scholarly journals A Comparative Analysis of Chemical, Thermal, and Mechanical Post-Process of Fused Filament Fabricated Polyetherimide Parts for Surface Quality Enhancement

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5880
Author(s):  
Ariadna Chueca de Bruijn ◽  
Giovanni Gómez-Gras ◽  
Marco A. Pérez
Keyword(s):  
Surface Quality ◽  
Production Systems ◽  
Morphological Changes ◽  
Dimensional Accuracy ◽  
Thermal Treatments ◽  
Dimensional Changes ◽  
Advantages And Disadvantages ◽  
Post Process ◽  
Electron Scanning Microscopy ◽  
Manufacturing Technologies

Additive manufacturing technologies are increasingly being used in production systems because they shorten product development time and production cost, but surface integrity remains a limitation to meet the standards set by conventional manufacturing. In this research article, two chemical, one thermal, and three mechanical finishing operations are proposed to post-process fused filament fabricated Ultem 9085 parts. Their effects on the parts’ surface quality and dimensional accuracy (changes in their width, height, length, and mass) are examined through optical and electron scanning microscopy, and the advantages and disadvantages of each method are discussed. Microscope evaluation has proven to be a powerful tool to observe apparent differences and understand the nature of different morphological changes. Results indicate that chemical and thermal treatments and ball burnishing are good candidates to significantly enhance the finish of the parts, despite requiring the use of solvents or provoking dimensional changes to the parts. The effects of abrasive mechanical treatments are more moderate at a macroscopic scale, but the surface of the filaments suffers the most remarkable changes.

The Accuracy of the Plastic Parts Milling Process Executed by a Six Axes Robot

2015 ◽  
Vol 808 ◽  
pp. 339-344 ◽  
Author(s):  
Alexandru Popan ◽  
Nicolae Bâlc ◽  
Bogdan Luca ◽  
Alina Popan ◽  
Alexandru Carean
Keyword(s):  
Surface Quality ◽  
New Technology ◽  
Dimensional Accuracy ◽  
Milling Process ◽  
Good Precision ◽  
Plastic Part ◽  
Advantages And Disadvantages ◽  
Machine Parts ◽  
Plastic Parts

The objective of this paper is to analyze the precision of plastic parts made by using robot milling. Currently, the robots have good precision, rigidity, flexibility and they are able to machine parts. By using a six axis Kuka robot and an electric spindle, a plastic part was milled. The paper presents the advantages and disadvantages of this new technology, analyzing the dimensional accuracy, surface quality and costs.

Research Status of Subsequent Machining of Laser Cladding Layers

2020 ◽  
Vol 15 ◽  
Author(s):  
Lei Li ◽  
Yujun Cai ◽  
Guohe Li ◽  
Meng Liu
Keyword(s):  
Tool Wear ◽  
Surface Quality ◽  
Laser Cladding ◽  
Wear Surface ◽  
Chip Formation ◽  
Cutting Temperature ◽  
Dimensional Accuracy ◽  
Cutting Parameters ◽  
Cladding Layer ◽  
Cladding Layers

Background: As an important method of remanufacturing, laser cladding can be used to obtain the parts with specific shapes by stacking materials layer by layer. The formation mechanism of laser cladding determines the “Staircase effect”, which makes the surface quality can hardly meet the dimensional accuracy of the parts. Therefore, the subsequent machining must be performed to improve the dimensional accuracy and surface quality of cladding parts. Methods: In this paper, chip formation, cutting force, cutting temperature, tool wear, surface quality, and optimization of cutting parameters in the subsequent cutting of laser cladding layer are analyzed. Scholars have expounded and studied these five aspects but the cutting mechanism of laser cladding need further research. Results: The characteristics of cladding layer are similar to that of difficult to machine materials, and the change of parameters has a significant impact on the cutting performance. Conclusion: The research status of subsequent machining of cladding layers is summarized, mainly from the aspects of chip formation, cutting force, cutting temperature, tool wear, surface quality, and cutting parameters optimization. Besides, the existing problems and further developments of subsequent machining of cladding layers are pointed out. The efforts are helpful to promote the development and application of laser cladding remanufacturing technology.

