scholarly journals DETERMINING OF MAGNETIC ABRASIVE POLISHING OF OPTICAL POLYMERS FOR SENSITIVE ELEMENTS OF RADIATION INDICATORS

2020 ◽  
Vol 2 (36) ◽  
pp. 26-34
Author(s):  
O. Titarenko ◽  
◽  
N. Zubkova ◽  
S. Novak ◽  
◽  
...  
Keyword(s):  
Surface Layer ◽  
Optical Fibers ◽  
Process Parameters ◽  
Vibration Frequency ◽  
Vibration Amplitude ◽  
Optical Polymers ◽  
Abrasive Particles ◽  
Powder Particles ◽  
Magnetic Abrasive Polishing ◽  
Monitoring Devices

Extending the durability of functioning of the sensitive elements of radiation indicators and increasing their reliability and safety are the main requirements for producers of modern radiation reconnaissance and monitoring devices. The proposed solutions for construction improving of products provide for the usage of optical fibers and the corresponding formation of loop-shaped channels in the finished sensitive polymer element. Potential possibilities of using magnetic abrasive polishing for finishing channel surfaces are considered. For the chosen construction of the polishing head, the material and form of the powder particles composition and the process parameters are proposed. The effect of the frequency and amplitude of vibration of abrasive particles on the depth of their penetration into the surface layer of the polymer is investigated. It has been determined that the widest possibilities of using powders of the composition Fe - C - Si - Ti with a diameter of d = 50 – 400 μm have a mode when the pressure of the air flow by feeding particles is maintained at a level of 1 atm, the magnetic induction of the field in the working gap is 0.8 T, the vibration amplitude of the particles is a = 0.4 mm, and the vibration frequency varies in the range f = 25 – 30 Hz.

scholarly journals Droplet Generation in a Flow-Focusing Microfluidic Device with External Mechanical Vibration

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 743
Author(s):  
Zhaoqin Yin ◽  
Zemin Huang ◽  
Xiaohui Lin ◽  
Xiaoyan Gao ◽  
Fubing Bao
Keyword(s):  
Microfluidic Device ◽  
Vibration Frequency ◽  
Linear Correlation ◽  
Vibration Amplitude ◽  
Mechanical Vibration ◽  
Droplet Generation ◽  
Flow Focusing ◽  
Generation Frequency ◽  
External Vibration ◽  
Shrinkage Process

The demand for highly controllable droplet generation methods is very urgent in the medical, materials, and food industries. The droplet generation in a flow-focusing microfluidic device with external mechanical vibration, as a controllable droplet generation method, is experimentally studied. The effects of vibration frequency and acceleration amplitude on the droplet generation are characterized. The linear correlation between the droplet generation frequency and the external vibration frequency and the critical vibration amplitude corresponding to the imposing vibration frequency are observed. The droplet generation frequency with external mechanical vibration is affected by the natural generation frequency, vibration frequency, and vibration amplitude. The droplet generation frequency in a certain microfluidic device with external vibration is able to vary from the natural generation frequency to the imposed vibration frequency at different vibration conditions. The evolution of dispersed phase thread with vibration is remarkably different with the process without vibration. Distinct stages of expansion, shrinkage, and collapse are observed in the droplet formation with vibration, and the occurrence number of expansion–shrinkage process is relevant with the linear correlation coefficient.

Modelling of the Ultrasonic Shot Peening Process

2005 ◽  
Vol 490-491 ◽  
pp. 67-72 ◽  
Author(s):  
C. Pilé ◽  
Manuel François ◽  
Delphine Retraint ◽  
Emmanuelle Rouhaud ◽  
Jian Lu
Keyword(s):  
Process Parameters ◽  
Vibration Frequency ◽  
Shot Peening ◽  
Boltzmann Distribution ◽  
Perfect Gas ◽  
Average Speed ◽  
Speed Distribution ◽  
Almen Intensity ◽  
Ultrasonic Shot Peening ◽  
The Impact

The aim of this work is to reach a better understanding of the ultrasonic shot-peening process and, in particular, the evolution of the shot speed distribution. A simple 1D modelling of the interaction between the shots and the sonotrode is carried out. The impact is considered as inelastic with an energy absorption that depends on the speed of the shot. It is found that after about 10 interactions (» 1s) the speed distribution in the chamber follows a Maxwell-Boltzmann distribution, which is the distribution found in a perfect gas at equilibrium. The influence of various process parameters such as the sonotrode amplitude, the vibration frequency on the average speed and on the Almen intensity is studied.

