scholarly journals ANALYSIS OF MULTI-DISC GRINDING PROCESS OF RICE GRAINS

Author(s):  
Weronika Kruszelnicka
1992 ◽  
Vol 7 (2) ◽  
pp. 82-92 ◽  
Author(s):  
B. J. Ulrich ◽  
A. K. Srivastava ◽  
M. A. Elbestawi

Author(s):  
Sawsen Youssef ◽  
Olivier Calonne ◽  
Hédi Hamdi

For complex part geometry, hand grinding is one of finishing and super finishing process the most used in mechanical industry. Surface integrity is today one major concern for industrials. The surface integrity is defined by a set of important characteristics of ground surface as surface geometric parameters (roughness, …), mechanical behaviour of the subsurface (hardness, residual stress, …) and structural changes of the material in the near surface. High heat and pressure, high strain and strain rate observed during hand grinding process, strongly influence surface integrity. Therefore, the surface behaviour, in terms of resistance to corrosion and crack initiation depends on how the process was conducted. The purpose of this study is to understand the effects of thermal and mechanical plastic deformation induced on the surface of components. The action of the disc-grinding wheel on the workpiece is modelled by a moving heat flux on the surface. The challenge is to be able to find the shape and intensity of thermomechanical load entering the workpiece in accordance with the hand disc grinding process and taking into account specific parameters of the process. In a first part, a mechanical description of the action of the disc-wheel on the surface is proposed in order to develop an analytic formulation of the grinding power and the heat flux density. They are function of the disc-grinding wheel velocity, the feed speed and the applied forces. This expression is then used in a finite element modelling to perform thermomechanical simulations of the hand disc-grinding process. In a first stage, heating and cooling are computed. They give maximum temperature reached, temperature gradients and cooling kinematic. In a second stage, thermomechanical computation is conducted in order to compute residual stresses induced by this abrasion process. A discussion based on experimental results obtained by XRD method is then proposed and some local explanation are given on the way the material structure has changed leading to a structural hardening in the 50 first microns beneath the ground surface.


2019 ◽  
Vol 8 (1) ◽  
pp. 130
Author(s):  
I B Werdi Putra ◽  
Yohanes Setiyo ◽  
I Gusti Ngurah Apriadi Aviantara

 Rice is a staple food for the people of Indonesia. Even though Indonesia is an agrarian country, Indonesia currently imports rice. In producing rice from rice there are obstacles. One of the main obstacles is post-harvest handling of rice with high yield loss during post-harvest. The amount of post-harvest loss occurs because most farmers still use traditional methods or the handling is not good and right. The purpose of this study was to determine the relationship between the capacity of the grinding machine and the quality of sosoh rice produced by the mill and to know the quality comparison of various types of grinding machine capacity. The research was carried out in the area of ??Wanasari Village, Tabanan-Bali to find out the quality of sosoh rice in the region. Head Rice is broken rice grains, both healthy and defective, which have a size greater than or equal to 6/10 part of the average length size of whole rice grains that can pass through the surface of the indented plate basin with a requirement of 4.2 mm hole size. Rice husk is a protective cover from rice grains which is separated from seeds during the grinding process. In the grinding process, there is rice which remains the husk which is caused by the power / rpm of the grinding machine which is too low because the friction force produced by the engine is not sufficient for the overall release of rice husk


2019 ◽  
pp. 503-511
Author(s):  
Weronika Kruszelnicka ◽  
Adam Idzikowski ◽  
Katarzyna Markowska ◽  
Robert Kasner

2019 ◽  
Vol 1 (1) ◽  
pp. 503-511 ◽  
Author(s):  
Weronika Kruszelnicka ◽  
Adam Idzikowski ◽  
Katarzyna Markowska ◽  
Robert Kasner

Abstract The main aim of the grinding process is size reduction. For such formulated purpose of grinding, the particles dimensions after grinding process are the major quality determinant indicated in many works concerning size reduction. In this paper original quality index integrating size reduction and energy consumption in the grinding process was proposed. The aim of the study is to create method for grinding process quality assessment. The problem was formulated as a question: (1) is it possible to create mathematical description of grinding process quality? (2) what grinding parameters influence on the grinding quality index? To resolve the problem, original quality index was developed and experiment on a multi-disc mill was conducted. On the basis of obtained results it was found that discs angular speed affects the grinding process quality.


1988 ◽  
Vol 54 (7) ◽  
pp. 1298-1303
Author(s):  
Toshikatsu NAKAJIMA ◽  
Yoshiyuki UNO ◽  
Takanori FUJIWARA ◽  
Atsunori IKEJIRI ◽  
Kazuhito OHASHI

One of efficiency indicators of grain grinders is grain granulometric composition. The basis of mixed fodder is crushed grain, the particles of which must have a leveled granulometric composition for subsequent mixing and obtaining a high-quality feed mixture. In agricultural production, hammer crushers are widely used, in which the destruction of grain occurs due to the impact of a hinged hammer. The main disadvantage of these crushers is that not the entire surface of the hammers is involved in grinding, thus reduces grinding process efficiency. A slightly different principle of material destruction is laid down in the basis of the proposed design of the shock-centrifugal grinder. Main work is performed by flat impact elements located on the rotor, which serve to accelerate crushed particles with subsequent impact of them on the bump elements. An important step in the design of new constructions of shock-centrifugal grinders is to determine size and location of the impact elements on the rotor, without which the grinding process is not possible. In the calculation method presented, the dependencies for determining the velocities and angles of a single particle flight from the surface of a flat impact element for its specified dimensions are proposed. Two variants of an impact element location on the rotor are considered and analyzed: radial and at an angle in the direction of rotor rotation. As a result of research carried out, it is noted that in the case of inclined position of an impact element on the rotor an increase in flight speed and flight angles change in crushed particles, which gives the opportunity to have a positive effect on grinding process.


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