scholarly journals Evaluation of dimensional accuracy of dental bridges manufactured with conventional casting technique and CAD/CAM system with Ceramill Sintron blocks using CMM

2018 ◽  
Vol 12 (4) ◽  
pp. 264-271 ◽  
Author(s):  
Alireza Izadi ◽  
Fariborz Vafaee ◽  
Arash Shishehian ◽  
Ghodratollah Roshanaei ◽  
Behzad Fathi Afkari
Keyword(s):  
Reference Model ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Three Dimensions ◽  
Casting Technique ◽  
Dimensional Changes ◽  
Conventional Casting ◽  
Cad Cam ◽  
Milling Method ◽  
Measuring Machine

Background. Recently, non-presintered chromium-cobalt (Cr-Co) blocks with the commercial name of Ceramill Sintron were introduced to the market. However, comprehensive studies on the dimensional accuracy and fit of multi-unit frameworks made of these blocks using the coordinate measuring machine (CMM) are lacking. This study aimed to assess and compare the dimensional changes and fit of conventional casting and milled frameworks using Ceramill Sintron. Methods. A metal model was designed and scanned and 5-unit frameworks were fabricated using two techniques: (I) the conventional casting method (n=20): the wax model was designed, milled in the CAD/CAM machine, flasked and invested; (II) the milling method using Ceramill Sintron blocks (n=20): the wax patterns of group 1 were used; Ceramill Sintron blocks were milled and sintered. Measurements were made on the original reference model and the fabricated frameworks using the CMM in all the three spatial dimensions, and dimensional changes were recorded in a checklist. Data were analyzed with descriptive statistics, and the two groups were compared using one-way ANOVA and Tukey test (α=0.05). Results. The fabricated frameworks in both groups showed significant dimensional changes in all the three dimensions. Comparison of dimensional changes between the two groups revealed no significant differences (P>0.05) except for transverse changes (arch) that were significantly greater in Ceramill Sintron frameworks (P<0.05). Conclusion. The two manufacturing processes were the same regarding dimensional changes and the magnitude of marginal gaps and both processes resulted in significant dimensional changes in frameworks. Ceramill Sintron frameworks showed significantly greater transverse changes than the conventional frameworks.

scholarly journals MODEL-BASED DESIGN OF AM COMPONENTS TO ENABLE DECENTRALIZED DIGITAL MANUFACTURING SYSTEMS

2021 ◽  
Vol 1 ◽  
pp. 2127-2136
Author(s):  
Olivia Borgue ◽  
John Stavridis ◽  
Tomas Vannucci ◽  
Panagiotis Stavropoulos ◽  
Harry Bikas ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Manufacturing Systems ◽  
Production Systems ◽  
Data Generation ◽  
Production Networks ◽  
Model Based ◽  
Manufacturing Technologies ◽  
Am Processes ◽  
Final Consumer

AbstractAdditive manufacturing (AM) is a versatile technology that could add flexibility in manufacturing processes, whether implemented alone or along other technologies. This technology enables on-demand production and decentralized production networks, as production facilities can be located around the world to manufacture products closer to the final consumer (decentralized manufacturing). However, the wide adoption of additive manufacturing technologies is hindered by the lack of experience on its implementation, the lack of repeatability among different manufacturers and a lack of integrated production systems. The later, hinders the traceability and quality assurance of printed components and limits the understanding and data generation of the AM processes and parameters. In this article, a design strategy is proposed to integrate the different phases of the development process into a model-based design platform for decentralized manufacturing. This platform is aimed at facilitating data traceability and product repeatability among different AM machines. The strategy is illustrated with a case study where a car steering knuckle is manufactured in three different facilities in Sweden and Italy.