Thermal Performance Improvement of a Heat Sink With Piezoelectric Vibrating Fins

2010 ◽  
Author(s):  
Hee Seung Park ◽  
Sung Jin Kim
Keyword(s):  
Natural Frequency ◽  
Performance Improvement ◽  
Thermal Performance ◽  
Vibration Frequency ◽  
Heat Sink ◽  
Vibration Amplitude ◽  
Piezoelectric Actuators ◽  
Convection Heat ◽  
Heat Transfer Characteristics ◽  
Heat Sink Temperature

A heat sink with piezoelectric vibrating fins is developed through attaching piezoelectric actuators to the fins of a heat sink, and the heat transfer characteristics of the heat sink are experimentally investigated. Thermal performance improvement of the heat sink by the vibration of the fins is observed compared to the thermal performance of a natural convection heat sink with static fins under a fixed heat sink geometry condition. The thermal performance of the heat sink changes as the vibration amplitude of the fins or the vibration frequency of the fins changes. Particularly, if the vibration frequency of the fins matches up to the natural frequency of the fins, the vibration amplitude is significantly increased by resonance and the thermal performance also increases. The natural frequency of the fins changes with the heat sink temperature because the geometry of the fins changes and the properties of the fins change due to the temperature change.

Variations of a Ni-P Surface Layer After Nanoparticle Impacts

2005 ◽  
Author(s):  
J. Xu ◽  
J. B. Luo ◽  
G. S. Pan ◽  
W. Zhang ◽  
X. C. Lu
Keyword(s):  
Surface Layer ◽  
Microscopic Examination ◽  
Wear Mechanisms ◽  
Erosive Wear ◽  
Experimental Results ◽  
Phosphorus Concentration ◽  
Fluid Medium ◽  
Abrasive Particles ◽  
Nano Scale ◽  
Surface Collision

In CMP, erosive wear regarded as one of the wear mechanisms underlying the interaction between the abrasive particles and polished surfaces can occur when materials are removed from surface collision of particles which are carried by a fluid medium. In this paper, the microscopic examination of the NiP coatings after nanoparticle impacts is performed. The experimental results indicate that craters and scratches can be observed in the surface after nanoparticle impacts, and crystal grains in nano-scale and element phosphorus concentration can be found in the sub-surface layer of the impacted surface.

Enhancement in Microhardness of Free Machining Brass in Ball Burnishing

2020 ◽  
Vol 12 (2) ◽  
Author(s):  
Pavana Kumara ◽  
G.K. Purohit
Keyword(s):  
Plastic Deformation ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Process Parameters ◽  
Surface Texture ◽  
Ball Burnishing ◽  
Abrasive Particles ◽  
Metal Finishing ◽  
Burnishing Process ◽  
Machined Surfaces

The burnishing process is becoming an attractive way among post-machining, metal finishing techniques due to its excellent features. The burnishing process carried out with ball or roller, smooth out the protrusions due to the plastic deformation and increases the surface texture. This paper presents the results of three ball burnishing conditions carried out on cylindrical free machining brass components. Influence of abrasive particles (abrasive assisted burnishing, AAB) during burnishing is investigated and compared with the burnishing carried out without (plain burnishing, PB) and with-coolant (lubricated burnishing, LB) conditions. The response surface methodology (RSM) is used to optimize the microhardness in terms of four process parameters. Result obtained indicates that the microhardness of the pre-machined surfaces increases by 12-29 percent. The AAB results in 141.67 percent higher microhardness than the PB and 41 percent more than the LB condition.

Methodology for Modelling Diffusion Bonding in Powder Forging

2016 ◽  
Vol 716 ◽  
pp. 817-823
Author(s):  
Yi Wang ◽  
Idris K. Mohammed ◽  
Daniel S. Balint
Keyword(s):  
Process Parameters ◽  
Diffusion Bonding ◽  
Bonding Process ◽  
Volume Element ◽  
Particle Packing ◽  
Forging Process ◽  
Forming Load ◽  
Temperature Load ◽  
Powder Particles

Interfacial bonding has a significant influence on the quality of processed components formed by powder forging. Consequently, modelling the bonding process is important for controlling the condition of the components and predicting optimum forging process parameters (e.g. forming load, temperature, load-holding time, etc.). A numerical model was developed in the present work to simulate diffusion bonding (DB) during the direct powder forging (DF) process. A set of analytical equations was derived and implemented in the finite element (FE) software Abaqus via a user-defined subroutine. The DB model was validated using a two-hemisphere compression simulation. The numerical results demonstrated that the DB model has the ability to: 1) determine the bonding status between powder particles during the forging process, and 2) predict the optimum value for key powder forging process parameters. The DB model was also implemented in a representative volume element (RVE) model which was developed in an earlier work to simulate the powder forging process by considering particle packing and thermo-mechanical effects.

