DE102010032618A1 - Blow mold for use in construction kit for manufacturing of containers, particularly canisters, has two tool components, particularly tool halves, which are movable against each other for opening and closing tool - Google Patents

Abstract

The blow mold has two tool components (1), particularly tool halves, which are movable against each other for opening and closing the tool. The tool components have recesses in one or multiple edge areas (4) or corner areas (5) of the mold space.

Description

The invention relates to a blow mold for the production of containers made of thermoplastic material, in particular canisters, with at least two tool components, for. B. tool halves, which are movable to open and close the tool or the mold against each other. Preferably, the container or canister produced by way of blow molding is of rectangular cross-section, ie. h., The canister has essentially the basic shape of a cuboid, wherein the edges and corners of such a cuboid are usually rounded and thus equipped with suitable radii.

In the course of producing such hollow body by blow molding z. B. an extruder with a blow head a tubular preform, which is then surrounded while still hot by a mold or blow mold and expanded by means of a blow mandrel introduced compressed air, so that the respective hollow body receives the inner contour of the blow mold or the mold. For this purpose, the tool halves are generally movable in the horizontal direction against each other to open the tool and close.

For the production of different containers or canisters different molding tools are usually used in practice. This assumes that the container manufacturer has a separate mold for each type of container.

In order to allow a certain flexibility in the product design, without the need for a complete, separate set of tools for each different design, was in the US 3,807,928 has already proposed a device for blow molding with a two-part mold for the production of plastic bottles, wherein the mold is divided into a neck part and a body part, so that different neck shapes can be combined with the same or different body parts.

From the DE 28 48 131 In addition, one knows a form set in the manner of a modular construction for blow molding an extruded plastic blank to container-like objects similar in shape, but different dimensions. Each of the mold halves is composed of several separable elements, so that by combining different elements molds for the production of different containers and in particular containers of different dimensions can be realized. However, construction and assembly of such a mold are relatively expensive.

In practice, moreover, there is a need to produce different containers which are identical in their basic structure and size and differ only in certain areas and in particular in the edges and / or corner areas. For example, containers having a specific volume (for example 20 l) are known, which may be formed either smoothly or also with a groove structure in the edge regions. Groove structures in the region of the edges and / or corners can be for design reasons, but also for technical reasons, for. B. be provided to increase the stability. So far, it is necessary to use different tools for such different containers.

Further, venting the mold often causes problems in practice. The bleeding time influences the cycle time for the blow molding.

The invention has for its object to provide a blow mold for the production of containers made of thermoplastic material of the type described above, which allows for simple and inexpensive construction and simple and cost-effective assembly variable production of different container types. In addition, a blow mold with improved ventilation properties to be created.

To solve this object, the invention teaches in a generic blow molding tool of the type described above that one or more tool components (eg tool halves) in each case have a recess in one or more edge regions and / or corner regions of the molding space, into which a separate and preferably interchangeable insert is used, which on its inner side facing the mold cavity a contour associated with the container to be formed, for. B. edge and / or corner contour has.

According to a first aspect, the invention is based on the finding that a blow molding tool can be easily adapted or modified in the edge and / or corner regions if recesses are provided in the edge regions and / or corner regions, into which then interchangeable Inserts are used. For different configurations of the edge regions or corner regions of the container, consequently, different inserts can be used in one and the same molding tool, so that the basic structure of the molding tool does not have to be changed. It is only an exchange of (inner) inserts in the edges or corners required. Thus, for example, with one and the same mold, both containers with smooth edge regions and containers with edge regions with a groove structure can be produced, wherein only the correspondingly designed inserts must be mounted. It is therefore not necessary to manufacture or stockpile different tools for containers with different edge structures. This makes it easy to produce containers with a wide variety of designs and requirements. For example, containers with groove structures or similar profiles in the edge regions may be required to optimize the stability of the container, especially in stackable containers. However, in other contexts it may also be desired to produce containers with smooth corner areas and edge areas. Alternatively and additionally, it may be desirable to provide design elements, lettering or similar designs in the corner areas. All this can be realized with the help of edge and / or corner inserts according to the invention, without the basic structure of the tool must be changed. In particular, the fact that the tool is very stable in spite of everything and is very easy to assemble, since in particular not all the form elements are completely modular and not always a corresponding container must be assembled from a variety of components is advantageous. Rather, only an exchange of arranged in the interior of the tool inserts, so that the forces absorbing basic structure of the tool is not changed.

