JPS60171111A - Preparation of formed object of thermoforming material sheet - Google Patents

Abstract

PURPOSE:To prevent the thermoforming material sheet, that is discharged from an extruder etc., from becoming thinner or uneven in thickness or torn by attracting and retaining the sheet is softened state with a vacuum attracting plate falling nearly in synchronization with the sheet. CONSTITUTION:The softened thermoforming material sheet S that is discharged or fed from an extruder or a press roll device in the form of sheeting and continues to have thermal energy in the kneaded state is attracted and retained by vacuum attracting force to a vacuum attracting plate 7 falling nearly in synchronization with the falling speed of the sheet. In that state a sheet forming device such as a vacuum forming device etc. is dropped to perform a forming process.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a molded body of a thermoformable material sheet.

More specifically, sheets of thermoformable materials such as thermoplastic resins, semi-vulcanized rubber, and polyurethane rubber (including films, plates, and laminated (composite) materials) are used as materials, and appropriate sheets are used in this equipment, press molding equipment, etc. The present invention relates to a method of manufacturing a desired sheet molded body by processing with a forming device.

Conventionally, the raw material, aged formable material sheets (hereinafter abbreviated as material sheets), was produced in advance and cut into a predetermined size or rolled and stocked, and then cooled to room temperature to harden. Before applying, it is heated and softened using a heating device. Then, the heat-softened material sheet is applied to a sheet forming device to obtain the desired sheet molded body.

However, this has the following problems.

(a) A large amount of thermal energy is required to bring a material sheet that is cured at room temperature into a heat-softened state that can be molded.

(b) Advanced technology, skill, heating equipment, and heat treatment time are required to heat-soften relatively thick material sheets or laminated material sheets as uniformly as possible over the entire material sheet. In general, the softening state of such material sheets during molding is often such that even though the surface part is sufficiently softened, the inside is insufficiently softened, resulting in poor overall formability or problems with the molding die. There is a tendency that the degree of transfer of the uneven pattern to the surface of the sheet molded product due to the uneven pattern such as grains carved on the molding surface is poor.

In order to obtain a molded material sheet that is thermoeconomically advantageous and has good formability and transferability of the uneven pattern on the surface, it is possible to obtain a molded material sheet that is matured and formed as a material sheet as described above and is cooled to room temperature. Instead of heating and softening the hardened material, we use sheets of polypropylene, rumored to be polyethylene, etc., which are in a nearly molten state and are discharged from an extruder.
Alternatively, thermoformed materials such as high-temperature vinyl chloride, E No. V-A, T/PiIE resin No. resinous rubber-based materials, etc., which are sheeted from a rolling roll device, still have cross-current heating energy and are in a softened state. It is preferable to adopt a method in which the sheet of the elastic material is subsequently introduced into a sheet forming device and subjected to forming processing.

However, the problem in this case is that if the material sheet that is continuously discharged or sent out from the extruder or rolling roll device is simply allowed to hang down in order to be introduced into the sheet forming device, the above-mentioned problem occurs. Immediately after production, the raw material sheet has a high degree of softening at high temperatures, so it stretches due to its own weight during the descending process, resulting in thinning or uneven thickness before it is sufficiently descended into the sheet forming device. This thinning and uneven thickness due to the weight of the material sheet during the downward drooping process occurs most notably in material sheets made of materials with high high temperature fluidity, such as polypropylene resin. In addition, in the case of material sheets with relatively thick walls or material sheets with high specific gravity due to a large amount of fillers (wood flour, talc, carbon calcium, etc.), the above-mentioned thinning and uneven thickness phenomenon due to their own weight may occur. This begins to occur at the beginning of the descending process, and the sheet may eventually break before it is fully introduced downward into the sheet forming device.

