is not possible to carry out in-depth process analysis. This paper presents a qualitative framework for analyzing factors causing PV and estimating their influence on overall performance of the process.

Fuzzy analytic hierarchy process is used to evaluate the weight of each factor and Bayesian network (BN) is utilized to address the uncertainty and conditional dependencies among factors in each step of the process. The weighted values are fed into the BN for evaluating the impact of each factor to the process. A three axiom-based approach is utilized to partially validate the proposed model.

A case study is conducted on fused filament fabrication (FFF) process in order to demonstrate the applicability of the proposed technique. The result analysis indicates that the proposed model can determine the contribution of each factor and identify the critical factor causing variability in the FFF process. It can also helps in estimating the sigma level, one of the crucial performance measures of a process.

The proposed methodology is aimed to predict the process quality qualitatively due to limited historical quantitative data. Hence, the quality metric is required to be updated with the help of empirical/field data of PV over a period of operational time. Since the proposed method is based on qualitative analysis framework, the subjectivities of judgments in estimating factor weights are involved. Though a fuzzy-based approach has been used in this paper to minimize such subjectivity, however more advanced MCDM techniques can be developed for factor weight evaluation.

As the proposed methodology uses qualitative data for analysis, it is extremely beneficial while dealing with the issue of scarcity of experimental data.

The prediction of the process quality and understanding of difference between product target and achieved reliability before the product fabrication will help the process designer in correcting/modifying the processes in advance hence preventing substantial amount of losses that may happen due to rework and scraping of the products at a later stage.

This qualitative analysis will deal with the issue of data unavailability across the industry. It will help the process designer in identifying root cause of the PV problem and improving performance of the process.

‘THE most interesting years of my industrial life’ is the way the writer of this column would describe the three and a half years of office as editor of Time and Motion Study.

This paper aims to present new qualitative and quantitative data about the recently released “BigRep ONE” 3 D printer led by the design of a one-off customized stool.

A design for additive manufacturing (DfAM) framework was adopted, with simulation data iteratively informing the final design.

Process parameters can vary manufacturing costs of a stool by over AU$1,000 and vary print time by over 100 h. Following simulation, designers can use the knowledge to inform iteration, with a second variation of the design being approximately 50 per cent cheaper and approximately 50 per cent faster to manufacture. Metrology data reveal a tolerance = 0.342 per cent in overall dimensions, and surface roughness data are presented for a 0.5 mm layer height.

Led by design, this study did not seek to explore the full gamut of settings available in slicing software, focusing predominantly on nozzle diameter, layer height and number of walls alongside the recommended settings from BigRep. The study reveals numerous areas for future research, including more technical studies.

When knowledge and techniques from desktop 3 D printing are scaled up to dimensions measuring in meters, new opportunities and challenges are presented for design engineers. Print times and material costs in particular are scaled up significantly, and this study provides numerous considerations for research centers, 3 D printing bureaus and manufacturers considering large-scale fused filament fabrication manufacturing.

This is the first peer-reviewed study involving the BigRep ONE, and new knowledge is presented about the practical application of the printer through a design-led project. Important relationships between material volume/cost and print time are valuable for early adopters.

In the previous decade, unmanned aerial vehicles (UAVs) have turned into a subject of enthusiasm for some exploration associations. UAVs are discovering applications in different regions going from military applications to activity reconnaissance. The purpose of this paper is to overview a particular sort of UAV called quadrotor or quadcopter.

This paper includes the dynamic models of a quadrotor and the distinctive model-reliant and model-autonomous control systems and their correlation.

In the present time, focus has moved to outlining autonomous quadrotors. Ultimately, the paper examines the potential applications of quadrotors and their part in multi-operators frameworks.

This investigation deals with the review on various quadrotors, their applications and motion control strategies.

The purpose of this paper is to explore what underlies the development of the consumer 3D printing industry and gain insight into future developments and its potentially disruptive impact on the existing manufacturing industry.

A combination of approaches was followed. Initially a consumer 3D printer was purchased to gain first-hand experience as part of a practical research case study. Results were discussed with manufacturers and additional information was sought, and triangulated, via a survey and an exploratory bibliometric study.

Many characteristics are in place to identify consumer 3D printing as a potential disruptive technology for the manufacturing industry. For example, the cost of consumer 3D printing is lower than for traditional manufacturing. However, the current adoption rate is low and the user friendliness and technological capabilities need to improve.

The main limitation is the exploratory nature of the study which does not allow generalizations.

If developments and adoption patterns continue, then traditional manufacturing industries, distribution channels and the transportation sector may become threatened.

Technological advances in consumer manufacturing can potentially threaten several economic sectors, which can lead to loss of jobs and affect budgets of states of countries that depend on sales tax.

One of the first studies to employ experiments in combination with other methods to gain insight into adoption patterns and the disruptive nature of consumer 3D printers specifically, rather than industrial 3D printers or new business models as a result of 3D printing technology.

This case study aims to investigate how locally additively manufactured functional parts can make African metrology institutes more sustainable and independent. These institutes provide calibration services, which links the measurement units to industrial and everyday measurements. This traceability is critical to overcome technical barriers to trade and industrialisation. Most African countries have such a designated institute that requires advanced scientific instrumentation. These instruments are custom-built for a specific application, hard to procure or sometimes obsolete. Servicing these instruments or obtaining spare parts are also difficult. The purpose aims to evaluate if three-dimensional (3D) printing can significantly improve this situation, by providing six institutes with a 3D printer and training.

Therefore, a 3D printer pilot project was launched, involving six African metrology institutes, with the aim of developing the basic manufacturing capabilities of these institutes so that they can produce functional parts. The project included training on both digital part modelling and 3D printer usage. This case study reviews the technology selection method, project risks, needs, challenges and results, with the aid of research questions.

The results of the project illustrate how additive manufacturing (AM) has started to enable metrology in Africa and how it can be expanded to the general scientific endeavour on the continent.

The success of this project can be used to motivate the further adoption of AM in African National Metrology Institutes, as well as other scientific institutes.

The project is the first AM project of its kind for African National Metrology Institutes.