scholarly journals Effect of fiber flocculation and filling design on refiner loadability and refining characteristics

BioResources ◽  
2008 ◽  
Vol 3 (2) ◽  
pp. 403-424
Keyword(s):  
Cutting Speed ◽  
Total Power ◽  
Short Fibers ◽  
Noticeable Effect ◽  
Floc Size ◽  
High Cutting Speed ◽  
Different Types ◽  
Wide Groove ◽  
Design Characteristics ◽  
Gap Width

The loadability of a pulp refiner was studied using refiner data such as gap movement, total power, no-load power, and net refining power. Two different types of pulp and three different types of refiner filling were used in the study. The floc formation and floc size of each pulp was studied in a flow channel simulating filling grooves. The loadability of the pulp refiner was linked to refining effects such as fiber shortening, and internal and external fibrillation. The trapping point of the refiner, and therefore refiner loadability, was found to be more related to fiber characteristics such as fiber length and coarseness, while being less dependent on refining consistency in the range of 2.0-5.5%. The data on the formation of flocs and floc size was used to explain the trapping of fibers between refiner bars and the refiner gap width. Filling design characteristics such as groove width and cutting speed affect the gap width and trapping of flocs inside the refiner. Fillings with high cutting speed tend to break flocs composed of long and short fibers at the same rate and therefore both types of floc maintain the same gap width. On the other hand, wide-groove fillings with lower cutting speed have a gentler effect and the differences in fiber characteristics are easily reflected in the gap width and trapping point. Fillings with low cutting speed have a greater straightening effect than fiber cutting, whereas narrow-bar fillings have a more noticeable effect on fiber cutting, external fibrillation, and fiber swelling.

Mechanism of Variable Helix Tools in Suppressing Chatter Using Process Damping for Machining Titanium Alloys at Low Cutting Speed

2013 ◽  
Vol 773-774 ◽  
pp. 370-376
Author(s):  
Muhammad Adib Shaharun ◽  
Ahmad Razlan Yusoff ◽  
Mohammad S. Reza
Keyword(s):  
Titanium Alloy ◽  
Cutting Speed ◽  
Milling Process ◽  
Cutting Process ◽  
Chatter Vibration ◽  
Process Damping ◽  
High Cutting Speed ◽  
Titanium Machining ◽  
Different Types ◽  
Variable Helix

Titanium is difficult-to-cut materials due to its poor machinability and thermal conductivity when machining at high cutting speed. To overcome this machining titanium alloy problem, this study in interaction between machining structural system and the cutting process are very important. One of the main problems in the cutting process is chatter vibration. Due to chatter problem, the mechanism to suppress chatter named, process damping is a useful method can be manipulated to improve the limited productivity of titanium machining at low speed machining in milling process. In the present study, experiment are conducted to evaluate and study the process damping mechanism in milling using different types of variable tools geometries. These tools are variable he-lix/uniform pitch, variable pitch/uniform helix and variable helix and pitch and uniform helix/pitch. The result showed that the variable helix and pitch tools is very significantly improve process damping performance in machining titanium alloy compare to traditional of regular tools and other irregular tools.

DEFORMATION AND CRACKING OF THE PLATFORM JOINT OF THE PREFABRICATED-MONOLITHICRC BUILDING FRAME

2020 ◽  
Vol 90 (4) ◽  
pp. 38-47
Author(s):  
VL.I. KOLCHUNOV ◽  
◽  
D.V. MARTYNENKO ◽  
Keyword(s):  
Reinforced Concrete ◽  
Plane Stress State ◽  
Hollow Core ◽  
Finite Element Scheme ◽  
Element Scheme ◽  
Joint Structure ◽  
Numerical Studies ◽  
Distributed Load ◽  
Different Types ◽  
Design Characteristics

A computational model and the results of numerical studies of the structure of a platform joint in a reinforced concrete precast-monolithic frame of a building from panel-frame elements of industrial production are presented. Modeling of the plane stress state of the joint structure is carried out by a finite element scheme, using finite elements of different types and a nonlinear law of deformation to determine the design characteristics of reinforced concrete. The parameters of deformation of the platform joint structure at different loading levels, including stage-by-stage cracking and destruction, have been determined. The schemes of distribution and stress concentration zones in the characteristic sections of the platform joint are established when the distributed load is transferred from the frame of the panel-frame to the hollow-core floor panels and concrete for embedding the joint in the presence of a cavity in the frame frame for centering elements.

