DE102012215312A1 - Method for manufacturing inner container of e.g. refrigerator for cooling foodstuffs, involves deforming base part to container by thermoforming, and filling material thin spot of plastic produced during thermoforming by filling material - Google Patents

Abstract

The method involves providing a base part (6) made of plastic. The base part is deformed to an inner container by thermoforming. A material thin spot (8) of the plastic produced during the thermoforming is targetedly filled by a filling material (9). The filling material is sprayed or spreaded. The filling is performed after trimming of an intermediate mold part (7) and before or after stamping of the mold part to the container, where the mold part is produced from the base part by thermoforming. The thin spot is detected by a thickness measurement locally and/or relative to a depth. The filling material is a two-components-reaction adhesive. An independent claim is also included for a container.

Description

The invention relates to a method for producing a container of a household refrigerating appliance, in which a base part made of plastic is provided and this is deformed by thermoforming the container. Furthermore, the invention relates to a container for a household refrigerator and a corresponding household refrigeration appliance.

From the DE 10 2009 045 658 A1 is a household refrigerator with an inner container known, wherein the inner container is made by a thermoforming.

In addition, from the DE 10 2010 029 583 A1 a household refrigerator and a manufacturing method for such a refrigerator known. There, an inner container is manufactured by thermoforming, and an evaporator is attached to the inner container by an adhesive attachment. The adhesive attachment can be generated during the thermoforming, using appropriate adhesives are used.

In the manufacture of inner containers for a domestic refrigeration appliance made of plastic by means of thermoforming process and geometriebedingt caused bodies that fall below an application required minimum wall thickness. If these thin layers of material are recognized after the thermoforming process, the produced inner container or the generated inner door is currently ground and returned to the process chain as regranulate.

However, if these thin spots are not recognized, then these manufactured parts are passed with quality defects in the further manufacturing process chain. Such thin areas can cause damage to the parts during the subsequent processing steps, which are then unusable and must be disposed of. In addition, it is type-specific required that due to complex shapes provided for such inner container boards or bases with a high material thickness must be used to meet the required minimum wall thickness in critical areas of the thermoformed parts. As a result, although the minimum required wall thickness can be achieved in most areas, but at the same time there is an unnecessarily high wall thickness in other areas of the thermoforming part. For a plastic material is wasted on the one hand, on the other hand, if necessary, the wall thickness designed to undesirable high specific points.

It is known that, in the case of currently occurring thin areas, these are to be repaired expensively by masking with an adhesive tape on the foam side of the inner container. In addition to a high workload, this also makes it possible to reinforce three-dimensional structures only to a limited extent. In addition, an increase in the material thickness of the output board occurs to compensate for the thin areas. As a result, higher material costs arise and, in addition, higher cycle times with regard to production occur. In addition, with such a material thickness increase optionally a subsequent assembly to other parts no longer or only more difficult.

It is an object of the present invention to provide a method and a container and a household refrigerator with such a container, with which or in which the container design is improved with respect to occurring material thin points.

This object is achieved by a method, a container and a domestic refrigerator according to the independent claims.

In a method according to the invention for producing a container of a household refrigerating appliance, a base part made of plastic is initially provided. This is then deformed or thermoformed by thermoforming, so that at the end of the manufacturing process, the container to be produced is formed. An essential aspect of the invention is to be seen in that at least one thin material point of the plastic produced during thermoforming is specifically filled by a filling material. By doing so, the above-mentioned problems can be solved. In particular, no waste of material occurs more so that basically thicker base parts must be provided as required. By selectively refilling the material thin areas, the material thickness can be generated evenly and appropriately and the thin area can also be topped up precisely and precisely. In addition, this procedure can be very easily integrated into the manufacturing process, so that the related manufacturing and labor costs can be kept very low.

It is preferably provided that the material thin point is filled with an adhesive. On the one hand, such a filling material is extremely suitable with regard to the arbitrary deformability to completely fill up the thin material point. On the other hand, an embodiment is achieved by this material, in which the filler material is very hard afterwards and withstands corresponding mechanical loads. In addition, by such an adhesive also a reliable mechanical connection with the material of the Base part or then already transformed intermediate molding achieved. In particular, the surface design of the filled-in thin-area region is then also possible in a very precise manner, so that, in particular, a stepless surface design and a corresponding transition to the surfaces adjoining the original material thin point are achieved.

In addition, the filling with an adhesive is particularly easy to integrate into the manufacturing process and a corresponding production line is in this regard easily or upgrade.

It is preferably provided that the filling material is sprayed on. In particular, by using a spray head, the locally very focused and quantitatively very precisely metered application of the filling material can be achieved. On the one hand, this has significant advantages with a view to the fastest possible replenishment of such thin material points, so that the manufacturing process can also be minimized in terms of time. In addition, by such spraying the material distribution on or in the thin spot very possible. Thus, it can also be done very appropriate to the amount of adhesive applied so that no waste occurs here and no extensive further post-processing of the adhesive is required and, if necessary, a partial removal is avoided.

