The In-Process Dressing Characteristics of Vitrified Bonded CBN Grinding Wheels

1993 ◽  
Vol 115 (1) ◽  
pp. 200-204 ◽  
Author(s):  
J. Williams ◽  
H. Yazdzik
Keyword(s):  
Cubic Boron Nitride ◽  
Matrix Material ◽  
Carbon Steels ◽  
Grinding Wheel ◽  
Scanning Electron Micrographs ◽  
Dimensional Tolerance ◽  
Wear Process ◽  
Cbn Wheel ◽  
The Matrix ◽  
Grinding Machine

When grinding carbon steels, creep-resistant materials, and other metals such a titanium, cubic boron nitride (CBN) has become recognized as the preferred choice over Al2O3 and SiC. The succes or failure of the grinding process with CBN lies in the mechanical dressing of the wheel because mechanical dressing is accompanied by very large stresses that distort the grinding wheel and deflect the grinding machine. One recent approach is to true the CBN wheel mechanically and then dress the wheel during the actual grinding manufacturing process. This work observes the dressing of vitrified bonded CBN during the actual like cycle in the production process of steel bearings. Scanning electron micrographs of CBN wheel surfaces are related to surface topography measurements of both wheel and bearing using a Tallysurf machine. In addition, the compositions of the wheel surfaces were checked using the SEM x-ray spectrography facilities. In-process dressing was determined to comprise three distinct stages: the primary or initial dressing, the secondary occurring during steady-state grinding, and finally the tertiary stage after which dimensional tolerance is lost. It was found that the life characteristics of the CBN wheel are quite different than current theories predict. Instead of the limitation of grinding being due to work material loading of the wheel and subsequent dulling of the grains, it was found that the CBN grains remain unchanged and a wear process occurs in the matrix material until the grains fall out and the wheels lose their dimensional tolerance.

Precision Grinding of SUS304 Using Metal Bonded CBN Wheel

2007 ◽  
Vol 24-25 ◽  
pp. 261-264 ◽  
Author(s):  
Y. Hasuda ◽  
Y. Suzuki ◽  
Y. Tadokoro ◽  
S. Kinebuchi ◽  
T. Ohashi ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Ground Surface ◽  
Grinding Wheel ◽  
Precision Grinding ◽  
Wear Process ◽  
Cbn Wheel ◽  
Grinding Conditions ◽  
Wear Of Grinding Wheel ◽  
Stock Removal ◽  
Fundamental Experiment

The fundamental experiment of the grinding of the stainless steel using the metal bonded CBN wheel which was excellent in wear resistance was conducted. The most appropriate grinding conditions were obtained by clarifying wear process of grinding wheel and finished ground surface quality. When grinding was carried out up to stock removal 7000mm3/mm, radial wear of grinding wheel %R is 3μm and surface roughness Rz was 0.5μm or less. The grinding ratio Gr becomes about 3000, and long life grinding with little change of surface roughness was possible.

A Study on a High-Speed NC Gear Grinding Machine Using Screw-Shaped CBN Wheel

1992 ◽  
Author(s):  
T. Emura ◽  
L. Wang ◽  
A. Arakawa
Keyword(s):  
High Speed ◽  
Reduction Gear ◽  
Grinding Wheel ◽  
Magnetic Head ◽  
Two Phase ◽  
Cbn Wheel ◽  
Gear Grinding ◽  
Phase Type ◽  
Rotary Speed ◽  
Grinding Machine

Abstract This paper describes a basic study for the development of a high-speed NC gear grinding machine using screw-shaped CBN wheel. Gear grinding machines using screw-shaped grinding wheel have already developed by Reishauer and others. However, their productivity is not high, because they use one thread type grinding wheel and the rotary speed of the workspindle is very low. The maximum rotary speed of the grinding spindle developed by the authors is 12,000 rpm and that of workspindle is 3,000 rpm. They are enough speed for gear grinding. The desired accuracy for an angle sensor of grinding spindle is more than 20 ″pp in the case of the multithread type grinding wheel. The ordinary shaft encoder cannot respond at such a high-speed. Therefore the authors used a magnetic scale of high-accuracy and an induction type magnetic head. After experiments, it became clear that two-phase type PLL proposed by T. Emura is useful for detecting low level signals obtained from the magnetic head. Since the maximum rotary speed of the workspindle is raised to 3,000 rpm, we cannot use any reduction gear. Thus a direct-drive method with an inertial damper was used. The workspindle is controlled by using the two-phase type PLL. When we grind gears, the initial setting between rotary angles of grinding wheel and work is required. The authors tried to automatically set the initial rotary angles by using a CCD camera and a microcomputer.

