The Mechanisms of Material Removal in the Fluidized Bed Machining of Polyvinyl Chloride Substrates

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
M. Barletta ◽  
V. Tagliaferri ◽  
F. Trovalusci ◽  
F. Veniali ◽  
A. Gisario
Keyword(s):  
Fluidized Bed ◽  
Polyvinyl Chloride ◽  
Process Parameters ◽  
Material Removal ◽  
High Speed ◽  
Mesh Size ◽  
Main Process ◽  
Machining Time ◽  
Polymeric Substrates ◽  
The Impact

In this paper, the mechanisms of material removal during the fluidized bed machining (FBM) of polymeric substrates are analyzed. Cylindrical components composed of polyvinyl chloride (PVC) were exposed to the impact of abrasives while rotating at high speed within a fluidization column. The interaction between the Al2O3 abrasive media and the PVC surfaces was studied to identify the effect of the main process parameters, such as the machining time, the abrasive mesh size, and the rotational speed. The change in the surface morphology as a function of the process parameters was evaluated using field emission gun—scanning electron microscopy (FEG-SEM) and contact gauge profilometry. An improvement in the finishing of the processed surfaces was achieved, and the related mechanisms were identified. The roles of the impact speed and the contact conditions between the abrading particles and the substrate were also investigated.

scholarly journals The Impact of 3D Printing Process Parameters on the Dielectric Properties of High Permittivity Composites

Designs ◽  
2019 ◽  
Vol 3 (4) ◽  
pp. 50 ◽  
Author(s):  
Athanasios Goulas ◽  
Shiyu Zhang ◽  
Darren A. Cadman ◽  
Jan Järveläinen ◽  
Ville Mylläri ◽  
...  
Keyword(s):  
3D Printing ◽  
Process Parameters ◽  
Relative Permittivity ◽  
Main Process ◽  
Fused Filament Fabrication ◽  
Layer Height ◽  
Additive Manufacturing Technology ◽  
The Impact ◽  
Printing Speed ◽  
Hatch Spacing

Fused filament fabrication (FFF) is a well-known and greatly accessible additive manufacturing technology, that has found great use in the prototyping and manufacture of radiofrequency componentry, by using a range of composite thermoplastic materials that possess superior properties, when compared to standard materials for 3D printing. However, due to their nature and synthesis, they are often a great challenge to print successfully which in turn affects their microwave properties. Hence, determining the optimum printing strategy and settings is important to advance this area. The manufacturing study presented in this paper shows the impact of the main process parameters: printing speed, hatch spacing, layer height and material infill, during 3D printing on the relative permittivity (εr), and loss tangent (tanδ) of the resultant additively manufactured test samples. A combination of process parameters arising from this study, allowed successful 3D printing of test samples, that marked a relative permittivity of 9.06 ± 0.09 and dielectric loss of 0.032 ± 0.003.

Magnetorheological (MR) Jet Finishing Technology

2004 ◽  
Author(s):  
William I. Kordonski ◽  
Aric B. Shorey ◽  
Marc Tricard
Keyword(s):  
High Precision ◽  
Material Removal ◽  
High Speed ◽  
Axial Magnetic Field ◽  
Fundamental Property ◽  
Cfd Modeling ◽  
Surface Shear Stress ◽  
Round Jet ◽  
Mr Polishing Fluid ◽  
The Impact

Conformal (or freeform) and steep concave optics are important classes of optics that are difficult to finish using conventional techniques due to mechanical interferences and steep local slopes. One suitable way to polish these classes of optics is by using a jet of abrasive/fluid mixture. In doing so, the energy required for polishing may be supplied by the radial spread of a liquid jet, which impinges a surface to be polished. Such fluid flow may generate sufficient surface shear stress to provide material removal in the regime of chemical mechanical polishing. Once translated into a polishing technique, this unique tool may resolve a challenging problem of finishing steep concave surfaces and cavities. A fundamental property of a fluid jet is that it begins to lose its coherence as the jet exits a nozzle. This is due to a combination of abruptly imposed longitudinal and lateral pressure gradients, surface tension forces, and aerodynamic disturbance. This results in instability of the flow over the impact zone and consequently polishing spot instability. To be utilized in deterministic high precision finishing of remote objects, a stable, relatively high-speed, low viscosity fluid jet, which remains collimated and coherent before it impinges the surface to be polished, is required. A method of jet stabilization has been proposed, developed and demonstrated whereby the round jet of magnetorheological fluid is magnetized by an axial magnetic field when it flows out of the nozzle. It has been experimentally shown that a magnetically stabilized round jet of MR polishing fluid generates a reproducible material removal function (polishing spot) at a distance of several tens of centimeters from the nozzle. In doing so, the interferometrically derived distribution of material removal for an axisymmetric MR Jet, which impinges normal to a plane glass surface, coincides well with the radial distribution of rate of work calculated using computational fluid dynamics (CFD) modeling. Polishing results support the assertion that the MR Jet finishing process may produce high precision surfaces on glasses and single crystals. The technology is most attractive for the finishing of complex shapes like freeform optics, steep concaves and cavities.

