scholarly journals Modeling of cutting forces in trochoidal milling with respect to wear-dependent topographic changes

2021 ◽  
Author(s):  
Jim A. Bergmann ◽  
Nils Potthoff ◽  
Tobias Rickhoff ◽  
Petra Wiederkehr
Keyword(s):  
Tool Wear ◽  
Aerospace Industry ◽  
Chip Thickness ◽  
Undeformed Chip Thickness ◽  
Trochoidal Milling ◽  
Physically Based ◽  
Cutting Inserts ◽  
Envelope Model ◽  
High Level

AbstractThe aerospace industry utilizes nickel-based super-alloys due to its high level of strength and corrosion resistance. To evaluate milling strategies regarding tool wear, the prediction of forces during these cutting operations is essential. This comprises the determination of the undeformed chip thickness. Due to the complex interdependencies of tool engagements, the determination of these thicknesses is challenging. A geometric physically-based simulation system was extended by a novel time-discrete envelope model to increase the precision of the calculated undeformed chip thicknesses. In order to take tool wear into account, digitized topographies of cutting inserts in different states of tool wear were modelled.

Investigation of the size effect on burr formation in two-dimensional vibration-assisted micro end milling

2011 ◽  
Vol 225 (11) ◽  
pp. 2032-2039 ◽  
Author(s):  
H Ding ◽  
S-J Chen ◽  
R Ibrahim ◽  
K Cheng
Keyword(s):  
Tool Wear ◽  
Size Effect ◽  
End Milling ◽  
Chip Thickness ◽  
Integrated Model ◽  
Burr Formation ◽  
Two Dimensional ◽  
Undeformed Chip Thickness ◽  
Cutting Edge Radius ◽  
Micro End Milling

In precision and micro cutting processes, the tool cutting edge radius is generally quite large compared to the undeformed chip thickness, which can cause ploughing/rubbing between the tool and the workpiece and thus affect surface finish, tool wear, and burr formation. This paper investigates the effect of the size effect on top burr formation in two-dimensional vibration-assisted micro end milling (2D VAMEM). This is achieved by studying the effects of the ratio of undeformed chip thickness to the cutting edge radius, and the ratio of the time when the undeformed chip thickness is less than the minimum chip thickness to the total cutting time on top burr formation, using a model that integrates the chip thickness model of the 2D VAMEM and the minimum chip thickness prediction model. The corresponding experiments are carried out to verify the integrated model. It is found that feed per tooth has a significant effect on the height of the top burr, and the use of vibration-assisted cutting in micro end milling can minimize the size effect and improve the cutting performance, thereby reducing the height of the top burr. In addition, selecting suitable vibration parameters can significantly decrease the height of the top burr. The integrated model can be used to optimize the machining parameters to reduce burr size and further study the size effect on cutting force, surface roughness, and tool wear in 2D VAMEM.

Determination of the Chip Width and the Undeformed Chip Thickness in Rotational Turning

2013 ◽  
Vol 581 ◽  
pp. 131-136
Author(s):  
István Sztankovics ◽  
János Kundrák
Keyword(s):  
Chip Thickness ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Characteristic Parameters ◽  
Cross Sectional ◽  
Undeformed Chip Thickness ◽  
Accurate Knowledge ◽  
Rotational Turning ◽  
Chip Removal

The accurate knowledge of the defining parameters of chip removal in rotational turning is necessary for the description of the complex kinematic relations. In this paper two characteristic parameters of the chip cross-sectional area undeformed equivalent chip thickness, chip width is defined. Lastly the application of the gained relation is shown for a specific example.

scholarly journals Investigation of Tool Wear and Chip Morphology in Dry Trochoidal Milling of Titanium Alloy Ti–6Al–4V

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1937 ◽  
Author(s):  
Dongsheng Liu ◽  
Ying Zhang ◽  
Ming Luo ◽  
Dinghua Zhang
Keyword(s):  
Titanium Alloy ◽  
Tool Wear ◽  
Titanium Alloys ◽  
High Efficiency ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Chip Morphology ◽  
Depth Of Cut ◽  
Trochoidal Milling ◽  
Radial Depth

