JPH0423889B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for press molding resin such as SMC.

Conventional technology In recent years, in press molding of resin materials such as SMC,
A press machine incorporating a slide balance support device has been developed, and it can produce molded products with uniform wall thickness, stabilize material flow, and reduce defective rates. Used for molding equipment, home appliance parts, etc.

Problems to be Solved by the Invention However, in the case of press molding using the above-mentioned balance support device, the position of the balance support device must be controlled by a certain amount during pressurization after fluid filling the cavity with a resin material such as SMC. Therefore, when molding products with large wall thickness or special materials with large shrinkage, the slide cannot follow the large amount of shrinkage and it is difficult to hold the slide with the specified pressure. Ta.

In addition, when molding materials with large expansion, since the center of the slide is pressed by a pressurizing cylinder, the side edges of the slide bend upward, creating a small gap between them and the balance support device. Something happened.

Furthermore, it has been found that not only the pressure applied to the slide increases, but also that the surface of the molded product is beautifully finished when the pressure is controlled according to a predetermined program schedule.

Means for Solving the Problems The present invention has been made in view of the above-mentioned problems, and in order to solve the above-mentioned problems, a balance support device is provided in the bed portion of the press machine, and resins such as SMC are In a press forming method that pressure-forms a material in equilibrium, the balance support device follows the slide without leaving the slide, and the pressure force on the slide can be increased or decreased, and if the supporting force of the balance support device that supports the slide increases by a predetermined amount, equilibrium is achieved. The support device is controlled to descend in steps of 0.01 to 0.1 mm, and if the supporting force decreases by a predetermined amount, the balance support device is controlled to rise in steps of 0.01 to 0.1 mm, and the resin material such as SMC is It is an object of the present invention to provide a press molding method for a resin material such as SMC, which is characterized by filling a required cavity and press molding into a desired shape.

Effects According to the present invention, the resin material such as SMC can be uniformly fluidly filled into the cavity by causing the slide to follow the balance support device disposed in the bed portion without leaving the slide. When the resin material contracts or expands due to a thermal reaction, the pressure of the slide is increased or decreased, and the supporting force of the equilibrium support device increases or decreases by 0.01~
By automatically controlling the steps of descending and ascending in steps of about 0.1 mm, resin materials such as SMC can be press-molded into a desired shape with a beautiful surface.

Example Hereinafter, the present invention will be explained based on examples.

FIG. 1 and subsequent figures show an embodiment of the present invention. The press device 1 is a hydraulic press, and as shown in Fig. 1, a slide 5 of the required rigidity is provided in the center surrounded by a crown 2, an upright 3, and a bed 4, and a pressure cylinder 6 is fixed to the crown 2. is freely driven by a hydraulic servo pump (not shown) as a hydraulic source, and the slide 5 is freely slidable toward the lower bed 4 side. On the lower surface of the slide 5 and the upper surface of the bed 4, an upper mold 7 and a lower mold 8 for press-molding required parts are arranged facing each other, and the lower mold of this mold device 9 8 on top of the sheet
A resin material 10 such as SMC is supplied by a material supply device not shown. In addition, at the four corners of the bed 4, there is a
Balance support device 11 such as a hydraulic servo cylinder with a small output of about 100% and a short stroke range
are vertically disposed, and the ends of the four corners of the lower surface of the slide 5 are supported in a balanced manner so that the slides can be raised and lowered in synchronization as shown in FIG. A required pressure detector 12 is connected to this balance support device 11 so that the pressure supporting the slide 5 can be detected as appropriate. In the pre-process of fluidly filling the resin material 10 into the cavity 13 formed by fitting the resin material 10 with the mold device 9, the reference register 14 shown in FIG. The comparator 15 compares the force with the reference setting force and controls the slide 5 appropriately so that the slide 5 follows the balance support device 11 without leaving it. In the post process in which the resin material 10 is filled into the cavity 13 and causes a thermal reaction, the slide 5 is applied with a constant predetermined pressing force as shown in FIG. 2, and the supporting force of the equilibrium support device 11 is adjusted as shown in FIG. The resin material 1 is calculated through the supporting force register 16 and the supporting force comparator 17.
0 shrinks and the supporting force increases by about 3 to 4%, the balance support device 11 is sequentially controlled downward in steps of 0.01 to 0.1 mm, and the resin material 10 expands and the supporting force increases by 3 to 4%.
~4% decrease will reduce the balance support device 11 by 0.01~
The rise is controlled sequentially in steps of 0.1 mm, so that the resin material 10 can be filled into a predetermined cavity 13 in just the right amount and press-molded. Although not shown, the mold device 9 is equipped with a steam or electric heating device to control the heating of the mold device 9 to a required temperature and cause a reaction in the resin material 10 to be loaded. It is something that exists. 18 is a position detector such as a linear scale that detects the position of the balance support device 11 and provides feedback.

