Plastic and nonmetallic article shaping or treating: processes – With measuring – testing – or inspecting – Positioning of a mold part to form a cavity or controlling...
Reexamination Certificate
1999-06-01
2001-07-10
Heitbrink, Tim (Department: 1722)
Plastic and nonmetallic article shaping or treating: processes
With measuring, testing, or inspecting
Positioning of a mold part to form a cavity or controlling...
C264S040700, C425S145000, C425S149000, C425S150000
Reexamination Certificate
active
06258303
ABSTRACT:
This application is based on Japanese Patent Application No. 10-184011 filed Jun. 30, 1998, the content of which is incorporated hereinto by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to techniques for monitoring and controlling an operation of an injection molding machine for producing a disc substrate, to improve the consistency in the quality of the produced disc substrate. More particularly, the present invention is concerned with an apparatus and a method of monitoring such an injection molding machine, which include a device for or step of displaying operation data of the machine, and a control apparatus for controlling the machine by using such a monitoring apparatus.
2. Discussion of the Related Art
Generally, a disc substrate used for molding an optical or magneto-optical disc is advantageously produced by injection molding using a resin material. Such a disc substrate is required to have a high degree of dimensional accuracy and excellent physical properties. To meet this requirement, an operation of an injection molding machine adapted to mold the disc substrate is required to be controlled with high accuracy and stability. To control the operation of the injection molding machine, it is considered to monitor its operating condition, by detecting an injection speed, an injection pressure, an operating position of an injection screw and other operating parameters, with suitable sensors or detectors. Operation data of the machine represented by the output signals of these sensors are stored in a memory, and are displayed on a suitable display device such as an oscilloscope.
JP-A-7-205245 (publication of an unexamined Japanese patent application) discloses a data analyzing apparatus including a microcomputer which is adapted to: process the output signals of various sensors provided on an injection molding machine; store operation data of the machine based on the output signals for each cycle of injection molding to produce a disc substrate; analyze the stored operation data; and display the stored operation data on a display device, together with numerical values obtained as a result of the analysis.
Such a known data analyzing apparatus is adapted to simply display the operation data, which are continuously varying during an injection molding operation of the machine. Therefore, the user or operator of the machine who observes the display device has difficulty to accurately estimate or recognize an influence of the present operating condition of the machine on the quality of the injection molded product. The machine operator is required to have long experience and intensive and extensive professional knowledge in order to monitor the operating condition of the machine based on the operation data provided on the display device. Thus, the known data analyzing apparatus does not assure a high degree of consistency in the quality of the product.
The above-identified publication also discloses a technique for displaying maximum and minimum values, rise and fall times and other numerical values of various operating parameters of the machine, which have been obtained by analyzing the stored operation data. However, those numerical values displayed are also operating parameter values which are continuously varying from time to time and which do not enable the machine operator or user to accurately monitor the operating condition of the machine.
Further, the known data analyzing or monitoring apparatus is arranged to store and analyze operation data obtained by the sensors and analyze the obtained operation data for each injection molding cycle or shot, and display a result of the analysis on the display device in the next injection molding cycle or cycles. Actually, however, this arrangement does not permit a prompt manipulation to adjust the operating condition of the machine based on the displayed data, during a series of injection molding cycles. Thus, the known apparatus suffers from a delayed feedback of the operation data to adequately control the injection molding operation.
SUMMARY OF THE INVENTION
It is a first object of the present invention to provide a monitoring apparatus which permits easy and accurate monitoring of an operating condition of an injection molding machine and the quality of a disc substrate molded by the machine.
A second object of this invention is to provide a control apparatus capable of controlling the injection molding machine with high accuracy, so as to maintain an optimum operating condition of the machine with high stability.
A third object of the invention is to provide a monitoring method which permits easy and accurate monitoring of the operating condition of the injection molding machine and the quality of the disc substrate molded by the machine.
A fourth object of the invention is to provide a recording medium which is accessible by a computer and which stores a control program to be executed by the computer to suitably practice the monitoring method indicated above.
The first object indicated above may be achieved according to a first aspect of this invention, which provides an apparatus for monitoring an operating condition of an injection molding machine adapted to mold a disc substrate by injection molding, the injection molding machine including a mold device having a stationary and a movable mold half which cooperate to define a mold cavity to be filled with a material to mold the disc substrate, and a sprue gate through which the material is injected into the mold cavity, the injection molding machine further including an injecting screw for injecting the material into the mold cavity through the sprue gate, the monitoring apparatus comprising a display device for displaying operation data relating to an operation of the machine, the monitoring apparatus further comprising: (a) first display control means operable on the basis of output signals of sensors provided on the injection molding machine, for controlling the display device to simultaneously or selectively display, as the operation data, waveforms of a plurality of operating parameters including at least four operating parameters selected from a group consisting of a speed of injection of the material into the mold cavity, a pressure of injection of the material into the mold cavity, a clamping pressure of the mold device, an amount of backward movement of the movable mold half, and a position of the injecting screw, the waveforms representing chronological changes of values of the above-indicated plurality of operating parameters, respectively; and (b) second display control means for controlling the display device to indicate a first point of time at which the sprue gate is closed, such that the first point of time is indicated together with the waveforms of the above-indicated plurality of operating parameters as displayed under the control of the first display control means.
In the monitoring apparatus constructed according to the first aspect of this invention, at least four operating parameters of the injection molding machine whose values vary with time are selected from among (1) the material injection speed, (2) the material injection pressure, (3) the mold clamping force, (4) the amount of backward movement of the movable mold half, and (5) the position of the injecting screw. These at least four operating parameters are detected on the basis of the output signals of the respective sensors. Based on these output signals, the first display control means is operated to control the display device to display at least the waveforms of the selected at least four operating parameters as respective continuous lines in a rectangular coordinate system wherein the values of the operating parameters are taken along one of two mutually perpendicular axes, while the time is taken along the other axis. The waveforms of all of the plurality of operating parameters may always be displayed simultaneously. Alternatively, the waveforms may be selectively displayed sequentially. For instance, the waveforms may be d
Hibi Kouzou
Seki Mitsunori
Burr & Brown
Heitbrink Tim
Kabushiki Kaisha Meiki Seisakusho
Luk Emmanuel
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