A Universal Pocket Plunge Milling Method to Decrease the Maximum Engagement Angle

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Nuodi Huang ◽  
Eugen Krebs ◽  
Jonas Baumann ◽  
Andreas Wirtz ◽  
Eva Maria Jaeger ◽  
...  
Keyword(s):  
Tool Life ◽  
Negative Influence ◽  
Concentric Circle ◽  
Plunge Milling ◽  
Radial Depth ◽  
Milling Method ◽  
Engagement Angle ◽  
Concentric Circles ◽  
Deep Cavities ◽  
The Given

Abstract Plunge milling has been proven to be an efficient strategy for machining of pockets with deep cavities and difficult-to-cut material. Previous work generates the plunge toolpath mainly by controlling the radial cutting width within the given value. However, uneven tool engagement angles may lead to excessive tool load and tool load fluctuations, which has a negative influence on tool life. In this study, a universal plunge milling toolpath generation method is proposed to improve tool life by decreasing the maximum tool engagement angle. A series of concentric circles with constant radius increment is utilized to generate a toolpath with constant cutting radial depth. Center of the concentric circle is determined based on the pocket contour. New detailed algorithms to generate plunge toolpath for basic cases have been developed. An automatic pocket subdivision algorithm has been developed by dividing the pocket into several subregions that are easy to be machined. Without loss of generality, the method is applicable for both open and closed pockets. It also works for pockets with and without islands inside. The method is implemented and verified successfully by machining experiments. The results provide strong evidence that the proposed method can reduce the maximum engagement angle over the entire toolpath and thus improve the tool life.

scholarly journals A Study on Interferential Tool Position Correcting Algorithm in Rough Machining of 3d Impeller Variable-axis Plunge Milling

2021 ◽  
Author(s):  
Lei Dong ◽  
Jie Wang
Keyword(s):  
Tool Path ◽  
Contact Point ◽  
Normal Vector ◽  
Sudden Increase ◽  
Rough Machining ◽  
Plunge Milling ◽  
Radial Depth ◽  
Milling Method ◽  
Tool Position ◽  
Cutter Position

Abstract The plunge milling method has remarkably improved the rough machining efficiency of 3D impeller channel. However, in conventional cutter position planning for plunge milling, interference at the end of every cutter position due to sudden increase of radial depth is inevitable, which may seriously compromise the service life of machine tool and cutter, as well as the cutting efficiency at the interferential phase. This study optimized the cutter axis vector for the tool path of conventional rough machining of 3D impeller variable -axis plunge milling to make the angle between the normal vector for workpiece surface at the cutter contact point and the cutter-axis vector of adjacent tool position increase gradually from outlet to inlet at the smallest scale. Based on this, an iterative algorithm for tool center position and safety height for the cutter was provided, thus making the hub allowance of the optimized tool path for plunge milling as small as possible without affecting the subsequent machining on the premise of avoiding the interferential phenomenon. Finally, the correctness of the proposed method was verified by relevant numerical examples.

scholarly journals Televisión abuse on our students´s side: how, when and why

Comunicar ◽  
2005 ◽  
Vol 13 (25) ◽  
Author(s):  
María-de-la-Cinta Aguaded-Gómez
Keyword(s):  
Primary Education ◽  
Negative Influence ◽  
Free Time ◽  
Social Aspects ◽  
Educational Community ◽  
Educational Levels ◽  
The Family ◽  
The World ◽  
Educación Primaria ◽  
The Given