Titanium alloys are widely used in the manufacture of aircraft and aeroengine components. However, tool wear is a serious concern in milling titanium alloys, which are known as hard-to-cut materials. Trochoidal milling is a promising technology for the high-efficiency machining of hard-to-cut materials. Aiming to realize green machining titanium alloy, this paper investigates the effects of undeformed chip thickness on tool wear and chip morphology in the dry trochoidal milling of titanium alloy Ti–6Al–4V. A tool wear model related to the radial depth of cut based on the volume of material removed (VMR) is established for trochoidal milling, and optimized cutting parameters in terms of cutting speed and axial depth of cut are selected to improve machining efficiency through reduced tool wear. The investigation enables the environmentally clean rough machining of Ti–6Al–4V.

Determination of the critical undeformed chip thickness in micromilling by means of the acoustic emission signal

2016 ◽  
Vol 46 ◽  
pp. 377-382 ◽  
Author(s):  
Marcelo A. Câmara ◽  
Alexandre M. Abrão ◽  
Juan Carlos Campos Rubio ◽  
G. Cristina D. Godoy ◽  
Bruno S. Cordeiro
Keyword(s):  
Acoustic Emission ◽  
Acoustic Emission Signal ◽  
Chip Thickness ◽  
Undeformed Chip Thickness ◽  
Emission Signal

Immediate implantation in a patient with chronic generalized parodontitis and apical granuloma

2019 ◽  
Vol 24 (2) ◽  
pp. 145-149
Author(s):  
A. I. Musienko ◽  
K. I. Nesterova
Keyword(s):  
Tooth Extraction ◽  
Tooth Root ◽  
Duration Of Treatment ◽  
Promising Direction ◽  
Aesthetic Result ◽  
Bone Atrophy ◽  
Alveolar Tissue ◽  
High Level ◽  
Immediate Implantation

Relevance. Rehabilitation of patients with moderate to severe generalized periodontitis is a leading problem in periodontology. It was the determination of the prospects for immediate implantation in patients with chronic periodontitis, combined with the pathology of the tooth root and maxillary sinus.Materials and methods. A group of 94 people with periodontitis and chronic odontogenic rhinosinus was observed who underwent sinus surgical treatment, tooth extraction and one-stage implantation with FRP growth factor according to the author's technology.Results. The method showed high efciency on the basis of assessing the clinical, aesthetic result and restoration of bone density after surgery.Conclusions. The developed technology is a promising direction, it allows to combine a high level of sanation of alveolar tissue with the advantages of immediate implantation, prevents bone atrophy, helps reduce the duration of treatment and the number of surgical and orthopedic interventions.

Methodical approaches to managing economic safety of tourism enterprises

2020 ◽  
pp. 160-164
Author(s):  
Leonid Tsubov ◽  
Oresta Shcherban
Keyword(s):  
Safety Management ◽  
Integrated Approach ◽  
Small Enterprise ◽  
Complex Nature ◽  
Efficient Management ◽  
Tourism Enterprises ◽  
High Level ◽  
Functional Components ◽  
Stimulation Control

The set of scientific-methodological tools to secure the mechanism of economic safety management of tourism entrepreneurship is examined as an aggregate of methods, tools, and conceptual activities directed at maintaining the high level of economic safety of tourism entrepreneurship. The features of managing the tourism enterprise and economic safety are analyzed. The basic valuation principles of the reliability and efficiency of the economic safety of the tourism enterprise are determined. The basic tasks of ensuring the economic safety of a small enterprise are outlined. The need to use the integrated approach that secures more opportunities to avoid threats and limits the danger of their emergence is emphasized. The most important principles for securing the economic safety of the tourism enterprise on the microeconomic level are described. Possible practical methods of risk management for the implementation of adopted decisions are proposed. The paper proves the fact that the complex nature of the management of the economic safety of the tourism enterprise and securing the sufficiently efficient management system of detecting and eliminating the threats are provided by the establishment of the management of the economic safety system of the tourism enterprise and its functional components. Research of the methodical approaches to the management of the tourism enterprises’ economic safety allows building and describing the functional structure of the mechanism of management of the tourist enterprise’s economic safety (it is formalized and described by 5 functions: determination of aims; planning; organization and adjusting; motivation and stimulation; control and monitoring).