Flexibles robotergeführtes Dornhonen*/Flexible, robot guided single-pass honing - Flexible honing of geometrically complex workpieces in small and medium lot size production

2015 ◽  
Vol 105 (06) ◽  
pp. 360-365
Author(s):  
E. Uhlmann ◽  
S. Zimmermann
Keyword(s):  
Surface Quality ◽  
Tribological Properties ◽  
Industrial Robot ◽  
Dimensional Accuracy ◽  
Lot Size ◽  
Flexible Robot ◽  
Single Pass ◽  
Machining Center ◽  
Geometrically Complex ◽  
Flexible Honing

Das Fertigungsverfahren Honen kommt zur Anwendung, wenn an Bauteile hohe Anforderungen hinsichtlich Form- und Maßgenauigkeit, Oberflächenqualität sowie tribologische Eigenschaften gestellt werden. Insbesondere das Honen von Bauteilen mit Bohrungen in verschiedenen Positionen und Winkellagen stellt eine Herausforderung dar. Mithilfe eines 6-Achs-Industrieroboters wurde ein Verdichtergehäuse in W-Bauform bearbeitet. Anschließend wurden die Arbeitsergebnisse mit konventionell gefertigten Bauteilen verglichen. &nbsp; In manufacturing, honing is used to meet high demands on shape and dimensional accuracy, surface quality, as well as tribological properties. In particular, the honing of workpieces with bore holes in various positions and angles represents a challenge. With the help of a six-axis industrial robot, a W-shaped compressor housing was machined and working results were compared with results produced on a machining center.

FUNCTIONAL METHODS OF EARLY DIAGNOSTICS OF AGE MACULAR DEGENERATION.(LITERATURE REVIEW)

2021 ◽  
Vol Special issue (2) ◽  
pp. 61-67
Author(s):  
Azamat Yusupov ◽  
◽  
Mukhiddin Ziyoviddinov ◽  
Shavkat Mukhanov ◽  
O.O. Sobirov
Keyword(s):  
Literature Review ◽  
Macular Degeneration ◽  
Contrast Sensitivity ◽  
Morphological Changes ◽  
Pigment Epithelium ◽  
Sensitivity Study ◽  
Age Related Macular Degeneration ◽  
Functional Diagnostics ◽  
Advantages And Disadvantages ◽  
Age Related

This article provides an unsystematic literature review devoted to analyzing the currently existing methods of functional diagnostics for age-related macular degeneration.The essence, advantages and disadvantages, and literature data on the use of such methods asphotostresstest, electrooculography, dark adaptation study, contrast sensitivity function assessment, light and color sensitivity study,electroretinographyand critical flicker fusion frequencyare described.Based on the analysis of literature data, itis shownthat currently, there is a need to searchfor informative and accessible methods of functional diagnostics in age-related macular degeneration, especially for its early diagnosis. The analysis has shown that the existing methods are mainly aimed either at fixing secondary morphological changes in the layer of pigment epithelial cells, at identifying the pathology of the pigment epithelium in conjunction with determining the function of photoreceptor elements, or at a comprehensive assessment of the structures of several layers of the retina. Keywords:age-related macular degeneration; methods of functional diagnostics; photostress test; electrooculography; contrast sensitivity

scholarly journals Effects of Sintering Behaviors on Dimensional Accuracy, Surface Quality, and Mechanical Properties of Stereolithography-printed 3Y-ZrO2 Ceramics

2021 ◽  
Author(s):  
Cheng Zhang ◽  
Zhaoliang Jiang ◽  
Li Zhao ◽  
Weiwei Guo ◽  
Chengpeng Zhang
Keyword(s):  
Mechanical Properties ◽  
Dental Implants ◽  
Surface Quality ◽  
Dimensional Accuracy ◽  
Scanning Speed ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Air Atmosphere ◽  
Length Width ◽  
Technical Guide

