Cutting Geometry in a Rotary Mill

2020 ◽  
Vol 40 (4) ◽  
pp. 323-326
Author(s):  
V. G. Shalamov ◽  
A. V. Plaksin ◽  
S. D. Smetanin
Keyword(s):  
Cutting Geometry ◽  
Rotary Mill

scholarly journals Determination of the Bucket Wheel Drive Power by Computer Modeling Based on Specific Energy Consumption and Cutting Geometry

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3892
Author(s):  
Ildiko Brînaș ◽  
Andrei Andraș ◽  
Sorin Mihai Radu ◽  
Florin Dumitru Popescu ◽  
Iosif Andraș ◽  
...  
Keyword(s):  
Computer Modeling ◽  
Specific Energy ◽  
Specific Energy Consumption ◽  
Open Pit ◽  
Drive Power ◽  
Improve Energy Efficiency ◽  
Cutting Geometry ◽  
Wheel Drive ◽  
Efficiency Increase ◽  
Time Required

Starting from the general principles of material cutting, with applicability to coal and overburden excavation using bucket wheel excavators (BWEs), this paper proposes another method for calculating the drive power of the bucket wheel excavator by computer modeling. This approach required two steps. In the first step, the volume of the excavated material for one slewing movement of the boom and for a particular excavation geometry was determined, and the slewing time in the open pit coal mine was measured. In the second one, the values of the specific energy (SE) consumption for cutting were determined by laboratory tests on samples of material taken from the open pit mine. The proposed method allows for the estimation of the load of the bucket wheel drive motor by taking into account only the specific energy necessary for the cutting of the material, the excavated volume during one slewing, and the time required to excavate this volume, and not the wear coefficients of the teeth or bucket edge. This method is important for establishing the correlation between the height of the excavated slice and the slewing speed of the boom in order to optimize the drive power of the bucket wheel and thus improve energy efficiency, increase the performance of excavators, and reduce operating costs.

scholarly journals An Investigation of the High-Frequency Ultrasonic Vibration-Assisted Cutting of Steel Optical Moulds

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 460
Author(s):  
Canbin Zhang ◽  
Chifai Cheung ◽  
Benjamin Bulla ◽  
Chenyang Zhao
Keyword(s):  
Surface Roughness ◽  
Ultrasonic Vibration ◽  
High Frequency ◽  
Optical Glass ◽  
Contact Point ◽  
Cutting Speed ◽  
Optical Quality ◽  
Machining Parameters ◽  
Nose Radius ◽  
Cutting Geometry

Ultrasonic vibration-assisted cutting (UVAC) has been regarded as a promising technology to machine difficult-to-machine materials such as tungsten carbide, optical glass, and hardened steel in order to achieve superfinished surfaces. To increase vibration stability to achieve optical surface quality of a workpiece, a high-frequency ultrasonic vibration-assisted cutting system with a vibration frequency of about 104 kHz is used to machine spherical optical steel moulds. A series of experiments are conducted to investigate the effect of machining parameters on the surface roughness of the workpiece including nominal cutting speed, feed rate, tool nose radius, vibration amplitude, and cutting geometry. This research takes into account the effects of the constantly changing contact point on the tool edge with the workpiece induced by the cutting geometry when machining a spherical steel mould. The surface morphology and surface roughness at different regions on the machined mould, with slope degrees (SDs) of 0°, 5°, 10°, and 15°, were measured and analysed. The experimental results show that the arithmetic roughness Sa of the workpiece increases gradually with increasing slope degree. By using optimised cutting parameters, a constant surface roughness Sa of 3 nm to 4 nm at different slope degrees was achieved by the applied high-frequency UVAC technique. This study provides guidance for ultra-precision machining of steel moulds with great variation in slope degree in the pursuit of optical quality on the whole surface.

Dispersion of ceramic clays in a rotary mill

1975 ◽  
Vol 32 (9) ◽  
pp. 584-585
Author(s):  
A. S. Sladkov ◽  
V. V. Knyazev ◽  
V. P. Fel'chak ◽  
Yu. A. Dzhim ◽  
V. G. Tishchenko ◽  
...  
Keyword(s):  
Rotary Mill

Use of replaceable working equipment to expand the functionality of the excavator

2021 ◽  
pp. 32-38
Author(s):  
Keyword(s):  
Economic Feasibility ◽  
Design Calculation ◽  
Frozen Ground ◽  
Frozen Soils ◽  
Existing Structures ◽  
Equipment Replacement ◽  
Rotary Mill ◽  
Scope Of Application ◽  
Urban Conditions ◽  
The City

