DE102018114002A1 - Method and device for producing a container - Google Patents

Abstract

The invention relates to a method and a device for producing a container, in particular for producing a container that is open on one side and has a wall that is at least partially conical by means of a deep-drawing device in a drawing step, wherein a material is clamped in the form of a plate and then formed, having an outer drawing ring with a drawing radius and an inner drawing ring with a shoulder area, the outer drawing ring encasing the inner drawing ring, the material being stretched over the drawing radius on the outer drawing ring during the drawing process and with its top at least on the shoulder area of the inner drawing ring and with its underside on part of a core, with the shoulder area of the inner drawing ring being a tangential extension of the drawing radius and a continuous flow of material running over the drawing radius, the drawing radius being constant during the forming and never s changes. According to the device, the shoulder area of the inner drawing ring is conical and is designed to protrude from the drawing radius of the outer drawing ring, the drawing radius of the outer drawing ring extending tangentially with respect to the shoulder area of the inner drawing ring such that the shoulder area of the inner drawing ring is a tangential extension of the drawing radius of the outer pull ring.

Description

The invention relates to a method and a device for producing a container with an at least partially conical wall and is used in particular for the production of unilaterally open containers application.

Such unilaterally open containers are often made today in 2 to 3 steps. This gradual, gentle forming technology prevents wrinkles in the unripped area of the container.
Alternatively, the preference and finish of the container can be combined in one step. This method is known as the Auble method, wherein the required press stroke is extended by the amount of the advantage, whereby the output unit output decreases and a trimming of the box must be made separately.
Alternatively, manufacturers manufacture such containers in one step and tolerate wrinkles during forming.

In the publication DE 26 26 685 A1 is a device for the production of open-sided deep-drawn parts with an extension on the opening side, in particular of Stufenranddosen for Aufreißdeckel on a single-acting crank press disclosed. According to the device, an outer and inner draw ring are provided on the upper die in the cutting punch, wherein the outer draw ring is disposed on a guide ring lying on the outer pressure pad. The inner drawing ring is arranged with its collar in a recess of the outer drawing ring. Between the tool upper part and the inner drawing ring, a hollow cylinder of a spring pressure base is arranged, wherein an annular disc mounted in the hollow cylinder of the spring pressure base is arranged between the inner pressure pad on the upper tool part and the marking and embossing device. In the tool lower part, a spring is mounted between a stepped pressure pin and a trimming ring.
During the working stroke, the inner pressure pad acts on the inner drawing ring and the marking and embossing device via the spring pressure base. Until the seating of the inner drawing ring on the step edge of the box, the collar of the inner drawing ring is located on the annular surface of the recess of the outer drawing ring. The inner pressure pad is increasingly deformed. During the last phase of the deep-drawing process of the inner drawing ring, the drawing operation of the outer drawing ring begins with deformation of the outer pressure pad.

According to the document, the pressure pads are made of polyurethane. The disadvantage is that the polyurethane component is format dependent and must be developed and manufactured individually.
Since mostly non-round conical containers are to be produced, the polyurethane must also be given a non-circular shape. This complicates the production in addition and drives up the cost.
Furthermore, the system can be retrofitted into existing tools only at great expense. Another disadvantage is that polyurethane shows relaxation behavior and lasting shape change over time with alternating load. Thus, the force-displacement curve of the pressure pad over the lifetime is not constant, whereby the forming result varies over time.
This uneven deformation result is exacerbated by the fact that the outer drawing ring is located at the bottom dead center of the press on the polyurethane pad. This changes the forming result when the ram end position changes.

Since the structure of the tool differs significantly from the design for cylindrical container, a conversion of the tool is excluded or uneconomical. The inefficiency of the, mentioned in the document solution also increases due to the complex structure of the tool with guide ring and stepped pressure pin.