Abstract Sintering process is essential to acquire the final components by stereolithography (SLA), which is a promising additive manufacturing technology for the fabrication of complex, custom-designed dental implants. 3Y-ZrO2 ceramics at different sintering behaviors in air atmosphere were successfully obtained in this study. Firstly, the curing properties of homemade pastes were studied, and the penetration depth and critical exposure of the pastes were calculated as 17.2 μm and 4.80 mJ/cm2, respectively. The green ceramic parts were performed at 154 mW laser power and 6000 mm/s scanning speed. Then, the dimensional accuracy, surface quality, and mechanical properties of 3Y-ZrO2 ceramics were investigated. The shrinkages of length, width, and height were 26%~27 %, 30%~31 %, and 27%~33 % in sintered ceramics, respectively. The Ra values of XOY, YOZ, and XOZ surfaces showed an anisotropic feature, and they were smallest as 0.52 μm, 2.40 μm, and 2.46 μm, respectively. Meanwhile, the mechanical properties presented a similar trend that they grew first and then dropped at various sintering behaviors. The optimal parameters were 1500 ℃, 60 min, and 4 ℃/min, and the maximum relative density of 96.18 %, Vickers hardness of 12.45 GPa, and fracture toughness of 6.35 MPa·m1/2 were achieved. Finally, the X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS) analysis demonstrated that no change was observed in crystal transformation and phase composition, and the organic was completely removed in sintered ceramics. This research is expected to provide a technical guide for the fabrication of ceramics for dental implants using SLA technique.

scholarly journals A Review for Southern Highbush Blueberry Alternative Production Systems

2020 ◽  
Author(s):  
Yang Fang ◽  
Gerardo H. Nunez ◽  
Mariana Neves da Silva ◽  
Douglas A. Phillips ◽  
Patricio R. Munoz
Keyword(s):  
Open Field ◽  
Production Systems ◽  
Academic Research ◽  
Highbush Blueberry ◽  
Entry Barrier ◽  
Advantages And Disadvantages ◽  
Alternative Systems ◽  
Southern Highbush ◽  
High Yields ◽  
Field Production

Southern highbush blueberry plantations have been expanded into worldwide non-traditional growing areas with elite cultivars and improved horticultural practices. This article presents a comprehensive review of current production systems &ndash; alternatives to traditional open field production &ndash; such as production in protected environments, high-density plantings, evergreen production, and container-based production. We discuss the advantages and disadvantages of each system and compare their differences to the open field production. In addition, potential solutions have been provided for some of the disadvantages. We also highlight some of the gaps existing between academic studies and production in industry, providing a guide for future academic research. All these alternative systems have shown the potential to produce high yields with high quality berries. Alternative systems, compared to the field production, require higher establishment investments and thus create an entry barrier for new producers. Nevertheless, with their advantages, alternative productions have potential to be profitable.

Influence of Manufacturing Process on the Fatigue Strength of Gears

2014 ◽  
Vol 1018 ◽  
pp. 269-276
Author(s):  
Andrea Reiß ◽  
Ulf Engel
Keyword(s):  
Fatigue Strength ◽  
Surface Quality ◽  
Fatigue Behavior ◽  
High Surface ◽  
Research Work ◽  
Dimensional Accuracy ◽  
Cold Forging ◽  
Hardness Distribution ◽  
Forming Process ◽  
High Surface Quality

With cold forging processes it is possible to produce parts characterized by high strength, high dimensional accuracy and high surface quality. In order to optimize the forming process and to be able to use the advantages of cold forging specifically and combined, it is necessary to find correlations between manufacturing parameters on the one side, strength and other properties like hardness distribution and surface quality of the component on the other side. The research work covered in this paper focuses on the correlation of the components properties influenced by its manufacturing history and their fatigue strength. The used component is a gear produced by a lateral cold forging process. For the investigations an experimental setup has been designed. The aim for the design of the setup is to reproduce the real contact condition for the contact of two gears. To obtain different component properties the production process of the gear was varied by producing the parts by a milling operation. First of all, the components’ properties, for example hardness distribution, remaining residual stresses, orientation of fibers and surface quality, were determined. The components’ fatigue behavior was determined using a high frequency pulsator and evaluated in terms of finite life fatigue strength and fatigue endurance limit. These examinations were used to produce Woehler curves for the differently manufactured components with a certain statistical data analysis method.

Sign in / Sign up

Export Citation Format

Share Document