The present invention is directed to the latter manufacturing method, that is, the raw material sheet, which is discharged or sent out from an extrusion type or rolling roll device and is still in a softened state due to crosstalk heating energy, is subsequently transferred to a sheet forming device. Regarding the method of downward introduction and forming processing, it eliminates the above-mentioned problems of thinning, uneven thickness, and tearing of the material sheet due to its own weight as it is introduced downward into the sheet forming equipment, which is thermoeconomically advantageous. In addition, it is possible to efficiently mass-produce molded bodies of aged formable material sheets with higher quality moldability etc. at low cost.

That is, the present invention takes a sheet of maturing formable material, which is continuously sheeted or sent out from an extruder or rolling roll device and is still in a softened state due to the crosstalk heating energy, to the descending speed of the sheet. A maturing formable material sheet characterized in that it is sucked and held by vacuum suction force on the surface of a vacuum suction plate that descends approximately in synchrony, and is introduced downward into a sheet forming device such as a vacuum forming device for forming processing. The gist is a method for manufacturing a molded object.

A detailed explanation will be given below based on an illustrated example.

In FIG. 1, 1 is a part of the main body of an extruder as a raw material sheet manufacturing device, 2 is a head portion of the extruder, and 3 is a sheet manufacturing die attached to the head portion. The thermoformable material (S) that is the raw material is continuously extruded from the downward outlet of the die 3 with a wall thickness of, for example, 0.7 to 2.5 cm at a predetermined extrusion speed, and then extruded to the next position of the die 3. The sheet passes between the pair of sheet thickness adjusting rollers 4 and 5 provided, is deflected downward along the lower roller surface of the pair of rollers, and as it is extruded from the die 3, it droops downward at Mtht.

Reference numeral 6 denotes a vacuum forming device as a sheet forming device disposed below the pair of sheet thickness adjusting rollers 4 and 5. 6
1 is a vertically arranged vacuum forming mold which is the main body of the i-device; 62 is a molding surface; 63 is a vacuum suction hole bored in the molding surface; 64;
is a vacuum chamber formed within the thickness of the mold 61, and each of the vacuum suction holes 63 mentioned above communicates with this vacuum chamber. 65 is a vacuum pipe connecting the vacuum chamber 64 and the vacuum pump ■P, 66
is an electromagnetic opening/closing pulp installed in the middle of the pipe. When the valve 66 is opened, each vacuum suction hole 63 of the molding surface 62 enters an air suction state. 67 is a cooling water introduction pipe buried within the thickness of the mold 61.

The material sheet S passing through the pair of sheet thickness adjusting rollers 4 and 5 and hanging down continuously moves downward on the front side (forming surface 62 side) of the mold 61 as it is extruded from the die 3.

7 is formed in synchronization with the descending speed of the descending material sheet S, when the surface on the mold 61 side of the material sheet S descending on the front side of the mold 61 is the front surface and the surface on the opposite side is the back surface. It is a vacuum suction plate that is moved downward by a drive mechanism such as an air cylinder (not shown) while the front side of the mold is in contact with the back surface of the material sheet S from top to bottom, and it is designed to fully cover the effective molding surface area of the mold 61. It has an area that can be covered.

Reference numeral 71 indicates a number of vacuum suction holes opened on the side surface in contact with the back surface of the material sheet of the vacuum suction plate, and 72 indicates a vacuum chamber formed within the thickness of the chain plate, and each of the above-mentioned vacuum suction holes communicates with this vacuum chamber. are doing. 73 is a vacuum pipe connecting the vacuum chamber 72 and the vacuum pump Vp, and 74 is an electromagnetic opening/closing valve provided in the middle of the pipe. When the valve 74 is opened, each vacuum suction hole 71 enters an air suction state. 75 is a heater buried within the thickness of the chain plate for the purpose of heating and keeping the vacuum suction plate 7 warm; 76;
is a material sheet cutting blade disposed on the upper side of the vacuum suction plate 7, and the mold 6 is cut by a drive mechanism 77 such as a fluid pressure cylinder.
Moves forward and backward relative to 1.

