JPS5917940B2 - Blow molding equipment and molding method using sheet materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blow molding apparatus and a molding method for manufacturing various molded products by bonding two thermoplastic sheet materials together.

Conventionally, in sheet blow molding of small containers and pins, two sheets of material are transferred between two upright heaters or vertically opposed heaters, heated and softened, and then sandwiched between a pair of split molds and clamped. After that, high-pressure air is injected between both sheet materials to form the material.

However, with this method, especially when molding thick and large products, although it is possible to heat the chipped side of the sheet material, it is difficult to heat the inner surface uniformly. Residual stress was generated, and there was a problem that it was impossible to eliminate eaves marks such as shrinkage after molding, deformation, or vertical burrs on the parting. In addition, when obtaining a blow-molded product, the deep-drawn part in particular has a thin wall, but there is a problem that the product breaks in the mold during molding and cannot be molded. In the present invention, a sheet material of an appropriate thickness having a shape corresponding to the lever part is attached to the deep drawing part in advance and is integrated, and this is heated and molded, so that the deep drawing part is not damaged. A product with uniform thickness can be obtained. In view of this, the present invention provides three upright heaters that can be moved up and down, thereby making it possible to adjust the thickness as desired even for large sheet materials, and to uniformly cover both sides of the material, as well as locally increasing the thickness as described above. , provides a blow molding device for sheet material using a heating device equipped with a heating means that can increase and decrease local heating in the deep drawing part, and furthermore, provides a blow molding device for sheet materials even if it is a large thick product or a uniformly thick product. To provide a blow molding method using a sheet material that can be quickly and easily molded even if there is a partially thick wall or a deep drawn part.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the apparatus of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 to 3, reference numeral 1 denotes a blow molding apparatus for molding various articles using two thermoplastic sheet materials 2, 2, and includes a means 3 for transporting the sheet materials 2,
It is composed of a preheating chamber 4 and mold clamping means 5.

The transfer means 3 has two wires R, 7 suspended between the upper ends of a pair of columns 6, 6 provided at the front and rear.
The fixed column 9 is fitted into the base column 8 so as to be movable up and down.
A rotating shaft 10 is held at the upper end of the fixed column 9 in the left-right direction. Two pulleys 1J11, 11 and one chain gear 12 are integrally fixed to the rotating shaft 10, and the chain gear 12 is connected to the base column 8 via a chain belt 13 inside the column 6.
It is linked to a manual handle 14 provided in the. The wire T is suspended endlessly between the pulleys 11, 11 of both the supports 6, 6, and a plurality of clamping fittings 15 for the sheet material 2 are attached at predetermined intervals, so that the two sheet materials 2 are clamped. It is suspended by a metal fitting 15 facing the wire r, and is moved by operating the manual handle 14. 16 is a tension roll of wire r, and a supporting member 1T is attached to the fixed column 9.
It is installed through.

The preheating chamber 4 is a movement path for the sheet material 2 (between both supports 6, 6)
It is installed so that it can be moved up and down.

The mold clamping means 5 is installed in the movement path of the sheet material 2 in close proximity to the preheating chamber 4, and the base 18 is moved along the rail 18a by rollers 18b.
A fixed base 19 is provided above through a threaded rod 19a so as to be movable up and down by rotation means (not shown). A pair of clamping frames 20, 20 are held on both sides of the fixed base 19 so as to be movable in the left and right direction by rods 21, and a split mold 22 is movably inserted into the clamping frame 20. A hydraulic rod 23 is connected to the back side of the split mold 22, and a male cavity 24 is formed in one split mold 22 and a female cavity 24 is formed in the other split mold 22 on the opposing surfaces. The split mold 22 has a plurality of suction passages 25, particularly deep cavities 24.
In order to prevent the pre-produced product inside the mold clamping from remaining on the cavity 24 side, the suction passage 25 provided in the cavity 24 with a deep groove has a lower than atmospheric pressure generated around the high-pressure air passage. Suction with vacuum pressure. Furthermore, an injection means 26 for injecting high-pressure air between the sheet materials 2 and 2 after mold clamping is provided in the split mold 22 so as to be able to appear and retract from the surface of the cavity 24, and the injection means 26 is a syringe provided in the pressurized air passage. The tip is inserted into the sheet material 2. Further, a hydraulic cylinder 2r is connected to the lower part of the mold clamping means 5, and three upright heaters 29 are fixed to a vertically movable pedestal 28. It moves to the side of the man at appropriate intervals, and is covered with a red man wire heater, ceramic, etc. Upright heater 29
The width, length, and heating temperature can be adjusted according to the distance, length, and width between the sheet material 2 and the sheet material 2.
It is arranged so that the surface can be uniformly heated or a part can be heated to a high temperature locally, so that it can be set to a high or low temperature locally, and
A high-temperature heater is disposed in a locally thick portion or movable toward or away from the sheet material 2 depending on the thickness thereof. Reference numeral 30 denotes an air supply pipe which is installed above the mold clamping means 5 and is movable underground, and is used to supply air between the sheet materials 2 or perform low-pressure temporary mold clamping while exhausting more air than necessary during this mold clamping process. After that, high pressure air is introduced to complete the main mold clamping.

One or more air supply pipes 30 can be installed at any cavity position depending on the shape of the molded product. That is, at the time of mold clamping, the two sheets are closed on the entire parting line to form a bag, and at the same time low pressure air is blown into the bag from the air supply pipe 30 to form a pre-produced bag, or as shown in FIGS. 8 and 9. While moving the mold clamping frame 20 that encloses the split molds 22, 22, the heating sheets 2, 2 are supplied from above, and the air supply pipe 30 is moved along the arrow to enter the inside of the pre-produced product 43. Inflate it by injecting low-pressure air, advance the split mold 22 as shown in Figure 9, clamp the mold, and fold it back.
A molded product having a hollow portion 33 can also be obtained. First, with the action of the blow molding device 1, the blow molding process is performed. I will explain the mold method.

First, two rectangular sheet materials 2 are placed facing each other and suspended from a wire r via a clamping fitting 15, and then attached to a manual handle 14.
is operated and moved, enters the preheating chamber 4, and is preheated to a predetermined temperature (for example, in the case of A, B, and S materials, 120
℃). Subsequently, the sheet material 2 is transferred from the preheating chamber 4 to the mold clamping means 5.
The three upright heaters 29 are raised to be located between the opposing parts of the sheet material 2 and on both sides of the sheet material 2, and heated to a softening point near the melting point ( For example, in the case of A, B, SVf4 materials, it is around 210℃~230℃)
, soften. Subsequently, after moving the upright heater 29 downward, both mold clamping frames 20 are moved closer to each other, and heated air is supplied from above between the sheet materials 2 from the air supply pipe 30 to The surrounding area is closed and pre-produced while preventing coalescence (see Figure 8). Thereafter, the sheet material 2 is sucked onto the inner surface of the cavity 24 by suctioning air through the suction path 25 at a pressure below atmospheric pressure, while the split mold 22 is moved close (see FIG. 9). Then, the injection means 26 is inserted between the sheet materials 2 and high pressure air (5 to 10 Kg/Crii) is injected to complete the molding. Thereafter, the split mold 22 and the mold clamping frame 20 are separated to remove the molded product, and the next sheet material 2 is moved between the split molds 22 and the above-described operation is repeated. Note that the worker 31 in FIG. 1 is inspecting whether the sheet material 2 located between the upright heaters 29 is normal or not, and the support column 6 is moved up and down and suspended from the wire 7. The height of the sheet material 2 to be processed can be adjusted to correspond to the split mold 22.

Figures 4 to 5 show molded products produced by the apparatus of the present invention, and Figures 4 to 5 show a ski 32 in which two hollow sections 33 are formed, and the hollow sections 33 have heat-insulating and Polyurethane foam that doubles as reinforcement or F, R, P for reinforcement
It is filled with reinforcing material 34 such as. Figure 6 and r
The figure shows collectors 35a and 35b of a solar water heater made of PE and PP materials, and the collector 35a in FIG.
The periphery is a whole surface welded part 31a that is synchronized like a spectacle. Incidentally, although not shown in the drawings, an entrance/exit is integrally provided in the water supply/drainage passage 36a. The collector 35b in FIG. 7 is also a similar product, and is an integrally molded product with a small diameter passage 36b formed in the welded portion 3Tb. Other molded products include double-walled helmets and boats. 10 to 1r show the sheet material 2 partially thickened to correspond to the molded product, and the sheet material 2 shown in FIG. The molded product 39 shown in FIG. 11 is pin-shaped, and since the elongation rate of the body part 39a is large during molding, the body part 39a is Sheet material 2 corresponding to
The central part is thicker.

Fig. 12 shows a product with a uniform thickness after attaching an auxiliary sheet material 38 to the central part of one of the two sheet materials 2 to make it thicker. Correspondingly, the thickness and color can be varied arbitrarily by means of the auxiliary sheet material 38. Alternatively, a plurality of sheet materials of different colors may be attached in advance using a partially transparent or limited color sheet as a substrate. The sheet material 2 shown in FIG.
The sheet material 2 shown in the figure is thickened by pasting an auxiliary sheet material 40 on the peripheral edge, and the auxiliary sheet materials 38 and 4 correspond to the shape, color, and elongation of the molded product, respectively.
It is formed using 0.

Figures 15 to 17 show a small double-structured container 41, and the upper edge 41a is thin, but as shown in Figure 15, an auxiliary sheet material 42 is attached to that part and heat-softened molded. The entire upper edge was made uniform. That is, container 4
Since the upper edge 41a of 1 is bent into a hook shape, the peripheral edge of one of the sheet materials 2 has a large elongation rate during molding, and the part where the elongation rate is large is particularly thin, so this part is auxiliary. By pasting the sheet material 42, the thickness will be uniform after molding. Incidentally, in this embodiment, the transfer means 3 is operated by a manual handle 14, but a timer, a VS motor, a hydraulic motor, etc.
The drive may be automatically controlled by engagement of a limit switch or the like, and the sheet conveying means is not limited to the wire T, but various types such as a chain may be used. As described above, according to the apparatus of the present invention, the three upright heaters are controlled such that the heater temperature becomes weaker as they move upward relative to the vertical length, and are provided so as to be movable up and down, making it possible to mold large-walled products. Even in cases where the inner rows of sheet materials are heated uniformly, residual stress is less likely to occur after forming, which prevents shrinkage and deformation, as well as the ability to heat vertically on the parting line. It is possible to eliminate eaves marks such as burrs. In addition, according to the present heating method, since the upright heaters are located at the opposing parts of the two sheets of material and on the sides of the two notches, it is possible to quickly and uniformly control and heat the inner surface of the sheet materials. Since the work can be carried out reliably and excellent blow products or double-structured products are molded without using a parison, blowdown can be reduced and products with uniform thickness can be molded at high speed.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention; FIG. 1 is a side view of the blow molding device, FIG. 2 is a cross-sectional view of the mold clamping means, FIG. 3 is a front view of the upper part of the movable column, and FIG. FIG. 5 is a plan view of the ski; FIGS. 6 and 7 are perspective cross-sectional views of the collector; FIG. 8 is a schematic diagram of the mold clamping means during pre-production; 10 is a partially omitted sectional view of the mold clamping means showing blow molding using another sheet material; FIG. 11 is a sectional view of the pin molded product; FIG. 12 Figures 15 to 15 each show the shape of each figure. FIG. 16 is a partially sectional perspective view of a molded container with a part omitted, and FIG. 1R is an enlarged sectional view of the upper edge of the same. 1... Blow molding device, 2... Sheet material, 3... Transfer means, 4... Preheating chamber, 5... Mold clamping Means, 6... Support, r.
...Wire, 15 ... Clamping fitting, 18.
...Base, 19...Fixed stand, 20...
...Mold clamping frame, 22...Split mold, 24...
...Cavity, 25...Suction path, 26...
... Injection means, 28 ... Frame, 29 ...
...Upright heater, 30...Air supply pipe, 38
, 40, 42... Auxiliary sheet material.

Claims (1)

[Scope of Claims] 1. A transport means for moving two thermoplastic sheet materials toward each other is provided, and a preheating chamber for the sheet material and a mold clamping means adjacent to the preheating chamber are provided in the movement path of the sheet material. The mold clamping means is provided with a pair of opposing split molds that can be moved toward and away from each other, and three upright heaters that appear and retract between the opposing parts of the split molds that can be moved up and down. Furthermore, an air supply pipe for supplying air between the sheet materials is provided at an arbitrary position on the opposing part of the split mold, and a male or female cavity is provided on the opposing surface of the split mold. A suction path for sucking air at a pressure below atmospheric pressure is opened on the side of the mold having the cavity, and an injection means for injecting high-pressure air between the sheet materials after the mold is clamped is connected to the mold toward the cavity. The upright heaters are provided on the side of the mold so as to be freely retractable, and are located on the opposing sides of both sheet materials and on the sides of both rows to heat the sheet material to near its melting point, and then the mold is clamped to heat the inside and outside of the sheet material. A blow molding device for sheet materials that is characterized by molding by suction and pressure. 2. A blow molding device using a sheet material according to claim 1, wherein an auxiliary sheet material is locally attached to the sheet material to change the thickness and color of the sheet material in accordance with the shape of the molded product. . 3. The sheet material is provided with an auxiliary sheet material having a predetermined thickness and size attached to a portion where the elongation rate is large depending on the depth, width, etc. of the molded product, as described in claim 1 or 2. Blow molding equipment using sheet materials. 4 Two thermoplastic sheet materials are placed facing each other and entered into a preheating chamber, heated to an appropriate temperature, then transferred to the mold clamping means for the next process, and the three upright heaters of the mold clamping means are placed facing each other The entire surface of the sheet material is heated uniformly or locally to a softening point near the melting point by moving and clamping the sheet material to the side and both rows, and the sheet material is softened to the appropriate molding temperature, and the upright heater is moved back. After that, while supplying predetermined low-pressure air between the sheet materials, both sheet materials are welded and closed around the mold surface or with a preceding mold of a frame mold that fits the split mold, or with an appropriate mold clamping mold. Then, either a pair of split molds are brought close to each other with the sheet material sandwiched between them, or the pre-blown product between opposing parts of the split molds is heated to a temperature below atmospheric air through a suction passage opened in a cavity on the opposing surface of the split molds. Means for injecting pressurized air by suctioning air with pressure to exhaust residual air between the split molds surrounding the cavity surface, and adsorbing the sheet material into the corresponding limited space of the cavity, and injecting pressurized air at or just before mold clamping. A blowing method using a sheet material, in which the internal air pressure of a pre-blown product in a predetermined space is evacuated to prevent it from rising as mold clamping progresses, and low-pressure air is held, and high-pressure air is injected from around the cavity at the same time as mold clamping is completed. Molding method. 5. A blow molding method using a sheet material according to claim 4, wherein the sheet material is locally affixed with an auxiliary sheet material that changes the thickness and color of the sheet material in accordance with the shape of the molded product. . 6. The sheet material is provided with an auxiliary sheet material having a predetermined thickness and size attached to a portion where the elongation rate is large depending on the depth, width, etc. of the molded product, as described in claim 4 or 5. Blow molding method using sheet material.