Increasing the range of replaceable working equipment for hydraulic single-bucket excavators allows to expand the scope of application significantly, increase the efficiency of its usage, as well as the mobility of these machines. The purpose of the study is to design working equipment replacement items, used for hydraulic single-bucket excavator for digging frozen soils in the city Vladivostok. The main tasks of the study are to analyze frozen soils in the region and their existing structures, select a layout scheme for further design calculation, evaluate the economic feasibility of the proposed hydraulic excavator working equipment design replacement items, used for digging frozen soils in Vladivostok city. Keywords excavator, replacement equipment, frozen ground, urban conditions, rotary mill, vibro-ripper, hydraulic hammer, bucket-ripper, tusk-ripper, gripper-tongs working body

Distribution of Working Angles in a Rotary Mill

2020 ◽  
Vol 40 (4) ◽  
pp. 327-329
Author(s):  
S. D. Smetanin ◽  
V. G. Shalamov
Keyword(s):  
Rotary Mill

Effect of Periodic Drilling Force on Instability in a Drilling Process

2005 ◽  
Vol 219 (8) ◽  
pp. 733-742 ◽  
Author(s):  
B W Huang ◽  
H K Kung ◽  
A W L Yao
Keyword(s):  
Numerical Analysis ◽  
Thrust Force ◽  
Dynamic Instability ◽  
Drilling Process ◽  
Twist Drill ◽  
Unstable Condition ◽  
Drilling Force ◽  
Cutting Geometry ◽  
Drilling Quality ◽  
Spinning Speed

The periodic drilling force effect on the dynamic instability of a drill in a drilling process was investigated. This investigation involves the cutting geometry drilling force from the two active parts of a twist drill subjected to small fluctuations during the drilling process. Theoretically, at some drilling force, this small drilling force fluctuation may lead the system into a dynamically unstable condition. Most hole location errors, reaming, and drill fractures occur in this unstable drilling process phase. The dynamic instability in a drilling process is an important issue in increasing the drilling quality and production rate. In this article, a pretwisted beam with a moving Winkler-type elastic foundation is used to simulate the drill and drilling process. Numerical analysis indicates that the unstable regions are enlarged and shifted to a lower frequency suddenly as the drill bites into a workpiece. It is also observed that the thrust force, spinning speed, and pretwisted angle effects drastically change the dynamic instability of drilling.

Fractional Skin Harvesting: Device Operational Principles and Deployment Evaluation

2014 ◽  
Vol 8 (4) ◽  
Author(s):  
Walfre Franco ◽  
Joel N. Jimenez-Lozano ◽  
Joshua Tam ◽  
Martin Purschke ◽  
Ying Wang ◽  
...  
Keyword(s):  
Donor Site ◽  
Fluid Flows ◽  
Skin Grafting ◽  
Donor Site Morbidity ◽  
Skin Wound ◽  
Skin Tissue ◽  
Hypodermic Needle ◽  
Cutting Geometry ◽  
Tissue Core ◽  
Thickness Skin

As an alternative method to conventional split-thickness skin grafts (STSGs), we recently proposed fractional skin grafting (FSG), which consists in harvesting hundreds of microscopic skin tissue columns (MSTCs) to place them directly into the skin wound (Tam et al., 2013, “Fractional Skin Harvesting: Autologous Skin Graft Without Donor Site Morbidity,” Plast. Reconstructive Surgery–Global Open, 1(6)). This paper (i) introduces the concept and operational principles of a simple but robust fractional skin harvesting (FSH) device and (ii) presents the quantitative evaluation of the deployment of the FSH device with respect to different harvesting-needle sizes. The device utilizes a hypodermic needle with a specific cutting-geometry to core skin tissue mechanically. The tissue core is removed from the donor site into a collecting basket by air and fluid flows. The air flow transports the tissue core, while the fluid flow serves the purpose of lubrication for tissue transport and wetting for tissue preservation. The design and functionality of the device were validated in an animal study conducted to establish preclinical feasibility, safety and efficacy of the proposed FSH device and FSG method. The FSH device, operating at 55.16 kPa (8 psi) gauge pressure and 208 ml/min saline flow rate, cored 800 μm diameter × 2.5 mm length skin columns using a 1.05/0.81 mm outer/inner diameter needle. The MSTC harvesting rate was established by the user at 1 column/sec. For this columns size, about 50 MSTCs are required to cover a 1.5 cm × 1.5 cm wound. In comparison to STSGs, the proposed FSG method results in superior healing outcomes on the donor and wound sites. Most important, the donor site heals without morbidity by remodeling tissue, as opposed to scarring. The FSH device has the capability of extracting full-thickness skin columns while preserving its viability and eliminating the donor site morbidity associated with skin grafting.

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