SU1323412A1 - Press unit - Google Patents

Description

   one

The invention relates to mechanical engineering, in particular to the design of equipment for metal forming.

A press unit is known that contains a press with a not full weight; The organisa- tion is the sensors of the speed of pressing and the temperature of the workpiece and tool, as well as control systems.

In this system, the pressing mode does not take into account the deviations of the mechanical properties in separate batches of blanks and the processing parameters that change during the pressing process. The consequence of this is the low quality of the billets subjected to quenching under isothermal pressing conditions and insufficient reliability of the plant operation.

Improving the reliability and quality of products is achieved by the fact that the press unit containing a press with actuators, pressing speed and temperature sensors of the workpiece and tool, as well as a control system is equipped with an electric heating device installed at the press outlet with temperature sensors at its entrance and exit. performed in the form of modular modeling, adaptation and determination of the mechanical properties of the workpieces connected with melodies, as well as control units We have a press and an electric heating device, while the temperature sensors at the inlet and outlet of the press and the speed sensors are connected to the blocks of modeling, adaptation and determining the mechanical properties of the workpieces, and the TeNsnepaTypM sensors, at the input and output of the electric heating device, with the control unit of these devices, and the outputs the control unit of the executive bodies of the press is connected to these bodies, and its input is connected to the output of the modeling unit "

Figure 1 presents the block diagram of the installation; Fig. 2 is a graph of the variation in the speed of pressing; In FIG. 3, the dependence of the temperature of the workpiece at the exit of the press during processing.

The press set contains press 1 with a sensor for 2 press speeds of ani, temperature sensors and for

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five

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the inlet 3 and the outlet 4 of the press are the executive bodies 5, the electric heating device 6 with temperature sensors and at its input, and the output 8. the quenching device 9 and the control system 10, which consists of the electric heating device control unit 11, the adaptation unit 12, unit 13 modeling, and a unit 14 for determining the mechanical properties of the pressed blanks, as well as a unit 15 for controlling the executive bodies of the press. The electric heater control unit 11 has four inputs, two of which are connected to temperature sensors 7 and 8 at the electric heater input and output, the other two are connected to the pressing speed sensor 2 and to the output of the modeling unit 13, and the output is connected to electric heating device 6, Adaptation unit 12 has four inputs connected to sensors 3 and 4 at the inlet and outlet of the press, press speed sensor 2 and the output of modeling unit 13, and the output is connected to one of the inputs of model 13 The four other inputs of which are connected with sensors 3 and 4 of the inlet and outlet of the press, with the sensor 2 of the pressing speed and with the output of the block 14 for determining the mechanical properties of the workpieces, and four outputs are connected with the inputs of the control units with an electric heating device 11, adaptation 12 , controlling the executive bodies of the press 15 and the block 14 for determining the mechanical properties of the pressed blanks, the other three inputs of which are connected to the sensors 3 and 4 of the inlet and outlet temperatures of the press and the sensor 2 of the pressing speed. od coupled to the input of block 13 simulation. The control unit 15 of the executive bodies of the press has two entrances connected with the modeling unit 13 with the position sensor of the executive bodies of the press 5, and the output is connected with the executive bodies: the bodies of the press 5. I

Press Setting Control

performed as follows.

First, by the known average values of the mechanical properties of the pressed blanks (the actual mechanical properties, however, have a significant variation around their average sign

for the difference from one batch of blanks to another) determine the basic law of variation of the speed of pressing over time (the basic model of the pressing process), which has the form (Fig.2)

V (t) V, -h

(V, -V) exp (At), (l)

where V (t) is variable in time t

pressing speed; V), respectively, the initial speed of pressing and at the stationary stage of the process;

(L) is a variable parameter depending on the value of the mechanical properties of Cd of the pressed blanks (type of function I is determined experimentally or by calculation).

Before pressing each batch of blanks belonging to one heat, 5-6 blanks are taken from it and they are experimentally pressed. During the experimental pressing process, the actual mechanical properties of the molded batch of blanks are determined based on the results of measuring the temperature of the press product at the press outlet (inside the batch mechanical properties vary slightly). The determination of the actual mechanical properties of each batch of blanks is made using a formula relating the temperature of the press product at the exit of the press with the main technological parameters of the extrusion and the mechanical properties of the billet, which has the form (Fig. 3)

0 (t) 0.t- ®st -b.) Exp (- fit), (2)

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de 9t is the temperature of the press product at any moment of pressing f,

- billet temperature,

- temperature of the press product

b. 9

st

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at the stationary stage of the extrusion process, which coincides with the temperature 0 (t) at t i 1, 5-2 min,

(tg is a variable parameter hanging from the mechanical properties of the workpiece c (the form of the function 9 determined 55

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are experienced or calculated by)

The values of the mechanical properties of the blanks Tg obtained from expression (2) are substituted in the expression (1) and thus the model of the pressing process is adjusted (the control systems are adapted to the mechanical properties of the pressed blanks that vary from batch to batch).

