JP3707649B2 - Swivel injection molding machine with multiple mold clamping devices - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a molding machine that enables injection and filling of resin for each mold clamping device by turning one injection device with respect to a plurality of mold clamping devices.
[0002]
[Problems to be solved by the invention]
The mold for injection molding in an operating state repeats the operation of holding a high-temperature molten resin at a predetermined time, cooling it, and discharging it to the outside. For this reason, the temperature repeatedly rises and falls within a certain range. However, in the case of a mold for newly starting an injection molding operation, there is no state of receiving heat by contact with the molten resin. Therefore, the temperature is lower than that of the operating mold.
[0003]
When the molten resin is injected and filled into the mold at a low temperature, a filling situation different from that in the normal operation state appears. That is, since the mold has cooled down, a clogging phenomenon of the molten resin at a specific portion of the mold cavity that does not occur in a normal operation state occurs.
[0004]
In particular, in a narrow passage as a molten resin flow path in the mold cavity, the heat of the molten resin is easily taken away as much as the mold is cooled, and the viscosity of the molten resin increases. In spite of the fact that the cavity to be filled with the resin still remains in the front, the flow of the molten resin is blocked on the way.
[0005]
At this time, if no further filling is stopped, there will be no problem, but the amount of resin that is completely filled in the entire mold cavity is measured in the tip of the injection barrel. The presence of the cavity at the point where it is stopped means that the resin that has not been filled still remains on the injection barrel side, and the filling operation will be continued. As a result, problems arise.
[0006]
Within the mold cavity, there are a large number of core pins for shaping the product shape. Of course, it is the narrow core pin that is easy to break. However, when pressure is applied with the ultra-fine core pin and the collar surrounded by the molten resin, the pressure is applied equally from all sides. Therefore, it does not receive bending stress in a specific direction, and therefore does not break.
[0007]
However, in the state where the ultra-fine core pin is looking into the cavity as described above, the core pin is subjected to non-uniform stress through the solidified resin once it is additionally filled into the resin that is about to harden. Therefore, there is a high possibility that it will be bent or broken.
Therefore, if resin clogging occurs and a cavity is formed ahead of it, further filling action must be stopped, but it is impossible to know such a situation from the outside. is there.
[0008]
In addition, when the mold temperature at the start-up is particularly low, resin clogging also occurs in fairly large narrow portions and ridges, and as the mold temperature rises, the size of the narrow portion where resin clogging occurs decreases. Go. Therefore, from a stochastic viewpoint, the lower the mold temperature is, the larger the total size of the voids that are generated, and the smaller the mold temperature is, the smaller the total size of the voids is. it is conceivable that.
[0009]
The present invention has been conceived from the above circumstances, and the object of the present invention is to solve the above-mentioned problems at the initial stage when the mold is started up by controlling the injection filling of the resin into the mold. Even with a swivel injection molding machine that performs injection injection filling of resin for each die by making one injection device correspond to the mold clamping device, both normal molding operation and mold startup can be performed. is there.
[0010]
[Means for Solving the Problems]
In the present invention according to the above object, the injection device is mounted on the turntable on the upper surface of the bed, a plurality of mold clamping devices are arranged radially on the side of the bed along the circumference of the turntable, and the injection device is swiveled. In a swivel injection molding machine configured to be compatible with each mold clamping device by movement, when performing the startup work of the mold attached to the mold clamping device, resin injection into the mold is performed for a while from the first time. In the meantime, the resin amount is made smaller than the required amount, and the resin amount is gradually increased according to the number of injection fillings, and an injection program that finally reaches the measured value during normal operation is set in advance. It is configured so that the injection operation is automatically performed, and the above-mentioned mold startup operation is performed on all mold clamping apparatuses at the start of operation or any mold clamping. Equipment Consisting configuration capable of performing relative Tagged new mold, is that.
[0011]
The above injection program consists of a combination of the measured value expressed as a percentage of the measured value during normal operation and the number of times the shot is repeated with the measured value (shot). In addition, the resin amount is automatically increased to reach the measured value during normal operation.
[0012]