Although not shown in the figure, the vacuum forming apparatus 6 described above, including the vacuum suction plate 7 and its drive mechanism, is connected to a tripartite or rotary set of apparatus carrier mechanisms in which two or more units are connected in series or in multiple units. The carrier mechanism moves the vacuum forming device 6 to the lower position (material picking position) of the pair of sheet thickness adjusting rollers 4 and 5, where the material sheet S is continuously lowered. As will be described later, after the material is removed, the vacuum forming device 6 is used to process the subsequent material sheet S.
The sheet S is lowered at the same speed as or faster than the descending speed of the sheet S, and is moved from the descending path of the sheet S to the lateral molded object take-out position, and for one method of vacuum forming equipment, it is replaced with the above-mentioned material take-out position. It should be moved to a specific position.

Therefore, when the vacuum forming device 6 in (1)- is moved to the material taking position, the vacuum suction plate 7 has its lower side aligned with the sheet thickness adjusting roller pair 4-5 and the upper side of the mold 6. It is in a pulled up position located at approximately intermediate position A. When the vacuum forming device 6 moves to the material picking position, the vacuum suction plate 7 moves downward in synchronization with the descending speed of the material sheet S, which is continuously hanging down from the pair of sheet thickness adjusting rollers 4 and 5. be done. Further, the valve 74 is switched and held open, and each vacuum suction hole 71 of the vacuum suction plate 7 enters an air suction state. The material sheet cutting blade 76 is held in the retracted position shown by the solid line in FIG. The valve 66 on the side of the vacuum forming device 6 is kept closed.

(2) When the material sheet S hanging down from the sheet thickness adjusting roller pair 4-5 exits between the roller pair 4 and 5, it descends in synchronization with the descent of the sheet S, and the vacuum is in the vacuum suction state. The back side successively contacts the surface of the vacuum suction plate 7 and moves down the front side of the mold 61 while being sucked and held by the surface of the vacuum suction plate 7. That is, the material sheet S is sucked and held by the vacuum suction plate 7 and descends while being weight supported.
Even a material sheet with high high temperature fluidity can be introduced downward into the vacuum forming apparatus 6 side without any problem for a sufficient length without causing thinning, uneven thickness, or tearing due to self-weight stretching. It is also possible to lower the material sheet S while keeping it warm by heating the chain plate 7 to an appropriate temperature by embedding a heater 75 in the vacuum suction plate 7 as shown in the example shown in FIG.

(3) When the lower end of the vacuum suction plate 7 holding the material sheet S by suction as described above reaches the predetermined position B on the lower end side of the mold 61, it is detected by a mechanical sensor (not shown) such as a micro switch. sensor, photoelectric sensor, etc.).

(4) Based on the detection signal, the vacuum suction plate 7 is moved forward toward the mold 61 by a drive mechanism (not shown), and the material sheet S is placed between the front side of the mold 61 and the vacuum suction plate 7. It's like being stuck in a sandwich. At the same time, the cutting blade 76 is moved forward, thereby cutting the sheet portion pressed into the front side of the mold 61 and the subsequent sheet portion above it. Figure 2)
. On the other hand, the valve 74 on the vacuum suction plate 7 side is switched to the position where the vacuum chamber 72 is opened to the atmosphere, and the valve 6 of the mold 61 example
6 is switched open. As a result, the material sheet pressed between the front side of the mold 61 and the vacuum suction plate 7 is sucked toward the molding surface 62 side of the mold 61 and vacuum-formed along the molding surface (second In this case, the material sheet can be subjected to vacuum/pressure forming by blowing out air from the vacuum suction holes 71 of the seven vacuum suction plates.

The operations of the above-mentioned parts are executed substantially simultaneously based on the above-mentioned detection signals.

(5) Also, when the material sheet cutting by the cutting blade 76 is completed, the device carrier mechanism is operated and the vacuum forming device 6 including the vacuum suction plate 7 is connected to the subsequent sheet thickness adjusting roller pair 4 and 5 side. It moves downward at the same speed as or faster than the descending speed of the material sheet (as shown by the two-dot chain line in Fig. 2), and is released from the descending path of the subsequent material sheet to the side molded body take-out position. . During this time, the pressing of the material sheet against the mold 61 by the plate 7 and the suction of the sheet to the molding surface 62 by the vacuum suction hole 63 continue.