Such a blow molding tool is particularly preferably used for the production of rectangular-shaped canisters and consequently essentially cuboidal canisters. The mold cavity is thus substantially rectangular in shape with a rectangular cross-section. In such a configuration, it is expedient if, in the region of one or more edges, preferably in the region of all four edges, recesses are provided, in each of which one or more inserts are inserted. In principle, however, the invention also encompasses embodiments in which interchangeable inserts are not arranged in all edge regions, but only in a few edge regions.

It is basically known that the individual tool components, eg. B. the tool halves, each in turn are formed in several parts and have a plurality of superposed moldings. So can a tool half z. B. composed of a shoulder part, a middle part and a bottom part. In such an embodiment, the invention proposes that the molded parts each have one or more recesses, in each of which an insert is inserted. Such use of a molding can be such. B. extend over the entire height of this molding. Consequently, each individual molded part can be assigned a separate insert. Thus, the invention proposes that in the case of a tool component which is composed of shoulder part, middle part and bottom part, the shoulder part and the bottom part each have a plurality of corner recesses (eg two corner recesses) and the middle part has several edge recesses (eg two edge recesses ) and that each Eckausnehmung a separate corner insert and each edge recess is associated with a separate edge insert.

In such embodiments, in which the tool components or mold halves are each again formed in several parts, consequently, a separate insert can be attached to each individual molding, so that the individual moldings can then be mounted and used in a conventional manner. It is basically known that the individual molded parts (eg shoulder part, middle part and bottom part) are firmly connected to each other, eg. B. are screwed. Even with such an embodiment, it may be appropriate to assign each individual molding a separate use. However, there is also the possibility that an insert extends over several moldings, for. B. together on the shoulder part and the middle part.

Alternatively, however, blow molding tools are used in particular in which individual mold parts of a mold half are movable relative to one another during operation. In particular, blow molds with lowerable bases are known, i. h., The tool halves are connected or equipped with lowerable bottom halves. In particular, in such embodiments, it is expedient if the individual moldings, z. B. the middle part on the one hand and the bottom part on the other hand separate inserts are assigned.

It is always expedient for the inserts (eg edge inserts and / or corner inserts) to be detachably and therefore exchangeably fixed in the recesses (eg edge recesses and / or corner recesses). This can be realized for example by means of screws or screw connections. The screws are preferably introduced from the outside through suitable holes of the tool in the inserts, preferably the backs. This ensures that the contour is not affected by the fastening means.

According to a second aspect, which assumes independent significance, the invention is based on the recognition that the design with recesses and inserts for the edge and / or or corner areas not only the adaptability of the tool to different needs is improved, but with the help of inserts can also improve the venting of the container in the course of blow molding. So it is generally known to realize the venting on the parting planes of the tool halves and optionally on the parting planes of the individual mold parts of a mold half. Nevertheless, it often causes difficulties to remove the considerable amounts of air quickly from the tool. The cycle time is therefore often limited by the difficulties encountered during venting. In the context of the invention, it is now possible to realize an additional venting or an improved venting via the inserts in the edge or corner areas. Because of the gaps between the insert and the recess, the air can escape between the preform and the tool and be guided into the area of the parting planes. This succeeds, although the inserts do not extend to the outer surface of the tool and thus the joints between insert and recess do not extend continuously to the outer surface. Because it is already sufficient that the air can reach over the joint in the region of the parting plane of the tool, so that thereby the ventilation is improved.