Another significant disadvantage of the prior art and in particular the publication DE 26 26 685 A1 is that the outer and inner drawing ring lie with respect to the front side on a plane. As a result, the drawing radius is simultaneously a geometric shape element of the wall of the container open on one side. It is endeavored to choose the drawing radius for a smooth transformation as large as possible. The radii of the container wall, however, should be made small in order to increase the stability of the container. Thus, the choice of the radius is a compromise.

From the publication DE 1 452 779 A1 a deep drawing press is known, wherein the deep drawing press has a plurality of telescopically formed punches, which are retractable into dies, wherein the working stroke is limited by stops.
By means of the deep-drawing press manufactured shell-like flat blanks or the like produced in a first process step in extremely deep-drawn containers or tubes can be transformed.
The deep drawing press has a plurality of telescopically slidable drawing mandrels, which are retractable in pulling jaws. There are stops for limiting the relative approach movement between an outer mandrel and a first mold jaw provided for axially delimiting a drawing channel formed by the front end of the outer mandrel and a first surface facing the forming jaw for the passage of the workpiece. The outer mandrel is further formed coupled during one or more Nachziehvorgänge with an inner mandrel.

A method of producing metal cans and metal cans made therefrom are known from the document DE 698 25 930 T2 known. The method discloses one or more drawdown stages in which the sidewalls are reduced in thickness by stretching and in the can base an inwardly projecting dome is created bounded by upstanding walls. The walls enclose an angle between 0 ° and 5 ° with respect to the vertical. The said method is used to produce beverage cans. The starting material used is a steel strip or steel sheet which is coated with a polymer material.

The object of the invention is to develop a method and an apparatus for producing a container, which have a simple structural design and a simple manufacturing process and ensure the wrinkle-free or low-wrinkle production of a container open on one side. Furthermore, the retrofitting of a tool for cylindrical containers without conical portion on containers with conical portion should be possible.

This object is achieved with the characterizing features of the first and tenth patent claim.

Advantageous embodiments emerge from the subclaims.

The inventive method relates to the production of a container, in particular the production of a container open on one side with an at least partially conical wall by means of a deep-drawing device in a drawing stage. According to the method, a material is clamped in the form of a board and then reshaped, wherein the deformation takes place by means of an outer drawing ring with a drawing radius and an inner draw ring with a shoulder region, wherein the outer draw ring encloses the inner draw ring.

During the drawing process, the material is stretched over the drawing radius on the outer drawing ring and abuts against the shoulder region of the inner drawing ring with its upper side and on its underside on at least parts of a core. The shoulder area of the inner drawing ring lies in a tangential extension of the drawing radius, whereby a continuous flow of material extends over the drawing radius, the drawing radius being constant during the forming. The drawing radius has material contact during the complete forming and is supplemented by a second radius on the inner draw ring at a certain point of the forming.
This tangential transition does not create a kink in the material and thus a continuous flow of material can be generated. The material is stretched over the core. The drawing gap established between the outer drawing ring and the core is continuously narrowed during the forming until the conical portion is formed.

The deep-drawing process is designed such that the inner drawing ring is moved to an end position and the outer drawing ring is subsequently moved further so that the outer draw ring forms the cylindrical portion of the container wall of the container which is open on one side. The cylindrical portion of the container wall is formed between the outer drawing ring and the core.

In an advantageous embodiment, the board is punched during the press stroke between a cutting ring and a punch, the board between the punch and a fold holder clamps.
The optional trimming of the material, or of the container produced on one side, is carried out in the lifting movement after the material has been formed between the ram and a trimming ring arranged parallel to the core at this end.

According to the method, in an advantageous embodiment, in a dead center of the device, the inner and outer draw ring are blocked by a pressure plate.

Preferably, the pressure for the deformation of the material is applied via a press-side die cushion and transferred by means of bolts in the tool, on the pleat holder.

The unilaterally open container is ejected during the return stroke with the trimming ring from the lower tool and clamped by the inner drawing ring with the upper tool taken up.