Further, the sheet vacuum-formed along the molding surface 62 is cooled down to a predetermined temperature at which it can be taken out by the cooling effect of the cooling water introduction pipe 67 embedded in the mold 61.

(6) The vacuum suction plate 7 retreats from the front side of the mold 61 after the vacuum forming device 6 moves to the molded object take-out position;
Then, it is pulled upward from the front surface of the mold 6 and moved to the suction position of the original material sheet S.

Valve 66 can also be switched to a closed position or to a position that opens vacuum chamber 64 to the atmosphere. The molded body is then taken out from the mold 61 manually or automatically by a robot device.

(7) On the other hand, the next vacuum forming device is alternately moved to the material collecting position, and the operations and steps in (1) to (8) above are executed by this device.

In this way, the two vacuum forming apparatuses are moved to the material taking position alternately in the Z-shaped traverse method, or multiple vacuum forming apparatuses are sequentially moved and driven by the rotary set to form a sheet from the sheet thickness adjusting roller pair 4φ5 to a predetermined value. The vacuum forming process is continuously performed on the material sheet S which is continuously descending at a high speed.

In the illustrated example above, the extruder 1 serving as the material sheet manufacturing device may be a rolling roll device.

The material sheet S is a sheet in the form of a laminate formed by coextrusion, and is a sheet formed by continuously bonding together each sheet extruded or rolled from two or more extruders or/and rolling roll devices. It may also be a laminated sheet that is sufficiently softened by kneading and heating energy.

Alternatively, the sheet may be extruded, discharged or rolled from an extruder or/and rolling device, and then laminated with another material layer on one or both sides.

The vacuum forming device 6 as a sheet forming device may be a pressure forming device, a vacuum pressure forming device, or a press forming device. The material sheet was introduced downward between the open mold and the opposing jig or between the female and male molds, and the material sheet, which was suctioned and held by the vacuum suction plate 7, was formed on the molding surface of the mold. The material sheet is moved and held by the suction force of the vacuum suction hole, and the vacuum suction plate 7 is removed from between the mold and the opposing jig or between the female and male molds, and then the mold is clamped to form the material sheet. .

Trimming of unnecessary portions of the sheet material around the outside of the effective molding area of the molded body can be performed simultaneously with sheet molding by using a trimming blade. It is also possible to use vacuum force. FIG. 3 shows an example in which vacuum force is used, and 79 is the mold 6 of the vacuum suction plate 7.
This is an annular groove having a substantially V-shape in cross section and formed in the surface portion of the material sheet pressing surface for the material sheet 1. The opening width and depth of the groove are about twice and about 5 to 10 times the thickness of the material sheet, respectively. Further, a vacuum suction hole 79a is opened at the bottom of the groove. After the plate 7 presses the material sheet S against the molding yIi61, the valve 80 is opened, whereby the sheet portion corresponding to the groove 79, that is, the sheet at the boundary between the effective molding area of the material sheet S and the unnecessary sheet portion. Is the part inside groove 79? By being sucked and stretched to a large extent, the material can be thinned and even cut. 81
is an auxiliary heater embedded in the forming mold 61 side via a heat insulating material 82 in order to actively heat the sheet portion to be stretched to promote stretching.

This trimming method is effective for trimming parts of the molded body that cannot be trimmed in the mold clamping direction. Although some debris remains around the outside of the molded product, it can be easily removed after taking out the molded product. Compared to performing the trimming process in a separate process, cutting costs and man-hours are not required, resulting in lower costs. It can also be used to make holes inside molded objects.

The groove 79 may be provided on the mold 61 side. In the case of a press molding mold or a pressure molding mold, it may be provided on the mating mold or the material sheet holding jig.