For this purpose, it may be particularly expedient to match the inserts on the one hand and the recesses on the other hand in their cross-section such that a gap is provided on the back between the insert and the recess, which serves to vent the mold space in the course of the blow molding. In this case, it is possible to introduce vent grooves or vent surfaces into the insert and / or into the recess, so that the air can flow from the mold space into the rear vent channel. Such grooves or vent surfaces are basically known from the field of parting planes. Alternatively or additionally, it is within the scope of the invention that in the use of one or more venting recesses, for. B. venting slots or holes are introduced, which connect the mold space with the rear venting gap. In order to avoid that grooves or ventilation surfaces and / or ventilation slots affect the surface of the hollow body to be produced, it is expedient to work with relatively narrow slots or grooves. The lateral vent surfaces or vent grooves, for example, a depth of 0.01 to 0.1 mm, preferably 0.02 to 0.06 mm, z. B. 0.04 mm. The vent slots, for example, a width of 0.01 to 0.08 mm, preferably 0.01 to 0.05 mm, z. B. 0.03 mm. For example, these may be wire-eroded ventilation slots. The slots can also be introduced differently, z. B. by laser cutting or by a layer structure. The slots may extend, for example, in the longitudinal direction of the respective insert, wherein they preferably do not extend over the entire height of the insert, but only over a partial area, so that the stability of the insert is not significantly impaired. But it can also be provided slots in the transverse direction.

Overall, the ventilation properties of the blow molding tool can be significantly improved by the measures described. In particular, the cycle times can be optimized and consequently reduced. During the blowing process, it is possible to switch to high-pressure operation earlier than before. Incidentally, an optimized wall thickness distribution can be achieved. Because of the optimized ventilation in the area of the edges or corners, it is achieved that the preform rests faster in these areas than before. Thus, the material thickness remains available, so that overall the desired wall thickness distribution, z. B. a uniform wall thickness distribution can be achieved.

The invention also relates to a kit with a blow mold of the type described and with a plurality of interchangeable inserts, wherein an edge and / or corner recess are each assigned a plurality of different uses. The interchangeability of the inserts is consequently of particular importance in the context of the invention. However, it is also within the scope of the invention that the blow molding tool is equipped only with a single insert or a single type of inserts, so that then no adaptation to different conditions takes place. Nevertheless, the mold according to the invention is characterized by an improved ventilation behavior.

In the following the invention will be explained in more detail with reference to a drawing showing only one exemplary embodiment. Show it

1 a blow molding tool in a considerably simplified representation,

2 a middle part of a blow molding tool in a plan view,

3 the middle part according to 2 in a side view,

4 an edge insert for a central part to 2 .

5 a shoulder part of a blow molding tool in a plan view,

6 a corner insert for a shoulder part 5 .

7 a bottom part of a blow molding tool in a plan view,

8th a corner insert for a bottom part after 7 .

9a , b, c a corner insert for a shoulder part in a modified embodiment.

In the figures, a blow molding tool for the production of containers and in particular canisters made of thermoplastic material is shown. This is in particular a canister with a substantially rectangular cross section and consequently a canister with a cuboid basic shape.

The blow molding tool consists essentially of two tool components, namely two mold halves 1 together. The tool halves are movable against each other for opening and closing the blow mold. On the inside, the tool halves point 1 a form space 2 forming contours 3 on.

According to the invention, the tool halves 1 in the edge areas 4 and corner areas 5 of the cavity each recesses 6 . 7 on which bets 8th . 9 are used, these inserts 8th . 9 on her the form space 2 facing inner sides each having a container to be molded contour associated.

In the context of the invention, consequently, the inserts can be 8th . 9 to customize the mold to make different container types. By exchanging the inserts 8th . 9 can be z. B. container with a smooth edge portion on the one hand and with an edge region with groove structure on the other hand produce. This should be based on the 1 to 8th be explained.