scholarly journals The impact of process parameters on mechanical properties of parts fabricated in PLA with an open-source 3-D printer

2015 ◽  
Vol 21 (5) ◽  
pp. 604-617 ◽  
Author(s):  
Antonio Lanzotti ◽  
Marzio Grasso ◽  
Gabriele Staiano ◽  
Massimo Martorelli
Keyword(s):  
Mechanical Properties ◽  
Open Source ◽  
Process Parameters ◽  
Computer Aided Design ◽  
Fused Deposition Modeling ◽  
Testing Machine ◽  
Main Process ◽  
Content Type ◽  
Fused Deposition ◽  
The Impact

Purpose – This study aims to quantify the ultimate tensile strength and the nominal strain at break (ɛf) of printed parts made from polylactic acid (PLA) with a Replicating Rapid prototyper (Rep-Rap) 3D printer, by varying three important process parameters: layer thickness, infill orientation and the number of shell perimeters. Little information is currently available about mechanical properties of parts printed using open-source, low-cost 3D printers. Design/methodology/approach – A computer-aided design model of a tensile test specimen was created, conforming to the ASTM:D638. Experiments were designed, based on a central composite design. A set of 60 specimens, obtained from combinations of selected parameters, was printed on a Rep-Rap Prusa I3 in PLA. Testing was performed using a JJ Instruments – T5002-type tensile testing machine and the load was measured using a load cell of 1,100 N. Findings – This study investigated the main impact of each process parameter on mechanical properties and the effects of interactions. The use of a response surface methodology allowed the proposition of an empirical model which connects process parameters and mechanical properties. Even though results showed a high variability, additional ideas on how to understand the impact of process parameters are suggested in this paper. Originality/value – On the basis of experimental results, it is possible to obtain practical suggestions to set common process parameters in relation to mechanical properties. Experiments discussed in the present paper provide a variety of data and insight regarding the relationship among the main process parameters and the stiffness and strength of fused deposition modeling-printed parts made from PLA. In particular, this paper underlines the shortage in existing literature concerning the impact of process parameters on the elastic modulus and the strain to failure for the PLA. The experimental data produced show a good degree of compliance with analytical formulations and other data found in literature.

An Investigation of Factors Affecting and Optimizing Material Removal Rate in Computer Controlled Ultra-Precision Polishing

2014 ◽  
Vol 625 ◽  
pp. 446-452
Author(s):  
Lai Ting Ho ◽  
Chi Fai Cheung ◽  
Liam Blunt ◽  
Sheng Yue Zeng
Keyword(s):  
Process Parameters ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Orthopedic Implants ◽  
Polishing Process ◽  
Factors Affecting ◽  
Ultra Precision ◽  
Computer Controlled ◽  
The Impact

There are numerous parameters and steps involved in a computer controlled ultra-precision polishing process (CCUP). The success of CCUP relies heavily on the understanding and optimization of material removal when new materials and new surfaces are polished. It is crucial to optimize the polishing parameters to enhance the effectiveness of the polishing process and to assess the impact of different process parameters on the material removal rate of particular difficult-to-machine materials such as CoCr alloys, which is commonly used in orthopedic implants. This paper aims at studying the process parameters and optimization of the parameter to enhance the material removal rate and quantify the contribution of process parameters.

