Simple design and high technical and operational features of single-screw pumps are attracting attention of many enterprises which take into consideration market demand for oil field and accessory equipment. Also, the merits of such pumps are possible application lbr pumping contaminated and viscous fluids, absence of dead space, and speedy dismantling for complete cleaning of all parts of the pump from residues of the pumped product.Small-lot production of parts of such pumps in nonspecialized situations is difficult to organize because of the difficulty in making one of the key parts, namely, the rotor: first, it is necessary to solve the technical problems relating to selection of appropriate schemes and conditions of machining, and, second, to ensure higher efficiency and proper use of the versatile equipment.Rotor of a single-screw pump has a spatially intricate screw surface. The working part of the rotor generally consists of a large number of disks of increasingly smaller thickness whose centers lie on the screw (helical) line of a given lead [1, 2]. Any section of the rotor perpendicular to the axis is a circle of a constant diameter with its center shifted relative to rotor axis by a design-assigned eccentricity.At present, the working part of the rotor of a single-screw pump is shaped as follows: -by form tools;-by straight-turning tools with creation of kinematics of shaping by a scheme of "enveloping" turning; -by straight-turning tools on digitally (numerically) controlled machines with programming of the profile in the longitudinal and transverse directions;-by milling with hob cutters applying the method of spinning on slot-cutting (gear-milling) machines; and -by line (horizontal) milling on machines having a digital program control. Of the above-listed methods, for small-lot production worthy of special attention is machining by the enveloping turning scheme (Fig. 1) whose distinctive features are high efficiency, kinematic precision of reproduction of the profile, satisfactory quality of the machined surface, possibility of regulating operation conditions, and achievable precision level. In order to realize this scheme, use may be made of such available technological equipment as screw-cutting, backing-off, thread-milling, slot-milling, and gear-milling machines.This method is known as "vortical" (planetary) turning [1, 2] (by comparison with a similar scheme of thread shaping). However, it must be noted that use of such a term for rotor machining gives a distorted notion about the nature of the machining process.The essential difference between the "vortical" turning method and the method of turning in machining of rotor of single-screw pump is the difference in the nature of functioning of the tool.In the first case, the diameter of the circle of motion of the cutter tips (noses) is roughly 1.6 times larger than the diameter of the circumference of the work surface. As a result, the cutters remain in contact with the work surface only for a short time and perform no cutting function over the ...

No abstract