Signals on the change in the speed of pressing go to the control unit 14 of the executive bodies of the press, which controls the magnitude of the opening of the throttle valve of the executive bodies of the press as follows

lb (v, rr) uV, (3)

where b is the throttle movement

dampers;

uV is the magnitude of the change in the speed of pressing; DR is the pressure drop in the supply line in the working cylinder of the press;

V is the value of the pressing speed at a given time;

{(V, uP) is a function whose type is determined experimentally.

I

After adapting the process model

Pressing (according to the results of determining the actual mechanical properties of the pressed blanks - investigation of the external environment) in the process of pressing the blanks remaining in this batch, additional heating of the press products at the press outlet to the hardening temperature, which always exceeds the press product the output of the press and cannot be achieved only by changing the speed of pressing. Additional heating is carried out in the electric heating device 6, which, along with heating, allows for the creation of back pressure during the pressing process, which also has a favorable effect on the quality of the press products, in connection with the improvement of the stress state of the pressed material. The amount of additional heating is determined by the difference in temperature of the press-product of the 13 LIA at the input of the electric heating device 6 and the temperature required. DIMA for hardening products. In this case, the control of the amount of additional heating is carried out simultaneously (consistently) with the temperature adjustment of the press product by changing the pressing speed. The hardening of the press products is carried out in a quenching device 9 installed at the outlet of the electric heating device 6.

The control system operates as follows.

The modeling unit 13, in conjunction with the control unit 15, controls the executive bodies of the press, receiving from sensors 3.4 and 2 data on the temperature of the workpiece and the press product, as well as the speed of pressing and the position of the executive bodies 5 of the press, according to (2) and ( 3), the temperature control of the press product by changing the speed of pressing effects on

Complementary organs of the press. The control unit 11 of the electric heating device 6, having data from the sensors 2j7 and 8 on the pressing speed and the temperature of the press products at the input and output of the electric heating device 6, controls. additional heating of the press products to the quenching temperature (the second step of controlling the temperature of the press product). In this case, the control unit 11 of the electric heating device communicates with the pressing simulation unit 13, receiving signals from it about a change in the pressing speed. Such a connection enhances the quality and reliability of control, as it provides the possibility of foreseeing a change in speed.

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pressing and, in addition, duplicates the work of the sensor 2 pressing speed in case of its failure. Adaptation unit 12, having from sensors 3,4 and 2 data on the temperature of the workpiece and a press product and press speed, as well as data on the actual mechanical properties of the blanks from block 14, determining the mechanical properties of the pressed blanks, corrects the modeling block 13 ( the law of change in the speed of pressing) (1) according to the formula (2), the operation of the adaptation block 12 and the block 14 for determining the mechanical properties of the pressed blanks allows you to build a flexible control system capable of adapting to changes in the mechanical their properties of different batches of blanks.

Such a press plant control system permits the implementation of coordinated two-step temperature control of the press products in a narrow temperature range (not exceeding 10-15 ° C) necessary for tempering products directly on the press table. The two-stage temperature control of the press products is achieved by adjusting the pressing speed over time, the law of which is determined by the level of mechanical properties of the pressed blanks, as well as by additional heating to the hardening temperature in an electric heating device, the value of which depends on the pressing speed and temperature of the product the press.

The efficiency of using a press unit is determined by the increase in the quality of products and its reliability.

st

VNIIPI Order 2918/21

Random polygons pr-tie, Uzhgorod, st. Project, 4

Circulation 56A Subscription

Claims (1)

PRESS INSTALLATION, which contains a press with executive bodies, sensors for pressing speed and temperature of the workpiece and tool, as well as a control system, characterized in that, in order to increase its reliability and product quality, it is equipped with an electric heating device installed at the press outlet with temperature sensors at its inlet and outlet, and the control system is made in the form of interconnected blocks of modeling, adaptation and determination of the mechanical properties of the workpieces, as well as control units the press and electric heating device, while the temperature sensors at the inlet and outlet of the press and the speed sensors are connected to blocks for modeling, adapting and determining the mechanical properties of the workpieces, and the temperature sensors at the inlet and outlet of the electric heating device are connected to the control unit g device, and the outputs of the control unit of the executive bodies of the press are connected to these bodies, and its input is connected to the output of the modeling unit. SU, „, 1323412