Mechanisms for Sawing of Refractory Bricks with Diamond Blades

2009 ◽  
Vol 16-19 ◽  
pp. 1143-1148
Author(s):  
Yi Qing Yu ◽  
Yuan Li ◽  
Xi Peng Xu
Keyword(s):  
Specific Energy ◽  
Normal Force ◽  
Experimental Studies ◽  
Horizontal Force ◽  
Slurry Erosion ◽  
Diamond Grit ◽  
Circular Sawing ◽  
Force Components ◽  
Refractory Bricks ◽  
Spindle Power

Experimental studies were undertaken to investigate the mechanisms for circular sawing of refractory bricks with diamond segmented saw blades. Three kinds of diamond segments of different hardness were fabricated for the saw blades. The vertical and horizontal force components and the spindle power were measured in sawing. Based on the measurements of force and power, the specific energy and the normal force per diamond grit were obtained. The normal force per grit in the sawing of refractory bricks was found to be only 5% of the static compressive strength of diamonds used in the present study, but fractures of diamonds were still popular on the segment working surfaces after sawing. The power, horizontal force, and the specific energy were found to increase with segment hardness. The specific energy obtained from the measured power was basically comparable to the values obtained from a theoretical equation to calculate the specific energy associated with slurry erosion to the bond matrix of segments.

Sawing of Granite with Side-Slotted Diamond Segments

2006 ◽  
Vol 315-316 ◽  
pp. 103-107
Author(s):  
Yi Qing Yu ◽  
Y.F. Zhang ◽  
Yuan Li ◽  
Xi Peng Xu
Keyword(s):  
Normal Force ◽  
Tangential Force ◽  
Operating Parameters ◽  
Vertical Force ◽  
Cutting Zone ◽  
Circular Sawing ◽  
Diamond Saw ◽  
Force Components ◽  
Saw Blade ◽  
Resultant Forces

The present study was undertaken to examine the feasibility of circular sawing of granite with a newly shaped diamond saw blade. Three slots were formed on each side of each segment of the saw blade. Side-slotted segments and traditional segments were compared under same operating parameters. Measurements were made of the horizontal and vertical force components and the consumed power in order to obtain the tangential and normal force components. The surfaces of worn blade segments were examined by a scanning electron microscope. The consumed powers, normal and tangential force components for the side-slotted segments were found to be lower than those of the traditional segments. The position of resultant forces for the side-slotted segments is a little further away from the bottom of the cutting zone than the traditional segments. SEM observations indicated that the wear of the side-slotted segments was similar to sawing with traditional segments.

Experimental Investigation of the Bore Honing Process

1993 ◽  
Vol 115 (4) ◽  
pp. 406-414 ◽  
Author(s):  
J. Lee ◽  
S. Malkin
Keyword(s):  
Specific Energy ◽  
Normal Force ◽  
Removal Rate ◽  
Considerable Variability ◽  
Test Rig ◽  
Normal Forces ◽  
Head Displacement ◽  
Fundamental Investigation ◽  
Expansion Pressure ◽  
Spindle Power

A fundamental investigation is reported on the mechanics of the bore honing process. An experimental test rig was developed consisting of a honing machine instrumented with sensors to measure spindle power, expansion pressure, and honing head displacement and interfaced to a computer for data acquisition and analysis. Experimental results are presented, which show the effects of applied normal force and grit size on the power, removal rate, specific energy, stone wear, honing ratio, and surface roughness for honing of cast iron bores with silicon carbide abrasive stones. Considerable variability in honing behavior was observed due to stone inconsistency and differences in stone properties from different manufactures, but the results are reasonably consistent when cross-plotted versus removal rate rather than applied normal force. Slower removal rates, obtained with smaller applied normal forces and effectively harder stones, resulted in relatively less stone wear and smoother surfaces, and finer abrasive grit sizes led to relatively more stone wear and smoother surfaces. An analysis of the results indicates that the forces and specific energy associated with the process can be separated into chip formation, plowing, and sliding components, which is similar to what is found for grinding processes.

Forces and Energy in Circular Sawing and Grinding of Granite

2000 ◽  
Vol 123 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Xipeng Xu ◽  
Yuan Li ◽  
Stephen Malkin
Keyword(s):  
Normal Force ◽  
Tangential Force ◽  
Chip Thickness ◽  
Undeformed Chip Thickness ◽  
Unit Width ◽  
Wide Range ◽  
Grinding Conditions ◽  
Cutting Zone ◽  
Circular Sawing ◽  
Force Components

An investigation is reported of the forces and energy in circular sawing and grinding of gray granite. Measurements were made of the forces and power over a wide range of sawing and grinding conditions. Calculated tangential force components were found to be much different than the measured horizontal force components for sawing, but the two forces were almost identical for grinding. The location of the resultant force was proportionally further away from the bottom of the cutting zone with longer contact lengths. For sawing, the normal force per grain was nearly proportional to the calculated undeformed chip thickness. The G-ratios at different sawing rates reached a maximum value at the same intermediate undeformed chip thickness, which was attributed to a transition in the diamond wear mechanism from attrition to fracture at a critical normal force per grain. SEM observations indicated material removal mainly by brittle fracture, with some evidence of ductile plowing especially for grinding and to a lesser extent for sawing. The corresponding fracture energy was estimated to constitute a negligible portion of the total energy expenditure. About 30 percent of the sawing energy might be due to the interaction of the swarf with the applied fluid and bond matrix. Most of the energy for sawing and grinding is attributed to ductile plowing. Analogous to recent studies on grinding of ceramics and glass, the power per unit width was found to increase linearly with the generation of plowed surface area per unit width.