The abuse of over watching Television by our alumnae is a fact that worries all the educational community. Every day, the teachers observe how the alumnae, at all educational levels, follow patterns of behaviour, keeping values and reproducing roles that have been seen and defended by our television stations. This abuse leads to a series of implications, not only in the educational area, but in the family circle as well, in relational and social aspects. Our aim is to know the negative influence of this phenomena on a particular population, and to contrast the results with other investigations developed in other contexts. This study was initiated on a group of alumnae form the 2º term of primary education, in the province of Huelva. The principal objective consisted of deepening the awareness in the world of our pupils: questioning the use of their free time and knowing their habits and behaviour. Finding out the amount of time they dedicate to watching television, where they watch it, with whom and why it attracts them so enormously. First of all, the qualities presented on television to attract the infant population was analysed, afterwards a sample of the studied population was selected, specifying the context where it was to be taken and the characteristics of the area, its educational centres and studied alumnae. Later, it was selected the instruments of data collected, among them, the questionnaire. Finally, study implications to determine the given conclusions were obtained. El abuso de la televisión por parte de nuestros alumnos es un hecho que preocupa a toda la comunidad educativa. Cada día los docentes observan cómo el alumnado de todos los niveles educativos sigue pautas de comportamientos, mantiene valores y reproduce modelos que han sido visionados y defendidos por nuestras televisiones. Este abuso conlleva una serie de implicaciones no sólo en el ámbito educativo sino también en el familiar y en consecuencia en el relacional y social. Con el propósito de conocer cómo influye este fenómeno en una población determinada y contrastar los resultados con otras investigaciones realizadas en otros contextos se inició este estudio en un grupo de alumnos del 2º ciclo de educación primaria de la provincia de Huelva. El objetivo principal consistía en profundizar en el mundo de nuestros escolares: indagando en el uso de su tiempo libre y conociendo sus hábitos y conductas, averiguando qué tiempo dedican a ver la televisión, dónde la visionan, con quién y porqué les atraía enormemente. En un primer momento se analizaron las cualidades que presentaba la televisión para atraer a la población infantil, seguidamente se selecciono la muestra de la población estudiada especificando el contexto donde se iba a llevar a cabo y las características de la zona, sus centros educativos y los alumnos estudiados. Seguidamente se seleccionaron los instrumentos de recogida de datos, entre ellos el cuestionario. Finalmente se obtuvieron unas implicaciones del estudio para detallar las conclusiones obtenidas.

The Examination of the Economical Effectiveness of Forest Fire Suppression by Using Theoretical Fire Spread Models

2016 ◽  
Vol 15 (1) ◽  
pp. 85-92
Author(s):  
Ágoston Restás
Keyword(s):  
Forest Fire ◽  
Economic Efficiency ◽  
Fire Suppression ◽  
Fire Spread ◽  
Concentric Circle ◽  
Model Based ◽  
Actual Fire ◽  
Concentric Circles ◽  
Circle Model ◽  
Rectangular Model

It is commonly known that firefighting is very expensive solution; therefore it isn’t useless to study it by the criteria of efficiency. But the meaning of efficiency for fire managers can be different from the meaning of efficiency for economists. From an economic viewpoint, it is stricter than from a technical view. Method: this research used geometric aspects of the fire spread created rectangular and concentric circles models and used basic mathematic calculations and logical conclusions. Results and discussion: The rectangular model shows the criteria of economic efficiency of firefighting. Moreover, the results from rectangular model can be transferred also to the section of concentric circles model. Based on the concentric circle model we can define both the economic efficiency of fighting forest fire and minimal criteria of successful suppression expressed by the elementary information we have regarding the actual fire.

Tool life prediction by RSM for cryogenic milling of inconel 718

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nurul Hayati Binti Abdul Halim ◽  
Che Hassan Che Haron ◽  
Jaharah A. Ghani ◽  
Muammar Faiq Azhar
Keyword(s):  
Tool Life ◽  
Inconel 718 ◽  
High Speed ◽  
Metal Cutting ◽  
Milling Process ◽  
Average Error ◽  
Depth Of Cut ◽  
Content Type ◽  
Radial Depth ◽  
Ball Nose Milling