FIG. 4 shows a modification, in which reference numeral 9 denotes an endless rotating belt device vertically disposed between the pair of sheet thickness adjusting rollers 4 and 5 and the vacuum forming device 16. The endless bell) 91 has a length and width that are appropriately larger than the length and width of the material sheet necessary for application to the vacuum forming device 6, and is a material that still has sufficient cross-wire heating energy and is in a softened state. The sheet S is made of a non-adhesive and heat-resistant material, and is itself breathable or has many small suction holes formed in each part of its surface.

The belt 91 is constantly rotationally driven in the counterclockwise direction of the arrow by a drive mechanism (not shown) at a circumferential speed that is substantially synchronized with the downward drooping speed of the material sheet S from the sheet thickness adjusting roller pair 4 and 5 side. .

Reference numeral 92 denotes a vacuum chamber disposed between the downward movement side belt 91a and the upward movement side belt 91b of the rotary belt 91;
3 is a vacuum pipe connecting the vacuum chamber 92 and the vacuum pump Vp, and 94 is an on-off valve provided in the middle of the vacuum pipe. When valve 94 is opened, vacuum chamber 9
2, the surface side of the downward movement side belt 91a of the rotating bell) 91 becomes air suction state. Reference numeral 95 denotes a material sheet cutting device disposed at an open position between the pair of sheet thickness adjusting rollers 4 and 5 and the endless rotating belt device 9.

The vacuum suction plate 7 is the lowering movement side bell) 9 of the above-mentioned rotating bell) 91.
It is waiting with the position facing 1a as its home position.

As a result, the rotating bell) 91 is driven to rotate, and the opening/closing valve 9
4 is opened and the downward moving side belt 91a of the rotating bell) 91 is held in an air suction state, the material sheet S is continuously suspended downward from the sheet thickness adjusting roller pair 4 and 5 side. Next, the belt 91a of this material S is sequentially vacuum-adsorbed and held on the surface of the downward moving side belt 91a of the rotary belt 91 in the air suction state.
The material sheet S is attached to the belt 91a by suction and holding against the surface.
The weight is supported by the tensile force of , and the material descends over a sufficient length without substantially causing thinning, uneven thickness, or tearing due to stretching under its own weight.

When the lower end of the material sheet descends to a desired position llC on the lower end side of the rotary belt 91, this is detected by a sensor (not shown), and at that point the cutting device 95 operates to cut the material sheet S between the sheet thickness adjusting rollers. 4, 5 and rotating belt device 9
Cut in between. The cut material sea) S continues to be the rotating bell) 91's descending moving side belt 9! ! It is held by suction on the L side.

On the other hand, the valve 74 on the side of the vacuum suction plate 7 is opened, and each vacuum hole 71 on the front surface of the plate enters the air suction state, and the vacuum suction plate 7
is driven forward, and its front surface closely contacts the surface of the material sheet S which is suctioned and held on the surface of the bell) 91a and adsorbs the material sheet S. After this close contact, the valve 94 of the vacuum chamber 92 on the rotary belt device 9 side is temporarily rotated to a position where the inside of the chamber 92 is opened to the atmosphere, or conversely, air is pumped into the chamber 92. As a result, the suction of the material sheet S to the surface 91a is released. During this release, the vacuum suction plate 7
The material sheet (S) is sucked and held on the front side of the material sheet (S) and then retreated, leaving the side of the bell () 91a and being driven downward at a speed faster than the peripheral rotational speed of the subsequent bell () 91 to form the material in the vacuum forming device i6 below. When the vacuum suction 7 holding the material sheet S moves away from the belt 91a side (as shown by the two-dot chain line), the valve 94 of the vacuum chamber 92 is returned to the open state and the bell) 91a is in the air suction state. becomes.

The material sheet S held by the vacuum suction plate 7 and introduced into the vacuum forming apparatus 6 is subjected to the forming process in the same manner as in the example shown in FIGS. 1 and 2 described above. The vacuum suction plate 7 then moves back to the home position (solid line water position) facing the surface of the bell) 91a again.