On the Geometric Accuracy of RepRap Open-Source Three-Dimensional Printer

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
Antonio Lanzotti ◽  
Domenico Maria Del Giudice ◽  
Antonio Lepore ◽  
Gabriele Staiano ◽  
Massimo Martorelli
Keyword(s):  
Open Source ◽  
Process Parameters ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Scientific Data ◽  
Correct Selection ◽  
Geometric Feature ◽  
Main Process ◽  
Geometric Features ◽  
The Impact

In the field of additive manufacturing (AM) processes, there is a significant lack of scientific data on the performance of open-source 3D printers in relation to process parameter values. The purpose of this paper is to assess the impact of the main process parameters on the accuracy of a set of typical geometric features, as obtained with an open-source 3D printer, the RepRap Prusa-Mendel I2. For this purpose, a benchmarking part was set up, composed of elementary shapes, representing a series of different geometric features. By means of a DoE approach, it was possible to assess the effects of two process parameters—layer thickness (Lt) and flow rate (Fr)—on five geometric features: cube, sphere, cylinder, cone, and angled surface. A high resolution Laser Scanner was used to evaluate the variation between the acquired geometric feature and the corresponding 3D computer-aided design (CAD) nominal model. On the basis of experimental results, it was possible to analyze and discuss the main effects of the above-mentioned process parameters on each geometric feature. These results can help RepRap users in the correct selection of process parameters with the aim of improving the quality of prototypes.

Impact of Process Parameters on the Auto Claw-Pole Thixoforming Process

2011 ◽  
Vol 295-297 ◽  
pp. 1625-1630 ◽  
Author(s):  
Van Luu Dao ◽  
Sheng Dun Zhao ◽  
Wen Jie Lin ◽  
Xiao Mei Yuan
Keyword(s):  
Process Parameters ◽  
Hot Forging ◽  
Main Process ◽  
Forming Process ◽  
Billet Temperature ◽  
Forming Technology ◽  
Punch Speed ◽  
Initial Billet ◽  
Die Temperature ◽  
The Impact

Thixoforming of steel is a potential forming technology, which can realize near-net-shape forming process with good quality in one forming step. In this paper, thixoforming process was used to replace the conventional hot forging process to form the auto claw-pole. The finite element code Forge2008Ó was used to simulate the auto claw-pole thixoforming process. The impact of three main process parameters such as initial billet temperature, punch speed and die temperature on the forming process were investigated. The reasonable process parameters for the auto claw-pole thixoforming were obtained: initial billet temperature 1430~1440°C, punch speed 100~200mm/s and die temperature 300~400°C.

scholarly journals A tailored heating element for resistance welding of complex shaped joining surfaces

2020 ◽  
pp. 089270572098204
Author(s):  
Erik Dahl ◽  
Helmut Schürmann ◽  
Christian Mittelstedt
Keyword(s):  
Process Parameters ◽  
Electrical Power ◽  
Welding Process ◽  
Electrical Energy ◽  
Measuring Method ◽  
Heating Element ◽  
Main Process ◽  
Climate Conditions ◽  
Lap Shear ◽  
The Impact

To obtain a larger freedom of design for structural components, a single wire heating element which is capable of welding large and complex shaped surfaces has been developed. The processing window for welds of endless-carbon-fiber-reinforced polyamide 6 (CF-PA6) using the developed heating element is investigated, varying the main process parameters electrical power, electrical energy and joining pressure. The influence of these process parameters on the quality of the welded joints is judged by single and double lap shear tests and by the analysis of micrographs. As a result, recommendations for the processing parameters are derived. The climate conditions of the specimens are varied to analyze the impact of moisture on the shear-transmitting joints whereby an accelerated method for conditioning of PA6 specimens is used. Furthermore, a sensor-free method for monitoring the temperature of the welding process is presented and compared with a classical measuring method.

Understanding Process Parameter Effects of RepRap Open-Source Three-Dimensional Printers Through a Design of Experiments Approach

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Antonio Lanzotti ◽  
Massimo Martorelli ◽  
Gabriele Staiano
Keyword(s):  
Design Of Experiments ◽  
Open Source ◽  
Process Parameters ◽  
Laser Scanner ◽  
Scientific Data ◽  
Engineering System ◽  
Main Process ◽  
The Impact ◽  
Selection Of

With a view to enabling additive manufacturing (AM) processes, today, open-source, low-cost 3D printers are systems with great potential. However there is a significant lack of scientific data on the performance of open-source 3D systems and on the selection of adequate process parameters that can help to improve the quality of the parts. The purpose of this paper is to assess the effects of the main process parameters on the dimensional accuracy of a specific open-source 3D printer, the RepRap Prusa-Mendel I2. This study consisted of a benchmarking part, involving elementary shapes representing a series of different features. By means of a full factorial DoE (Design of Experiments), with three factors (layer thickness, deposition speed, and flow rate), three levels, and three replications, 81 parts were obtained. Subsequently, a laser scanner (D700 Laser Scanner—3Shape, Denmark) was used as high resolution reverse engineering system in order to evaluate the variation between real parts and nominal geometry. The impact of the main process parameters was evaluated and optimal combinations were analyzed. On the basis of the results obtained in the experiments, practical suggestions for the settings of common process parameters were formulated. Test results serve to improve the quality of AM parts through the most appropriate selection of the main process parameters.