Purpose The purpose of this study is to present the tool life optimization of carbide-coated ball nose milling inserts when high-speed milling of Inconel 718 under cryogenic CO2 condition. The main aims are to analyze the influence level of each cutting parameter on the tool life and to identify the optimum parameters that can lengthen the tool life to the maximum. Design/methodology/approach The experimental layout was designed using Box–Behnken RSM where all parameters were arranged without combining their highest and lowest values of each factor at the same time. A total of 29 milling experiments were conducted. Then, a statistical analysis using ANOVA was conducted to identify the relationship between the controlled factors on tool life. After that, a predictive model was developed to predict the variation of tool life within the predetermined parameters. Findings Results from the experimental found that the longest tool life of 22.77 min was achieved at Vc: 120 m/min, fz: 0.2 mm/tooth, ap: 0.5 mm and ae: 0.2 mm. ANOVA suggests the tool life of 23.4 min can be reached at Vc: 120.06 m/min, fz: 0.15 mm/tooth, ap: 0.66 mm and ae: 0.53 mm. All four controlled factors have influenced the tool life with the feed rate and radial depth of cut (DOC) as the major contributors. The developed mathematical model accurately represented the tool life at an average error of 8.2 per cent when compared to the actual and predicted tool life. Originality/value These experimental and statistical studies were conducted using Box–Behnken RSM method under cryogenic CO2 condition. It is a proven well-known method. However, the cooling method used in this study is a new technique and its effects on metal cutting, especially in the milling process of Inconel 718, has not yet been explored.

Influence of Cutting Parameters and Tool Geometric Angles on TC4 Titanium Alloy Chip Shape

2012 ◽  
Vol 490-495 ◽  
pp. 3912-3915 ◽  
Author(s):  
Wei Hua Wu ◽  
Wen Min Chen ◽  
Xue Hui Wang ◽  
Can Zhao
Keyword(s):  
Titanium Alloy ◽  
Tool Life ◽  
Cutting Parameters ◽  
Helix Angle ◽  
Rake Angle ◽  
Serrated Chip ◽  
Tc4 Titanium Alloy ◽  
Chip Shape ◽  
Radial Depth ◽  
Geometric Angles

To select reasonable cutting parameters, improve the processing surface quality, and extend the tool life, this paper uses four solid carbide end milling tools to process TC4 titanium alloy, and analyses the influence of the difference cutting parameters and the geometric angles to chip shape. The experiment results indicate that the degree of serrated chip shape is increased by increasing the feed rate under the condition of certain spindle speed. But the degree of serrated chip shape may be decreased by the adoption of small axial and radial depth, or bigger rake angle and smaller helix angle. Select larger rake angle, cutting edge is sharp, the metal deformation of cutting layer is small, which can reduce the friction force when chip flowing through the tool rake face, so that the cutting force and cutting temperature decreases accordingly.The greater the helix angle is, the worse the chip removal conditions is, and the degree of serrated chip becomes larger, the blade is more sharp, easily crack, and the tool life decreases. So relatively small helix angle is better. The choice of angles is interrelated with each other, the selection of some angle separately cannot get the desired reasonable value.

Experimental Study of Cutting Performance and Tool Wear in Dry Side Milling of Aluminum Alloy with DLC-Coated HSS-Co Cutter

2012 ◽  
Vol 523-524 ◽  
pp. 64-69
Author(s):  
Yoshio Mizugaki ◽  
Kazuki Takafuji ◽  
Koichi Kikkawa ◽  
Teppei Kuroda ◽  
Taro Kimura
Keyword(s):  
Aluminum Alloy ◽  
Tool Wear ◽  
Tool Life ◽  
Cutting Speed ◽  
Cutting Performance ◽  
Experimental Results ◽  
Steel Matrix ◽  
Milling Cutter ◽  
Side Milling ◽  
Radial Depth

This paper presents the experimental results of cutting performance and tool wear of a milling cutter in dry side milling of aluminum alloy A2017. The milling cutter consists of Co-bonded High-Speed-Steel matrix with Diamond-Like-Carbon coating (abbrev. DLC-coated HSS-Co cutter). The machining experiments were carried out under cutting speed of 63 to 189 [m•min-1] and feed of 0.08 [mm/tooth/rev], and the criterion of tool life was the generation of gauge and/or scratch on a machined surface. The experimental results support that the DLC-coated cutter in up cutting has good performance among four types of combination by the presence or absence of coating and the up/down cutting manner. They also showed that the tool life of DLC-coated cutter in up cutting under cutting speed of 157 [m•min-1] was corresponding to the cutting distance of 80 [m] with average width of flank wear 102 [μm] and that in down cutting was 60 [m] with 85 [μm]. In the range of cutting distance up to 100 [m], the resultant cutting force with the DLC-coated cutter was smaller than that with a non-coating cutter. In case of the DLC-coated cutter in up cutting under the cutting speed of 189 [m•min-1], a chatter vibration occurred during the initial cutting distance. In case of the radial depth of cut of 1.5 [mm], it lasted up to the cutting distance of 10 [m] and more.