1 First of all, that shows each tool half 1 from several moldings 10 . 11 . 12 composed of shoulder part 10 , Middle part 11 and bottom part 12 ,

The shoulder part 10 is in 5 and 6 represented, the middle part 11 is in the 2 to 4 shown and the bottom part 12 in the 7 and 8th ,

It can be seen that both the shoulder parts 10 and the middle parts 11 as well as the bottom part 12 each in the edge areas 4 or corner areas 5 recesses 6 . 7 in which the inserts according to the invention 8th . 9 are used. It is indicated in the figures that on the one hand inserts 8th . 9 with a smooth surface 15 and then stakes 8th . 9 with a groove structure 16 can be used. A comparative analysis of the 2 to 8th moreover, that shows every molding 10 . 11 . 12 each separate inserts are assigned. Every shoulder part 10 has two corner recesses 7 on, in each of which a corner insert 9 is used. The same applies to the floor parts 12 , The middle part 11 has two edge recesses 6 on, in each case an edge insert 8th is used. In the 2 . 3 . 5 and 7 the respective molded part is shown in a corner area with inserted insert and in the other corner without insert.

The figures also show that the inserts 8th . 9 in each case over the entire height of the respective molded part 10 . 11 . 12 extend. Incidentally, it can be seen that the individual inserts 8th . 9 firm but releasable in the recesses 6 . 7 are used, for. B. are fixed by means of screws. It can also be seen that the molding tool with cooling channels 13 equipped. The stakes 8th . 9 are also with cooling channels 14 equipped. The individual molded parts (shoulder part 10 , Middle part 11 and bottom part 12 ) each equipped with separate cooling circuits.

The embodiment of the invention with the recesses 6 . 7 and the missions 8th . 9 also has the advantage of improved venting of the tool in the course of blow molding. Because through the joints between the recesses 6 . 7 and the missions 8th . 9 can the air out of the mold space 2 in the course of the blow molding in the back area behind the insert 8th . 9 reach. The stakes 8th . 9 and the recesses 6 . 7 are coordinated in their cross-section so that on the back of the inserts 8th . 9 or in the back corners of the recesses between the inserts 8th . 9 and the recesses 6 . 7 a gap is formed, which forms a vent channel. Via this ventilation channel, the air can reach the area of the parting planes of the blow molding tool, so that the venting is optimized. This gap is not shown in all figures. Example becomes on 5 directed.

The gap can be realized, for example, in that, with the same basic shape of the recess and the insert, the dimensioning is designed such that a gap remains. Another possibility is that the cross-sectional shape of the recess deviates from the cross-sectional shape of the insert in the back corners. Such a possibility is in 5 optionally indicated. There it can be seen that the recess 7 the back is equipped with "rounded corners". To realize the gap 17 is the use 9 around back corner with a flattening 19 provided so that between the flattening 19 and the rounded corner 18 the venting channel 17 as a gap arises.

The venting can be further improved if it is ensured by suitable measures that the air from the mold cavity quickly and reliably in the area of the venting duct 17 can escape. This can be the use 8th . 9 with side ventilation grooves or ventilation surfaces 20 be equipped. These are exemplary in 9 shown. These ventilation surfaces 20 , which may for example have a depth of 0.04 mm, ensure that the air from the mold cavity is laterally inserted between 8th . 9 and recess 6 . 7 in the area of the gap 17 can escape. Optionally or additionally, it may be expedient to vent vents 21 in the insert 8th . 9 contribute. This too is exemplary for use 9 in 9 shown. It can be seen that the slots 21 the mold cavity with the rear venting duct 17 connect. The slots 21 do not extend over the entire height of the insert 9 but only over a subarea. But it is also possible, more than one ventilation slots on top of each other, z. B. on the one hand from above and on the other hand from below into the insert 8th . 9 contribute. The possibility of vents 21 and grooves or vent surfaces 20 is to be provided in the 9 merely exemplified for use in the area of the shoulder part or the bottom part. However, these measures can also be used in the same way 8th for the middle part 11 be provided.

