CN1304351A

CN1304351A - Apparatus and method for twin sheet thermoforming

Info

Publication number: CN1304351A
Application number: CN99807113A
Authority: CN
Inventors: 丹尼尔·威滕－汉娜; 斯图尔特·沃恩
Original assignee: Fisher and Paykel Ltd
Current assignee: Fisher and Paykel Appliances Ltd
Priority date: 1998-06-10
Filing date: 1999-06-10
Publication date: 2001-07-18
Anticipated expiration: 2019-06-10
Also published as: KR20010052725A; TW407105B; EP1109661A4; WO1999064221A8; EP1109661A1; BR9911139A; CA2334663A1; AU744880B2; WO1999064221A1; JP2002517333A; AU4535499A; CN1107583C

Abstract

Apparatus for twin sheet thermoforming has each mould half incorporating a sheet support means which can hold a sheet by its edge and support the sheet during heating and wherein at least one of the sheet support means can retract during thermoforming. The sheets are supported clear of each mould half by the supports but are heated from between. A movable heater may carry sheets while simultaneously heating and transfer heated sheets to the mould halves of the thermoforming apparatus.

Description

The apparatus and method that are used for twin sheet thermoforming

Background of the present invention

Invention field

The present invention relates to be used for the apparatus and method of twin sheet thermoforming, particularly relate to a kind of improved method and apparatus, it does not need a sheet material scaffold.

The prior art general introduction

Twin sheet thermoforming becomes more and more general in the moulding of large piece article.Carried out some application, such as refrigerator cabinet and other big apparatus cabinets, this point can be for example referring to United States Patent (USP) 5374118.This specification has been described a kind of technology, and wherein the sheet material of two extruding is directly carried between opposed half module, and they are combined in together then, to form the panel of a cabinet.Because material is extruded continuously, and molding process is a non-continuous process, so this method has produced serious material processed problem and waste of material problem.Therefore, in the art, the plasticity sheet material that cooling can be heated before molded immediately is considered to more suitable.

An example of this method is described among the open WO 96/25287 of PCT, and it provides a typical thermoforming process, and wherein a pair of sheet material is by a frame fixation and separate.This sheet material is heated in the outside of mould, and the framework that carries sheet material is inserted between two half modules, and half module and the therebetween framework that is supporting sheet material are combined in together then.This technology comprises many steps consuming time in a production life cycle, this has increased additional complexity to machine conversely, if this arts demand is operated the factory floor space that needs are unnecessary and comprise important optional equipment in the automation mode.

Therefore, an object of the present invention is to provide the device and/or the method that are used for twin sheet thermoforming, it is intended to overcome above-mentioned shortcoming or provides a useful selection to the public to the major general.

General introduction of the present invention

A first aspect of the present invention is to propose a kind of device that is used for twin sheet thermoforming, and it comprises:

A pair of opposed half module, it can move between an open position and a closed position in the thermoforming process,

The sheet material supporting arrangement relevant with each described half module, each sheet material supporting arrangement links to each other with their half modules separately, and be configured to and keep a thermoplastic sheet around its periphery, this sheet material supporting arrangement is formed at and keeps each sheet material when described half module is positioned at its open position separated from one anotherly, each described half module, its separately supporting arrangement and the sheet material that keeps by described supporting arrangement define a pressurized volume together

The device relevant with each described half module, it can produce a controlled pressure reduction between each defined volume and its outside.

Another aspect of the present invention is to propose a kind of method that is used for twin sheet thermoforming, and it comprises:

On each of a pair of half module, keep a heated thermoplastic sheet, so that the volume of a sealing to be provided between described sheet material and described half module, draught head between each space that is controlled at each sheet material simultaneously and seals between the half module separately, sagging to prevent arbitrary described sheet material

Change described pressure reduction, occur in, and only take place to contact with each other and form the part place of seam betwixt to guarantee the thin space between sheet material,

Move described half module close to each otherly, increase the pressure reduction effect simultaneously, and make the welding zone of each described sheet material seat itself by an annular, and

Continue to make described half module close to each other, being joined together in described welding zone, and between described welding zone, form a seam.

Another aspect of the present invention is to provide a kind of device that is used for twin sheet thermoforming, wherein each half module comprises a sheet material supporting arrangement, this device can keep a sheet material by its edge, and during heating support described sheet material, and wherein at least one described sheet material supporting arrangement is recalled when thermoforming.

For a person skilled in the art, for the present invention,, many structural changes and broadly different embodiment can be arranged not departing under the claims institute restricted portion.Disclosure herein and description are illustrative purely, and limit on not being intended in all senses.