Specific Energies in Sawing with Diamond Segments and Grinding of a Diamond Segment

2008 ◽  
Vol 375-376 ◽  
pp. 375-379
Author(s):  
Yi Qing Yu ◽  
Yuan Li ◽  
Xi Peng Xu
Keyword(s):  
Experimental Study ◽  
Specific Energy ◽  
Horizontal Force ◽  
Diamond Sawblade ◽  
Spindle Power

An experimental study was undertaken to compare the mechanisms of two different processes to dress metal-bonded diamond segments. In one case, a piece of vitrified SiC wheel was used as workpiece and sawn by diamond segments attached to a sawblade. In another process, a diamond segment was used as workpiece and ground by an Al2O3 wheel. Spindle power was measured in sawing and horizontal force was monitored in grinding, in which case the latter was then used to get the consumed power in grinding. Specific energies were then calculated from the measured or converted power. For sawing of SiC wheel with the diamond sawblade, the maximum specific energy was found to be only 0.5 J/mm3, whereas the specific energy was up to 25 J/mm3 in the grinding of the diamond segment.

Performance of Diamond Segments in Different Machining Processes

2004 ◽  
Vol 471-472 ◽  
pp. 77-81 ◽  
Author(s):  
Xi Peng Xu ◽  
Y.B. Hong ◽  
S. Chen
Keyword(s):  
Weight Loss ◽  
Surface Grinding ◽  
Vertical Force ◽  
Machining Processes ◽  
Wear Performance ◽  
Wear Weight Loss ◽  
Circular Sawing ◽  
Iron Based ◽  
Force Components ◽  
Refractory Bricks

An investigation is reported of the performance of diamond impregnated segments in three machining processes - circular sawing of granite with diamond segments, dressing of diamond segments with refractory bricks and surface grinding of diamond segments with an alumina wheel. Two kinds of segments were fabricated by incorporating diamonds (either coated or uncoated) into an iron-based bond matrix. Measurements were made of the horizontal and vertical force components in the machining processes. SEM was used to examine the diamond-matrix bonding states and the ground surfaces of the segments. The changes of forces and segment wear (weight loss and wear performance) were found to be basically consistent for the three machining processes.

Effects of the Wear Characteristics of Brazed Diamond Grits on Grinding Forces

2007 ◽  
Vol 24-25 ◽  
pp. 233-238 ◽  
Author(s):  
You Ji Zhan ◽  
Yuan Li ◽  
Hui Huang ◽  
Xi Peng Xu
Keyword(s):  
Normal Force ◽  
Single Layer ◽  
Diamond Wheel ◽  
Grinding Process ◽  
Grinding Forces ◽  
Diamond Grit ◽  
Pull Out ◽  
Long Time ◽  
The Mean ◽  
Force Components

Grinding forces, protrusion and wear of diamond grit have been studied in grinding granite with a single-layer brazed diamond wheel. The experiment results indicate that the primary wear progression of diamond grits in the whole grinding process follows the mode of whole, micro-fractured, macro-fractured and pull-out when grinding granite with the brazed diamond wheel. The proportions of the whole, fractured, pull-out, break flat and the mean height protrusion of grains are more closely related to grinding forces. The grinding forces decreased with the increasing proportions of whole and break flat grains, and the tangential and normal force components increased with the gradual wear of the brazed diamond wheel during a long-time grinding process.

The Effects of Machining Parameters on the Position of Resultant Force in Sawing of Granite

2011 ◽  
Vol 487 ◽  
pp. 357-360
Author(s):  
Cong Fu Fang ◽  
Xi Peng Xu
Keyword(s):  
Relative Position ◽  
Normal Force ◽  
Resultant Force ◽  
Vertical Force ◽  
Machining Parameters ◽  
Circular Sawing ◽  
Force Components

The effects of the machining parameters on the relative position of the resultant force were analyzed in circular sawing of granite with a diamond segmented blade. The horizontal and vertical force components and the power were measured. Calculated tangential and normal force components were subsequently used to calculate the relative position of resultant force besides the horizontal and vertical force components. It was found that the value of the relative position of resultant force in down sawing is less than that in up sawing. The shift of sawing swarf has heavy influence on the relative position of resultant force.

scholarly journals Effect of Water-Based Nanolubricants in Ultrasonic Vibration Assisted Grinding

