Writing interrelated programs for the MK-56 calculator

Abstract

Despite the limited number of commands available (up to 98), the MK-56 calculator can be used to perform complex calculations requiring a large number of commands. This is accomplished by writing several interrelated programs so that data obtained from one program is inserted into the next programs and so forth, until all of the necessary parameters are obtained. Here, no intermediate entries are necessary all o f the operations reduce to the completion of a single table. Described below is an example of writing interrelated programs to design the rolls for a multistand mill which is to produce rectangular tubes. To obtain such tubes, the initial circular tube is shaped in several four-high stands with individual drives. In the example we will use, the calculations will be limited to determination of the dimensions of the tube in each stand (Fig. I and Table 1). The initial data for the calculations is as follows: number of stands n, wall thickness S, radius of curvature of the finished shape r c, dimensions of the sides of the tube A and B, diameters of the rolls D ~' and D b. During the shaping of a circular tube into a rectangular tube, the perimeter of the tube is reduced. This reduction can be determined from the empirical formula (3). The radius of curvature of the tube in each stand is calculated from the condition of a uniform load distribution on all of the stands. Here, it is assumed that the work done in shaping the polygonal tube is directly proportional to the logarithm of the ratio of the mean radii (over the neutral layer) of curvature of the tube in two adjacent stands (Eqs. (7)-(9) in Table 1). In rolling a circular tube into a rectangular tube in plane rolls, deflection of the inside surfaces of the tube is unavoidable. To circumvent this problem, the working part of the roll body should be made concave. The critical radius of concavity (when there should theoretically be no convexity or sagging of the surfaces) can be determined from empirical formula (10)i To guarantee the absence of such deflection, this radius is decreased by a factor of 1.2 for the last stand. The radii for the other stands are determined from the condition of a constant ratio of the radii of the adjacent stands, beginning with the circular tube. The formulas were divided into three groups and were used as the basis for writing three interrelated programs. The arrows in Table 2, with the number of the program at the beginning, indicate which initial data is necessary for the given program. The numbers under the parameters indicate the program used to determine them. There is yet one more innovation. The calculator indicates the method to be^Ssed (PP or BT) to enter data. When the display reads "0," it is necessary to use the method BT. When the display reads "88", the method PP must be employed. Also, when the second method is used, it is not necessary to press the key PP after the last parameter. Thus, a single rule can be formulated: press S/P after the last parameter when entering the initial data.