Therefore, for example, standard setting values such as the speed, position, and supporting force of the pressure cylinder 6 and the balance support device 11 are programmed in advance, and then, for example, with the upper mold 7 of the mold device 9 raised, the material is A predetermined amount of resin material 10 is supplied onto the lower mold 8 from the supply device, and the slide 5 is lowered at high speed as shown in FIG. is fitted into the lower mold 8, the upper mold 7 is brought into contact with the resin material 10, and the resin material 10 is flow-filled into a predetermined cavity 13. Before flowing through this cavity 13, the pressure detector 12 of the balance support device 11
The descending speed of the slide 5 is controlled by comparing the supporting force detected by the reference setting force with the reference setting force. Therefore, even if the deformation resistance, heating conditions, etc. of the resin material 10 to be molded are slightly different, the slide 5 can be lowered by following the balance support device 11 without leaving it, and the resin material 10 can be flow-filled as appropriate. It is something that can be done. When a thermal reaction occurs in the resin material 10 and it begins to shrink, the pressure of the slide 5 will be applied to the balance support device 11 in accordance with the amount of shrinkage of the resin material 10, and the support detected by the pressure detector 12 will be If the force increases by about 3 to 4%, the balance support device 11 is controlled to descend in steps of 0.01 to 0.1 mm as shown in FIG. Furthermore, when the resin material 10 expands due to a thermal reaction, the load on the balance support device 11 decreases, and if the support force detected by the pressure detector 12 decreases by about 3 to 4%, the balance is maintained as shown in FIG. Support device 11 from 0.01
The rise is controlled sequentially in 0.1mm increments. In this way, the balance support device 11 is controlled to rise and fall as appropriate, and the resin material 10 is pressurized for a certain period of time until the reaction hardening is completed as shown in the figure.
A molded product of a predetermined shape is press-molded. Therefore, not only resin materials with a large amount of shrinkage, but also a wide variety of resin materials that expand,
It is possible to mold beautiful molded products with no voids, no sink marks or unevenness on the outer surface, shorten molding time, and eliminate trial and error in press control, allowing smooth press forming. It is something that can be done.

In the above embodiment, the slide in the subsequent process is raised and lowered in a stepwise manner, but it is also possible to control the rise and fall so that the slide ascending and descending curve becomes a smooth curve, corresponding to the rise and fall of the slide. It is preferable to gradually reduce the amount of elevation and descent. It is also possible to increase or decrease the pressing force of the slide in response to the resistance of the resin material independently of the balance support device.

In the above embodiment, the supporting force of the balance support device was adjusted according to the expansion and contraction of the resin material.
The pressing force of the slide may be controlled to be increased or decreased in accordance with the program schedule of the molding material, and the elevation of the balance support device may be controlled in accordance with the detection of the support force of the balance support device at that time. By doing this, deflections and distortions of the slide, balance support device, mold device, and bed can be corrected, and the molded product can be press-molded with a beautiful appearance without any unevenness on its surface.

In the above example, the resin material was press-molded by controlling the position of the balance support device, but pressure sensors as small as possible were installed at the four corners of the lower mold in the cavity part of the mold device. , the pressurizing pressure of the molding material at the four corners of the cavity of the mold device of the fluidized resin material is detected respectively, and the inflection point of the characteristic curve function of the contraction and expansion of the material in the molding process of the resin material is detected. Switch from position control to pressure control of the balance support device at an appropriate point in time,
It is also possible to perform press molding by synchronizing the support pressures of the four equilibrium support devices at the four corners, and it is also possible to perform press molding by appropriately changing the position control. By switching to pressure control, position control can be corrected due to thermal distortion of the mold device, etc., and a molded product of higher quality can be obtained.

In addition, the molding material is not limited to SMC material.
A resin material reinforced with glass fibers, carbon fibers, metal fibers, etc. can also be used, and in addition to the above-mentioned sheet materials, gel-like fluid materials can be similarly applied.

Effects of the Invention As described above, according to the present invention, the pressing force on the slide is increased or decreased, and the balance support device is moved up and down according to the detection of the support force of the balance support device, and the balance support device is moved up and down to follow the slide without leaving it. Since it can be molded, it is possible to obtain molded products with a beautiful appearance without unevenness or sink marks, and
Even if various conditions such as the heating temperature and reaction rate of the molding material are slightly different, the press can be controlled almost optimally, and the conventional trial and error press molding process can be avoided.

[Brief explanation of drawings]

Fig. 1 is a partially omitted side sectional view of a device used in an embodiment of the present invention, Fig. 2 is an explanatory diagram of press adjustment in the above usage example, and Fig. 3 is a control block diagram of the balance support in the same above. be. DESCRIPTION OF SYMBOLS 1... Press device, 5... Slide, 9... Mold device, 10... Resin material, 11... Balance support device, 13... Cavity.

Claims (1)

[Claims] 1. In a press molding method in which a balance support device is installed in the bed of a press machine to pressure-form a resin material such as SMC in a balanced manner, the balance support device follows the slide without leaving it and increases or decreases the pressing force on the slide. If the supporting force of the equilibrium support device that supports the slide increases by a predetermined amount, the balance support device will increase by 0.01~
While controlling the descent sequentially in steps of about 0.1mm,
If the supporting force decreases by a predetermined amount, the balance support device will be adjusted by 0.01~
A press molding method for a resin material such as SMC, which is characterized in that the resin material such as SMC is filled into a required cavity and press-molded into a desired shape by sequentially controlling the rise in increments of about 0.1 mm.