Even when resin clogging occurs in the middle of such a mold, the resin that should be filled no longer remains in the injection barrel, and as a result, no further injection filling is performed. Bending or bending of the core pin or the like due to the injection pressure after clogging is prevented, and injection filling with a resin amount commensurate with the reduction in the total size of the gap is also possible.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The illustrated embodiment is a case where three mold clamping devices are provided, and the injection device 1 is mounted on a central portion of a turntable 3 provided on the upper surface of the injection bed 2 so as to freely advance and retract. On the three sides of the injection bed 2, first to third mold clamping devices 4, 5, 6, which are located radially along the circumference of the turntable 3, respectively, have respective beds 7, 8, 9. The injection bed 2 is integrally connected so as to be in contact with the side surface of the injection bed 2.
[0014]
An annular large gear 10 is concentrically mounted around the lower surface of the turntable 3, and the rotation of the bed-side electric servomotor 12 is transmitted by the small gear 11 meshed with the large gear 10. 10 is configured to turn the turntable 3 together with the injection device 1.
[0015]
An operation unit 13 is formed on the working side of the injection bed 2, and a display panel 14 for an injection program is provided on the operation unit 13. As shown in FIG. 3, the display panel 14 is provided with a weighing display unit 15 for starting up a mold together with other display units 16.
[0016]
The measurement display unit 15 for starting up the mold includes 1 to 5 step fields, a measurement ratio field, and a number of times (shot) field. The measurement ratio and the number of times can be displayed for each step field. The weighing value displayed in the weighing ratio column is displayed as a percentage of the weighing value during normal operation, and the injection program increases the amount of resin at each step and reaches the weighing value during normal operation at the final step. It is assembled.
[0017]
In the swivel type injection molding machine in which such an injection program is preset, the turntable 3 is rotated together with the injection device 1 by the operation of the electric servo motor 12, and the nozzle side of the injection device 1 is connected to each mold clamping device 4, The molding operation is performed while facing any one of 5 and 6, but when any one of the mold clamping devices 4, 5 and 6 is changed to a new mold by exchanging the mold, injection control for the mold is performed. Is switched to the injection program for starting up the mold, and only when the injection apparatus 1 corresponds to the mold clamping apparatus equipped with the mold, the weighing and injection filling of the resin is performed according to the preset injection program. .
[0018]
For this reason, even if it is a swivel type injection molding machine that continuously performs molding operation for each mold clamping device while making one injection device 1 correspond to each mold clamping device 4, 5, 6, it operates normally. And mold startup can be performed, and after startup is complete, everything is in a normal operating state. Therefore, the molten resin clogging phenomenon due to the low temperature at the initial stage of mold startup is prevented, and injection filling of the resin amount commensurate with the decrease in the total size of the voids is also performed, so normal for mold startup An inefficient means of stopping work on other mold clamping devices in operation is not necessary.
[0019]
Even when there is no mold replacement, when all the mold clamping devices 4, 5 and 6 start operating, it is necessary to start up the molds attached to them. In addition, the injection control can be switched to the injection program for starting up the mold, and the resin can be weighed and injected according to a preset injection program, and then the injection control can be shifted to the normal operation state.
[Brief description of the drawings]
FIG. 1 is a schematic plan view of a swivel type injection molding machine provided with a plurality of mold clamping devices according to the present invention.
FIG. 2 is a side view of the same.
FIG. 3 is a display panel of an injection program.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Injection device 2 Injection bed 3 Turntable 4, 5, 6 Clamping device 10 Large gear 11 Small gear 12 Electric servo motor 13 Operation part 14 Display panel 15 Start-up measurement display part

Claims (2)

An injection device is mounted on the turntable on the upper surface of the bed, and a plurality of mold clamping devices are arranged radially on the side of the bed along the circumference of the turntable. In the swivel type injection molding machine configured to be compatible sequentially,
When starting up the mold attached to the above mold clamping device, the resin injection into the mold will be less than the required amount for a while from the first time, and the resin amount will be according to the number of injection fillings. A plurality of features characterized in that an injection program that increases gradually and finally reaches a measured value in normal operation is set in advance, and an injection operation according to the injection program is automatically performed A swivel injection molding machine equipped with a mold clamping device. The above-described mold start-up operation can be performed on all mold clamping apparatuses at the start of operation or on a new mold attached to any mold clamping apparatus. A swivel type injection molding machine comprising a plurality of mold clamping devices according to claim 1.

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