Leader of work: d. t. s. prof. Ìalyshko I. A.

INTRODUCTION

Main indexes which determine products competitiveness are high consumer properties and low cost. High quality of new products and possibility to produce it rapidly are provided by multi-operational machine-tools and flexible production systems. However high price of equipment results into the growth of products cost, and accordingly makes them incompatible. At while processing details on automatic transfer lines with fixed connection, especially when there are a plenty of equipment built into a line, the reliability of equipment reduces and a unit cost increases.

The most effective way of unit cost reduction is a concentration of transitions due to the use of the axial combined instrument.

Combined instrument can be used for processing both step and smooth cylinder openings, which are 35% of all the surfaces which are utilized in a machine building. The prime price reduction of openings processing is achieved due to the use of combined instrument with optimum structural parameters.

Theory of combined instrument design, was developed methodology of which is directed to increase to productivity of the technological system. The basis of a model of a combined instrument design is the equation equalization of productivity. Value of structural parameters and workings processes, which make a design model, is determined from the terms of most productivity of technological system and set exactness of processing.

1.COMBINED INSTRUMENT – AS A WAY TO INCREASE THE EFFICIENCY OF THE AUTOMATED PRODUCTION

1.1 Places of combined instrument application

In the conditions of the automated production, especially flexible, one there is an increase of unit cost. It is possible to increase the efficiency of the automated production by concentrating of operations or transitions. However at the high degree of concentration of operations the complication of equipment is increased, and its reliability diminishes, and accordingly, outages increase and a unit cost grows. The concentration of transitions increases complication of instrument, and equipment becomes simpler. The amount of refuses, related to the instrument (breakages, baling of shaving) thus increases, and time on adjusting of instrument diminishes.

Compatibility of operations or transitions depends on necessary exactness of processing and roughness of surface. The accepted procedure of operations implementation and transitions determines the type of instrument, necessary for their realization.

Most efficiency of operations or transitions concentration is achieved at due to the using combined instrument.

The widest class of surfaces which are utilized in a machine building are surfaces of rotation. They are more than 70% of all the surfaces which are utilized in a machine building. Openings occupy near 50% of the general amount of all the surfaces. Openings which can be processed using combined instrument account for 90%.

It is necessary to point out, that on multi-operational machine-tools and automatic transfer lines, cabinet-type details are mostly processed, where openings account for 75% from all the processed openings.

Thus, openings which can be treated axial KI make to 35% from all of the processed openings which are utilized in an engineer.

Axial combined instrument is made on the base of drills, spot facers, involutes, markers or their combinations.

The use combined instrument provides the followings advantages:
- basic technological time, and also auxiliary time, is abbreviated, related to approach and taking of instrument, time, expended in his replacement and adjusting, and accordingly, rises both technological and cyclic productivity;
- the amount of technological equipment diminishes, what the use of electric power diminishes due to, floor spaces are abbreviated, the amount of basic and auxiliary workers diminishes, reliability of work of automatic transfer lines rises, and accordingly, an unit cost goes down;
- coincidence of axes rises and exactness of location of butt-end surfaces, processed openings.

The high degree of concentration of cuttings edges in combined instrument provides cutting away of plenty of metal. And it, in same queue, increases the concentration of forces and cutting temperature on the dutiful of instrument which worsens the terms of his work.

Increase of amount of metal, worsens his location and transporting for to the bit ditches, and it in end-point can result in baling of shaving. Baling of shaving can take a place also at presence of ledges on the surfaces of bit ditches. It is observed at a wide difference between the diameters of degrees of instrument. Baling of shaving results in the increase of forces of friction, and accordingly, and temperatures. Growth of forces of friction results in the increase of laying out of opening and roughness of surface, and sometimes and to the fracture of instrument. Growth of temperature increases tearing down of instrument. Taking into account that the concentration of cuttings edges increases a cutting temperature, period of firmness combined instrument can be considerably less than, than at one-dimensional instruments.

Growth of forces cutting, related to the concentration of cuttings edges, also results in laying out of opening. Besides the change of total size of cutting forces, characteristic for the combined chart cutting, results in the error of the longitudinal a cut opening. It is necessary to point out that disadvantages of combined instrument are inherent mostly to the one-dimensional instrument. Taking into account much self-reactance character of influences of workings processes in combined instrument, disadvantages that are inherent to one-dimensional instrument, during work of combined instrument become more evident.

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