High-precision method for controlling uniformity of discharging of extruder

Abstract

The invention discloses a high-precision method for controlling the uniformity of discharging of an extruder. The method comprises the following steps: inputting a grammage parameter of a product in a storage of a controller, utilizing the controller to collect and store the rotating speed of the screw of the extruder and the flow amount A of the raw materials in unit time metered by a weighing device at the last time; calculating the discharging amount B every time the screw of the extruder rotates for a circle based on the flow amount A of the raw materials in unit time, and utilizing the controller to adjust the rotating speed of a pull roll at any time according to the change of the B so as to meet the grammage parameter of the product. The method disclosed by the invention has the advantage of calculating the corresponding discharging amount every time the screw of the extruder rotates for a circle by using calculated weight (parameter A) of the raw materials entering the extruder in unit time in the prior art, thereby adjusting the rotating speed of the pull roll of the discharging port of the extruder; and when the discharging amount every time the screw of the extruder rotates for a circle has a certain deviation, the controller can adjust the rotating speed of the pull roll, thereby greatly improving the control precision which can be improved by one order of magnitude.

Description

technical field [0001] The invention relates to a high-precision control method for improving the discharge uniformity of an extruder, which is mainly used for plastic extruders and other extruders with similar working principles. Background technique [0002] The uniformity (number of grams per meter, commonly known as meter weight) control of the output (such as film, wire, cable, plastic pipe, silk thread, etc.) of the existing extruder (such as plastic extruder) is mainly adopted by weighing The weight of the raw material entering the extruder per unit time measured by the measuring device (hereinafter referred to as the A parameter) controls the speed of the discharge traction roller at the exit of the extruder. When the A parameter increases beyond a certain level, the controller increases the traction roller accordingly. speed, and vice versa. The disadvantage of this control method is: because the weighing device measures A parameter, it needs to collect a certain t...

AI Technical Summary

Problems solved by technology

The disadvantage of this control method is: because the weighing device measures A parameter, it needs to collect a certain time interval Δt and the weight W of raw materials entering the extruder within this time interval, A parameter=W / △t

The controller can calculate the A parameter at least once to adjust the speed of the traction roller accordingly. It can be seen that the control accuracy of this control method is very low, resulting in a high scrap rate

[0003] In addition, the existing extruder is blocked due to the impurities in the raw materials (especially recycled raw materials) or the impurities generated by the long-term high temperature, which affects the uniformity of the product and leads to a decrease in output

[0004] In the prior art, the long-term wear and tear of the extruder screw will also reduce the extrusion volume per cycle of the extruder screw, thus affecting the uniformity and output of the product

The controller cannot memorize the current (A parameter) data due to power failure due to various reasons, and needs to be tested again to operate normally, which also affects production efficiency

[0005] In addition, in the prior art, when the output decreases, it cannot be found in time, so the production efficiency will also be reduced

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