Simulation of Fully Sintering Dental Zirconia Milling Process Based on Discrete Element Method

2013 ◽  
Vol 568 ◽  
pp. 49-54
Author(s):  
H.B. Wu ◽  
Q.P. Sun ◽  
Dun Wen Zuo
Keyword(s):  
High Speed ◽  
Cutting Tool ◽  
Cutting Speed ◽  
Element Model ◽  
Discrete Element ◽  
Milling Process ◽  
Discrete Element Model ◽  
Surface Cracks ◽  
Coating Technology ◽  
Cutting Speeds

Discrete element model of fully sintering dental zirconia was constructed and calibrated. Based on the model, the dynamic process of low-speed milling of zirconia was simulated, and the effects of different cutting speeds, cutting widths and federates on the formation of surface cracks were also analyzed. Results show that residue cracks number and maximum depth increases significantly with increase of the cutting width, while the influence of cutting speed and federates is not distinct. That shows the possibility of high-speed machining on fully sintering dental zirconia with development of coating technology of cutting tool.

Simulation on Cutting Temperature during High-Speed Milling Aluminum Alloy 7055

2013 ◽  
Vol 328 ◽  
pp. 486-490 ◽  
Author(s):  
Liang Tan ◽  
Chang Feng Yao ◽  
Wei Zuo ◽  
Dao Xia Wu
Keyword(s):  
Aluminum Alloy ◽  
Theoretical Basis ◽  
High Speed ◽  
Cutting Tool ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Element Model ◽  
Milling Process ◽  
High Speed Milling ◽  
Milling Parameters

To optimize the parameters of high-speed milling of aluminum alloy 7055 and provide a theoretical basis for cutting temperature control, a finite element model of high-speed milling process of aluminum alloy 7055 was developed with AdvantEdge. Based on these models, the effect of milling parameters on cutting temperature is investigated by single factor experiments. And the temperature distribution of workpiece and cutting tool is predicted. The results show that the highest temperature occurs at close to the tool tip in the rack face, the temperature increases with an increase in cutting speed and feed per tooth, while other parameters have a less significant effect on cutting temperature.

Study on Machining Mechanism of Glass Using Discrete Element Method

2014 ◽  
Vol 577 ◽  
pp. 108-111 ◽  
Author(s):  
Ying Qiu ◽  
Mei Lin Gu ◽  
Feng Guang Zhang ◽  
Zhi Wei
Keyword(s):  
Discrete Element Method ◽  
Element Model ◽  
Discrete Element ◽  
Rake Angle ◽  
Milling Process ◽  
Micro Milling ◽  
Discrete Element Model ◽  
Machined Surface ◽  
Damage Depth ◽  
Element Method

The discrete element method (DEM) is applied to glass micromachining in this study. By three standard tests the discrete element model is established to match the main mechanical properties of glass. Then, indentating, cutting, micro milling process are simulated. Results show that the vertical damage depth is prevented from reaching the final machined surface in cutting process. Tool rake angle is the most remarkable factor influencing on the chip deformation and cutting force. The final machined surface is determined by the minimum cutting thickness per edge. Different cutting thickness, cutter shape and spindle speed largely effect on the mechanism of glass.

Discrete Element Simulation of the Stress Wave in High Speed Milling

2017 ◽  
Author(s):  
Yifei Jiang ◽  
Jun Zhang ◽  
Yong He ◽  
Hongguang Liu ◽  
Afaque Rafique Memon ◽  
...  
Keyword(s):  
High Speed ◽  
Cutting Tool ◽  
Cutting Speed ◽  
Discrete Element ◽  
Rake Angle ◽  
Stress Waves ◽  
High Speed Milling ◽  
Element Simulation ◽  
Chip Size ◽  
Distribution Of Stress

As cutting tool penetrates into workpiece, stress waves is induced and propagates in the workpiece. This paper aims to propose a two-dimensional discrete element method to analyze the stress waves effects during high speed milling. The dependence of the stress waves propagation characteristics on rake angle and cutting speed was studied. The simulation results show that the energy distribution of stress waves is more concentrated near the tool tip as the rake angle or the cutting speed increases. In addition, the density of initial cracks in the workpiece near the cutting tool increases when the cutting speed is higher. The high speed milling experiments indicate that the chip size decreases as the cutting speed increases, which is just qualitatively consistent with the simulation.

Design and Test of a Double-Curved Guiding Groove for a High-Speed Precision Seed-Metering Device

2020 ◽  
Vol 63 (5) ◽  
pp. 1349-1360
Author(s):  
Pan Xue ◽  
Yujun Hao ◽  
Wan Jiao ◽  
Jie Ren ◽  
Feifei Yang ◽  
...  
Keyword(s):  
Inclination Angle ◽  
High Speed ◽  
Element Model ◽  
Discrete Element ◽  
Travel Speed ◽  
Curved Surface ◽  
Discrete Element Model ◽  
Release Point ◽  
Seed Spacing ◽  
Seed Metering Device

