DE1527908A1 - Method of forming a cup-shaped container - Google Patents

Description

mptiNG. H.LJMJSWaöEJti dipl. ing .rf. CARPENTER

Poetsdiedc-Könto: bank account; Telephone "''. R« i srf>

8 Munich 2, Rosental 7, 2

(Kustermann Passage)

^ 29 _t April 1966

American G ^: än Company-, CorpOration of lew-Jersey, 100 Park-ivenue, Jei-iörTr, .Ι.Υ.10017, USA

Method of forming a cup shape. Container

The invention relates to a method for forming a mainly made of a metal with comparatively worse Drawability of the existing cup-shaped container, in which a flat Blank by deep drawing the shape of a cup with a Bottom wall and.ein cylindrical side wall, the thickness of which that of the bottom wall is almost the same and then the cup for thinning: and lengthening the side wall at least ■ is subjected to a "flattening operation" ... _ ·:

Furthermore, the invention relates to the container obtained above.

In this process, deep drawing usually passes

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in that the blank is “pressed through” a drawing die by means of a punch actuated by a press. When flattening the. Drawn cups are usually passed through one or more platforms, the inside diameter of which is smaller than the outside diameter of the cup and. the inside diameter of which is getting smaller and smaller. -. , V. . ■. _:

. The term "drag" used in the description is that Shaping recessed parts by conveying the plush Flow of metal in forms and, refers to one Work step in which a peripheral edge of a flat blank is after directed inside and at the same time by means of a drawing punch and smoothed into a shape and folded into the shape of a cup ir.it-, loose side wall, the thickness of which corresponds to that of the original. sprünglxGhen blank almost corresponds. Subsequent further pulling of the cup vvird only πι Ehr- sndmaterial in pulled up the side wall and this thereby lengthened, whereby however, the outside diameter of the cup is significantly reduced.

'. That. "Flattening" can be the thinning of the walls of a deeply drawn object by reducing ■ the distance between ■. Stamp and shape are designated. When flattening, the cup side wall is lengthened by reducing its corner, der.Becher-.

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Inside, however, it is not reduced in size. This is done in the generally in that the cup is snugly on a stamp or mandrel. -Applied and cup and mandrel through a flat or Reducing form is pressed, the diameter of which 'is slightly smaller than the cup outside is better; in the process, the excess metal is pressed back and a longer but thinner side wall is created obtain.

The flattening is sometimes compared with the extrusion of letsllen, since the metal is actually ^li v, ek équetscht "virä. However, the punch pushes the part downwards and thereby \\ ith the ilaterial in rLlttvtrfahren "sucked". At Jer Extrusion v; ird. the Ivletall in the same ia-ciituii- wiefxer stamp through a Fern: "pushed". In teiäeti procedure Y.ira das ... etall however 'squeezed'.

-. 'I would like to draw and have very much b & i aerating naiitlcscr Aluriiriiux container used v.ira, step, with .application of this technology: in the production of seamless contents tr "from a let all" iit relative drawability, v «Ie £ .B. Steel, difficulties auf.:■■'Verii-utlich this mainly attributed ^ dai.Stahl zuführet a much higher to ^ -: m yield strength than AluniiniuiL nat.- Since the Stahl.bein "I ieiieo and:

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is subjected to an extraordinarily large mechanical deformation, especially when flattening, it often breaks and the bottom of the container is often pierced. V

By the invention, the above-mentioned disadvantages in the production of containers from a metal with bad drawability eliminated.

The method according to the invention is particularly characterized in that, in addition to the operations described above a thin layer at least on the surface of the blank corresponding to the outside of the finished container is applied from a metal whose drawability is significantly higher than that of the base metal of the blank.

further advantages, details and features of the invention, result from the following description. On the drawing the invention is illustrated using a preferred embodiment, for example, namely show:

Fig. 1 on an enlarged scale, a view of a cut open, steel sheet coated with a softer metal;

Figure 2 is a sectional view of the set of pulling and platforms

as well as the one for pressing the sheet metal blank through 909884/0088

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d © n. Forms at z ^ used en Doras; _ . . Mg * 3 to 5 sectional views corresponding to Eigv 2 : the device and the in the desired shape.

honored container, and Fig. 6 partially torn and cut, a perspective View of the finished container »:

In a "preferred Durchfuhrungsform The thickness is set to a the Fachmann.bekannte softly a sheet or strip of cold-rolled, low carbon steel electrolytically with a thin .Zinnschicht provided" This process corresponds. Generally, the usual in the can industry tinning. Constitute 2innsQhiGht can Depending on the length and thickness of the finished side wall and the desired tin thickness of the finished side wall: vary widely. The final tin thickness must be sufficient to completely cover both surfaces of the finished side wall when the MaterialdiGke is to be reduced by half are also possible stronger Beschichtungsn, for economy jedjQch ^is. preferably a minimum thickness needed.

In the present specification, as a coating material Tin is used for the steel sheet. It has, however found that other, softer metals than the base metal can be used for coating, for example copper in the case of steel. Zinc, brass, nickel, silver, etc. Of course other base metals can also be used. The main condition is that. the coating metal is softer is as: the base metal.

