JPH0985819A - Molding of thermoplastic resin sheet and demolding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly peel a thermoplastic resin sheet from a mold surface at a time of demolding in a molding method closely bonding a heated thermoplastic resin sheet to the mold surface to shape the same into a mold surface shape and demolding the molded object from the mold surface. SOLUTION: A heated thermoplastic resin sheet 50 is closely bonded to a mold surface to be molded into a mold surface shape and the molded sheet is demolded from the mold surface to mold a thermoplastic resin sheet. In this molding method, a pin 1 of which the leading end is formed into an engaging part 12 is thrust in a part of the thermoplastlc resin sheet from the outside of a mold at a time of demolding to engage the engaging part of the pin with the thermoplastic resin sheet and, thereafter, the pin is kept away from a mold 60 to peel the thermoplastic resin sheet from the mold surface.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for molding a thermoplastic resin sheet and a demolding device.

[0002]

2. Description of the Related Art Conventionally, there has been a vacuum forming method as a method for forming a thermoplastic resin sheet. In this vacuum forming method, a heated thermoplastic resin sheet is suction-adhered to a mold surface to shape it into a mold surface shape, and after cooling is fixed to the mold surface shape, it is released from the mold surface.

The demolding is performed by blowing gas from inside the mold toward the thermoplastic resin sheet on the mold surface, or by sucking the thermoplastic resin sheet from outside the mold with a suction cup and peeling it from the mold surface. There is.

However, depending on the shape of the product, the thermoplastic resin sheet may be required to have a deep undercut portion or a bag shape in which the mold surface is wound. In these cases, the undercut portion or In the bag-shaped portion, the thermoplastic resin sheet was strongly engaged with the mold surface, and the thermoplastic resin sheet could not be peeled off from the mold surface by blowing the gas or sucking with a suction cup. In that case,
The thermoplastic resin sheet has to be manually peeled off from the mold surface, which is a troublesome task. There is also a problem that automatic molding cannot be performed.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a molding method in which a heated thermoplastic resin sheet is brought into close contact with a mold surface to form a mold surface shape, and then the mold surface is demolded. An object of the present invention is to provide a molding method capable of reliably peeling a plastic resin sheet from a mold surface and capable of automatic molding, and a demolding apparatus therefor.

[0006]

The invention relating to a method for molding a thermoplastic resin sheet is directed to a method in which a heated thermoplastic resin sheet is brought into close contact with a mold surface to form it into a mold surface shape, and then the mold surface is removed from the mold surface. In the method for molding a plastic resin sheet, at the time of releasing from the mold, a pin having a locking portion at its tip is pierced from outside of the mold into a part of the thermoplastic resin sheet to fix the locking portion of the pin to the thermoplastic resin sheet. It is characterized in that the thermoplastic resin sheet is peeled from the mold surface by locking the pin to the mold and then moving the pin away from the mold.

Further, at the time of releasing the mold, a gas may be blown from the mold surface toward the thermoplastic resin sheet, or the thermoplastic resin sheet may be sucked out of the mold.

On the other hand, the invention relating to the demolding device is a demolding device for peeling off a thermoplastic resin sheet shaped so as to be in close contact with the mold surface from the mold surface. The present invention is characterized by including a pin having a locking portion at a tip thereof that pierces and locks the resin sheet, and a forward / backward moving means for moving the pin forward / backward from the outside of the mold toward the mold.

Further, in the demolding device, a holding member having a pin insertion hole formed and a tip of a peripheral wall thereof serving as a holding portion of the thermoplastic resin sheet is provided on the outer periphery of the pin, and a locking portion from the holding portion to the tip of the pin is provided. Is a preferred example. In that case, it is preferable that the corners of the inner peripheral surface of the pressing portion are chamfered.

Further, it is a preferable example that the demolding device further includes a lateral moving means for laterally moving the pin outside the mold with respect to the mold to convey the thermoplastic resin sheet.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an example of a demolding device used in the thermoplastic sheet molding method of the present invention, FIGS. 2 to 7 are stepwise cross-sectional views of an example of the molding method of the present invention, and FIG. FIG. 9 is a partial cross-sectional view showing the operation at the time of molding, and FIG. 9 is a cross-sectional view showing the time of demolding in another example.

