Pressurizing control method and pressurizing control system for low-pressure casting
First Claim
1. In a low-pressure casting in which molten metal is introduced into a cavity of a casting mold under a pressure applied to the surface of the molten metal according to a preset reference pressurizing pattern,a pressurizing control method of controlling the pressure applied to the molten metal surface comprising the steps ofcorrecting said reference pressurizing pattern when that the cavity has been filled with molten metal is detected,controlling the pressure applied to the molten metal surface according to the reference pressurizing pattern after the correction,calculating the pressure difference between a set pressure at a predetermined time in the reference pressurizing pattern after the correction and a set pressure at the corresponding time in the reference pressurizing pattern before the correction, andcorrecting a set pressure for the period up to the time the cavity is filled with molten metal in the reference pressurizing pattern as a current reference pressure pattern for the next casting cycle on the basis of the calculated pressure difference.
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Accused Products
Abstract
In a low-pressure casting in which molten metal is introduced into a cavity of a casting mold under a pressure applied to the surface of the molten metal according to a preset reference pressurizing pattern, the reference pressurizing pattern is corrected when that the cavity has been filled with molten metal is detected and the pressure applied to the molten metal surface is controlled according to the reference pressurizing pattern after the correction. The pressure difference between a set pressure at a predetermined time in the reference pressurizing pattern after the correction and a set pressure at the corresponding time in the reference pressurizing pattern before the correction, is calculated and a set pressure for the period up to the time the cavity is filled with molten metal in the reference pressurizing pattern for the next casting cycle is corrected on the basis of the calculated pressure difference.
14 Citations
20 Claims
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1. In a low-pressure casting in which molten metal is introduced into a cavity of a casting mold under a pressure applied to the surface of the molten metal according to a preset reference pressurizing pattern,
a pressurizing control method of controlling the pressure applied to the molten metal surface comprising the steps of correcting said reference pressurizing pattern when that the cavity has been filled with molten metal is detected, controlling the pressure applied to the molten metal surface according to the reference pressurizing pattern after the correction, calculating the pressure difference between a set pressure at a predetermined time in the reference pressurizing pattern after the correction and a set pressure at the corresponding time in the reference pressurizing pattern before the correction, and correcting a set pressure for the period up to the time the cavity is filled with molten metal in the reference pressurizing pattern as a current reference pressure pattern for the next casting cycle on the basis of the calculated pressure difference.
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18. In a low-pressure casting in which molten metal is introduced into a cavity of a casting mold under a pressure applied to the surface of the molten metal according to a preset reference pressurizing pattern, said preset pressure reference pattern including
(i) a pre-pressurizing period starting from the beginning of the pressurizing process to a time when the molten metal is raised to a gate of the casting mold; -
(ii) a filling period starting from a time when the molten metal begins to be introduced into the cavity to a time when the molten metal has filled the cavity, the pressurizing rate for the pre-pressurizing period being greater than that for the filling period; (iii) a pressure increasing period starting from the time when the molten metal has filled the cavity to a time when the pressure is increased by a predetermined value from the pressure value at the time of starting this period, the pressurizing rate for this period being greater than that for the filling period; and (iv) a pressure holding period starting from the time when the pressure increasing period is finished, in this period the pressure is held at a constant level such that the molten metal is solidified; a pressurizing control method for controlling the pressure applied to the molten metal surface comprising the steps of; correcting said reference pressurizing pattern when that the cavity has been filled with molten metal is detected by a molten metal sensor, controlling the pressure applied to the molten metal surface according to the reference pressurizing pattern after the correction, calculating the pressure difference between a set pressure in the time section from the pressure increasing period through the pressure holding period in the reference pressurizing pattern after the correction and a set pressure at the corresponding time in the reference pressurizing pattern before the correction, and correcting a set pressure for the time section from the pre-pressurizing period through the filling period in the reference pressurizing as a current reference pressure pattern for the next casting cycle on a basis of the calculated pressure difference. - View Dependent Claims (19, 20)
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Specification