Incidentally, it is within the scope of the invention to further improve the described venting function in that a connection of the venting channels or the joints is made with vacuum, so that an active extraction is feasible.

The figures show, moreover, that the recesses 6 . 7 and the stakes 8th . 9 in the area of the back corners can actually be "square" or alternatively with "rounded edges". While in the area of the middle section 11 the recesses 6 and the stakes 8th Are formed "angular" are the recesses 7 and the stakes 9 in the area of shoulder part 10 and bottom part 12 rounded on the back. However, it is also within the scope of the invention to round off the recesses and / or the inserts also in the region of the middle part. As a result, if necessary, the stability of the tool can also be improved.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 3807928 [0004]
• DE 2848131 [0005]

Claims (9)

Blow molding tool for the production of containers made of thermoplastic material, in particular canisters, with at least two tool components ( 1 ), z. B. tool halves ( 1 ), which are movable against each other for opening and closing the tool, wherein the tool components ( 1 ) inside a mold space ( 2 ) forming contours ( 3 ), characterized in that one or more tool components ( 1 ) in one or more edge regions ( 4 ) and / or corner areas ( 5 ) of the mold space in each case a recess ( 6 . 7 ) into which a separate and preferably exchangeable insert ( 8th . 9 ) is inserted, which on its the form space ( 2 ) facing inside has a contour associated with the container to be molded. Blow mold according to claim 1, for the production of cross-sectionally substantially rectangular canisters with a z. B. substantially rectangular shape space, characterized in that in one or more edge regions, preferably in all four edge regions, recesses are provided, in each of which one or more inserts are used. Blow mold according to claim 1 or 2, wherein each tool component ( 1 ), z. B. tool half ( 1 ), each having a plurality of parts and a plurality of superimposed molded parts ( 10 . 11 . 12 ), z. B. each a shoulder part ( 10 ), a middle part ( 11 ) and / or a floor part ( 12 ), characterized in that the molded parts ( 10 . 11 . 12 ) one or more recesses ( 6 . 7 ), in each of which one or more inserts ( 8th . 9 ) are used, which z. B. over the height of the molding ( 10 . 11 . 12 ). Blow mold according to one of claims 1 to 3, wherein each tool component ( 1 ) from shoulder part ( 10 ), Middle section ( 11 ) and bottom part ( 12 ), characterized in that the middle part ( 11 ) two edge recesses ( 6 ) with two edge inserts ( 8th ) and that the shoulder part ( 10 ) and the bottom part ( 12 ) two Eckausnehmungen with two Eckeinsätzen ( 9 ) exhibit. Blow mold according to one of claims 1 to 4, characterized in that the inserts ( 8th . 9 ) detachable and z. B. interchangeable in the recesses ( 6 . 7 ) are attached, z. B. are screwed. Blow mold according to one of claims 1 to 5, characterized in that the inserts ( 8th . 9 ) with cooling channels ( 14 ), z. B. cooling holes are provided. Blow mold according to one of claims 1 to 6, characterized in that the inserts ( 8th . 9 ) and the recesses ( 6 . 7 ) are matched in cross section to one another in such a way that between the insert ( 8th . 9 ) and recess ( 6 . 7 ) A gap ( 17 ), which is the venting of the mold space ( 2 ) in the course of blow molding. Blow mold according to claim 7, characterized in that in the insert ( 8th . 9 ) one or more vent openings, z. B. vents ( 21 ) and / or one or more lateral vent grooves or surfaces ( 20 ) are introduced, which the mold space ( 2 ) with the rear ventilation gap ( 17 ) connect. Kit with a blow molding tool according to one of claims 1 to 8 and with a plurality of exchangeable inserts ( 8th . 9 ), wherein a recess ( 6 . 7 ) each have several differently configured inserts ( 8th . 9 ) assigned.

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