2018 ◽  
Vol 2 (4) ◽  
pp. 80 ◽  
Author(s):  
Mir Molaie ◽  
Ali Zahedi ◽  
Javad Akbari
Keyword(s):  
Surface Roughness ◽  
Specific Energy ◽  
Material Removal ◽  
Normal Force ◽  
Tangential Force ◽  
Process Efficiency ◽  
Multiwall Carbon Nanotube ◽  
Ultrasonic Vibrations ◽  
Mql Grinding ◽  
Water Based

Currently, because of stricter environmental standards and highly competitive markets, machining operations, as the main part of the manufacturing cycle, need to be rigorously optimized. In order to simultaneously maximize the production quality and minimize the environmental issues related to the grinding process, this research study evaluates the performance of minimum quantity lubrication (MQL) grinding using water-based nanofluids in the presence of horizontal ultrasonic vibrations (UV). In spite of the positive impacts of MQL using nanofluids and UV which are extensively reported in the literature, there is only a handful of studies on concurrent utilization of these two techniques. To this end, for this paper, five kinds of water-based nanofluids including multiwall carbon nanotube (MWCNT), graphite, Al2O3, graphene oxide (GO) nanoparticles, and hybrid Al2O3/graphite were employed as MQL coolants, and the workpiece was oscillated along the feed direction with 21.9 kHz frequency and 10 µm amplitude. Machining forces, specific energy, and surface quality were measured for determining the process efficiency. As specified by experimental results, the variation in the material removal nature made by ultrasonic vibrations resulted in a drastic reduction of the grinding normal force and surface roughness. In addition, the type of nanoparticles dispersed in water had a strong effect on the grinding tangential force. Hybrid Al2O3/graphite nanofluid through two different kinds of lubrication mechanisms—third body and slider layers—generated better lubrication than the other coolants, thereby having the lowest grinding forces and specific energy (40.13 J/mm3). It was also found that chemically exfoliating the graphene layers via oxidation and then purification prior to dispersion in water promoted their effectiveness. In conclusion, UV assisted MQL grinding increases operation efficiency by facilitating the material removal and reducing the use of coolants, frictional losses, and energy consumption in the grinding zone. Improvements up to 52%, 47%, and 61%, respectively, can be achieved in grinding normal force, specific energy, and surface roughness compared with conventional dry grinding.

An optimal wheel-torque control on a compliant modular robot for wheel-slip minimization

Robotica ◽  
2015 ◽  
Vol 35 (2) ◽  
pp. 463-482 ◽  
Author(s):  
Avinash Siravuru ◽  
Suril V. Shah ◽  
K. Madhava Krishna
Keyword(s):  
Friction Coefficient ◽  
Normal Force ◽  
Experimental Studies ◽  
Traction Force ◽  
Static Stability ◽  
Wheel Speed ◽  
Torque Control ◽  
Modular Robot ◽  
Wheel Slip ◽  
Wheel Torque

SUMMARYThis paper discusses the development of an optimal wheel-torque controller for a compliant modular robot. The wheel actuators are the only actively controllable elements in this robot. For this type of robots, wheel-slip could offer a lot of hindrance while traversing on uneven terrains. Therefore, an effective wheel-torque controller is desired that will also improve the wheel-odometry and minimize power consumption. In this work, an optimal wheel-torque controller is proposed that minimizes the traction-to-normal force ratios of all the wheels at every instant of its motion. This ensures that, at every wheel, the least traction force per unit normal force is applied to maintain static stability and desired wheel speed. The lower this is, in comparison to the actual friction coefficient of the wheel-ground interface, the more margin of slip-free motion the robot can have. This formalism best exploits the redundancy offered by a modularly designed robot. This is the key novelty of this work. Extensive numerical and experimental studies were carried out to validate this controller. The robot was tested on four different surfaces and we report an overall average slip reduction of 44% and mean wheel-torque reduction by 16%.

Nonlinear Dynamics of Orthogonal Metal Cutting: Experimental Studies

1999 ◽  
Author(s):  
Chee-Hoe Foong ◽  
Marian Wiercigroch ◽  
William F. Deans
Keyword(s):  
Nonlinear Dynamics ◽  
Cast Iron ◽  
Metal Cutting ◽  
Thrust Force ◽  
Experimental Studies ◽  
Vertical Direction ◽  
Systematic Analysis ◽  
Orthogonal Metal Cutting ◽  
Time Histories ◽  
Force Components

Abstract The elimination of chatter is one of the major aims in machining to improve geometrical accuracy and surface finish. In this study, occurrence of chatter was investigated experimentally using a specially designed rig by examining time histories of the cutting and thrust force components. A broad experimental study was conducted using brass, cast iron and aluminium samples. It was found that by changing the horizontal stiffness of the rig, the thrust force variations (in the vertical direction) were completely eliminated for the cast iron samples. A systematic analysis of the chip formation for the aluminium alloy is presented.

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