JPH089181B2 - Press molding method for resin materials such as SMC - Google Patents

Description

TECHNICAL FIELD The present invention relates to a press molding method for a resin material such as SMC.

2. Description of the Related Art In recent years, the applicant has developed a press device that equips a bed part with an equilibrium support device that supports the slide in equilibrium and press-molds a sheet-shaped resin material such as SMC into a desired shape. . This press device is preferable because it is possible to precisely perform position control by the equilibrium support device, and it is possible to automatically maintain the pressure balance between the pressing force of the upper pressure cylinder and the supporting force of the equilibrium support device. .

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-mentioned pressing device, the equilibrium supporting devices must be arranged at the four corners of the bed, and the equilibrium supporting device is increased.

Means for Solving the Problems The present invention has been made in view of the above points, and in order to solve the above problems, a pressurizing cylinder of a required pressurizing force is press-molded on a crown portion of a hydraulic press device. The slide on which the upper mold of the mold device is fixed is arranged so that it can be driven up and down freely over a sufficient distance along the upright of the press device with a small-capacity lifting device on the upper surface of this slide. The rod of the pressure cylinder is arranged to be retractable or bendable, and when the slide is raised, the rod of the pressure cylinder is inserted into the slide or bent on the slide, and the slide is pushed when the slide is lowered. Then, press molding is performed so that the upper surface of the slide is abutted or extended so that it can be pressed, and the molding material of the resin material such as SMC is loaded into the mold device by the above-mentioned pressure cylinder. In the softened state, by controlling the position of the pressure cylinder, the upper mold is balanced with the lower mold on the bed to flow-fill into the predetermined mold cavity, while the molding cylinder hardens, the pressure cylinder Another object of the present invention is to provide a method for press-molding a resin material such as SMC, which is characterized in that the molding material is press-molded into a desired shape while maintaining pressure balance by switching to the pressure control of the pressing force.

Operation According to the present invention, when the slide is raised, the rod of the pressure cylinder can be inserted into the slide or bent over the slide, and when the slide is lowered, the pressure cylinder is placed on the upper surface of the lowered slide. Since the rod can be brought into contact with the slide to press the slide, the stroke of the pressurizing cylinder can be shortened, and the influence of the compressibility of hydraulic oil can be reduced as much as possible to perform press molding. Further, in press molding, when the molding material is in a softened state, the molding cylinder can be fluidly filled with the molding material by position control which is easier to balance control than pressure control of the pressure cylinder. Then, when the molding material is in the process of reaching a cured state, press molding is performed while maintaining a pressure balance by pressure control that requires a predetermined pressing force, and accurate press molding can be performed without a balance support device.

Examples Hereinafter, the present invention will be described based on Examples.

FIG. 1 and the following are examples of the present invention. The press device 1 is a hydraulic press, and as shown in FIG.
A slide 5 having a required rigidity is arranged in a central portion surrounded by the upright 3 and the bed 4, and a mold device 6 is provided on a lower surface of the slide 5.
The upper mold 7 is attached to the upper surface of the bed 4 via the bolster 8 and the lower mold 6 of the mold device 6 is attached to the SMC between the mold devices 6.
A sheet-shaped resin molding material 10 such as the above is charged and press-moldable as shown in FIG. As shown in FIG. 1, the slide 5 attached to the upper mold 7 is a lower capacity bed 11 which is a lifting device 11 for a small capacity hydraulic cylinder attached to the crown 2 or the upright 3 on both sides of the slide 5. The upright 3 is slid along a guide (not shown) of the upright 3 so that it can be moved up and down. Further, as shown in the figure, the rod insertion hole 12 is formed in the upper portion of the slide 5 symmetrically in the left-right direction and the front-rear direction so as to have a predetermined depth. An opening / closing plate 13 with various rigidity is horizontally swingably arranged by an opening / closing device 15 such as a hydraulic cylinder via a link mechanism 14.
The rod insertion hole 12 can be freely opened and closed by an opening / closing plate 13. As shown in FIGS. 1 and 4, the crown 2 portion above the slide 5 having the openable and closable rod insertion hole 12 faces the rod insertion hole 12 in a left-right and front-rear symmetrical manner. One pressurizing cylinder 16 with a required pressurizing force is fixed so that the rod 17 of the pressurizing cylinder 16 can be inserted into the rod insertion hole 12 and pressurized when the slide 5 is lifted as shown in FIG. When the rod 17 of the cylinder 16 is inserted into the rod insertion hole 12 and the slide 5 is lowered to perform press molding as shown in FIG. 2, the rod insertion hole 12 is closed by the opening / closing plate 13,
The rod 17 is brought into contact with the closed opening / closing plate 13, and the slide 5 is pressed by the pressure cylinder 16 to perform press molding. Therefore, the pressurizing cylinder 16 does not have to have a long stroke that follows the vertical movement of the slide 5 as in the conventional case, and the pressurizing range of the mold device 6 in the mold clamped state is relatively short. The stroke can be used, and the processing accuracy and response speed can be improved by the compressibility of hydraulic oil.