The method can be illustrated such that during the press stroke, the blank is punched between a cutting ring and a punch, the blank being clamped between the punch and a fold holder. The necessary pressure is applied via a press-side die cushion and transferred by means of bolts in the tool, on the fold holder, with a trimming ring rests on this bolt at the same time. The cone angle of the material to be formed or the board is reduced during the forming between the drawing radius of the outer drawing ring and the core, wherein the drawing gap during the forming is continuously formed until the conical region on one-sided open container narrows. Subsequently, the inner drawing ring is placed on the immovable core and springs against one or more gas springs. After this step, the outer draw ring forms the cylindrical portion of the container wall, with the drawing gap between the outer draw ring and the core.

The invention further relates to a device for producing a container, wherein the device is designed in particular in the form of a deep drawing device for the production of unilaterally open containers.
The device comprises a split draw ring in the form of an inner and an outer draw ring, wherein the outer draw ring encloses the inner draw ring.
The inner draw ring has a shoulder region in such a way that the shoulder region of the inner draw ring is conical. The outer pull ring has a pull radius, wherein the shoulder portion of the inner pull ring is opposite to the pull radius of the outer pull ring. The pull radius of the outer pull ring extends tangentially with respect to the shoulder area of the inner pull ring such that the shoulder area of the inner pull ring is a tangential extension of the pull radius of the outer pull ring. This tangential transition does not create a kink in the material, as a result of which a continuous flow of material can be generated. By dividing the draw ring into an outer and an inner draw ring, the cone angle of the material to be formed during the forming between the draw rings and the core is reduced and wrinkling is minimized.

The position of the inner drawing ring relative to the outer drawing ring is preferably secured by means of gas pressure springs. The gas springs are dimensioned such that they apply at least the pulling force component in the axial direction in order to prevent an undefined, unwanted dodging of the inner Ziehrings.

The outer drawing ring is durable in an advantageous embodiment by means of springs in a defined position. These springs are preferably designed in the form of disc springs, wherein the disc springs, which hold the outer draw ring in the defined position also apply at least the pulling force component in the axial direction. Both spring systems, gas springs and disc springs, work independently until the complete formation of the container open on one side and can be dimensioned and adjusted separately.

During the press stroke, the board is punched between the cutting ring and the punch. This board is stuck between the stamp and the fold holder. The necessary pressure for the thermoforming process is preferably applied by means of the device via a press-side die cushion and transferred by means of bolts in the tool, on the pleat holder. At the same time the trimming ring rests on this bolt.

The elimination of polyurethane components creates constant force-displacement relationships of the spring systems over a long period of time since no permanent shape changes of these polyurethane components occur.

Furthermore, the use of standard components instead of format-dependent individual components is possible, which further reduces costs.
In addition, can be dispensed with a guide ring and a remote pressure pin in the solution.
A conversion of existing cylindrical tools is possible by a similar structure. The bolt of the disc spring assemblies is preferably replaced by the gas spring. The gas spring is thus a component with a double function.

The trimming of the container open on one side may be integrated in the device or implemented as an optional component of the production technology.
The inventive method provides the preparation in a drawing stage and the possibility of integrating the trimming of the container open on one side also optionally in this operation. In addition, the conversion of an existing tool for cylindrical containers without conical portion on containers with conical portion is possible.

The invention will be explained in more detail below using an exemplary embodiment and associated drawings.

• 1 eine Schnittdarstellung einer erfindungsgemäßen Vorrichtung,
• 2 eine Detailansicht der der Materialklemmung während der Formung,
• 3 eine Detailansicht des inneren und äußeren Ziehringes,
• 4 eine schematische Darstellung der Anordnung des inneren und äußeren Ziehringes.

Show it:

• 1 a sectional view of a device according to the invention,
• 2 a detailed view of the material clamping during molding,
• 3 a detailed view of the inner and outer drawing ring,
• 4 a schematic representation of the arrangement of the inner and outer drawing ring.

The 1 to 3 show the almost closed mold state of the thermoforming device just before reaching the dead center of the device. At this time, the conical portion of the container is already fully formed. Followed in the remaining remaining stroke, the shaping of the cylindrical portion and the trimming of the can.