Cutting Performance and Wear Mechanism of Si3N4-Based Nanocomposite Ceramic Tool

2010 ◽  
Vol 443 ◽  
pp. 324-329 ◽  
Author(s):  
Bin Zou ◽  
Chuan Zhen Huang ◽  
Han Lian Liu ◽  
Jin Peng Song
Keyword(s):  
Wear Resistance ◽  
Wear Mechanism ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Cutting Performance ◽  
Nano Particles ◽  
Ceramic Tool ◽  
Tool Materials ◽  
High Cutting Speed ◽  
The Matrix

Si3N4/TiN nanocomposite tool and Si3N4/Ti(C7N3) nanocomposite tool were prepared. The cutting performance and wear mechanism of Si3N4-based nanocomposite ceramic tool was investigated by comparison with a commercial sialon ceramic tool in machining of 45 steel. Si3N4-based nanocomposite ceramic tool exhibits the better wear resistance than sialon at the relatively high cutting speed. The increased cutting performance of Si3N4-based nanocomposite ceramic tool is ascribed to the higher mechanical properties. Nano-particles can refine the matrix grains and improve the bonding strength among the matrix grains of Si3N4-based nanocomposite ceramic tool materials. It contributes to an improved wear resistance of the cutting tools during machining.

Study of a High Performance AFM Probe-Based Microscribing Process

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Keith Bourne ◽  
Shiv G. Kapoor ◽  
Richard E. DeVor
Keyword(s):  
Tool Wear ◽  
High Performance ◽  
Cutting Speed ◽  
Rake Angle ◽  
Motion Platform ◽  
High Cutting Speed ◽  
Working Volume ◽  
Afm Probe ◽  
Tool Motion ◽  
Five Axis

In this paper, a mechanical microscribing process is described that combines AFM probe-based microscribing with a five-axis microscale machine tool motion platform in order to achieve high scribing speeds, a large working volume, and the capability of cutting curvilinear patterns of grooves. An experiment is described that demonstrates groove formation, groove shape, and tool wear when long grooves are formed using multiple tool passes. A second more systematic experiment is described in which short-distance single-pass cutting tests were used to explore the effects of cutting speed, nominal tool load, and AFM probe mounting angle on groove geometry, tool wear, effective rake angle, and chip formation. Lastly, an experiment is described in which a long curvilinear groove is cut. It is shown that the most well-formed grooves were cut and acceptable tool wear was achieved, when using a high cutting speed, high nominal tool load, and low probe mounting angle. The capability of cutting grooves as long at 82 mm but with depths of only a few hundred nanometers, using a single tool pass at cutting speeds as high at 25 mm/min is demonstrated.

Experimental Investigation of Performance Characteristics for Savonius-Style VAWTs: A Comparative Study

2021 ◽  
Author(s):  
Diplina Paul ◽  
Abhisek Banerjee
Keyword(s):  
Wind Turbines ◽  
Coefficient Of Performance ◽  
Total Power ◽  
Speed Ratio ◽  
Mechanical Loads ◽  
Tip Speed Ratio ◽  
Ac Motor ◽  
Different Types ◽  
Laminar Air Flow ◽  
Rotor Profiles

Abstract Savonius-style wind turbines are mainly gauged by two types of coefficients namely: (i) coefficient of power (CP) and (ii) coefficient of torques (CT). Coefficient of power is defined as the ratio of power generated by the turbine to the total power available to the turbine from the free-flowing wind. This is synonymous to the operational efficiency of the wind turbine. Coefficient of torque reflects the torque generating ability of the turbine. In this manuscript, experiments have been performed using three different types of rotor profiles for Savonius-style wind turbines (SSWTs) namely, classical SSWT, Benesh type SSWT and elliptical shaped SSWT using oriented jets. Using deflector plates the orientation of jets have been varied from 20° to 70°. Addition of deflector plates to the wind turbines, assists in maximizing the utilization of wind energy. Experiments have been performed in the laminar air flow. Mechanical loads have been used to study Coefficient of performance (CP) and coefficient of torque (CT) as a function of tip speed ratio (TSRs). The velocity of the wind is adjusted by varying the rheostat that controls the AC motor for the wind tunnel systems. Experimental results indicated that optimum performance could be achieved from all three types of SSWT variants at TSR ∼ 0.70. Out of the three designs studied in this manuscript, elliptic shaped SWT yielded best coefficient of performance equal to 0.39 at TSR = 0.70.