scholarly journals Study of Well Waters from High-Level Natural Radiation Areas in Northern Vietnam

2021 ◽  
Vol 18 (2) ◽  
pp. 469
Author(s):  
Van-Hao Duong ◽  
Thanh-Duong Nguyen ◽  
Miklos Hegedus ◽  
Erika Kocsis ◽  
Tibor Kovacs
Keyword(s):  
Natural Radionuclide ◽  
World Health ◽  
Natural Radiation ◽  
Lifetime Cancer Risk ◽  
Northern Vietnam ◽  
Health Organization ◽  
High Level ◽  
Radiological Hazard Indices ◽  
Well Waters

The determination of natural radionuclide concentrations plays an important role for assuring public health and in the estimation of the radiological hazards. This is especially true for high level radiation areas. In this study, 226Ra, 228Ra and 238U concentrations were measured in well waters surrounding eight of the high-level natural radiation areas in northern Vietnam. The 226Ra, 228Ra and 238U activity concentrations vary from <1.2 × 10−3–2.7 (0.46), <2.6 × 10−3–0.43 (0.07) and <38 × 10−3–5.32 Bq/L (0.50 of median), respectively. 226Ra and 238U isotopes in most areas are in equilibrium, except for the DT-Thai Nguyen area. The calculated radiological hazard indices are generally higher than WHO (World Health Organization) recommendations. Average annual effective dose and excess lifetime cancer risk values due to drinking well water range from to 130 to 540 μSv/year and 7.4 × 10−6 to 3.1 × 10−5, respectively.

Colorimetric Determination of Aklomide (2-Chloro-4-Nitrobenzamide) in Poultry Feed

1969 ◽  
Vol 52 (3) ◽  
pp. 438-441
Author(s):  
Glenn M George ◽  
A C Daftsios ◽  
Joseph L Morrison
Keyword(s):  
Nitro Group ◽  
Poultry Feed ◽  
Colorimetric Determination ◽  
Average Recovery ◽  
Low Level ◽  
Color Development ◽  
Titanium Trichloride ◽  
High Level

Abstract The coccidiostat aklomide is extracted from feed with methanol and assayed colorimetrically by reduction of the nitro group to anamine with titanium trichloride and subsequent color development with t he Bratton-Marshall reaction. Thirteen laboratories studied the method collaboratively on two levels of medicated feed. Overall average recovery was 106.5% of the oretical for the low level and 104.5% of the oretical for the high level. The method is recommended for adoption as official first action

scholarly journals Revealing the constituents of Egypt’s oldest beer using infrared and mass spectrometry

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mohamed A. Farag ◽  
Moamen M. Elmassry ◽  
Masahiro Baba ◽  
Renée Friedman
Keyword(s):  
Large Scale ◽  
Beer Brewing ◽  
Chemical Signatures ◽  
Chemical Determination ◽  
Materials Used ◽  
High Level ◽  
Beer Production ◽  
First Time ◽  
Detailed Chemical

Abstract Previous studies have shown that the Ancient Egyptians used malted wheat and barley as the main ingredients in beer brewing, but the chemical determination of the exact recipe is still lacking. To investigate the constituents of ancient beer, we conducted a detailed IR and GC-MS based metabolite analyses targeting volatile and non-volatile metabolites on the residues recovered from the interior of vats in what is currently the world’s oldest (c. 3600 BCE) installation for large-scale beer production located at the major pre-pharaonic political center at Hierakonpolis, Egypt. In addition to distinguishing the chemical signatures of various flavoring agents, such as dates, a significant result of our analysis is the finding, for the first time, of phosphoric acid in high level probably used as a preservative much like in modern beverages. This suggests that the early brewers had acquired the knowledge needed to efficiently produce and preserve large quantities of beer. This study provides the most detailed chemical profile of an ancient beer using modern spectrometric techniques and providing evidence for the likely starting materials used in beer brewing.

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