During the press stroke becomes a material M in the form of a circuit board between a cutting ring 47 and a stamp 52 punched. This board jams between the stamp during the process 52 and a pleat holder adjacent to the plunger along the longitudinal axis of the device 42 ,
The pressure required for the process is applied via a press-side die cushion and by means of bolts 39 in the tool, on the fold holder 42 transfer. On this bolt 39 is a trimming ring 40 on, by means of the container in a return stroke is ejected. The system on the pressure pin is at least one, preferably several springs 41 secured.

During the drawing process, the material is reshaped by means of a two-part drawing die, wherein the outer drawing ring 55 a drawing radius 551 has, on which the material M is tense. The material M Lays down to a shoulder area 601 of the inner drawing 60 on. Here is the shoulder area 601 of the inner drawing ring 60 the tangential extension of the drawing radius 551 of the outer drawing ring 55 , This tangential transition does not create a kink in the material M , which can be spoken of a continuous flow of material. The material is at least over parts of a fixed core 37 curious; excited. The drawing radius ( 551 ) has material contact during the complete forming and is during the forming by a second radius ( 602 ) on the inner drawing ring ( 60 ) added.

The drawing gap narrows continuously during the deformation until the conical region is completely formed on the container which is open on one side. Now the inner drawing ring sets 60 on the immovable core 37 on. The press stroke is not finished yet in this position.
After putting on the inner drawing ring 60 on the core 37 the pull ring springs 60 against a gas spring 57 on.

In the following continuing stroke movement forms the outer drawing ring 55 the cylindrical portion of the container wall.
The drawing gap is between the outer drawing ring 55 and the core 37 on. During forming, the draw radius over which the material flows never changes.

After the one-sided open container is fully formed, sets the trimming ring 40 on a hard stop 33 on, with the press stroke is not yet completed.
In an advantageous embodiment, the trimming of the container open on one side takes place between the stamp in the following 52 and the trimming ring 40 , At the dead center of the press are both drawing rings 55 . 60 about one on the pulling rings 55 . 60 acting pressure plate 56 blocked out. It is achieved a constant end position and a constant forming result.
The unilaterally open container is the return stroke with the trimming ring 40 ejected from the lower tool and clamped by the inner drawing ring 60 taken upwards with the upper tool.
In an advantageous embodiment, a support of the clamping can take place by means of negative pressure or optionally integrated. After the trimming of the container, the wrinkle holder throws 42 the trimming waste ring from the lower tool.
A schematic representation of a partial section of the arrangement of the inner and outer drawing ring 60 . 55 is in 4 shown. The outer drawing ring 55 has a draw radius 551 on, over which the material M is stretched during the drawing process.

The inner drawing ring 60 has a shoulder area 601 on, which is arranged so that the material M to the shoulder area of the inner draw ring 60 invests. Preferably, the inner draw ring 60 from the outer drawing ring 55 completely wrapped.
The shoulder 601 is arranged so that it is the tangential extension of the drawing radius 551 represents. This tangential transition does not create a kink in the material, creating a continuous flow of material. During the forming never changes the drawing radius 551 over which the material M flows. By dividing the drawing ring into an outer 55 and an inner draw ring 60 becomes the cone angle of the material to be reshaped M during the forming between drawing radius 551 and core 37 reduces and minimizes wrinkling.