Performance Evaluation of PVD and CVD Coated Inserts during End Milling with DRY and MQL Condition

2017 ◽  
Vol 867 ◽  
pp. 165-170
Author(s):  
Isha Srivastava ◽  
Ajay Batish
Keyword(s):  
Tool Wear ◽  
Cutting Force ◽  
End Milling ◽  
Cutting Speed ◽  
Minimum Quantity Lubrication ◽  
Sem Analysis ◽  
Depth Of Cut ◽  
High Cutting Speed ◽  
Cutting Operation ◽  
En 31

The aim of this study were to evaluate the performance of PVD (TiAlN+TiN) and CVD (TiCN+Al2O3+TiN) coated inserts in end milling of EN–31 hardened die steel of 43±1 HRC during dry and MQL (Minimum quantity lubrication) machining. The experiments were conducted at a fixed feed rate, depth of cut and varying cutting speed to measure the effect of cutting speed on cutting force and tool wear of CVD and PVD-coated inserts. The performance of CVD and PVD-coated inserts under dry and MQL condition by measuring the tool wear and cutting force were compared. During cutting operation, it was noticed that PVD inserts provide less cutting force and tool wear as compared to the CVD inserts under both dry as well as the MQL condition because PVD inserts have a thin insert coating and CVD inserts have a thick insert coating, but PVD inserts experience catastrophic failure during cutting operation whereas CVD inserts have a capability for continuous machining under different machining. Tool wear has measured by SEM analysis. The result shows that MQL machining provides the optimum results as compared to the dry condition. MQL machining has the ability to work under high cutting speed. As the cutting speed increases the performance of dry machining was decreased, but in MQL machining, the performance of the inserts was increased with increases of cutting speed. MQL machining generates less cutting force on the cutting zone and reduces the tool wear which further increase the tool life.

Evaluation of drilling parameters on surface roughness and burr when drilling carbon black reinforced high-density polyethylene

2018 ◽  
Vol 52 (20) ◽  
pp. 2719-2727 ◽  
Author(s):  
Alper Uysal
Keyword(s):  
Surface Roughness ◽  
Carbon Black ◽  
High Density Polyethylene ◽  
Cutting Speed ◽  
Lower Surface ◽  
High Density ◽  
Effective Parameter ◽  
High Cutting Speed ◽  
Drilling Parameters ◽  
Drill Point

In this study, surface roughness and burr were investigated in drilling of pure and carbon black reinforced high-density polyethylene at three cutting speeds and feeds with three drill point angles. The measurement results of surface roughness of drilled holes were evaluated by Taguchi and analysis of variance statistical methods to specify the optimal drilling parameters and the effects of selected drilling parameters. According to the results, lower surface roughness and fewer burrs were obtained in drilling at high cutting speed and low feed with drill tools having small point angle and it was specified that the carbon black reinforcement reduced the surface roughness. Additionally, the optimal drilling parameters were determined as drill point angle of 80°, feed of 0.1 mm/rev and cutting speed of 120 m/min and the most effective parameter was found as drill point angle and the least effective parameter was found as feed.

Tool Wear of Polycrystalline Cubic Boron Nitride Compact Tools in Cutting Hardened Steel

2012 ◽  
Vol 488-489 ◽  
pp. 724-728 ◽  
Author(s):  
Tadahiro Wada
Keyword(s):  
Particle Size ◽  
Boron Nitride ◽  
Tool Wear ◽  
Tool Life ◽  
Cubic Boron Nitride ◽  
Cutting Speed ◽  
Hardened Steel ◽  
Polycrystalline Cubic Boron Nitride ◽  
Cbn Tool ◽  
High Cutting Speed

Using polycrystalline cubic boron nitride compact (cBN) tools, which have different cBN contents and cBN particle sizes, the influences of both the cBN content and the cBN particle size on tool wear in turning of hardened steel at various cutting speeds was experimentally investigated. Three types of cBN tools (a cBN content of 45-55% and 75%, and a cBN particle size of 0.5 μm and 5 μm, respectively) were tested. Furthermore, three kinds of chamfered and honed cutting edges were also used. The main results obtained are as follows: (1) In the case of the cBN tools with the same cBN particle size of 5.0 μm, the tool life of the cBN tool with a cBN content of 75% was longer than that of the cBN tool with a cBN content of 45% at low cutting speed. However, at high cutting speed, the tool life of the cBN tool with a cBN content of 75% was shorter. (2) The tool life of the cBN tool with both a cBN content of 55% and a cBN particle size of 0.5 μm was the longest. (3) The tool wear of cBN tools decreased with a decrease in chamfer width.

scholarly journals Study on Machinability of Resulfurized Steels under High Cutting Speed (2nd Report)

1987 ◽  
Vol 53 (11) ◽  
pp. 1779-1784
Author(s):  
Yasuo YAMANE ◽  
Biinghwa YAN ◽  
Hitosi USUKI ◽  
Norihiko NARUTAKI
Keyword(s):  
Cutting Speed ◽  
High Cutting Speed
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