Boots – shoes – and leggings
Patent
1988-02-02
1989-07-11
Silbaugh, Jan H.
Boots, shoes, and leggings
264 401, 264 405, 264 407, 318574, 318625, 36416701, 425135, 425161, 425165, 425166, B29C 4576
Patent
active
048477796
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to an injection-molding machine controlled by means of a numerical control unit (hereinafter referred to as NC unit), and more particularly, to a numerical control method for an injection-molding machine and an apparatus therefor, capable of executing a mold opening process simultaneously with a metering process.
In an injection-molding cycle, a metering process and a mold opening process are executed subsequent to an injection process and a hold process. The metering process can be started immediately after the completion of hold, while the mold opening process can be started after solidification of resin injected into a mold, that is, after the passage of a cooling period. Usually, the cooling period is shorter than a metering time, so that the cycle time for the manufacture of moldings can be shortened by opening the mold immediately after the termination of the cooling period.
In injection-molding machines using oil pressure as a drive source, various axes, such as an injection axis, metering axis, clamp axis, eject axis, etc., can be controlled independently and simultaneously. Therefore, mold opening is started the moment the cooling period terminates during the metering process, that is, metering operation and mold opening operation are executed simultaneously. According to injectionmolding machines in which the drive of servomotors for their axes is controlled by means of an NC unit, on the other hand, it is difficult for the NC unit to control a plurality axes simultaneously and independently, due the limited computing capability of the NC unit. Accordingly, the mold opening operation is performed after the metering operation is finished. Thus, the prior art injection-molding machines controlled by means of an NC unit require a long cycle time, and therefore, are low in production efficiency.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to shorten the cycle time by driving one axis of an injection-molding machine, controlled by means of an NC unit, simultaneously with another axis when step feed execution conditions are fulfilled while the second axis is being driven, so that a mold opening operation is performed simultaneously with a metering operation when a cooling period terminates during the metering operation.
In order to achieve the above object and other objects, a numerical control method for an injection-molding machine according to the present invention comprises (a) determining whether step feed execution conditions are fulfilled, (b) delivering information for specifying a step feed axis, step feed execution information including the displacement, moving speed, and moving direction of the step feed axis, and step feed command information, from a programmable machine controller for sequentially controlling the injection-molding machine, to a numerical control processing unit, used to control the drive of servomotors for axes of the injectionmolding machine, when the step feed execution conditions are fulfilled, and (c) alternately executing pulse distribution for the step feed axis, based on the step feed execution information, and pulse distribution for an axis separate from the step feed axis, by means of the numerical control processing unit responsive to the step feed command information, while the step feed execution conditions are fulfilled, thereby simultaneously driving the two axes of the injectionmolding machine.
A numerical control apparatus of the present invention, which is used to effect the aforementioned method, comprises a numerical control processing unit for controlling the drive of servomotors for axes of an injection-molding machine; a programmable machine controller for sequentially controlling the injectionmolding machine; and a memory unit accessible by both the numerical control processing unit and the programmable machine controller. The programmable machine controller includes determination means for determining whether step feed execution conditions are fulfilled, an
REFERENCES:
patent: 4629955 (1986-12-01), French et al.
patent: 4674053 (1987-06-01), Bannai et al.
patent: 4695237 (1987-09-01), Inaba
Hiroshi Umemoto
Masao Kamiguchi
Fanuc Ltd
Heitbrink Jill L.
Silbaugh Jan H.
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