Fuzzy Model for Electrostatic Fluidized Bed Coating

2014 ◽  
Author(s):  
Federica Trovalusci ◽  
Massimiliano Barletta ◽  
Oliviero Giannini
Keyword(s):  
Fluidized Bed ◽  
Process Parameters ◽  
Coating Thickness ◽  
Gas Flow ◽  
Fuzzy Model ◽  
Transformation Method ◽  
Model Parameters ◽  
Main Process ◽  
Fluidized Bed Coating ◽  
Control Procedures

The study concerns the coating process of metal substrates in an electrostatic fluidized bed (EFB). This eco-friendly process is profitably used to coat components of particularly complex shapes. Although this technology is widely spread in several industrial domains, the implementation of appropriate process control procedures is still object of investigation. A model was generated from experimental data with the aim of predicting, for any set of process parameters, the resulting coating thickness of the sample. With a design of experiment (DOE) approach, the experimental investigation, that is the base for the model, quantifies the coating thickness as a function of the main process parameters namely coating time, applied voltage, and gas flow rate fed into the fluidized bed. This study addresses the effect of the inherent uncertainties on the predicted coating thickness caused by the approximation in the model parameters. In particular, a fuzzy-logic based approach is used to describe the model uncertainties and the transformation method is used to propagate their effect on the thickness. The fuzzy results are then compared with the data produced by the experimentation leading to the evaluation of the membership level of the dataset to the uncertain model.

Magnetorheological Jet (MR JetTM) Finishing Technology

2005 ◽  
Vol 128 (1) ◽  
pp. 20-26 ◽  
Author(s):  
William I. Kordonski ◽  
Aric B. Shorey ◽  
Marc Tricard
Keyword(s):  
High Precision ◽  
Material Removal ◽  
High Speed ◽  
Axial Magnetic Field ◽  
Fundamental Property ◽  
Cfd Modeling ◽  
Surface Shear Stress ◽  
Round Jet ◽  
Mr Polishing Fluid ◽  
The Impact

Conformal (or freeform) and steep concave optics are important classes of optics that are difficult to finish using conventional techniques due to mechanical interferences and steep local slopes. One suitable way to polish these classes of optics is by using a jet of abrasive/fluid mixture. The energy required for polishing may be supplied by the radial spread of a liquid jet, which impinges a surface to be polished. Such fluid flow may generate sufficient surface shear stress to provide material removal in the regime of chemical mechanical polishing. Once translated into a polishing technique, this unique tool may resolve a challenging problem of finishing steep concave surfaces and cavities. A fundamental property of a fluid jet is that it begins to lose its coherence as the jet exits a nozzle. This is due to a combination of abruptly imposed longitudinal and lateral pressure gradients, surface tension forces, and aerodynamic disturbance. This results in instability of the flow over the impact zone and consequently polishing spot instability. To be utilized in deterministic high precision finishing of remote objects, a stable, relatively high-speed, low viscosity fluid jet, which remains collimated and coherent before it impinges the surface to be polished, is required. A method of jet stabilization has been proposed, developed, and demonstrated whereby the round jet of magnetorheological fluid is magnetized by an axial magnetic field when it flows out of the nozzle. It has been experimentally shown that a magnetically stabilized round jet of magnetorheological (MR) polishing fluid generates a reproducible material removal function (polishing spot) at a distance of several tens of centimeters from the nozzle. The interferometrically derived distribution of material removal for an axisymmetric MR Jet™ , which impinges normal to a plane glass surface, coincides well with the radial distribution of rate of work calculated using computational fluid dynamics (CFD) modeling. Polishing results support the assertion that the MR Jet finishing process may produce high precision surfaces on glass and single crystals. The technology is most attractive for the finishing of complex shapes like freeform optics, steep concaves, and cavities.

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