Damping Integrated Technology in Three Concentric Circles Stereoscopic Applications on Steel Arch Truss

2013 ◽  
Vol 788 ◽  
pp. 594-597
Author(s):  
Peng Yu Li ◽  
Zhi Chang Gao
Keyword(s):  
Dynamic Characteristics ◽  
Concentric Circle ◽  
Viscous Dampers ◽  
Shock Absorption ◽  
Modal Characteristics ◽  
Integrated Technology ◽  
Damping Effect ◽  
Space Truss ◽  
Truss Model ◽  
Concentric Circles

By the software SAP2000, this article established a 60 m span steel arch three concentric circle space truss model, derived modal characteristics, mastered the dynamic characteristics. By using isolation bearing, viscous dampers[1], shock absorption technology and integrated rear arch truss damping effect. Conclusions show that integrated damping technology, making the earthquake forces effectively reduced.

scholarly journals AMMI and GGE biplots for G×E analysis of wheat genotypes under rain fed conditions in central zone of India

2015 ◽  
Vol 7 (2) ◽  
pp. 656-661 ◽  
Author(s):  
Ajay Verma ◽  
Ravish Chatrath ◽  
Indu Sharma
Keyword(s):  
Maximum Yield ◽  
Central Zone ◽  
Concentric Circle ◽  
Environment Interaction ◽  
Wheat Genotypes ◽  
Ammi Analysis ◽  
Concentric Circles ◽  
Ideal Genotype ◽  
Genotype G1 ◽  
The Ideal

The highly significant environments, genotypes and G×E interaction observed by AMMI analysis of 17 wheat genotypes evaluated at 8 locations in the central zone of the country. Environments(E), genotypes -environment interaction(GE) and genotypes explained 68.8%, 17.6% and 3.2% of the total sum of squares respectively. First four interaction principal components accounted 33.7%, 30.2%, 14.6% and 12.6% of the G×E interaction variation, respectively. The highest positive IPCA1 score of genotype G8 followed by G11 and G10 supported by yield higher than the grand mean 21.8q/ha. Environments E4 (Jabalpur) and E8 (Partapgarh) recorded maximum yield 32.6q/ha and 28.4q/ha while lowest yield was realized in E1 (Arnej). GGE biplot analysis under polygon view indicated that G13 was better in E6 (Sagar), whereas G1 was better in E7 (Bilaspur) and E8 (Partapgarh). The genotype G1, at the centre of concentric circles, was the ideal genotype in terms of yield performance as compared to the other genotypes. In addition, G15 and G12, located on the next consecutive concentric circle, may be regarded as desirable genotypes.

Effect of Golden Ratio on the Beauty of Double Concentric Circles

1989 ◽  
Vol 69 (3-1) ◽  
pp. 767-770 ◽  
Author(s):  
Yoshiaki Nakajima ◽  
Hirohiko Ohta
Keyword(s):  
College Students ◽  
Golden Ratio ◽  
Concentric Circle ◽  
Aesthetic Preference ◽  
Concentric Circles ◽  
The Aesthetic

The effect of golden ratio for the aesthetic preference of double concentric circles was investigated. 124 Japanese college students were asked to choose one concentric circle in each 36 pairs combined among nine kinds of concentric circles. Analysis showed that the beauty of circles was the highest at stimulus No. 4 and two possible interpretations were indicated.

Experimental investigation on influence of engagement angle and tool geometry on plunge milling

2020 ◽  
Vol 108 (5-6) ◽  
pp. 1973-1981
Author(s):  
Nuodi Huang ◽  
Eugen Krebs ◽  
Jonas Baumann ◽  
Yuansheng Zhou ◽  
Shijing Wu ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Tool Geometry ◽  
Plunge Milling ◽  
Engagement Angle
Sign in / Sign up

Export Citation Format

Share Document