A Study on a High-Speed NC Gear Grinding Machine Using a Screw-Shaped CBN Wheel

1994 ◽  
Vol 116 (4) ◽  
pp. 1163-1168 ◽  
Author(s):  
T. Emura ◽  
L. Wang ◽  
A. Arakawa
Keyword(s):  
High Speed ◽  
Wave Length ◽  
Ccd Camera ◽  
Grinding Wheel ◽  
Direct Drive ◽  
Two Phase ◽  
Basic Study ◽  
Cbn Wheel ◽  
Gear Grinding ◽  
Grinding Machine

This paper describes a basic study for designing a high-speed NC gear grinding machine using a screw-shaped CBN wheel. Gear grinding machines using screw-shaped grinding wheels are quite prevalent. However, their productivity is not high, because the rotary speed of their spindles is very low. Therefore, the authors raised the maximum rotary speeds of the grinding spindle and the workspindle to 12,000 rpm and 3,000 rpm, respectively, in order to use a high-speed multithread CBN wheel. A magnetic scale whose wave length is long but pitch accuracy is high enough was used for detecting such a high-speed rotation. Since the wave length of the scale is long, a high-resolution interpolation using two-phase type PLL proposed by Emura was used. Both spindles are direct-drive type for removing backlash. When we grind gears, the initial setting between rotary angles of grinding wheel and work is required. The authors tried to automatically set the initial rotary angles by using a CCD camera.

Modeling Wear Process of Electroplated CBN Grinding Wheel

2015 ◽  
Author(s):  
Tianyu Yu ◽  
Ashraf F. Bastawros ◽  
Abhijit Chandra
Keyword(s):  
Life Expectancy ◽  
Cubic Boron Nitride ◽  
Grinding Wheel ◽  
Type Model ◽  
Wheel Wear ◽  
Modeling Framework ◽  
Workpiece Material ◽  
Wear Process ◽  
Workpiece Interaction ◽  
Cbn Grinding Wheel

The wear of Cubic Boron Nitride (CBN) grinding wheel directly affects the workpiece surface integrity and tolerances. This paper summarizes a combined experimental-modeling framework for CBN grinding wheel life expectancy utilized in both cylindrical and surface grinding. The presented fatigue type model is based on grit pullout mechanism and the associated state of damage percolation. The unique grit-workpiece interaction process leads to a non-uniform spatial distribution of the grit wear. The life expectancy model can be described as a function of the process parameters, grinding wheel geometry and topology, workpiece material properties, etc. The developed modeling framework will greatly enhance the understanding of electroplated CBN grinding wheel wear mechanism.

Wear-Resistance of Die Steel with Non-Smooth Surface Used to Pressure Casting Die Processed by Laser

2012 ◽  
Vol 155-156 ◽  
pp. 496-500
Author(s):  
L. Chen ◽  
T.J. Li ◽  
Zhi Wu Han ◽  
J. Chen
Keyword(s):  
Wear Resistance ◽  
Matrix Material ◽  
Area Ratio ◽  
Smooth Surfaces ◽  
Pressure Casting ◽  
Abrasive Particles ◽  
Die Steel ◽  
Wear Process ◽  
The Matrix ◽  
Better Than

Various non-smooth surfaces that are similar to the surfaces of animal biont are processed on the die steel by laser to improve the wear-resistance and life-span of die. The wear-resistance of various specimens was measured. The results show that the wear-resistance of specimens with non-smooth surfaces are better than that of the smooth specimen. The wear-resistance of specimen whole processed by laser is between the specimen in 2mm distance and 3mm distance. The shape and distributing distance of non-smooth unit affect the wear-resistance of non-smooth specimens because they affect the area ratio and the hardness of non-smooth unit. The non-smooth unit with higher hardness can underprop load, prevent abrasive particles from penetrating into the matrix material and block the wear progress during wear process. Thus the wear-resistance is improved.

Fabrication and Characterization of CU/B4C Surface Dispersion Strengthened Composite using Friction Stir Processing

2014 ◽  
Vol 59 (1) ◽  
pp. 83-87 ◽  
Author(s):  
R. Sathiskumar ◽  
N. Murugan ◽  
I. Dinaharan ◽  
S.J. Vijay
Keyword(s):  
Friction Stir Processing ◽  
Matrix Material ◽  
Composite Layer ◽  
Copper Surface ◽  
Chromium Steel ◽  
Copper Plate ◽  
Homogeneous Distribution ◽  
Scanning Electron Micrographs ◽  
Friction Stir ◽  
The Matrix

Abstract Friction stir processing has evolved as a novel method to fabricate surface metal matrix composites. The feasibility to make B4C particulate reinforced copper surface matrix composite is detailed in this paper. The B4C powders were compacted into a groove of width 0.5 mm and depth 5 mm on a 9.5 mm thick copper plate. A tool made of high carbon high chromium steel; oil hardened to 63 HRC, having cylindrical profile was used in this study. A single pass friction stir processing was carried out using a tool rotational speed of 1500 rpm, processing speed of 40 mm/min and axial force of 10 kN. A defect free interface between the matrix and the composite layer was achieved. The optical and scanning electron micrographs revealed a homogeneous distribution of B4C particles which were well bonded with the matrix. The hardness of the friction stir processed zone increased by 26% higher to that of the matrix material.

Polishing process effect on the image of dispersed precipitates

1984 ◽  
Vol 42 ◽  
pp. 534-535
Author(s):  
C.T. Hu ◽  
C.W. Allen
Keyword(s):  
Matrix Material ◽  
Specimen Preparation ◽  
Second Phase ◽  
Precipitate Particle ◽  
Polishing Process ◽  
Second Phase Particles ◽  
The Matrix ◽  
Surface Profiles ◽  
Thinning Process

One important problem in determination of precipitate particle size is the effect of preferential thinning during TEM specimen preparation. Figure 1a schematically represents the original polydispersed Ni3Al precipitates in the Ni rich matrix. The three possible type surface profiles of TEM specimens, which result after electrolytic thinning process are illustrated in Figure 1b. c. & d. These various surface profiles could be produced by using different polishing electrolytes and conditions (i.e. temperature and electric current). The matrix-preferential-etching process causes the matrix material to be attacked much more rapidly than the second phase particles. Figure 1b indicated the result. The nonpreferential and precipitate-preferential-etching results are shown in Figures 1c and 1d respectively.

Application of cross correlation to HREM images of surfaces

1987 ◽  
Vol 45 ◽  
pp. 754-755
Author(s):  
D. E. Luzzi ◽  
L. D. Marks ◽  
M. I. Buckett
Keyword(s):  
Cross Correlation ◽  
A Priori ◽  
Matrix Material ◽  
Correlation Method ◽  
Accurate Knowledge ◽  
Complex Image ◽  
Fourier Filtering ◽  
The Matrix ◽  
Low Pass ◽  
Data Reduction Technique

As the HREM becomes increasingly used for the study of dynamic localized phenomena, the development of techniques to recover the desired information from a real image is important. Often, the important features are not strongly scattering in comparison to the matrix material in addition to being masked by statistical and amorphous noise. The desired information will usually involve the accurate knowledge of the position and intensity of the contrast. In order to decipher the desired information from a complex image, cross-correlation (xcf) techniques can be utilized. Unlike other image processing methods which rely on data massaging (e.g. high/low pass filtering or Fourier filtering), the cross-correlation method is a rigorous data reduction technique with no a priori assumptions.We have examined basic cross-correlation procedures using images of discrete gaussian peaks and have developed an iterative procedure to greatly enhance the capabilities of these techniques when the contrast from the peaks overlap.

Impact Strength, Flexural Modulus and Wear Rate of PMMA Composites Reinforced by Eggshell Powders

2020 ◽  
Vol 38 (7A) ◽  
pp. 960-966
Author(s):  
Aseel M. Abdullah ◽  
Hussein Jaber ◽  
Hanaa A. Al-Kaisy
Keyword(s):  
Impact Strength ◽  
Wear Rate ◽  
Flexural Modulus ◽  
Matrix Material ◽  
Weight Fraction ◽  
Pure Pmma ◽  
Calcination Process ◽  
The Matrix ◽  
The Impact ◽  
Interface Bond

In the present study, the impact strength, flexural modulus, and wear rate of poly methyl methacrylate (PMMA) with eggshell powder (ESP) composites have been investigated. The PMMA used as a matrix material reinforced with ESP at two different states (including untreated eggshell powder (UTESP) and treated eggshell powder (TESP)). Both UTESP and TESP were mixed with PMMA at different weight fractions ranged from (1-5) wt.%. The results revealed that the mechanical properties of the PMMA/ESP composites were enhanced steadily with increasing eggshell contents. The samples with 5 wt.% of UTESP and TESP additions give the maximum values of impact strength, about twice the value of the pure PMMA sample. The calcination process of eggshells powders gives better properties of the PMMA samples compared with the UTESP at the same weight fraction due to improvements in the interface bond between the matrix and particles. The wear characteristics of the PMMA composites decrease by about 57% with increases the weight fraction of TESP up to 5 wt.%. The flexural modulus values are slightly enhanced by increasing of the ESP contents in the PMMA composites.

scholarly journals Self-Reinforced Nylon 6 Composite for Smart Vibration Damping

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1235
Author(s):  
Bidita Salahuddin ◽  
Rahim Mutlu ◽  
Tajwar A. Baigh ◽  
Mohammed N. Alghamdi ◽  
Shazed Aziz
Keyword(s):  
Matrix Material ◽  
Nylon 6 ◽  
Vibration Damping ◽  
Vibration Energy ◽  
Damping Factor ◽  
Passive Vibration Control ◽  
Reinforced Composite ◽  
Coiled Structure ◽  
The Matrix ◽  
3D Printed

Passive vibration control using polymer composites has been extensively investigated by the engineering community. In this paper, a new kind of vibration dampening polymer composite was developed where oriented nylon 6 fibres were used as the reinforcement, and 3D printed unoriented nylon 6 was used as the matrix material. The shape of the reinforcing fibres was modified to a coiled structure which transformed the fibres into a smart thermoresponsive actuator. This novel self-reinforced composite was of high mechanical robustness and its efficacy was demonstrated as an active dampening system for oscillatory vibration of a heated vibrating system. The blocking force generated within the reinforcing coiled actuator was responsible for dissipating vibration energy and increase the magnitude of the damping factor compared to samples made of non-reinforced nylon 6. Further study shows that the appropriate annealing of coiled actuators provides an enhanced dampening capability to the composite structure. The extent of crystallinity of the reinforcing actuators is found to directly influence the vibration dampening capacity.

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