Study of the determination of the rational operating regime of percussion drilling machines

operating regime of percussion drilling machines Zina RABBOUCHE , Lakhdar KHOCHEMANE , Ouafae BENNIS #3 #1 Mechanical department of Engineering, University of 20 Août 1955 Skikda Algerie #2 Research Laboratory of Physic Chemistry of Surfaces and Interfaces, University of 20 Août 1955 skikda #3 EA4229 – Research laboratory pluridisciplinaire of the mechanical and energy systems, University of Orleans France. 1 zinassar@yahoo.fr zinaboutaghane@gmail.com 2 Lakhdarkhochmane@yahoo.fr 3 ouafae.bennis@univ-orleansyahoo.fr


Study of the determination of the rational operating regime of percussion drilling machines INTRODUCTION
In the world the consumption of the raw materials did not cease growing. The rich countries would carry out some such as iron, the copper for which the exploitations must significant, be very mechanized and to produce in very great quantities to be profitable. The choice of mechanization has a direct incidence on the costs and the outputs. The objective of very undertaken is to ensure an optimal exploitation of its resources taking account of their various design features, economic and human [1].
One cannot speak about drilling without considering the properties physico rock mechanics to be cut down and the methods of their determination. Some are the conditions of operating have open sky or in the underground mines, drilling can be carried out by various machines, that we can join together in two large groups: hammer drills and the drills [2].
Drillability studies are mainly based on the empirical approach. There are different ways to define rock drillability. The concept of specific energy was proposed by Teale [3], Miller [4] and Pathinkar and Misra [5] as a guide to assess rock drillability. Rabia [6] stated that specific energy in terms of either unit volume or new surface area is not a fundamental intrinsic property of rock.
Percussive drilling is used extensively in mining and construction as a means for making holes in rock. Usually, the rock drill,containing a reciprocating hammer, is placed outside the hole, The percussive drilling mode is very widespread when mining ore deposits [7].  [8].
The appearance of the first perforator dating from 1839 made it possible to dig a well 20 m deep. In 1857, the French engineer Somelier modified a steam engine in a drilling machine which operates with the aid of compressed air. The great productivity achieved by perforators accelerated their improvement; towards the 1880s the hammer drill had almost the same pace as the current hammers.   IV.

CLASSIFICATION OF PNEUMATIC HAMMER DRILL
The classification of the mining machines is carried out according to energy used, the type of travelling gear, the weight and characteristics of construction. One meets part of this classification in the contents of this work, which is devoted to the study of the machines of drilling.The hammer drills or punching are intended for the drilling of the blast holes in the very hard, hard and average formations. One often uses them in the underground mines, the exploitations with open sky and the field of construction.The use of the pneumatic punchers is very widespread in mining work, considering the advantages which they have, such as: the simplicity of construction in comparison to the other types, an output raised enough and a safety during operation. V.

CONSTRUCTION OF PNEUMATIC HAMMER DRILL
The pneumatic puncher is a percussion machine made up of a cylinder, of a ratchet wheel, a device of distribution of compressed air, of a piston, of a casing, a helicoids stem and a chuck. The compressed air inlet is carried out through the ratchet wheel and the distributor of compressed air. The displacement of the piston of left on the right constitutes the working stroke and is carried out using the pressure of compressed air. The cylinder being separated by the piston in two rooms, one under pressure (left room), the other in depression (right room) that during drilling; at the time of the empty run, the role of the two rooms is reversed. The compressed air which penetrates in the right room is distributed using the mechanism of distribution. The piston starts to move at the end of its race, it strikes the hafting of the foil without any rotation because the head of the helical rod turns freely in the ratchet wheel. During the empty run of the piston, the head of the helical rod and fixed in the ratchet wheel by the pawls; the piston turns of a certain angle while being screwed to the helical rod, this rotation of the piston is transmitted to the foil through the casing with grooves and the revolving casing.
The ordering of the pneumatic puncher is ensured by a lever four positions: -blowing of the hole ; -stop; -Operation on average power; -Operation into full power; The greasing is ensured by an automatic greasing device assembled on the body of the hammer.

VI.
THE BASIC PARAMETERS OF THE PNEUMATIC PERFORATOR It is supposed that the pressure of compressed air in the rooms of the cylinder at the entry and during its exhaust is constant.
The basic parameters of the puncher are as follows: The useful surface area of the piston to carry out the way outward journey in (m²) is : And for the way return: The force applied to the piston during the way outward journey in (kgf) is equal to: And during the way return:

B. Determination maximum speeds of the piston
To simplify the determination speeds we admit that the movement of the piston to the opening of the exhaust port (under the action of the force Fa is uniformly accelerated. This is why the maximum speed of the piston at the distance l1 in (m/s) is determined by: .And that, at the distance l2 during the way return: According to formulas' (5) and (7), the speed of the piston during the way outward journey will be equal to: Then, according to formulas' (13) and (7) we can have : At the distance l3 the piston moves by inertia, this is why:

VII. CHOICE OF THE RATIONAL OPERATING MODE OF THE PERCUSSIVE DRILLING MACHINE
During the choice of the punchers, the principal question which worries us was always the productivity that the puncher under the well defined conditions can ensure, but this factor remains related to the operation of the machine, which in its turn depends on the properties of the rock, of the type of the tool and the parameters of the puncher without neglecting the factors which can have an influence on the choice of the operation, such as: maximum power, rate of advance maximum which can ensure the puncher, the height of penetration of the tool at the time of the destruction of the rock according to parameters' of the tool and the torque [14].

A. Height of penetration of the trepan
The height of penetration is a function of the energy of a blow of the piston:    V r (m/s)

5.20
The results of the experimental study carried out in the quarry conditions of fila fila: We apply the Matlab software to the results of the experimental study, we obtain: The curve ( ) Note that the variation in drilling speed increases as the penetration height increases. So the relationship is proportional.
The results obtained from the productivity of the perforator as a function of the drilling speed under the conditions of the filfila quarry represent in the following tables.   We apply the Matlab software to the results of the experimental study, we obtain: Curves: ( )  Note that the productivity of the pneumatic perforator increases as the drilling speed increases to improve the work organization. The productivity of the pneumatic perforator depends primarily on the parameters of the drilling regime because the latter determines the value of the drilling speed.the study of the curves presented leads to a recommendation on improving work organization, which gives us the opportunity to increase the operating productivity of the pneumatic puncher.
The following table shows the costs of the machine:  We apply the Matlab software to the results of the experimental study, we obtain: X. CONCLUSION In the experimental part, we studied the influence of the drill hole measurements on the drilling speed. Knowing that the setting parameters considerably influence the output parameters; the factors studied represent the values of the variables in the field at which the drilling process begins with the aim of obtaining the optimal values of these factors. The factors studied (number of blows of the piston, the energy of a blow of piston represent variables that is to say during the experimental drilling, we can give them determined values.
The productivity of the perforator depends on the parameters of the drilling regime. The graphical comparison of the results obtained theoretically with those obtained experimentally showed that the method closest to the actual results is that the theory of destruction of the rock.
As a result of the research carried out, it has been concluded that in the quarry conditions using the defined drilling means it is preferable to use the price criterion of one meter of drilled hole to determine the regime parameters of rational operation.