HighlightsThe instability of the seed release point in a seed-metering device is proved theoretically.A double-curved guiding groove at the seed-release point improves the seed-metering uniformity.A discrete element model was used to examine effects of the design parameters on the metering performance.The critical parameters for the double-curved guiding groove design were determined.Abstract. The instability of the seed release point in a seed-metering device is one of the main causes of the non-uniformity of seed spacing. To improve the seed spacing uniformity, a double-curved guiding groove (DGG) was designed based on the prerelease adaptive principle. The DGG was used at the seed release point of an existing high-speed precision soybean seed-metering device with a double-setting plate. The results showed that the prerelease curved surface of the DGG was capable of guiding seeds to be released at the same seed release point at all times, and the adaptive curved surface of the DGG prevented any changes in seed velocity caused by friction or collisions between seeds and the meter, thereby improving the seed spacing uniformity significantly. A discrete element model was developed and validated with laboratory tests. Through simulations using the model, the primary and secondary factors of the DGG impacting the qualified rate of seed metering (QRM) and the coefficient of variation of the seed spacing uniformity (CVU) were identified and were, in descending order, the spacing of prerelease (SPR), the starting position of prerelease (SPP), the inclination angle of the seed outlet (ASO), and the inclination angle of the receiving cup (ABR). Regression equations of the QRM and CVU with the two main impacting factors were then established. For a planter travel speed of 10 km h-1, the optimal SPR was 10 mm, and the optimal SPP was 40°, where the QRM was 100% and the CVU was 16.61%. When compared to seed metering without the DGG, the CVU was reduced by 2.55%, showing that the DGG significantly improved the uniformity of seed spacing. Keywords: Double-curved guiding groove, Discrete element method, Seed-metering device, Travel speed, Uniformity.

Effect of Boronizing on Cutting Performance of Ti(C,N)-Based Cermet Tool

2013 ◽  
Vol 589-590 ◽  
pp. 390-394
Author(s):  
Hai Dong Yang ◽  
Ju Li Hu ◽  
Yu Ming Zou ◽  
Xiao Yang ◽  
Xiao Jun Liu
Keyword(s):  
High Speed ◽  
Cutting Tool ◽  
Great Influence ◽  
Cutting Speed ◽  
Cutting Performance ◽  
Test Results ◽  
Negative Effects ◽  
High Speed Cutting ◽  
Ceramic Cutting Tool ◽  
Cutting Speeds

Through the experiment of cutting 45 steel, the influence of boronizing on Ti (C,N)-based ceramic cutting performance in different cutting speeds were discussed. The test results indicated that: regardless of boriding, cutting speed has a great influence on the life of Ti (C,N)-based ceramic cutting tool. Within the limit of 200~400 m/min, the lower the cutting speed is, the longer tools life. At the minimum speed, boronizing greatly improves cutting performance and doubles tool life. It has no significant but negative effects once over 300 m/min. The decrease of the abrasion resistance of boronized layer is mainly influenced by the intense thermal shock of high speed cutting.

scholarly journals Wear Characteristics of Cutting Tool in Brittle Removal of a Ductile Meta in High-Speed Machining

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1679
Author(s):  
Guosheng Su ◽  
Yuhao Wang ◽  
Zhitao Han ◽  
Peirong Zhang ◽  
Hongxia Zhang ◽  
...  
Keyword(s):  
Tool Wear ◽  
Pure Iron ◽  
High Speed ◽  
Cutting Tool ◽  
Cutting Speed ◽  
Rake Face ◽  
Workpiece Material ◽  
Wear Characteristics ◽  
Ductile Metal ◽  
Cutting Speeds

The contact stress and heating effect between the cutting tool and workpiece in metal machining is symmetrical. However, the symmetry may be destroyed by changes in the workpiece material mechanical properties, such as ductility. The goal of this study is to reveal the wear characteristics of the cutting tool in machining a ductile metal with the cutting speed at which the metal is embrittled by the high-strain-rate-embrittle effect (HSREE). Orthogonal high-speed turning experiments were carried out. Pure iron type DT8 was cut at different cutting speeds, ranging from 1000 m/min to 9000 m/min. The shape and morphology of the chips obtained in the experiment were observed and analyzed by optical microscope and scanning electron microscope (SEM). Tool wear characteristics at different cutting speeds were observed. It shows that the pure iron becomes completely brittle when the cutting speed is higher than 8000 m/min. On the rake face, the coating of the cutting tool bursts apart and peels off. A matrix crack originates in the cutting edge or rake face and extends to the flank face of the cutting tool. The effects of HSREE on the tool wear is discussed. The findings of this study are helpful for choosing a suitable tool for brittle cutting of the ductile metal pure iron with very high cutting speed and solving the problems in machining due to its high ductility and high stickiness.

scholarly journals Discrete element model for general polyhedra

2021 ◽  
Author(s):  
Alfredo Gay Neto ◽  
Peter Wriggers
Keyword(s):  
Frictional Contact ◽  
Virtual Work ◽  
Particle Surface ◽  
Element Model ◽  
Discrete Element ◽  
Discrete Element Model ◽  
Principle Of Virtual Work ◽  
Dynamics Model ◽  
Railway Ballast ◽  
Multibody Dynamics Model

AbstractWe present a version of the Discrete Element Method considering the particles as rigid polyhedra. The Principle of Virtual Work is employed as basis for a multibody dynamics model. Each particle surface is split into sub-regions, which are tracked for contact with other sub-regions of neighboring particles. Contact interactions are modeled pointwise, considering vertex-face, edge-edge, vertex-edge and vertex-vertex interactions. General polyhedra with triangular faces are considered as particles, permitting multiple pointwise interactions which are automatically detected along the model evolution. We propose a combined interface law composed of a penalty and a barrier approach, to fulfill the contact constraints. Numerical examples demonstrate that the model can handle normal and frictional contact effects in a robust manner. These include simulations of convex and non-convex particles, showing the potential of applicability to materials with complex shaped particles such as sand and railway ballast.

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