Plastic article or earthenware shaping or treating: apparatus – Control means responsive to or actuated by means sensing or... – Means responsive to abnormal condition completely stop...
Patent
1986-07-08
1987-12-01
Chiesa, Richard L.
Plastic article or earthenware shaping or treating: apparatus
Control means responsive to or actuated by means sensing or...
Means responsive to abnormal condition completely stop...
425137, 425138, 425150, 425589, B29C 4584
Patent
active
047101199
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to an injection molding machine and, more particularly, to an injection molding machine which uses a servo motor as a drive source for driving its clamp mechanism and in which a mold is prevented from being damaged.
Conventional injection molding machines use hydraulic pressure as a drive source for a clamp mechanism thereof. If foreign matter is present in the mold and the mold is clamped without removing the foreign matter, it may damage the mold. In order to prevent this, so-called mold protection has been conventionally performed, wherein the clamp mechanism is driven at a minimum hydraulic level, and when the mold is abutted against foreign matter upon this movement, it is prohibited from moving further, thereby protecting the mold.
SUMMARY OF THE INVENTION
It is the object of the present invention to allow the above mold protection even if the clamp mechanism of an injection molding machine is driven by a servo motor.
In order to achieve the above object, the injection molding machine of the present invention uses a servo motor as a drive source for driving a mold clamp mechanism which operates a mold, and comprises a position detector for detecting the position of the mold, and an NC control unit for controlling the servo motor. The NC control unit has a torque limit function for setting the torque output from the servo motor below a predetermined value, and comprises a mold position discriminating means for discriminating whether a mold protection start position and a mold contact position in the mold have reached corresponding preset values based on a detection output from the position detector; an elapsed time discriminating means for discriminating whether a preset predetermined time period after a point in time at which the mold reaches the preset mold position, has elapsed; and an alarm means for generating an alarm when the predetermined period of time has elapsed before the mold reaches the preset contact position. During the mold clamping operation, when the mold reaches the mold protection start position, the NC control unit outputs a torque limit instruction to close the mold with a small drive force corresponding to the preset limit torque output. If the mold does not reach the mold contact position within the predetermined period of time, an alarm is produced to protect the mold.
As described above, according to the present invention, mold protection can be performed easily by the torque limit function of the NC control unit, and the torque limit value can be set arbitrarily, thereby allowing easy control.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a main part of an injection molding machine having a mold protecting function according to an embodiment of the present invention; and
FIG. 2 is a flow chart of a program for executing the mold protection using the injection molding machine of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a block diagram of a main part of an injection molding machine according to an embodiment of the present invention. In FIG. 1, reference numerals 1 and 1' denote mold members; 2, a clamp mechanism for opening/closing the mold members 1 and 1'; M, a servo motor for driving the mold clamp mechanism 2; P, a position detector provided in the servo motor M for detecting the operating position of the movable mold member 1; 3, a servo circuit for controlling the servo motor M; 4, an NC control unit; 5, a central processing unit (to be referred to as a CPU hereinafter); and 6, an input/output circuit connected to the servo circuit 3, the CPU 5, and the position detector P.
A ROM 7 stores a control program for controlling the injection molding machine. A RAM 8 temporarily stores data and processes operations. A manual input unit 9 is used for setting the operating positions of the mold member 1 (at which various instructions and a torque limit instruction ofr mold protection (to be described later) are supplied), a torque limit value corresponding to the torque limit
REFERENCES:
patent: 2372833 (1945-04-01), Jobst
patent: 2391362 (1945-12-01), Strauss
patent: 2801442 (1957-08-01), Moslo
patent: 2923973 (1960-02-01), Ninneman
patent: 3452399 (1969-07-01), Blumer
patent: 3525382 (1970-08-01), Devol
patent: 3642401 (1972-02-01), Wilson
patent: 3736087 (1973-05-01), Ruegg
patent: 3942928 (1976-03-01), Kelz
patent: 4473345 (1984-09-01), McDowall
Chiesa Richard L.
Fanuc Ltd.
LandOfFree
Injection molding machine using servo motor and having mold prot does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Injection molding machine using servo motor and having mold prot, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Injection molding machine using servo motor and having mold prot will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1928611