It can also be provided that the filling material is painted on. For example, the application of an adhesive bead can also take place here. Likewise, a combination of spraying with a brushing done. In a brushing, both the caterpillar application and a surface application is included.

It is preferably provided that the filling material is filled into the material thin point after the completion of the thermoforming. Such a procedure is particularly advantageous in that a further undesired deformation of the intermediate molding part no longer occurs and the material thin point is already relatively accurate in terms of its dimensions and can be filled with the corresponding filling material.

It is preferably provided that the filling of the material thin point with the filling material is carried out after a trimming of the intermediate molded part produced by the thermoforming. This also situations can be avoided in which unwanted deformations or mechanical force influences occur during trimming, so that if necessary, the filler would again remove from the thin area or possibly even deformed so that again no desired material thickness would be available.

It is preferably provided that the filling of the material thin point with the filling material is carried out before or after a punching of the intermediate molding produced by the thermoforming to the container.

It is provided, in particular, that a material thin point is detected and recognized locally by a thickness measurement and / or with respect to the thin point depth. This can be done for example by appropriate measurements during and / or after thermoforming. By such a precise localization of material thin points filling with filler material can be done very quickly and accurately. It is thus selectively targeted only applied at the points adhesive in which a material reinforcement and thus material thickening should take place. This is also optimized in terms of the amount of adhesive. Thus, depending on the situation, only so much adhesive is filled into the corresponding material thin point until a particularly flush surface design with the adjacent surface areas is achieved.

The thickness measurement and / or localization of a material thin point can be done by a variety of measurement methods. For example, a measurement by means of laser, ultrasound etc. can be carried out here. For example, in current serial production, the containers are measured regularly, approximately every fiftieth part, by means of ultrasonic sensors at previously defined locations. If the measurement results deviate from the nominal value, the production machine is readjusted.

It can be provided in the context that the occurrence of a material thin point is continuously checked locally and / or temporally, in particular at least temporarily carried out already during the thermoforming.

It is preferably provided that the material thin point is filled with filling material so far that a flush transition to the surface area of the plastic adjacent to the material thin point is produced.

By this filling of the generated material thin points on the thermoforming part with the filling material, the required properties are achieved, for example with regard to rigidity of the component and / or diffusion-tightness.

It is particularly advantageous that thereby also formed in three-dimensional structures Material thin points can be filled and the surfaces can be designed accordingly. Thus, ribs or local undercuts can be filled accordingly.

In particular, filling with the filling material is an automated process that is performed during the manufacturing process of the container. This is preferably done by means of a robot and an adhesive application unit. In addition, a suction unit can also be provided, which can perform an adhesive suction.

The adhesive application unit preferably comprises one or more application heads or application units. The components required to deliver the adhesive are also provided. In addition, a control unit is provided, which controls the adhesive application unit as a function of recognized material thin points which are detected by corresponding detectors.

The thickness of the applied filler layer depends on the residence time and / or the speed of movement as well as the flow rate of the applicator head used.

The applied filling material may be the same or foreign to the plastic of the base part.

For example, as a filler material, a two-component reaction adhesive can be applied, in particular sprayed.

With regard to a fully automatic introduction of the filling material into a material thin point, the number and position of the points to be reinforced or the thin material points and the application amount of the adhesive per thin point must be defined for each container to be produced. If, for example, in the case of a procedure and a specific shape design of a container, it is already known in advance where such material thin points occur, then it can be predetermined in the automatic production process when and in what quantities adhesive is locally applied to the then already known material thin points.

By doing so, a manufacturing process can be made possible for each individual shaping of a container, in which the robot is controlled with positions and movement speeds defined and this takes place automatically.

It can also be provided that the wall thickness can be increased stepwise by applying it several times to the same thin material points on the component. By the proposed method, it is also possible that the provided base parts are already made thinner available, since the then occurring material thin points can be selectively filled. As a result, plastic material can be saved. By also achieving a reduction of the cycle time or the heating time during thermoforming, an energy saving of the production process can also be made possible.

Embodiments of the invention are explained in more detail below with reference to schematic drawings. Show it:

1 a perspective view of an embodiment of a household refrigerator according to the invention;

2 various manufacturing states in producing an embodiment of a container according to the invention;

3 a schematic representation of a manufacturing plant for such a container; and

4 a simplified flow chart with substeps in the production of a corresponding container.

In the figures, identical or functionally identical elements are provided with the same reference numerals.

In 1 is a perspective view of a household refrigerator 1 which can be, for example, a refrigerator or a freezer or a combi appliance, which is provided for cooling and freezing refrigerated goods, in particular foodstuffs. The household refrigerator 1 includes an outer housing 2 which represents an outer container. In addition, it includes an inner container 3 whose walls have a reception room 4 for the refrigerated goods limit. A front loading opening of the inner container 3 is through a door 5 closable.

The inner container 3 is a one-piece component, which is formed by specific production.

