JPH0451491B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for monitoring a glass molding process, which is mainly applied to a press-blow type glass bottle molding machine.

(Conventional technology) Conventionally, in a glass bottle molding factory, all molded glass bottles are passed through a slow cooling furnace, and the bottles are inspected at the outlet side (cold end) to understand the occurrence of defects, and this information is sent to the molding machine. side (hot end)
An operating system is adopted in which the molding machine is controlled by feedback to the operator. However, in this conventional method, abnormalities in the molding process cannot be detected for several tens of minutes while the glass bottle passes through the slow cooling furnace, and a large number of defective products are produced during that time. Therefore, in recent years, efforts have been made to discover abnormalities in the molding process at hot ends, and some results have already been published.

Generally, the most easily discovered abnormality in the molding process at hot ends is an abnormality in glass weight (gob weight). Therefore, a method of measuring the weight of a glass bottle immediately after molding and automatically controlling the tube height of a glass feeder according to the measured value has been proposed for several decades. Recently, as shown in Japanese Patent Publication No. 59-43426, a sensor has been incorporated into the glass forming machine to detect, for example, the maximum stroke when the plunger plunges into the glass inside the rough mold, and thereby reduce the gob weight. Devices designed to detect fluctuations have also been proposed. However, this device can only detect abnormalities in gob weight, and cannot detect other abnormalities in the molding process.

(Problems to be Solved by the Invention) The present invention improves the current state of the art and makes it possible to immediately know at the hot end not only changes in gob weight but also other abnormalities that may occur during the press-blow molding process. It was completed for the purpose of monitoring the glass forming process.

(Means for Solving the Problems) The present invention uses a sensor rod in which a magnetic scale is embedded in the piston rod of the plunger mechanism of a glass molding machine, and a sensor head is attached to the cylinder side to continuously detect the vertical position of the plunger. The operating curve is compared with the operating curve during normal operation, and when a deviation of more than a predetermined value occurs, a defect signal is generated.

The present invention will be explained in more detail below with reference to illustrated embodiments. FIG. 1 is a sectional view of the plunger mechanism, where 1 is a cylinder, 2 is a piston, and 3 is a sectional view of a plunger mechanism.
is a piston rod, 4 is a cylinder head, 5 is a plunger attached to the upper end of the piston rod 3, 6 is an upper cylinder head that guides the plunger 5, 7 is a mouth mold that is brought into close contact with the upper surface of this upper cylinder head during molding; 8 is a rough mold for parison molding. In the present invention, the piston rod 3 is a sensor rod in which magnetic scales are embedded at a constant pitch, and a sensor head 9 is attached to the cylinder side to continuously detect the vertical position of the plunger. As the sensor head 9, an electromagnetic induction type head is used, which has a primary coil that is excited by alternating current with high frequency and a secondary coil that takes out the output voltage generated by electromagnetic induction.This output voltage is caused by the magnetic flux of the magnetic scale. The vertical position of the piston rod 3 and plunger 5 can be measured over a long range and with high accuracy on the order of μm by utilizing the fact that the magnetic scale changes in accordance with the amount of movement.

2 to 5 show operating curves of the plunger detected by such means, and the solid line indicates the operating curve during normal operation. When the plunger lowering air is turned off, the plunger 5
moves up to the loading position to receive the gob into the rough mold 8, and then when the plunger raising air is turned on, the plunger 5 moves up to form a parison. After that, the plunger raising air is turned off,
When the plunger lowering air is turned on, the plunger 5 is lowered to the lowest position and the parison is transferred to the finishing mold. Further, when no gob is supplied into the rough mold 8, the plunger 5 rises without being subjected to resistance, so that an operating curve as shown by the broken line in FIG. 2 is obtained. However, if an operating curve like the one shown by the dashed line is detected, it means that an abnormality has occurred, such as the capacity of the rough mold 8 is inaccurate or the gob weight has fluctuated. Therefore, if a deviation of more than a predetermined value occurs compared to the operating curve during normal operation, a defect signal is issued. However, the above content does not go beyond the prior art in which only the maximum stroke of the plunger was detected, and the advantages of the present invention become more clear in the case of FIGS. 3 to 5.

That is, if a momentary stop occurs during the upward movement of the plunger 5 from the loading position as shown in FIG. It can be seen that this caused a catch and prevented the plunger 5 from rising smoothly. Since such troubles cause defects such as wrinkles on the inner surface of the parison, a defect signal is issued when such a phenomenon is discovered. Further, as shown in FIG. 4, when the upward curve of the plunger 5 is gentler than the operating curve during normal operation, it can be seen that the friction of the plunger mechanism is large and the movement is slow. In this case, since the parison is formed slowly, the parison is formed with a gob that is colder than normal, which is likely to cause cracks. Further, as shown in FIG. 5, when the downward curve of the plunger 5 swells outward, it can be seen that the plunger 5 is experiencing some resistance when descending. In this case, molding defects are likely to occur due to excessive cooling of the inner surface of the parison.

Such malfunctions of the plunger 5 shown in Figs. 3 to 5 were completely undiscovered by the conventional technology, which only detected its maximum stroke. In order to find out what would work, we had no choice but to rely on the intuition of experienced workers. In contrast, according to the present invention, by comparing the operating curve of the plunger mechanism with the operating curve during normal operation,
Plunger malfunctions, which are the cause of many defects, can be detected easily and in real time, and defects can be eliminated from the line before the glass bottles formed through the forming process enter the lehr. Not only can the rate of bottle contamination be reduced, but it is also possible to immediately take measures to eliminate malfunctions.

(Effects of the Invention) As is clear from the above description, the present invention allows not only gob weight abnormalities but also many molding abnormalities that could not be detected at the hot end to be immediately detected at the hot end.
Since prompt action can be taken, the incidence of defective bottles can be reduced. Furthermore, since the present invention uses a sensor rod and a sensor head with embedded magnetic scales, the operating curve of a plunger mechanism with a large stroke can be known extremely accurately on the μm order, and even the slightest abnormality can be detected correctly. can. Therefore, the present invention greatly contributes to the development of industry as a method for monitoring glass molding processes that eliminates the problems of the conventional methods.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a plunger mechanism used in the present invention, and FIGS. 2 to 5 are graphs showing operating curves of the plunger under several abnormal conditions in comparison with operating curves under normal conditions. 3: Piston rod, 5: Plunger, 9: Sensor head.

Claims (1)

[Claims] 1 The piston rod of the plunger mechanism of a glass forming machine is a sensor rod with a magnetic scale embedded in it, and a sensor head is attached to the cylinder side to continuously detect the vertical position of the plunger, and its operating curve is compared to the operating curve during normal operation. A method for monitoring a glass forming process in which a failure signal is issued when a deviation of more than a predetermined value occurs in comparison.