LIST OF REFERENCE NUMBERS

33

fixed stop

37

core

39

bolt

40

Chopping ring

41

feather

42

blank holder

47

cutting board

52

stamp

55

Drawing ring outside

56

printing plate

57

Gas spring

58

Belleville spring

60

Draw ring inside

551

drawing radius

601

shoulders

602

Radius on the inner draw ring

M

Material / board

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

• DE 2626685 A1 [0003, 0006]
• DE 1452779 A1 [0007]
• DE 69825930 T2 [0008]

Claims (13)

A method for producing a container, in particular for producing a container open on one side with an at least partially conical wall by means of a deep-drawing device in a drawing stage, wherein a material is clamped in the form of a board and then formed, comprising an outer drawing ring with a drawing radius and an inner Drawing ring with a shoulder region, wherein the outer drawing ring surrounds the inner drawing ring, characterized in that during the drawing process, the material is stretched over the drawing radius on the outer drawing ring (55) and with its upper side at the shoulder region of the inner drawing ring (60) and its underside against at least parts of a core (37), wherein the shoulder region (601) of the inner drawing ring (60) represents a tangential extension of the drawing radius (551) and a continuous flow of material over the drawing radius (551), wherein the drawing radius (551 ) during the transformation ko nstant is. Method according to Claim 1 , characterized in that the drawing radius (551) during the entire forming material contact and during the forming by a second radius (602) on the inner draw ring (60) is supplemented. Method according to Claim 1 and 2 , characterized in that the inner drawing ring (60) is moved to an end position and subsequently the outer drawing ring (55) is moved further such that the outer draw ring forms the cylindrical portion of the container wall. Method according to one of Claims 1 to 3 characterized in that the drawing gap between the draw rings (55, 60) and the core (37) continuously narrows during forming until the conical portion is formed. Method according to one of Claims 1 to 4 , characterized in that in the lifting movement after the deformation of the material, a trimming of the container open on one side between a punch (52) and a parallel to the core (37) arranged adjoining the trimming ring (40). Method according to one of Claims 1 to 5 , characterized in that in a dead center of the device, the inner and outer draw ring (55, 60) are blocked by a pressure plate (56). Method according to one of Claims 1 to 6 , characterized in that the pressure for the deformation of the material applied via a press-side die cushion and by means of bolts (39) in the tool, on the fold holder (42) is transmitted. Method according to one of Claims 1 to 7 , characterized in that the container open on one side during the return stroke with the trimming ring (40) ejected from the lower tool and clamping by the inner drawing ring (60) with the upper tool is taken upwards. Method according to Claim 1 , characterized in that during the press stroke, the board between a cutting ring (47) and a punch (52) is punched, wherein the board between the punch (52) and a fold holder (42) jammed, wherein the necessary pressure on a press-side die cushion applied and by means of bolts (39) in the tool, on the fold holder (42) is transferred to this pin (39) simultaneously a trimming ring (40) rests and that the cone angle of the material to be formed during the forming between the drawing radius of the outer drawing ring and the core (37), wherein the drawing nip continuously narrows during forming until the conical region on the one-sided open container is fully formed, following which the inner draw ring (60) rests on the stationary core (37) and against one or more Compression springs (57) springs in, wherein the outer drawing ring (55) form the cylindrical portion of the container wall in the following t and the drawing gap between the outer draw ring (55) and the core (37) sets. Device for producing a container, in particular a deep-drawing device for the production of unilaterally open containers, the device having a divided drawing ring in the form of an inner and an outer draw ring (55, 60), characterized in that the inner draw ring (60) has a shoulder region ( 601) such that the shoulder region (601) of the inner Ziehrings (60) is conical and with respect to a Ziehradius (551) of the outer Ziehring (55) protrudes, wherein the Ziehradius (551) of the outer Ziehrings (55) tangentially in Regarding the shoulder region (601) of the inner pull ring (60) extends such that the shoulder region (601) of the inner pull ring (60) is a tangential extension of the pull radius (551) of the outer pull ring (55). Device after Claim 10 , characterized in that the position of the inner Ziehrings (60) relative to the outer drawing ring (55) by means of gas pressure springs (57) is secured. Device according to one of Claims 10 and 11 , characterized in that the outer draw ring (55) by means of springs in a defined position is preserved. Device according to one of Claims 10 to 12 , characterized in that on the bolt (39) rests a trimming ring (40), wherein the abutment of the trimming ring (40) on the bolt (39) via at least one spring (41) is secured.

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