Brief description of drawings

Fig. 1 is the cross-sectional view of a twin sheet thermoforming device according to an embodiment of the invention, and wherein sheet material and heater are positioned on the suitable position, and the sheet edge that is fixed keeps separating,

Fig. 2 is the perspective view of a thermal formation apparatus part shown in Figure 1, shows sheet material supporting arrangement, an adjacent element and a part of die cavity,

Fig. 3 is the cross-sectional view of a thermal formation apparatus part shown in Figure 1, and this moment, heater was removed, and the thermoforming process carried out a part,

Fig. 4 is a cross-sectional view similar with Fig. 3, and wherein thermoforming process is proceeded,

Fig. 5 is a cross-sectional view similar with Fig. 4, and wherein thermoforming operation is finished substantially, and two sheet materials are joined together,

Fig. 6 is a cross-sectional view of twin sheet thermoforming device in accordance with another embodiment of the present invention, and wherein seam forms die edge and is included in the sheet material supporting arrangement, and can realize finishing in intensely processed products molded,

Fig. 7 is the cross-sectional view of a device part shown in Figure 6, and wherein a part has been carried out in the thermoforming operation,

Fig. 8 is a cross-sectional view similar with Fig. 7, and wherein thermoforming operation is proceeded, and sheet material just engages,

Fig. 9 is a cross-sectional view similar with Fig. 8, and wherein the thermoforming operation is finished substantially,

Figure 10 is a cross-sectional view similar with Fig. 9, and wherein the thermoforming operation is finished, and molded middle finishing is finished by the cutting off effect between last sheet material supporting arrangement and the female die,

Figure 11 is a cross-sectional view that passes through a sheet material supporting arrangement according to an embodiment of the invention,

Figure 12 is a cross-sectional view that passes through two plate forming devices according to another embodiment of the present invention,

Figure 13 is a cross-sectional view by the two plate forming devices of Fig. 1 and a sheet material that has heater according to a further aspect of the invention,

Figure 14 is a cross-sectional view that reaches the relevant sheet material that has heater by a zone of two plate forming devices, describes the anchor clamps that are used for the sheet material transmission and comprised the hidden part that some are shown in broken lines,

Figure 15 is the perspective view of an embodiment that is suitable for holding the heater of different size sheet material,

Figure 16 is the perspective view of another embodiment that is suitable for holding the heater of different size sheet material.

Describe in detail

With reference to Fig. 1, with profile the device that is used for twin sheet thermoforming has been shown, it has a female die 1 and a upper mold section 2.Shown this thermal formation apparatus has a pair of

thermoplastic sheet

5,6 that remains on the appropriate location.Each

sheet material

5 or 6 is bearing on its

half module

1 or 2 separately by a sheet material supporting arrangement 11, and device 11 is connected on the body 10 of half module movably.The sheet material supporting arrangement of preferred form is one to be assemblied in the annular bearing element 11 in the annular groove 12, and it is around the die cavity 16 of this half module.

(for example by using a ring vaccum seal 20) keeps sheet material to this sheet material supporting member 11 along its edge 51.Other keep the mode of sheet material also can use around its edge.For example, a series of energy quilts are manual or automatic operation, and for example the anchor clamps by magnetic valve or the automatic hinged and downward locking of operating of pneumatic means can be used.Figure 11,12 and 14 shows the device that is used for fixing this class sheet material and will describe in further detail.

This supporting member 11 illustrates in the position of preferably launching fully basically, it for example can be by a series of pins and jack or the qualification of any other proper device, and can be pressed in the groove 12, so that it is this half module body 10 can lump together by meeting, adjacent up to the relative seam region 17 of half module.A series of springs 13 are arranged in the groove 12, and they are between the bottom 15 of the bottom surface 13 of supporting member 11 and groove 12, so that the resistance that supporting member 11 is pressed into that increases step by step to be provided.Obviously, can provide the device except that spring, such as mechanical actuator, hydraulic pressure or pneumatic actuator or any other suitable equipment of meticulous control, spring only is wherein least complicated a kind of selection.

When half module body 10 can lump together (adjacency of for example passing through supporting member 11) in the thermoforming process, sheet material supporting member 11 can automatically enter in the groove 12.Separate in order to produce the sheet material that is similar to existing jig frame device, adjacent element 19 can be provided, its apparent surface 18 from supporting member 11 extends, so that an adjacency section 28 to be provided betwixt.This adjacent element 19 also allows to provide passage between rational sheet material, for example, is used to insert pharoid 9 with heating thermoplastic sheet material 5,6.Inserting under the situation of heater, for example may need the separation that adds, this can separate or obtain by one or more adjacent elements 19 being prolonged pro rata and flexibly being pressed into a mode with amount of its length by the control template.As can be from seeing Fig. 2, this adjacency under the situation of the exact position of given half module and perfect rigidityization, still allows to enter the free space of die cavity inside in common thermoforming operation.In addition, wish that such adjacent element/device only provides below the half module side, open fully so that its end can keep, and

sheet material

5,6 can insert between the half module easily, hold up and keep with the device 20 that is fixed.

Load and the method for optimizing of heating is described back 13 to the 16 pairs of sheet material with reference to the accompanying drawings.

Referring now to Fig. 1 to 5, show a kind of thermoforming process that is undertaken by the device of Fig. 1.In Fig. 1, show the sheet material that is provided with heater 9 therebetween.This heater 9 for example can comprise a simple electrothermal heater, and is used for before processing the temperature of

thermoplastic sheet

5,6 is elevated to a suitable hot-forming temperature.This heater 9 is withdrawn subsequently.

During heating,

sheet material

5,6 will be softened to a certain degree, and this moment, they can not support the weight of oneself again.In case sheet material reaches its glass transition temperature, this point particular importance that will become usually.For ABS plastic sheet material, this will occur in about 90 ℃.In order to alleviate any sagging result, the pressure in each

chamber

24,25 can suitably be controlled, and with support plate, its

lumen

24,25 is limited by each

sheet material

5,6 and their

half modules

1,2 separately.

The detailed structure of each half module of being used for thermoforming and their die cavitys is not shown, and this is comprising little channel slot and the pore that provides air to enter die cavity 16, and they are used for the pressure in thermoforming process control die cavity.These holes can be used for support plate, to prevent sagging or depression.Sagging in order during heating to prevent, the pressure in the chamber 25 will remain under the ambient pressure, and the pressure in the chamber 24 will remain on the ambient pressure.

The known sheet material supporting system that has polytype based on pressure in thermoforming technology.At present an example of using is to use a beam sensor in sheet material one side, with detect sheet material whether " bubble " disturbs this light beam.According to sheet material from top or down surface bearing and sensor be arranged on which side of sheet material, the pressure in the controller control supporting cavity is to bring sheet material into a favourable situation.In an improved form, between supporting cavity and surrounding space, add an in check leakage, and pressure (plus or minus) the application time that applies a minimum, therefore, make according to the hysteresis effect of system that " bubble " vibrates continuously by the border of light beam.

Keep this control sagging, reach hot-forming temperature up to sheet material to sheet material.For ABS plastic, this is usually above 140 ℃.Consider that complexity such as forming shape etc. can indicate a higher forming temperature.

To depend on material, thickness and heater power total heat time heating time of sheet material.When using the thick ABS sheet material of 2-3mm, and do not sacrifice when heating under the speed of board quality providing efficient output, the typical total time that is used for heating process will be 120 seconds, and wherein sheet material is benefited from effective supporting at least in the half the time of total time.

Referring now to Fig. 3, heater 9 has been withdrawn, and half module is by close to each other to a certain extent.Adjacency section 28 between the adjacent element 19 of supporting member 11 has caused the compression of the spring 13 between the surface 15 of the groove 12 of the surface 14 of supporting member 11 and die body 10, so each supporting member 11 is compressed slightly.And the pressure in

chamber

24 and 25 is adjusted now, so the malleation in the chamber 24 is decrescence, and perhaps in addition a vacuum just be employed, and this vacuum and chamber 25 have been increased.Consequently softening

thermoplastic sheet

5,6 is drawn back, the part 52 that it makes each thermoplastic sheet with closing of mould with they separately a seam region 17 of half module contact.

Referring now to Fig. 4, half module continues and can be lumped together, and adjacency section 28 causes the further compression of spring 13 and further being pressed into of supporting member 11.Vacuum in the

chamber

25 and 24 is increased simultaneously, with continuation this thermoplastic sheet is drawn in the die cavity 16, and therefore begins to form final shape, and for example the part 53 of sheet material contacts the inner surfaces of die cavitys now.The fixing of limit 51 becomes not really important now, yet advises that still this limit is fixed tightly.

Referring now to Fig. 5,

half module

1 and 2 can be lumped together fully, and compress spring 13 this moment fully, so supporting member 11 is pressed in their chambeies 12 separately now fully.The continuation of vacuum is used each

sheet material

5,6 is drawn in the chamber fully in the die cavity 16, thereby is consistent with the shape in this

chamber.Half module

1 and 2 seam region 17 be adjacency fully, thereby forms a seam 55 between two

sheet materials

5,6 of thermoplastic.Preferably this

half module

1 and 2 has been lumped together by meeting, make it its more approach the thickness that seam forms two sheet materials in the zone 17, so material is compelled to leave seam 55, strengthens convex tendon 56 so that for example form one in the inboard of thermoforming part.

Therefore the thermoforming process has been finished basically.Now these parts allow cooling, can spray foam, and these parts can be removed and repair in due course.Owing to can also before finishing, these parts be pulled out from mould, the device of a finishing in molded can be provided, for example knife or cutting blade, perhaps a cutter of for example describing with reference to Fig. 6 to 10 is comprised in the mould, and it is positioned at seam region 17 places as shown in figure 12.

In Figure 12, the seam region of female die is provided with a resolution element 109, and it can be retracted into groove 110 backward when applying enough pressure for pre-compressed spring 111.Along with half module continue close, cooperate respectively on the

limit

112 and 113 of upper and lower half module, to cut the edge of formation from this part.This measure is further described below with reference to Fig. 6 to 10.

Referring now to Fig. 6, another embodiment has been described, it has been realized eliminating scaffold and has allowed with the identical purpose that is arranged on single heater heating thermoplastic sheet material therebetween, it has realized utilizing a method of cutting off to be implemented in the purpose of molded middle finishing again simultaneously, and this method is used the supporting member that can force down in the process of cutting off.Be noted that, in the embodiment shown in present embodiment and Fig. 1 to 5, all can only provide one can force down supporting member and realize identical whole structure.For example, in Fig. 6 to 10, the operation that does not change machine basically just can be fixed the supporting member 41 of sheet material.

Referring now to Fig. 6, these two half modules are no longer identical basically.Upper mold section 4 has an annular sheet metal supporting member 41 that can be pressed into a groove 42, and spring 45 is arranged between

relative face

44 and 43, an elastic force to be provided and to resist such being pressed into.A sheet material 8 keeps by vacuum tank seal 48, and it vacuumizes by managing 47, specifically sees the embodiment of Fig. 1 to 5.In the embodiment shown in fig. 6, the inner surface that can be pressed into element 41 self forms the part of die cavity.As mentioned above, the element 41 among Fig. 6 can be by integrally formed and as an intact part of the not moveable part of die body 40, and the performance of not appreciable impact thermal formation apparatus.This sheet material supporting member 41 has a little seam of giving prominence to from its lower surface to form zone 49, its contiguous vacuum seal 48 that is keeping the edge 80 of sheet material 8.Should give prominence to the effect on limit describes in the accompanying drawing of back.

Female die 3 has half mould body 30, and wherein sheet material supporting member 31 remains in the groove 32.First spring 35 is arranged in this groove 32, with action between the face 33 of the face 34 of supporting member 31 and main body 30.Another spring 36 is arranged on the bottom of groove 32, its only action between

face

34 and 33 when supporting member 31 fully is pressed into groove.The height of the degree of depth of groove and supporting member 31 is so set, thereby when fully being pressed into the seam that makes upper surface at supporting member 31 and forming on the plane that the zone is positioned at die surface 26, it will touch another spring 36.This reason provides with reference to Fig. 7 to 10.The limit 70 of sheet material 7 is fixing by vacuum seal 38, and it vacuumizes by managing 37.Because obviously, pipe 37 extends to the outside of supporting member 31, and one and half grooves are arranged in the die body 30, to allow forcing down of supporting member 31.

Embodiment as described above, the use of spring is based on a kind of selection of simplification.Many methods that other allow that the sheet material supporting member is pressed into can be predicted, such as mechanically actuated, air pressure supporting accurately or hydraulic support.These multiple choices do not depart from the scope of the present invention.

During use, a heater can be inserted between the thermoplastic sheet, and is used for thermoplastic sheet is heated to a hot-forming temperature, and the mode shown in this point and Fig. 1 is basic identical.The method of further preferred loading and heating sheet material is described below with reference to Figure 13 to 16.In case heater is removed, half module 3,4 is close to each other at leisure, is used for support plate 7,8 and prevents that sagging chamber 22,23 is evacuated in the past simultaneously, to separate sheet material by mode shown in the zone 71 and 81 of sheet material among Fig. 7.In this stage, because supporting member does not also have adjacency to cause

spring

35,45 compressions separately,

element

31 or 41 does not all begin to be pressed in its chamber separately.

Referring now to Fig. 8, expression thermoforming process is proceeded, half module 3,4 can be incorporated into a kind of like this degree so that sheet material supporting member 31 with 41 now with

limit

70,80 adjacency of each sheet material 7,8 that contacts therebetween, and contact the

seam region

39,49 of supporting

member

31,41 now.Chamber 22,23 continue to vacuumize the further moulding that has caused each sheet material, for example now descend the part 72 of thermoplastic sheet to contact die surface 26.

Referring now to Fig. 9, expression is further carried out forming process by continuing mobile half module.Spring 45 between the surface 44 of last sheet material supporting member 41 and the surface 43 of its corresponding recesses 42 is fully compressed now.Spring 45 between the surface 34 of following sheet material supporting member 31 and the surface 33 of its corresponding recesses 32 is compressed to a kind of like this degree now, so that supporting member 31 touches another spring 36 that is arranged in the groove.Yet different with upper support element 41, this lower support element 31 still has some available frees degree of forcing down.The part of thermoforming is shaped now more completely, and lower plate 72 is moulding fully now, and is resisted against on the die surface 26, almost completely moulding of upper plate 82, and vacuum is held in 23 little remainder relaying continuation of insurance in the chamber, to finish this task.Seam 74 begins to be formed in the zone between supporting

member

31 and 41 adjacency sections.

The final stage of this process is described among Figure 10.Half module further can be incorporated into together.Upper support element 41 is pressed in its corresponding grooves fully.Lower support element 31 is pressed further in its groove by the further compression of spring 35 and spring 36, and spring 36 is between the surface 33 of the surface 34 of supporting member 31 and its corresponding recesses 32.

Spring

35 and 36 elastic force mean that big pressure has been applied to the adjacency section between

seam region

39 and 49, to discharge plastic material from seam region 76, and on the inner chamber of the profile member of seam region, forming a convex tendon 75, this convex tendon provide the reinforcement of reality will for this weld.27 belows, limit of die body 30 have been forced down the welding zone 39 of supporting member 31 in this continuation campaign, so limit 27 of the welding of supporting member 41 zone 49 overlapping die bodys 30, and between has enough near tolerance, and seam and support region 77 have been cut away in the behavior of cutting off.

From the explanation and description of device and process; this point is fully aware of; promptly the invention provides a kind of method; can be supported with each half module by this method sheet material; and need not use an independent scaffold, and by half module being incorporated into together can carrying out the thermoforming process with a kind of shirtsleeve operation.In the system that reference Fig. 6 to 10 describes, also realized a kind of molded middle finishing operation that does not need additional cutter and part, and it has finished the reinforcement convex tendon in final element in addition.

Figure 11 has described a thermoplastic sheet 90 has been fixed to an another kind layout on the supporting member 91.In this arranges, be equipped with one and clamp bracket 92, it can rotate around a pivot 93.This can comprise that this bracket 92 of supporting leaves a protuberance 94 that extends from supporting member.This bracket 92 comprises a clamp arm 95, and it has one and is suitable for being pressed in sheet material 90 lip-deep clamping areas 96.One actuator 98 is connected to and clamps on the bracket 92, carries out one and rotatablely moves to handle it, is at least 90 degree usually.This actuator 98 can comprise a magnetic valve, and it has the advantage of controlled bearing pressure.Elastic strip seal 99 is arranged in the groove 100 on surface of supporting member 91.This elastic strip for example can be made by silicone rubber, and has a sealing strip 101 that raises from supporting member surface 102.In use, this clamping area 96 is pressed in sheet material on the elastic strip seal 99.Many such anchor clamps preferably are set, and are positioned at enough spaces to guarantee around the abundant sealing of 99 pairs of sheet materials of seal at the whole edge of sheet material.For the ABS sheet material of a 3mm, a kind of typical setting is the bracket that adopts the 45mm width, and it is spaced apart 50mm.

With reference to Figure 12, the anchor clamps that separate can scatter together at some some places and adjacency section 103, and bracket 107,108 can be separately positioned on the alternate position of (105) and following (106) half module, so that the motion of the bracket of each half module is not hindered by the bracket of other half modules.

Referring now to Figure 13 to 16, the preferred method and apparatus that loads and heat sheet material of expression.Figure 13 has described the basic skills that is applied on the described shaped device of Fig. 1 for example.A movable heater cartridges 115 is set, and it can move to a position between the upper and lower half module.This heater cartridges comprises upper and lower heater support 117,118, and it supports each respectively and is contained in sheet material on the half module 119,120.A heater 121 is arranged between the plate 122,123.Upper and lower heater preferably is set so that upper and lower sheet material add heat energy according to the influence of sheet metal thickness and independent control.Sheet material preheating on heater cartridges before introducing half module is allowed in this setting.Heater cartridges is not only as heater but also as the sheet material bearing part, therefore heats the required time of sheet material and will spend in the time that sheet material carries effectively overlapping.

In one approach, sheet material is heated to a temperature in advance in this heater cartridges, and it is guaranteed to be lower than glass transition temperature (for example 70 ℃).This preheating can be carried out more lentamente than the process of being carried out when this sheet material has remained on the appropriate location, and this point is preferred the use, because it guarantees a uniform heat distribution and infiltration, is convenient to later further heating.This heater cartridges is being carried sheet material and is being moved into place basically on the position between the half module.Heretofore, half module may be finished a thermoforming sequence or a cycle early.Sheet material is transferred on the sheet material supporting member of respective mold half then.In case transfer on the corresponding half module, describedly the supporting of sheet material is activated and keeps by the controlled pressure system.Before remove between the half module, this heater further heats, so that sheet material is elevated to hot-forming temperature.In the exemplary of using the thick ABS sheet material of 3mm, this further heating may need 60 seconds.This heater is removed then, and the thermoforming process described of beginning.

Actual sheet material transmits and comprises or half module can be incorporated into together, so that each half module is near they sheet material separately, perhaps traveling heater box (or its upper plate or its lower plate) is to contact with separately half module.

In another approach, use the time of half module that extra minimizing is arranged in each cycle, but it makes by the identical different sheet material of heater cartridges processing and becomes more complicated, this heater cartridges itself comprises controlled upward pressure chamber 124 and downforce chamber 125, each pressure chamber comprises a peripheral sheet material seal 126,127 and supporting arrangement, and it is enough to keep sheet material on the position of a sealing.Therefore, before transmission, heater can provide the supporting to upper and lower sheet material, and enters in this heater cartridges before the position between the mould that is used to transmit, and sheet material can be lifted to hot-forming temperature.This has reduced the required time of mould was set in each cycle, and allows in the given production time and increase cycle-index.In transport process, arranged a conversion time, wherein the supporting of sheet material is transformed into the pressure chamber of half module from the pressure chamber of heater cartridges.

Aspect the board dimension setting, sheet material remained on does not have big difficulty under the sealing state, and the absorption of the periphery described in Figure 13 sealing and supporting are suitable.But, there are some phenomenons to show, the heat of conduction can make the edge of sheet material more softening than desirable, and sealing may be owing to the distortion at sheet edge place is lost then.

Figure 14 has described one based on the supporting and the transfer system that clamp bracket, and it is very suitable for above-mentioned heating or transfer approach.This set uses the bracket 130 of actuator control in large quantities, and this is identical with the description of carrying out with reference to Figure 11.These brackets 130 preferably directly are not fastened to sheet material on the potted component 131, but are fixed to its outside slightly.This allows bracket 130 to work in the chamber in the supporting member that is formed at half module 134 and heater cartridges 135 132,133 respectively, and does not conflict with sheet material 136 or seal 131.If use higher hot-forming temperature, the auxiliary clamp (not shown) can be set, it was thrown off before being used for assisting fixing transport process, and this will reduce the integrality of the sheet material of neighboring area.Any adjacency for each half module can be provided with another chamber 137.To recognize that also this clamping setting can be applied on the sheet material supporting member of the half module in the thermoforming process of Fig. 6, because it has overcome the collision problem that may be associated with the sheet material clamping device that uses a machinery.

Be lifted to hot-forming temperature completely if cater to different board dimensions and sheet material, the sheet material heating before transmitting has very big difficulty, and this is because it need adapt to peripheral sealing arrangement.If but this method only is heated to below the glass transition temperature before being limited in transmitting, can provide supporting to heater cartridges so, this supporting is suitable for different board dimensions, but it does not provide a periphery sealing.The example of this layout is shown in Figure 15 and 16.

In Figure 15, heater cartridges 140 comprises many absorption support columns 141, and they evenly separate in whole heater cartridges, supports a sheet material with the many positions at its lower surface, and does not consider the size and dimension of this sheet material.The quantity of these support columns and interval will need to set according to the strength characteristics of sheet material under the predetermined transition temperature.

In Figure 16, a heater cartridges 145 comprises many bracket anchor clamps 142 that can move automatically, and they can be suitable for automatically relocating along a series of tracks 143 on the wall 144, and described wall passes heater cartridges and extends internally.The motion of bracket can realize by linear activated known way, and bracket can be arranged basically as shown in figure 14.

Carry in the heater cartridges of different size sheet material being suitable for, controlled if heater is segmentation, so that have only the zone with sheet material direct neighbor placed on it to activated in the heater, this will be very favorable so.This has reduced the waste of energy, and the spurious radiation of the free margins of guaranteeing the sheet material that is fixed the again heating element below the sheet material that is not located immediately at heats.When plan is used heater with diversified sheet material shape and size, this heater can be formed by many arbitrary regions, the grid of a rectangular area for example, its can independently be controlled, and shape that this is regional and structure can be specially adapted for the sheet material scope that will use.

In a kind of mode, the present invention has eliminated the needs to adjustable or different stationary fixture assemblies, and these anchor clamps need in traditional forming process, and is essential in whole forming process.The present invention allows that mould is changed apace and produces element, thereby has introduced suitable flexibility in very wide product scope in the vacuum forming process.

Because sheet material is circumferentially supported away from die surface, and because the seam of sheet material only contacted the seam region of mould immediately before fusion, so described sheet material keeps fully softening in seam region, so that good fusion character to be provided.This advantage is very obvious in the embodiment that disclosed wherein two the sheet material supporting arrangements of the present invention can both be withdrawn.

Some modification to described scheme will be clearly, and abovely not mention or describe all modification.A special example is in the fixed plate supporting member in arbitrary forming method.These modification do not depart from the scope of the present invention.

Claims

1. be used for the device of twin sheet thermoforming, comprise:

The sheet material supporting arrangement relevant with each described half module, each sheet material supporting arrangement links to each other with their half modules separately, and be configured to and keep a thermoplastic sheet around its periphery, this sheet material supporting arrangement is formed at and keeps each sheet material when described half module is positioned at its open position separated from one anotherly, each described half module, its separately supporting arrangement and the sheet material that keeps by described supporting arrangement define a pressurized volume together, and

The device relevant with each described half module, it can produce a controlled pressure reduction between each defined volume and outside thereof.

2. the device that is used for two plate formings as claimed in claim 1, it is characterized in that: one or more described sheet material supporting arrangements are movably with respect to half module separately, thereby, can described supporting arrangement be depressed with respect to described half module separately under the pressure of an adjacency section between described supporting arrangement and another supporting arrangement or the half module.

3. the device that is used for two plate formings as claimed in claim 2, it is characterized in that: described sheet material supporting arrangement can move with being adjacent to each other, and be provided with abutment means, this abutment means makes and keeps between the described sheet material separating, described sheet material supporting arrangement is adjacent to each other, when described half module moves to its closed position, described sheet material supporting arrangement is depressed with respect to their half modules separately, thereby make in use, each sheet material will with its separately a seam of half module form the zone and contact, and along with of the further motion of described half module to described closed position, forming the regional described zone that contacts with the seam of described half module in the sheet material will contact with each other, and be pressed in together by closing of described half module, to form a seam.

4. the device that is used for two plate formings as claimed in claim 1, it is characterized in that: described sheet material supporting arrangement comprises the welding zone of a fusion, under the enough vacuum of described enclosed volume, by it described sheet material is contacted, and by described half module closing to described closed position, it is adjacent to each other, thereby the seam region of described sheet material can be lumped together, to form a seam.

5. as any one described device that is used for two plate formings in the claim 1 to 4, it is characterized in that: it comprises the device that is used for from a moulding section automatic dressing seam region, in the described seam region one can be depressed under the plane of respective mold half of the described seam region of next-door neighbour, so that another described seam region and described half module are cooperated mutually, described seam region is pared off to cut off in the operation at one.

6. as any one described device that is used for two plate formings in the claim 1 to 5, it is characterized in that: described sheet material supporting arrangement comprises one from a surface of described supporting arrangement outstanding elastic strip and many isolated clamping elements, each described clamping element can rotate with respect to a surface of described clamping element, so that described sheet material is pressed on the described elastic strip, the interval of described clamping element is enough near, to form a continuous periphery sealing between sheet material and described elastic strip.

7. as any one described device in the claim 1 to 6, it is characterized in that: it comprises a heater assembly and a heater mobile device, to move described heater assembly between described half module when described half module separates, described heater assembly is suitable between a pair of sheet material this sheet material being heated.

8. device as claimed in claim 7, it is characterized in that: described heater assembly comprises the sheet material supporting arrangement that is located at its upper and lower side, in order to thereon, downside keeps a sheet material, when moving into place position between half module with box lunch, described sheet material can be sent on the described sheet material supporting arrangement of described each half module.

9. device as claimed in claim 8, it is characterized in that: described heater assembly comprises a upper and lower pressure chamber and a pressure feed passage, with allow will independent control pressure be applied in the described upper and lower chamber each, and the described heater sheet material supporting arrangement on each is suitable for carrying out the periphery sealing with a described sheet material in the described upper and lower side, seals each described chamber with each described sheet material in use.

10. install as claimed in claim 8 or 9, it is characterized in that: the described sheet material supporting arrangement of described heater assembly comprises many clamping elements that separate and relevant cooperation clamping surface, and the clamping element of described heater assembly is round the periphery setting of the described sheet material between each position of the clamping element of described half module sheet material supporting arrangement.

11. device as claimed in claim 10, it is characterized in that: each in the described clamping element of some of described at least heater assembly can move automatically, with in a plurality of position operation, thereby can be used for fixing the sheet material of different size with other clamping element.

12. device as claimed in claim 8, it is characterized in that: described sheet material supporting arrangement comprises the absorption supporting arrangement, its sting and and described sheet material is fixed on its non-molded surface, and they stride across described heater assembly and distribute, so that they can clamp the sheet material of different size.

13. as claim 11 or 12 described devices, it is characterized in that: described heater assembly comprises many heating element heaters, described element is provided with by the zone, and the described zone of described element links to each other with control device, is used for according to which zone of heated board dimension being controlled described heater assembly activateding.

14. a method that is used for twin sheet thermoforming comprises:

15. method as claimed in claim 14 is characterized in that it comprises the steps:

At the described sheet material of either side preheating of heater box movably,

Described sheet material is sent on the described half module,

Described heater cartridges is removed between described half module.

16. method as claimed in claim 15, it is characterized in that, the described preheating of described sheet material is limited in this underheat and is elevated to its glass transition temperature with the temperature with described sheet material, and described method also comprises the steps, promptly after described sheet material is sent on the described half module and before removing described heater cartridges further the described sheet material of heating to forming temperature.

17. method as claimed in claim 16 is characterized in that, the described preheating of described sheet material is enough to the temperature of described sheet material is elevated to their forming temperature, and described method also comprises the steps:

On a quilt, keep a malleation in the chamber of sheet material and heater cartridges sealing, keeping a negative pressure in the chamber between sheet material and the heater cartridges down at one.

18., it is characterized in that the step of the described sheet material of described transmission comprises as any one described method in the claim 14 to 17:

Described heater cartridges is placed between the described half module,

With each described half module and described heater assembly corresponding half put together, contact each sheet material up to a supporting arrangement that is arranged on each half module, and

Grasp each described sheet material with individual described supporting arrangement.

19. method as claimed in claim 18 is characterized in that, comprises described half module corresponding half step that puts together of each described half module and described heater assembly close to each other.

20. method as claimed in claim 18 is characterized in that, corresponding half step that puts together of each described half module and described heater assembly is comprised the upper and lower sheet material supporting of removing described heater assembly.

21., it is characterized in that the step that transmits described sheet material may further comprise the steps as any one described method in the claim 18 to 20:

Keep a controlled pressure in the space between each described sheet material and heater cartridges, being enough to can prevent to support floppily each described sheet material,

In case described each supporting arrangement grasps described sheet material, little by little introduce a controlled pressure in the space between each described sheet material and each described half module, and compensate the pressure that keeps in the space between each described sheet material and the heater cartridges, be positioned at the described pressure support in the described space between described sheet material and the described half module separately fully and prevent sagging up to each described sheet material

From described heater cartridges, discharge each described sheet material.

22. as any one described method in the claim 14 to 19, it is characterized in that, it further may further comprise the steps: described half module is further close to each other, one of them described seam region is suitable for being depressed with respect to its corresponding half module, this corresponding described half module and another described seam region cooperation cut off described seam region to cut off operation by one from moulding section.

23. device that is used for twin sheet thermoforming, wherein each half module comprises a sheet material supporting arrangement, this device can keep a sheet material by its edge, and during heating supports described sheet material, and wherein at least one described sheet material supporting arrangement can be recalled during thermoforming.

24. one kind basically with reference to accompanying drawing 1 described device.

25. one kind basically with reference to the described method that is used for twin sheet thermoforming of accompanying drawing.