The pressurizing cylinder 16 that can be press-molded with such a short stroke detects the position of the encoder detector or the like vertically attached to the side of the upright 3 so that the lowered position of the slide 5 can be detected. Position control is performed by a servo pump (not shown) or the like by the device 18, and the upper mold is lowered in equilibrium with respect to the lower mold 6 to clamp the mold device 6, and the molding material 10 in a softened state is obtained. The mold cavity 19 is uniformly fluidized and filled. Then, as shown in FIG. 5, when the slide 5 is lowered, the molding material 10 is cured and contracts and expands at an appropriate point in the reaction molding process. Switching to the pressure control of 10
Is sufficiently filled in the mold cavity 19 and hardened, and is pressed and held for a certain period of time for press molding. At the time of switching from the position control to the pressure control, for example, based on the characteristic curve function f (t) of contraction and expansion of the molding material 10, as shown in FIG. The position is detected by a detector or set by a timer or the like.

Further, the pressure control of the pressure cylinder 16 is performed by connecting the pressure detectors 20 to the four pressure cylinders 16 as shown in FIG. 6, and changing the pressure control from the position control to the pressure control. Memory circuit with reference pressure value
The pressure balances of the four pressurizing cylinders 16 are held while being compared by the comparators 22 based on the reference pressure value, and the press molding is performed according to the set program control. . Therefore, it is difficult to control both position control and pressure control without the equilibrium support device, and it is difficult to maintain the precision of the molded product within a certain quality by performing either one of the conventional control. Molding material 10 in the softened state up to the equilibrium control can be uniformly flow-filled into the mold cavity 19 with easy position control, and the final pressure during position control when pressure hardening and holding pressure is required Since the press molding can be performed while maintaining the pressure balance on the basis of, the eccentricity can be prevented from occurring, and a molded product having a constant quality and always having high accuracy can be obtained.

In the above embodiment, the case where four pressurizing cylinders are provided has been described, but an appropriate plurality can be press-molded according to the size of the press machine.

Further, although the rod of the pressurizing cylinder is inserted by providing the slide with the opening portion, the rod may be bent so as to be expandable and contractible to achieve the same purpose as described above.

The molding material is not limited to the SMC material, but may be a resin material reinforced with glass fiber, metal fiber, or the like, and is similarly applicable to a gel-like fluid material other than the above sheet material. It is a thing.

As described above, in the present invention, it is possible to form a pressurizing cylinder with a short stroke necessary for press forming without requiring a pressurizing cylinder with a long stroke that follows the vertical movement of a slide. The influence of the compressibility of hydraulic oil can be reduced, and the accuracy can be improved. Further, even if the equilibrium support device is not provided, the slide can be press-molded by effectively switching the position control and the pressure control, the precision of the molded product can be kept constant, and the device can be manufactured as inexpensively as possible.

[Brief description of drawings]

FIG. 1 and FIG. 2 are side cross-sectional views for the purpose of schematically explaining the embodiment of the present invention with a part omitted, FIG. 3 is a plan view with a part of the slide upper surface part omitted, and FIG. FIG. 5 is a plan view of the press machine, FIG. 5 is a diagram for explaining the press stroke and the characteristic curve of the molding material, and FIG. 6 is a block diagram for explaining the pressure control of the pressure cylinder. 1 ... Pressing device, 2 ... Crown, 5 ... Slide,
6 ... Mold device, 7 ... Upper mold, 9 ... Lower mold, 10 ...
Molding material, 12 …… rod insertion hole, 16 …… pressurizing cylinder, 17 …… rod.

Claims (4)

[Claims] 1. A pressurizing cylinder having a required pressurizing force is arranged in a crown portion of a hydraulic press device so as to be press-molded, and a slide having an upper mold of a mold device fixed thereto is pressed by a small-capacity lifting device. It is arranged so that it can be moved up and down freely over a sufficient distance along the upright of the device, and the rod of the above-mentioned pressure cylinder is arranged on the upper surface of this slide so that it can be retracted or bent, and pressure is applied when the slide is raised. The rod of the cylinder is inserted into the slide or bent on the slide, and when the slide is lowered, the slide is pressed and press-formed. The molding material of the resin material such as SMC loaded in the mold device with the pressure cylinder is balanced by the position control of the pressure cylinder in the softened state of the upper mold to the lower mold on the bed. Fluidizing and filling into a predetermined mold cavity, and when the molding material is hardening, the pressure cylinder is switched to pressure control of the pressing force to press-mold the molding material into a desired shape while maintaining the pressure balance. A method of press molding a resin material such as SMC, which is characterized in that 2. The pressurizing cylinder has a short stroke such that it can be press-molded by pressing a mold device in a clamped state, and it is required between the lower surface of the rod and the upper surface of the slide of the pressurizing cylinder. The method of press molding a resin material such as SMC according to claim 1, wherein a spacer having a thickness of 5 mm is attachable so that the slide is pressed by a pressure cylinder. 3. The method according to claim 1, wherein the switching from the position control of the pressurizing cylinder to the pressure control is program-controlled based on a curing characteristic curve accompanied by shrinkage and expansion of the molding material. Press molding method for resin materials such as SMC. 4. The pressure control of the pressurizing cylinder is set as a reference pressure when the pressure control is switched from the position control to the pressure control, and the press molding is performed while maintaining the pressure balance of the pressurizing cylinder based on the reference pressure. A method of press molding a resin material such as SMC according to any one of claims 1 to 3.