First, the demolding apparatus 10 of the present invention shown in FIG.
Will be described. The demolding device 10 is used when the thermoplastic resin sheet 50 is demolded from the mold surface 61 in a molding method in which the thermoplastic resin sheet 50 is closely adhered to the mold surface 61 for shaping. Further, the demolding device 10 of this embodiment is of a type that is hung on a rail 70 provided above the mold 60 in the thermoplastic sheet molding line, and includes a pin 11 and a forward / backward moving means 21. Both ends of the rail 70 are fixed to a pillar standing on the floor of the molding line of the thermoplastic resin sheet, or to a wall surface or the like.

The pin 11 is made of a thermoplastic resin sheet 50.
It is used for peeling off the thermoplastic resin sheet 50 from the mold surface 61 by being locked to, and is made of a rod-shaped body having the locking portion 12 at the tip. The locking portion 12 is a portion that pierces and locks the thermoplastic resin sheet 50. In addition to the arrowhead shape as in this embodiment, a protrusion for preventing slippage is formed on the side surface of a needle-shaped object having a sharp tip. It may be the one that has been done. This pin 11
It is attached to the forward / backward moving means 21 with the locking portion 12 facing downward. Further, it is preferable that a plurality of the pins 11 are provided around the mold surface 61 from the viewpoint of the mold release property of the thermoplastic resin sheet.

The advancing / retreating means 21 is for advancing / retreating the pin 11 in the vertical direction, and comprises a first advancing / retreating means 22 and a second advancing / retreating means 42 in this embodiment. The first advancing / retreating means 22 advances (lowers) the pin 11 toward the mold 60 when locking the pin 11 to the thermoplastic resin sheet 50 on the mold surface, and also moves the thermoplastic resin sheet 50 to the mold surface. This is for retracting (raising) the pin 11 when peeled from 61. In this embodiment, it is composed of an air or hydraulic cylinder device 23 attached downward to a suspending portion 45 to the rail 70, and a frame body 25 attached to the lower end of an operating member 24 thereof.

The frame 25 is composed of an upper plate 26 fixed to the operating member 24 and a side plate 27 provided downward on the peripheral edge of the upper plate 26. The side plate 27 is formed by the forward movement of the operating member 24. Are formed so as to surround the periphery of the mold surface 61. A cover member 28 is provided at the lower end of the side plate 27 to cover the thermoplastic resin sheet 50 on the mold surface 61 as the actuating member 24 advances. The covering member 28 has an inner surface shape substantially along the mold surface 61.
It is composed of a central portion 29 and a flange portion 30 on the outer periphery thereof.

The central portion 29 is formed of the thermoplastic resin sheet 5
When the gas is blown from the die surface 61 toward the thermoplastic resin sheet 50 at the time of demolding of 0, it is for pressing the thermoplastic resin sheet 50 from the outside of the die 60, and when the gas is not blown No longer needed.

On the other hand, the flange portion 30 is provided with a pressing member 31 for pressing the thermoplastic resin sheet around the pin 11 when the engaging portion 12 of the pin 11 is pulled out from the thermoplastic resin sheet 50. It is a thing. A through hole 31 is formed in the flange portion 30 at a position corresponding to the pin 11, and the pressing member 3 is provided in the through hole 31.
2 is fitted.

The pressing member 32 is a tubular member having a pin insertion hole 33 formed therein, and a lower end of a peripheral wall 34 thereof serves as a pressing portion 35. The pressing portion 35 is projected from the lower surface of the flange portion 30. In this state, the pin 11 is inserted into the through hole 31 of the flange portion 30, and the pin 11 is inserted into the pin insertion hole 33. Further, as shown in FIG. 8C, the corner 36 of the inner peripheral surface of the pressing portion 35 has a chamfered shape, and the corner 36 is pulled out when the locking portion 12 of the pin is pulled out from the thermoplastic resin sheet.
It is preferable that the thermoplastic resin sheet 50 is not damaged at the portion. In addition, in this embodiment, the pressing member 32 is formed as a member different from the covering member 28, but the flange portion 30 of the covering member 28 may be used as the pressing member. In that case, the through hole 31 of the flange portion 30 is a pin insertion hole, and the lower end of the peripheral wall of the through hole 31 is a pressing portion.

The second advancing / retreating means 42 retreats (raises) the pin 11 when the engaging portion 12 of the pin 11 after the mold release of the thermoplastic resin sheet 50 is pulled out from the thermoplastic resin sheet 50.
Thus, the pin locking portion 12 is housed in the pin insertion hole 33 from the pressing portion 35, while the thermoplastic resin sheet 50
When locking the locking portion 12 of the pin, the pin 11 is moved forward (downward) so that the locking portion 12 projects from the pressing portion 35. In this embodiment, the frame 2
5 side plate 27 is composed of a plurality of air or hydraulic cylinder devices mounted downward at predetermined intervals. The pin 11 is attached to the operating member 43 of the cylinder device. Although the second advancing and retracting means 42 of this embodiment is independently provided for each pin 11, a plurality of pins may be operated by one second advancing and retracting means.

The suspending portion 45 is a portion for suspending the demolding device 10 on the rail 70. The structure of the hanging portion 45 is an appropriate known structure according to the cross-sectional shape of the rail 70 and the like. For example, the rail 70 has an H-shaped cross section with flanges protruding from the upper and lower side surfaces thereof,
An example is one in which the upper part of the hanging part is engaged between the upper and lower flanges.

Further, in this embodiment, the suspending portion 45 is provided with a lateral moving means 46. The lateral moving means 46 is for laterally moving the pin 11 above the die 60, and in this example, the entire demolding device 10 is laterally moved. The lateral moving means 46 has a known structure. For example, the rail 7
0 has a shape in which a flange protrudes from the upper and lower side surfaces, and two wheels that are rotated by a drive motor are provided in the suspending portion 45 so as to sandwich the rail vertical portion between the upper and lower flanges. The entire mold device 10 is a rail 7
One that moves laterally along 0 is given.

The mold 6 for molding the thermoplastic resin sheet
A hole 62 into which the locking portion 12 at the tip of the pin 11 can be inserted is formed at a position corresponding to the pin 11 on the mold surface 61 of 0. The illustrated mold 60 is a vacuum molding mold, and a vacuum suction hole 63 is formed in the mold surface 61 thereof, and communicates with a vacuum suction device (not shown) outside the mold. Reference numeral 64 is a base that supports the mold 60.

Next, an example of a method of molding a thermoplastic resin sheet used when the mold releasing device 10 is used to remove a thermoplastic resin sheet will be described. 2 to 7 are schematic cross-sectional views showing the process stepwise.

In this example, the process from vacuum forming of the thermoplastic resin sheet 50 to carrying of the thermoplastic resin sheet after demolding is automatically performed. First, as shown in FIG. 2, the thermoplastic resin sheet 50 heated and softened by a heating means (not shown) such as a heater is used to form the mold surface 61 of the mold 60.
Cover. The thermoplastic resin sheet 50 is used for publicly known vacuum forming and is made of an appropriate thermoplastic resin such as vinyl chloride resin and ABS resin. Further, a conveyor device 75 for moving the demolded thermoplastic resin sheet 50 to a predetermined place is provided beside the mold 60.

At this time, the demolding device 10 is not positioned above the die surface 61 so as not to interfere with the work of covering the die surface 61 with the thermoplastic resin sheet 50.
In this embodiment, the demolding device 10 is located on the conveyor 75 next to the mold 60 and performs the work of dropping the previously molded thermoplastic resin sheet 51 onto the conveyor 75.

Next, as shown in FIG. 3, the thermoplastic resin sheet 50 on the mold surface is sucked onto the mold surface 61 to form the mold surface shape, and in this state, it is cooled and fixed to the mold surface shape. The cooling is performed by natural cooling or by blowing air or water onto the thermoplastic resin sheet 50.
Alternatively, it is appropriately performed by passing cooling water through a cooling pipe arranged in the mold 60. The heating conditions of the thermoplastic resin sheet 50, the suction force and the like are the same as those in the known vacuum forming.

After the cooling, the vacuum suction is stopped, and the thermoplastic resin sheet 50 is released from the mold as follows. First,
The demolding device 10 is moved above the die 60 by the lateral movement means 46 provided in the hanging portion 45. Subsequently, as shown in FIG. 4, the pins 11 are advanced (lowered) toward the thermoplastic resin sheet 50 on the mold surface 61 by the first advance / retract means 22. At this time, as well understood from FIG. 1, the pin 11 is in a state of being advanced (lowered) by the second advancing / retracting means 42, and the locking portion 12 at the leading end projects from the pressing portion 35.

Then, as the pin 11 is moved forward (downward), as shown in FIG.
Pierces and locks the thermoplastic resin sheet 50 on the mold surface. At that time, the advancement (descent) of the pin 11 by the first advancement / retraction means 22 is stopped.

At this time, a downward trimming blade (not shown) is provided on the side plate 27 of the frame 25 or the flange portion 30 of the covering portion 28, and the thermoplastic resin sheet 50 is formed.
The periphery of the may be cut and trimmed.

Subsequently, the pin 11 is retracted (raised) by the first advancing / retreating means 22 and is moved away from the die surface 61. As a result, as shown in FIGS. 5 and 8B, the thermoplastic resin sheet 50 is pulled upward by the pins 11, peeled from the mold surface 61, and released from the mold.
At that time, since the pin engaging portion 12 is engaged with the thermoplastic resin sheet 50 and the pin 11 is not easily disengaged from the thermoplastic resin sheet 50, the thermoplastic resin sheet 50 is formed on the mold surface 6.
It is surely peeled from 1.

At the time of demolding, the suction holes 6 on the mold surface
The vacuum suction device communicating with 3 may be switched to a gas supply device such as air, and a gas may be blown from the suction holes 63 toward the thermoplastic resin sheet 50 on the mold surface to assist the demolding.

After the thermoplastic resin sheet 50 is peeled from the mold surface 61 and pulled up above the mold surface 61, the lateral moving means 46 moves the mold releasing device 10 above the conveyor 75 beside the mold 60. As a result, the pin 11 also moves laterally, and the thermoplastic resin sheet 50 locked to the pin 11
Are conveyed above the conveyor 75.

In the demolding device 10 moved to the upper side of the conveyor 75, the pin 11 is advanced (lowered) by the first advancing / retracting means 22, and the thermoplastic resin sheet 50 locked to the pin 11 is transferred to the conveyor 75. Can be approached to.

Subsequently, (C) of FIG. 6 and FIG.
As shown in (D), the pin 11 is retracted (raised) by the second advancing / retracting means 42, and the locking portion 12 at the tip of the pin is housed in the pressing portion 35. At that time, the pin 11
Since the thermoplastic resin sheet 50a around the locking portion 12 of the pin collides with the pressing portion 35 and is prevented from rising, the pin 11
The locking portion 12 of is removed from the thermoplastic resin sheet 50. Further, since the corner 36 on the inner circumference of the pressing portion 35 is chamfered, there is no possibility that the thermoplastic resin sheet 50 will be broken by coming into contact with the corner 36.

The thermoplastic resin sheet 50 from which the pin 11 has been removed falls onto the conveyor 75 and is carried to the desired location by the conveyor 75. Reference numeral 76 is a conveyor 75
The shape holding block is arranged on the conveyor 75 in order to prevent the shape of the thermoplastic resin sheet 50 from collapsing above.

Thereafter, as shown in FIG. 7, in the demolding device 10, the pin 11 is retracted (raised) by the first advancing and retracting means 22 and the tip of the pin 11 is locked by the second advancing and retracting means. The part 12 projects from the pressing part 35, and is further moved to the upper side of the mold 60 by the lateral movement means 46 to be used for the next demolding.

FIG. 9 is a sectional view showing another embodiment.
In this embodiment, the demolding device 10A has a suction cup 77 connected to a vacuum suction device (not shown) at the center of the covering portion 28, and when the thermoplastic resin sheet 50 is demolded,
The thermoplastic resin sheet 50 is sucked to the upper side of the mold 60 by the suction cup 77 as the pin 11 retracts (raises). Thus, the thermoplastic resin sheet is more reliably released from the mold. Further, in addition to this suction, a means for blowing a gas from the suction hole 63 toward the thermoplastic resin sheet 50 on the mold surface may be used together.

In the above embodiment, an example is shown in which the demolded thermoplastic resin sheet 50 is carried to a desired place (above the conveyor 75) by the lateral moving means 46 and is automatically removed from the pin 11. The lateral movement means 46 is not provided, and the thermoplastic resin sheet 50 is attached to the pin 11 above the mold 60.
Alternatively, the thermoplastic resin sheet 50 may be manually removed from the pin 11 above the die 60 without providing the pressing portion 35 and the second advancing and retracting means 42.

Further, although the case where the vacuum forming method is used is shown in the above-mentioned embodiment, the forming method and the mold releasing apparatus of the present invention are not limited to the case where the vacuum forming method is used. Further, the forward / backward direction of the pin is not limited to the vertical direction but may be an oblique direction or a horizontal direction depending on the direction of the mold surface.

[0040]

As described above, according to the method for molding a thermoplastic resin sheet and the demolding apparatus of the present invention, a pin having a locking portion at its tip is pierced and locked in the thermoplastic resin sheet on the mold surface. However, since the thermoplastic resin sheet is peeled off from the mold surface while keeping away from the mold surface as it is, the pins are not easily detached from the thermoplastic resin sheet at the time of mold release, and the thermoplastic resin sheet can be reliably released from the mold. Further, if the position where the pin pierces is set outside the product portion, the hole portion formed in the thermoplastic resin sheet by piercing the pin can be removed by trimming to obtain the product. There is no loss of quality.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a demolding device used in a method for molding a thermoplastic resin sheet according to the present invention.

FIG. 2 is a cross-sectional view showing a case where a thermoplastic resin sheet is covered on a mold surface in an example of the molding method of the present invention.

FIG. 3 is a cross-sectional view showing when a thermoplastic resin sheet is sucked onto a mold surface in the example.

FIG. 4 is a cross-sectional view showing a state in which a pin is lowered toward a mold surface in the embodiment.

FIG. 5 is a cross-sectional view showing when the pin moves away from the mold surface in the example.

FIG. 6 is a cross-sectional view showing a state in which the pin laterally moves to the side of the mold in the example.

FIG. 7 is a cross-sectional view showing a state before proceeding to the next demolding in the example.

FIG. 8 is a partial cross-sectional view showing the operation at the time of demolding in the example.

FIG. 9 is a cross-sectional view showing another example during demolding.

[Explanation of symbols]

 11 Pins 12 Locking Part 21 Forward / Backward Means 35 Holding Part 45 Suspending Part 46 Lateral Moving Means 50 Thermoplastic Resin Sheet 60 Model 61 Mold Surface

Claims (7)

[Claims] 1. A method for molding a thermoplastic resin sheet, which comprises removing a mold from the mold surface after a heated thermoplastic resin sheet is brought into close contact with the mold surface to form the mold surface shape. The pin that has become the locking part is pierced from outside the mold into a part of the thermoplastic resin sheet, the locking part of the pin is locked to the thermoplastic resin sheet, and then the pin is moved away from the mold to generate heat. A method for molding a thermoplastic resin sheet, which comprises peeling a plastic resin sheet from a mold surface. 2. The method for molding a thermoplastic resin sheet according to claim 1, wherein a gas is blown from the mold surface toward the thermoplastic resin sheet at the time of demolding. 3. The method for molding a thermoplastic resin sheet according to claim 1, wherein the thermoplastic resin sheet is sucked to the outside of the mold when the mold is released. 4. A demolding device for peeling a thermoplastic resin sheet formed in close contact with a mold surface from the mold surface, wherein the thermoplastic resin sheet is stuck from the outside of the mold to the thermoplastic resin sheet on the mold surface. A demolding apparatus comprising: a pin having a locking portion at the tip thereof, and a forward / backward moving unit for moving the pin forward / backward from the outside of the mold toward the mold. 5. The pressing member according to claim 4, wherein a pin insertion hole is formed, and a tip of a peripheral wall of the pin serves as a pressing portion of the thermoplastic resin sheet, the pressing member is provided on the outer periphery of the pin, and the locking portion from the pressing portion to the pin tip is provided. A demolding device characterized in that it can be projected and stored. 6. The demolding device according to claim 5, wherein the corner of the inner peripheral surface of the pressing portion is chamfered. 7. The method according to any one of claims 4 to 6,
A demolding device comprising lateral moving means for moving a pin laterally with respect to the mold outside the mold to convey a thermoplastic resin sheet.