While the vacuum suction plate 7 receives the material sheet S from the belt 91a side, moves to the vacuum forming device 6 side, and returns to the home position again, the subsequent material sheet is continuously picked up from the sheet thickness adjusting roller pair 4 and 5 side. However, while the vacuum suction plate 7 returns to the home position, the subsequent material sheet S is successively suctioned and held on the surface of the bell) 91a and descends, so that the subsequent material sheet S is thinned due to its own weight stretching.
Problems of uneven thickness and tearing do not occur.

It is also possible to mold the sheet S by moving a vacuum forming mold into contact with the surface of the material sheet S that has been sucked onto the surface of the material sheet S (bell) 91a and lowered.

As described above, according to the method of the present invention, the raw material sheet, which is discharged or sent out from an extruder or rolling roll device and is still in a softened state due to cross-wire heating energy, is stretched by its own weight. It is possible to continuously lower the sheet and introduce it into a sheet forming apparatus for forming processing without substantially causing thinning, uneven thickness, or tearing.

Therefore, it is extremely thermoeconomically advantageous (energy saving) and more advantageous in terms of thermoeconomics (energy saving) than in the case where a material sheet that has been manufactured and stocked in advance and has cooled to room temperature and is in a softened state is heated and softened and then sent to a sheet forming device to be formed. Since the entire material is in a sufficiently softened state close to molten, it has good moldability and transferability of the uneven surface pattern, making it possible to efficiently mass-produce molded bodies of high-quality aged formable material sheets at low cost. .

It is also possible to obtain a molded body partially formed with ribs or provided with insert parts such as metal fittings (molding using a nested mold).

When the sheet forming device is a vacuum forming device, the forming surface 62 portion of the vacuum forming mold 61 is made into a porous type with a fired material mainly made of metal particle sprayed material or synthetic mullite with an uneven pattern formed on the surface. By this method, it is possible to obtain a molded article having an extremely clear uneven pattern transferred onto its surface. Moreover, it is possible to obtain a product without transfer of vacuum suction hole marks on the surface.

In the case of a press molding device, a concave portion is formed in a part of the molding surface of the mold, and a material similar to or different from the material sheet S is set in advance in the concave portion, so that molding corresponding to the concave portion can be performed. It is possible to obtain a molded article whose body portion is thickened or irregularly shaped.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the material sheet discharged from the extruder being suctioned and held on the surface of the vacuum suction plate, and then introduced into the vacuum forming apparatus by hanging down.
The figure is a schematic diagram of a state in which a material sheet is vacuum formed, FIG. 3 is a schematic diagram of an example in which the material sheet is trimmed by a vacuum stretching method, and FIG. 4 is a schematic diagram of a modified example. 1 is an extruder, S is an extruded material sheet, 4 and 5 are a pair of sheet thickness adjusting rollers, 6 is a vacuum forming device, and 7 is a vacuum suction plate. (Spontaneous) Procedural Amendment Written March 22, 1980 1. Indication of Case 1981 Patent Application No. 26874 2. Name of Invention Method for Manufacturing a Molded Body of Thermoformable Material Sheet 3. Person Making Amendment Case Relationship with Patent Applicant Name: Meiwa Sangyo Co., Ltd. 4, Agent: Kimura Building 5, 2-11-12 Yoyogi, Shibuya-ku, Tokyo, Subject of amendment: "Detailed Description of the Invention" section of the specification. 6. Contents of the amendment (1) On page 8 of the specification, lines 7-8, "Tripass" is amended to "Traverse." (2) Change “Vacuum suction 7” to “Vacuum suction plate 7” at the end of page 18.
” he corrected.

Claims (1)

[Claims] (1) The sheet of thermoformable material, which is continuously sheeted or sent out from an extruder or rolling roll device and is still in a softened state due to the crosstalk heating energy, is roughly synchronized with the descending speed of the sheet. The material is sucked and held by the vacuum suction force on the surface of a descending vacuum suction plate, and is then introduced downward into a sheet forming device such as a vacuum forming device to perform a forming process. A method for producing a molded body of a thermoformable material sheet, characterized in that: