DE102007053668A1 - Preform e.g. polyethyleneterephthalate preform, post treatment system, for manufacturing of polyethyleneterephthalate bottles, has stopper positioned in distanced manner from preform in cavities such that removal of preform is prevented - Google Patents

Abstract

The system has a receiving plate (1) with multiple post treatment cavities (2) and/or a pin plate (3) with multiple post treatment pins (4). A stop-and guiding element (9) i.e. stopper plate, provides a stopper (10) for a post treatment cavity of the receiving plate or for the post treatment pins of the pin plate. The stopper is positioned in a distanced manner from a preform that is arranged in post treatment cavities or on the post treatment pins such that complete removal of the preform from the post treatment cavity or the post treatment pins is prevented.

Description

The The present invention relates to a post-treatment system in an injection mold produced preforms with an ejector and a method for ejecting post-treated Preforms.

The Injection molding is one of the most important production methods of moldings. This is generally original heated as a powder or granules molding compound, plasticized and pressed under high pressure in a corresponding mold. The molding compound solidifies in the mold and is subsequently taken from the opened tool.

commercial PET bottles are generally made by stretch blow molding a Hohlkörperpreforms or hollow body preform produced. In this case, the hollow body preform is in a first step created by injection molding. That I to the injection molding subsequent stretch blow molding either immediately after preparation of the hollow body preform or at a later date.

at the production of the corresponding injection molds is a high effort is necessary because the injection mold on the one hand must be designed for very high pressures and on the other hand also correspondingly heated and / or cooled channels must have.

Usually There is an injection molding tool for the production of PET preforms from a variety, for. B. 96, cavities, in the appropriately trained Tool cores are introduced. With the tool closed, d. h. when the core is inserted into the appropriate cavity is, between the core on the one hand and the cavity on the other hand a space, the so-called form space formed. In this Space is then the plasticized plastic, z. B. PET, under high Pressure injected. Once the PET preform enough cooled, the mold can be opened and the Preform be removed.

Around the cycle times, d. H. the time from a spraying process up to to reduce the next injection, it is already common the preform at a very early stage out of shape to take that to the preform on its outer surfaces already is fixed, its inner realm, the so-called soul, however still is liquid. In this state, the preform is in Generally passed into a so-called receiving plate, which consists of a group of receiving cavities. So For example, it is the so-called vertical tools, d. H. those injection molding tools that are characterized by a vertical movement of a tool part relative to the others open, usual, the mold already after z. B. 10 seconds to open, a recording plate with retract appropriate receiving cavities into the mold, the individual preforms in the receiving cavities by gravity fall into it, the receiving plate with the preforms to exit the tool, to close the mold again and to start the next injection molding process. During the next injection molding process remain the previous preforms in the receiving cavity, which is usually cooled.

It Embodiments are also known in which the individual Preforms removed by means of a gripper unit from the mold and passed in the arranged outside the tool mold receiving plate become.

There the preform for cooling in the receiving cavity of the prior art a relatively long time must remain, so that usually already the next Preform are removed from the injection mold can, before the preform in the receiving cavity so far cooled, that he is taken without the risk of damage who can, it is common to use mounting plates which have several groups of receiving cavities, wherein each group has as many receiving cavities as that Injection mold provides preforms per injection cycle. The individual receiving cavity groups are then successively equipped with preforms, so that the individual preform longer than one injection cycle in the receiving cavity can remain.

Around The cycle time has been shortened in the last few years Many efforts have already been made to extend the preform a very early date from the injection mold refer to. Because the preform at such an early date is still relatively soft, higher demands on the Post-treatment provided. So is already isolated suggested been held in the receiving cavity preform additionally with a post-treatment pen, which is in the preform is introduced to cool or post-treat. Both However, this known devices with post-treatment pen, this is only briefly immersed in the preform.

From the WO 2007/062973 A device for the aftertreatment of preforms produced in an injection mold is already known. This machine has a plurality of aftertreatment tools, each having a receiving plate with a group of receiving cavities and a pin plate with a group of Nachbehandlungsstiften. Furthermore, a facility for Überfüh ren of the preforms from the injection mold provided each other in the at least two aftertreatment tools. For ejecting the post-treated preforms from the aftertreatment tools, compressed air is generally used. When in the WO 2007/062973 after the aftertreatment tools have been opened so that the preforms remain on the aftertreatment pins. To eject the preforms, the aftertreatment pins on a fluid outlet, which can be acted upon with compressed air. By applying compressed air, the preforms are blown by the aftertreatment pins and thus ejected.

Usually are the fluid outlets of each aftertreatment pins an after-treatment tool with one and the same compressed air line connected so that the compressed air application for all aftertreatment pins can only be switched on or off together. Basically It is possible, each aftertreatment pen with its own equipped controlled valve, which, however, the manufacturing cost and drive up the space required by the aftertreatment tools would.

at However, the known tool has been shown that it in some Applications may occur that individual preforms earlier from the aftertreatment pins than other preforms. However, once a preform has left the aftertreatment pen, is the fluid outlet of this aftertreatment pen directly to the Ambient pressure, resulting in a significant pressure drop in the compressed air line leads. Especially if a large part of the preforms removed from the pins is, it is usually no longer possible, one apply sufficiently high pressure via the compressed air line, around the remaining preforms from the aftertreatment pins to remove.

outgoing From this prior art, it is therefore an object of the present Invention, an aftertreatment system of the type mentioned to provide in which the preforms reliable the aftertreatment tool can be ejected.

According to the invention this problem is solved by a system for aftertreatment of preforms made in an injection mold with a post-treatment tool that has a receiving plate a plurality of Nachbehandlungskavitäten and / or a Having a pin plate with a plurality of aftertreatment pins, wherein a stop element is provided for each Nachbehandlungskavität the receiving plate or for each post-treatment pen the pin plate provides a stop which of a in the aftercare cavity or on the aftertreatment pen arranged preform spaced so positioned That can be a complete removal of the preform from the aftertreatment cavity or from the aftertreatment pen is prevented.

By These measures can be taken as a first step the preforms are released from the aftertreatment pin or from the aftertreatment cavity so they are already a bit of the aftertreatment pen or leave the aftertreatment cavity. At this point meet the preforms on the provided by the stopper element Stop, so they persist in this situation. The position is selected so that each preform compressed air, the from the aftertreatment pen or post-treatment cavity emanates, still a sufficiently large resistance opposes, so that no (or only a small) pressure drop occurs in the compressed air line. Only after it has succeeded all preforms so far from the aftertreatment pins or the After treatment cavities to solve that they Touch stop, the stop element can be removed, so that then the already pre-dissolved preforms easy can be ejected. It has been shown that through This measure can be prevented occasionally individual preforms remain in the aftertreatment tools, otherwise manually removed after an interruption of the manufacturing process would have to be.

In a preferred embodiment is the stop element formed as a stopper plate in the open aftertreatment tool between the receiving plate and pin plate can be positioned. It is thus possible to eject the preforms the aftertreatment tool to open this first, so that the preforms - depending on the embodiment - either on the post-treatment pins or - preferably - in the aftertreatment cavities remain. In the next Step is the stopper plate between the receiving plate and pin plate moved, so that provided for each preform a stop becomes. Thereafter, the aftertreatment pins or the Nachbehandlungskavitäten be subjected to compressed air, so that the preforms a bit far from the Nachbehandlungskavitäten or solve the aftertreatment pen and on the provided Hit the stop. Only after all preforms have been solved in this way were, the stop element is removed, so that the preforms can be completely ejected.

In a further preferred embodiment, a guide element for guiding the preforms from the aftertreatment tool is present seen, which can be moved with the aftertreatment tool open between receiving plate and pin plate of the aftertreatment tool. Such a guide element can be arranged for example on the stopper plate. The guide element is preferably designed as a substantially U-shaped rail in which, after complete ejection, the preforms are guided by gravity out of the aftertreatment tool alone. In principle, it is possible to further accelerate the ejection process in which an air flow is generated within the guide element.

In Another preferred embodiment has the guide element an impact surface opposite to the direction of ejection of the preform is inclined. It can happen that the ejected preforms hit the impact surface and be repulsed by this. It must prevents the already ejected preforms again get into the pin plate or cavity plate. By the inclination of the impact surface ensures that Do not return the preform back to the aftertreatment cavity or get back to the aftertreatment pen. In principle, any inclination is advantageous, but an angle between impact surface and ejection direction between 25 and 65 °, preferably between 40 ° and 50 ° and particularly preferably of about 45 ° is advantageous.

In a particularly preferred embodiment is additional provided a collecting surface, which is substantially parallel is arranged to the impact surface, wherein the collecting surface preferably smaller than the impact surface. The collecting surface serves just to preforms, sometimes from the impact surface were reflected, catch. If the collection area smaller than the impact surface, the opening may be the guide element through which the preforms in the Guide element to be guided, larger be formed.

Farther it is possible that impact surface and / or collecting surface Made of a material that does not have elastic properties having. In principle, it would also be possible to coat said surfaces with such a material. For example Rubber could be used. It is essential that one Part of the kinetic energy of the material with non-elastic Properties is absorbed, so that on the impact surface or Receiving surface impinging preform not pushed back so far becomes.

In Likewise, alternatively or in combination, the Stop surfaces are formed non-elastic, so that a pushing back of the preform from the stop surface is avoided.

In a particularly preferred embodiment is an outer Section of a leg of the U-shaped rail to the outside or bent inside, so that the bent portion the stopper element forms. This embodiment can be very inexpensive getting produced. In addition, this ensures that stop element and guide element are arranged directly next to each other, so that the plate on which the guide element attaches is, after the preforms far enough from the Nachbehandlungskavität or were solved by the aftertreatment pen that they rest against the stop of the guide element, only a small Distance must be moved laterally to allow removal of the preforms to enable.

A Another preferred embodiment has a device for transferring the preforms from the injection mold in the aftertreatment tool, preferably stop element and / or guide element on this transfer device are arranged. In this case, the transfer device a sampling plate with a plurality of sampling cavities be whose open ends are arranged on one side of the plate. In this embodiment, it is preferred that the stop element and / or guide element at the open ends of the removal cavities opposite side of the sampling plate are arranged. For example, after opening the after-treatment tool the transfer device already the next Group of preforms in the space between pin plate on the one hand and receiving plate on the other hand move while the previous group is still sitting in the aftertreatment cavities. The transfer device then preferably provides both stopper and guide element ready, so that first preforms the preforms, then finally ejected and then transfer the set of new preforms to the aftertreatment pins can be.

In With respect to the method, the object mentioned above is achieved by a process for the post-treatment of in an injection mold prepared preforms, wherein the preforms from the injection mold in Nachbehandlungskavitäten or aftertreatment pins transferred be the process of ejecting the preforms of the Aftercare cavities or from the aftertreatment pins after the aftertreatment takes place in two steps, wherein in the first Step all preforms around a first distance from the aftertreatment cavity or be moved by the aftertreatment pen and in the second step completely remove the preforms from the aftertreatment pins or taken from the Nachbehandlungskavitäten.

Preferably The movement of the preforms from the aftertreatment pins or from the after-treatment cavities after step 1 first for a certain period of time, e.g. B. about 0.5 Seconds, stopped, so that all preforms in their predissolved Be held in position before being ejected completely.

Further Advantages, features and applications of the present Invention will become apparent from the following description of a preferred embodiment and the associated Characters. Show it:

1 an embodiment of the present invention in a first position,

2 the embodiment of 1 in a second position,

3 the embodiment of 1 in a third position,

4 the embodiment of 1 in a fourth position and

5 the embodiment of 1 in a fifth position.

In 1 an aftertreatment tool is shown, which is a receiving plate ( 1 ) with after-treatment cavities ( 2 ) and a pegboard ( 3 ) with aftertreatment pins ( 4 ) having. The aftertreatment tool essentially corresponds to that in the WO 2007/062973 described tool. The aftertreatment tool is shown in its open position, ie the aftertreatment pins ( 4 ) do not reach into the aftertreatment cavities ( 2 ) one.

In this position, as a removal plate ( 5 ) formed transfer device in the open aftertreatment tool in the arrow direction in the in 1 shown position to be moved. The removal plate ( 5 ) has sampling cavities ( 6 ) in which a group of preforms ( 7 ) are included. The preforms ( 7 ) in the sampling cavities ( 6 ) come from an injection mold (not shown). The preforms ( 7 ) are taken out of the injection mold at such an early stage that they have not yet cooled completely. Although the outer and inner surfaces of the preform are already in the solid state, the inner region, the so-called soul, is still liquid. This preform must be post-treated to prevent re-softening of the outer surfaces and crystallization and consequent clouding. For this purpose, the preforms ( 7 ) on the aftertreatment pins ( 4 ), which are then applied to the receiving cavities ( 2 ) so that the preforms are cooled from the outside and the inside.

The Aftertreatment process as such is not part of the present Invention.

After the post-treatment, the aftertreatment tool can be opened again, as in 1 shown. In the receiving cavities ( 2 ) of the receiving plate ( 1 ) are then the aftertreated preforms ( 8th ). These are now cooled down so far that their inner area is fixed. In 1 Thus one recognizes that the removal plate ( 5 ) with the preforms still to be post-treated ( 7 ) already enters the opened aftertreatment tool while the already aftertreated preforms ( 8th ) still in the receiving cavities ( 2 ) are. On the open ends of the sampling cavities ( 6 ) facing away from the removal plate ( 5 ) are stop and guide elements ( 9 ) arranged. These stop and guide elements have the shape of a substantially U-shaped rail. One of the legs of the U-shaped rail is angled outwards and provides a stop surface ( 10 ) to disposal. The U-shaped rail is angled, so that the leg opposite the bent leg forms an angle of approximately 45 ° with the ejection direction.

In the first step, in 1 is shown, the sampling plate 5 positioned so that the of the stop and guide elements ( 9 ) provided attacks ( 10 ) are each positioned opposite the already aftertreated preforms. It can be seen that between the neck area of the already aftertreated preform and the stop element ( 10 ) a distance remains.

In the next step, the in 2 shown, the aftertreatment cavities ( 2 ) is pressurized with compressed air, so that the preforms ( 8th ) so far from the aftertreatment cavities ( 2 ) move out that the preform ( 8th ) on the stop ( 10 ) meets. To effect this, each after-treatment cavity ( 2 ) with a fluid outlet ( 11 ) by the compressed air into the bottom area of the Nachbehandlungskavität ( 2 ) can be admitted. It can be seen that in the in 2 only a very small proportion of the materials in the post-treatment cavities ( 2 ) introduced compressed air between the outside of the already aftertreated preform ( 8th ) and the inner surface of the Nachbehandlungskavität ( 2 ) can flow past, so that almost no pressure drop occurs on the pressure line side.

The aftertreatment tool remains for a short time interval, e.g. B. 0.5 seconds, in the in 2 position to ensure that all already finished preforms ( 8th ) with the stop ( 10 ) contact. In the next step, the removal plate ( 5 ) in the direction of the arrow, with the result that the preforms or preforms ( 8th ) no longer at the attacks ( 10 ), but in the receiving area of the guide element. As the aftertreatment cavities ( 2 ) are still subjected to compressed air, this has the consequence that the aftertreated preforms completely from the Nachbehandlungskavitäten ( 2 ) are pushed out. The preforms ( 8th ) then hit the impact surface ( 12 ), which includes an angle of 45 ° with the ejector. The impact surface is opposite the collecting surface ( 13 ) arranged. Impact surface ( 12 ) and collecting surface ( 13 ) are substantially parallel to each other, wherein the collecting surface ( 13 ) is significantly shorter than the impact surface, which is due to the curved stop surface ( 10 ) is conditional. The shortened collecting surface also has the advantage that the opening area of the guide element ( 9 ) is increased.

Both impact and collecting surface can be covered with a non-elastic material, so that the preform as far as possible to the bottom surface of the formed as a U-shaped guide rail guide ( 9 penetrates, as in 4 is shown. Due to gravity, the situation shown in the figures points into the drawing plane, the aftertreated preforms ( 8th ) along the guide element ( 9 ) on a possibly provided conveyor belt (not shown).

For In some applications, it may be beneficial if the Stop surface has non-elastic properties, to prevent the preform from being pushed back a few times from the stop surface before it comes to rest on the stop surface.

In the next step, the removal plate ( 5 ) moves yet another piece in the arrow direction, so that the not yet aftertreated preforms ( 7 ) with the aftertreatment pins ( 4 ) are aligned. In this position, the as yet untreated preforms ( 7 ), for example by means of compressed air on the aftertreatment pins ( 4 ) be handed over. After the transfer, the removal plate ( 5 ) are removed from the aftertreatment tool and the aftertreatment tool can be closed so that the on the post-treatment pins ( 4 ) sitting, post-treated preforms ( 7 ) into the after-treatment cavities ( 2 ) are used. In the closed state, the aftertreatment, which consists essentially of a cooling, in some cases also from a post-forming takes place.

1

mounting plate

2

Nachbehandlungskavitäten

3

Stiftplatte

4

post-treatment pins

5

removal plate

6

Entnahmekavitäten

7

nachzubehandelnde preforms

8th

aftertreated preforms

9

Stop- and guide elements

10

Stop element attacks

11

fluid outlet

12

impact surface

13

collecting area

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - WO 2007/062973 [0010, 0010, 0032]

Claims (16)

System for post-treatment of preforms produced in an injection mold ( 7 ) with an aftertreatment tool that has a receiving plate ( 1 ) having a plurality of after-treatment cavities and / or a pegboard ( 3 ) with a plurality of aftertreatment pins ( 4 ), characterized by a stop element which, for each after-treatment cavity of the receiving plate ( 1 ) or for each post-treatment pen ( 4 ) of the pegboard ( 3 ) provides a stop which of one in the Nachbehandlungskavität or on the aftertreatment pen ( 4 ) spaced preform can be positioned such that a complete removal of the preform from the Nachbehandlungskavität or from the aftertreatment pen ( 4 ) is prevented. System according to claim 1, characterized in that the stop element is designed as a stopper plate, which in the open aftertreatment tool between receiving plate ( 1 ) and. Pegboard ( 3 ) can be positioned. System according to claim 1 or 2, characterized in that a guide element for guiding the preforms ( 7 ) from the aftertreatment tool, which with open aftertreatment tool between receiving plate ( 1 ) and pegboard ( 3 ) of the aftertreatment tool can be moved is provided. System according to claim 3, characterized in that the guide element is arranged on the stopper plate. System according to claim 3 or 4, characterized that the guide element is a substantially U-shaped Rail is. System according to claim 3, 4 or 5, characterized in that the guide element has an impact surface ( 12 ), which is inclined with respect to the direction of ejection of the preform. System according to claim 6, characterized in that the impact surface ( 12 ) with the direction of ejection forms an angle between 25 ° and 65 °, preferably between 40 ° and 50 °, and more preferably about 45 °. System according to claim 6 or 7, characterized in that the guide element a collecting surface ( 13 ) substantially parallel to the impact surface ( 12 ), wherein the collecting surface ( 13 ) preferably smaller than the impact surface ( 12 ). System according to one of claims 6 to 8, characterized in that the impact surface ( 12 ) and / or collecting surface ( 13 ) of a material which has non-elastic properties, or is coated with such. System according to one of claims 5 to 9, characterized in that an outer portion of a leg of the U-shaped rail is bent outwards and a stop ( 10 ) forms the stopper element. System according to one of claims 1 to 10, characterized in that a device for transferring the preforms ( 7 ) is provided from the injection mold in the aftertreatment tool, wherein preferably stop element and / or guide element are arranged on this transfer device. System according to claim 11, characterized in that the transfer device comprises a removal plate ( 5 ) with a plurality of sampling cavities ( 6 ), the open ends of which are located on one side of the plate. System according to claim 12, characterized in that the stop element and / or guide element at the open end of the sampling cavities ( 6 ) opposite side of the removal plate ( 5 ) are arranged. System according to one of claims 1 to 13, characterized characterized in that a plurality of aftertreatment tools are provided. System according to one of claims 1 to 14, characterized in that the aftertreatment pins ( 4 ) and / or the aftertreatment cavities ( 2 ) with a fluid outlet ( 11 ) used for ejecting the preforms ( 7 ) from or from the aftertreatment pen ( 4 ) or the Nachbehandlungskavität is provided. Process for the aftertreatment of preforms produced in an injection mold ( 7 ), in which the preforms ( 7 ) from the injection mold in after-treatment cavities ( 2 ) or post-treatment pencils ( 4 ), characterized in that the process of ejection of the preforms ( 7 ) from the aftertreatment pins ( 4 ) or from the aftertreatment cavities ( 2 ) after the post-treatment in two steps, wherein in the first step all preforms ( 7 ) about a first distance from the aftertreatment cavity or from the aftertreatment pen ( 4 ) and in the second step the preforms ( 7 ) completely from the aftertreatment pins ( 4 ) or from the aftertreatment cavities ( 2 ).