scholarly journals DESIGN OPTIMIZATION AND PERFORMANCE TEST OF MAGNETIC PICKUP FINGER SEED METERING DEVICE

2021 ◽  
pp. 137-144
Author(s):  
Fei Liu ◽  
Zhen Lin ◽  
Dapeng Li ◽  
Tao Zhang
Keyword(s):  
Vibration Frequency ◽  
Magnetic Induction ◽  
Vibration Amplitude ◽  
Magnetic Force ◽  
Performance Test ◽  
Simulation Software ◽  
National Standard ◽  
Design And Optimization ◽  
Seed Metering Device ◽  
Magnetic Induction Intensity

As the core part of precision seeder, the performance of pickup finger seed metering device directly affects the seeding quality. Aiming at the problem that the traditional pickup finger seed metering device can be easily affected by the performance of spring material, and the reliability of spring decreases with the increase of service time, a magnetic pickup finger seed metering device is designed to open and close the pickup finger by magnetic force, so as to improve the stability of seed metering performance. Through the design and optimization of permanent magnet structure, cam structure and seed taking pickup finger structure, the magnetic force distribution of ring magnet is analysed by using ANSYS Maxwell magnetic simulation software. Under the working speed of 3.9km/h, the vibration frequency, vibration amplitude and magnetic induction intensity were selected for orthogonal test. The experimental results show that the optimal combination of factors is vibration frequency 6Hz, vibration amplitude 3.1mm and magnetic induction intensity 316.34mT. Under the condition of the combination of operation parameters, the seed arrangement performance is 91.7% of the qualified rate, 6.2% of the replant rate and 2.1% of the missed rate, which meets the requirements of the national standard for the performance of the seeder. This study can provide a reference for the optimization of the structure and the improvement of the seed metering performance of the pickup finger seed metering device.

scholarly journals Effect of laser-assisted ultrasonic vibration dressing parameters of a cubic boron nitride grinding wheel on grinding force, surface quality, and particle morphology

2021 ◽  
Vol 60 (1) ◽  
pp. 691-701
Author(s):  
Zhibo Yang ◽  
Wang Sun ◽  
Dongyu He ◽  
Daocheng Han ◽  
Wei Wang ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Surface Quality ◽  
Ultrasonic Vibration ◽  
Process Parameters ◽  
Cubic Boron Nitride ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Abrasive Particles ◽  
Dressing Force ◽  
Cbn Grinding Wheel

Abstract In this article, the laser-assisted ultrasonic vibration dressing technique was applied to the cubic boron nitride (CBN) grinding wheel to study the effect of various process parameters (namely, laser power, dressing depth, feed rate, and grinding wheel speed) on the grinding force, surface quality, and morphological evolution of CBN abrasive particles. The results showed that abrasive particles’ morphology mainly undergoes micro-crushing, local crushing, large-area crushing, macro-crushing, and other morphological changes. The dressing force can be effectively reduced by controlling the dressing process parameters. Besides, grinding tests are performed on the grinding wheel after dressing to reveal specimens’ surface quality. Excellent grinding characteristics and grinding quality of the grinding wheel were obtained by the proposed technique with the optimized process parameters.

Experimental and Numerical Investigation of the Catalytic Gas Carburization of Steel

2020 ◽  
Vol 989 ◽  
pp. 276-282
Author(s):  
Mikhail V. Maisuradze ◽  
Maksim A. Ryzhkov
Keyword(s):  
Mathematical Model ◽  
Numerical Modeling ◽  
Surface Layer ◽  
Process Parameters ◽  
Concentration Profile ◽  
Steel Plates ◽  
Carbon Surface ◽  
Surface Saturation ◽  
Modeling Data ◽  
Experimental And Numerical Modeling

The carbon surface saturation process of the steel plates during the catalytic gas carburization was under consideration. The rate of the carburization was determined, as well as the hardness of the diffusion layer, after quenching. A mathematical model based on experimental and numerical modeling data had been obtained. The carbon concentration profile of the surface layer was estimated depending on the carburization process parameters. A simplified simulation technique of the steel carburization was proposed.

Sign in / Sign up

Export Citation Format

Share Document