For this purpose, as shown in 2 , the exemplary intermediate manufacturing conditions of the inner container 3 shows, the production carried out. In a manufacturing process for this purpose, first a board or a base part 6 made of plastic. This is then reshaped by thermoforming, so that an intermediate molding 7 from the base part 6 is formed. The intermediate molding thus produced 7 has material thinning points at specific points 8th on. According to the further illustration in 2 become these material thin points 8th to terminating thermoforming with a filler 9 , which in the exemplary embodiment is an adhesive, filled. For this purpose, on the production line according to the embodiment shown, an applicator unit 10 mounted, which is a spray head in the embodiment shown. By means of this application unit 10 is locally very precise and quantitatively very precisely dosed the adhesive 9 sprayed on, leaving the material thin point 8th is completely replenished. In the far right presentation in 2 is then the intermediate molding 7 shown in which the material thin point 8th completely with the filler formed as an adhesive 9 is filled. It is also recognizable that a surface 9a the applied filling material 9 flush with an adjacent surface 7a of the intermediate molding 7 is.

The filling of the material thin point 8th with the filler 9 becomes after completion of the thermoforming and also after trimming the intermediate molded part produced by the thermoforming 7 carried out. It may also optionally before or after punching the intermediate molding produced by the thermoforming 7 to the container 3 be performed.

In 3 is a schematic representation of a manufacturing plant 11 shown with subcomponents. On a turntable 12 the plant 11 become the intermediate moldings 7 after having also started from the respective base parts 6 were thermoformed accordingly. There is a turntable with a conveyor belt provided. In addition, the facility includes 11 an industrial robot 13 with which the local positioning of the application unit 10 can be done quickly and accurately. In addition, a control unit 14 provided by means of which the control of the system 11 and in particular the subcomponents takes place.

It can be provided that the plant 11 also has one or more detectors, by means of which the material thin point 8th the individual intermediate moldings 7 be detected. However, it may also be provided that, depending on the already previously desired shapes of the container 3 that are to be generated, those sites are known where material thinning occurs. In such embodiments can already be predetermined and programmed in advance, as the robot 13 and the at least one application unit 10 must be controlled and positioned in order to fill the then already known material thin points with the filling material precisely.

In 4 is shown a simplified flow diagram with steps of manufacturing. It is there according to a step S1, the intermediate molding 7 transported on the conveyor belt. In a further step S2, the application unit 10 through the robot 13 brought to the specific position at which the subsequently machined intermediate molding 7 a material thin point 8th having. According to a step S3 then the material thin point 8th with the glue 9 filled and thus coated accordingly. It is then checked in a step S4, if more material thinning 8th on the currently to be processed intermediate molding 7 available. If this is not the case, according to the step S5 this just worked intermediate molding 7 transported on and then further processed as appropriate. If, however, it is determined in step S4 that at least one further material thin point 8th is present, it is jumped back to step S2, so that a partial increase in wall thickness by means of the adhesive in the form of the filling material 9 is carried out.

LIST OF REFERENCE NUMBERS

1

 Household refrigerator

2

 outer casing

3

 inner container

4

 accommodation space

5

 door

6

 base

7a

 surface

7

 Between the molded part

8th

 Material thin place

9

 filling material

9a

 surface

10

 application unit

11

 manufacturing plant

12

 turntable

13

 robot

14

 control unit

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 102009045658 A1 [0002]
• DE 102010029583 A1 [0003]

Claims (12)

Method for producing a container ( 3 ) of a household refrigerating appliance ( 1 ), in which a base part ( 6 ) is made of plastic and this by thermoforming the container ( 3 ) is deformed, characterized in that at least one generated during thermoforming material thin point ( 8th ) of the plastic targeted by a filler material ( 9 ) is refilled. A method according to claim 1, characterized in that the material thin point ( 8th ) is filled with an adhesive. Method according to claim 1 or 2, characterized in that the filling material ( 9 ) is sprayed on or painted over. Method according to one of the preceding claims, characterized in that the filling material ( 9 ) after completion of the thermoforming in the material thin point ( 8th ) is filled. Method according to one of the preceding claims, characterized in that the filling of the material thin point ( 8th ) with the filling material ( 9 ) after pruning one by thermoforming out of the base part ( 6 ) produced intermediate molding ( 7 ) is carried out. Method according to one of the preceding claims, characterized in that the filling of the material thin point ( 8th ) with the filling material ( 9 ) before or after punching by thermoforming from the base part ( 6 ) produced intermediate molding ( 7 ) to the container ( 3 ) is carried out. Method according to one of the preceding claims, characterized in that a material thin point ( 8th ) is detected and recognized locally by a thickness measurement and / or with respect to the depth. A method according to claim 7, characterized in that the occurrence of a material thin point ( 8th ) is checked continuously during thermoforming locally and / or temporally. Method according to one of the preceding claims, characterized in that the material thin point ( 8th ) as far as with filler material ( 9 ), that a flush transition to the material thin point ( 8th ) adjacent area ( 7a ) of the plastic is generated. Method according to one of the preceding claims, characterized in that a localized material thin point ( 8th ) quantitatively and / or locally defined on the material thin point ( 8th ) matched with filling material ( 9 ) is filled. Container, in particular inner container ( 3 ), which is produced by a method of the preceding claims. Household refrigeration appliance ( 1 ), which a container, in particular an inner container ( 3 ), according to claim 11.

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