The following is a result from a chemical analysis resulting percentage composition of a usable steel listed ;:

Carbon .........,. * .... 0.05-0.12

Sulfur .............. ,. Max. » ö, .G5

.. Phosphorus .................. J ^ f: 0.02

Silicon ..... ... .Ψ & ι 0.10 -

The typical, average, mechanical properties des.steel are: ^

co "'. ■■. ■■■■■" ■' ■ .-

g Limit tensile strength _: ...... ,,.: .. 73,200 P, SI (Pf and / Qiadratzü)

S Tensile strength ...; ............ 70,700 PSI, ** "." ■■■ .. ■ "■" - '■ ".' . '. ■ "■"" ^: ^ Tensile strength stress" * .... 13 1 °

^ Strength in impact resistance .... I ^

Hardness, .....,., .... ^ ....... ^ 6: 7 B3OT

The above information is of course with regard to the composition and properties average values and.can vary slightly from melt to melt. in the Other steel compositions are also within the scope of the invention usable.

While with the usual tin electroplating, the tin layer melted and after plating a flow-gloss process is subjected, such a work step should not take place according to the invention. That's how it is Tin plate in the so-called "matt" condition. The reason for this is described below. .

In Fig. 1, the steel shown in cross section has "6 a matt inner deposit 7 covering its surface.

After drying the electroplated tin sheet such as t punched out using a punch press, a round blank-.

FIG. 2 shows a set of molds, designated as a whole by 10, which are arranged in a mold carrier 12. .Both the form set 10 and the carrier .12 are placed in a suitable hydraulic press. A round mold 14 with a mold opening 16 is placed in a suitable position in the mold carrier 12

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intended. In addition to the top of the mold 14, the mold opening 1.6 has a rounded pulling surface 18.

Above mold 14 and in axial alignment with the mold opening 16, a cylindrical forming die 20 with an underside 22 is arranged such that it can move back and forth. The training of the End surface 22 determines the final shape of the object to be formed and can be flat, conical, spherical or a combination of these Be forms. In the preferred one shown in the drawing Embodiment, a flat-ended side 22 is used to achieve flat-ended containers.

The flat round blank is covered with a suitable oily Provided lubricant that soaks the matt tin layer 7; the Blank 8 is placed between the mold 14 and one above the mold arranged annular blank holder 24 is used. The inner diameter of the blank holder 24 is slightly larger than that Diameter of the punch: 20. A row spaced apart Guide openings 26 penetrate the blank holder along the outer edge. Bolts 28 with shafts 29 and heads 30 are screwed in the mold carrier 12; the shaft parts protrude through the openings 26 in the blank holder 24 upwards, on the one hand

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mim a

to prevent that: the blank holder transversely to the form 14. . sets and converts. on the other hand, its upward movement along the Longitudinal axis to allow the shape .:

On the underside of the blank holder 24 is a round one Recess 32 is provided which has approximately the same diameter as the blank; '8 and the depth of which is slightly less than the. Thickness of the blank; this recess 32 is used to To align the blank axially with respect to the mold opening 16, and to hold on. In this position, the marginal edge -34 of the blank 8 is between the mold 14 and the tubular ring holder 24 by means Compression springs 36 between the blank holder 24 and the bolt heads 30 are arranged around the bolt shafts 29, with fairly high set force, held.

That; upper end of the punch 20 is with a piston rod 38 connected, in turn by a suitable source of power, like e.g. a (not shown) hydraulic cylinder, operated: Is .., When actuated, the stamp '20 moves downwards uni brings the bottom ^ 22 of the stamp; in, touch with that Bohling 8 ...:, ■;

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. When the downward movement is continued, the punch 20 pulls the marginal edge 34 of the blank 8 continuously under the blank * holder 24 and presses it into contact with the pulling surface 18 of die 14. The edge 34 is thus drawn across the draw surface 18, stretched, and into the shape of a tube brought so that a cup-shaped object with a side wall 40 and a bottom 42 is formed (Fig. 3). To this Both the side wall 40 and the end 42 have time of the deep-drawn object is essentially one of the strength of the blank 8 corresponding thickness.

During the pulling, the force with which the edge of the sand 34 of the mold 8 between the blank holder 24 and the mold 14 is held in a. '»ert held, in which the blank 8 stretched rather plastically than wrinkled or folded. "if them under the. Blank holder is pulled out; this force is supposed to but not that big; the metal may be torn or split will. ■ ■

As a result, the metal is simultaneously subjected to two different forces while it is being drawn, dYes. _; one the marginal edge 34 of the blank; 8 acting ,, - originating from the holding force

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Compressive force and a tension or stretching force acting on the metal on the drawing surface 18 when the metal is brought from the flat to the tubular shape.

In general, the holding force is determined by the respective Forming operation determined. This is the case, for example, with deep drawing and flattening a tin-plated steel blank 15.5 cm in diameter and 0.045 cm thick in the shape of a container of a Diameter of 6.3 cm and a side wall thickness of 0.002 cm ^ an Ealtenkraft acting on the edge of the blank of about 10,000 pounds preferred. ■

While he is still in singriff with the drawing surface 18, the cup-shaped object arrives in an annular platform 44, which are arranged in the mold holder 12 below the mold 14 (FIG. 4) is. The platform 44 has a flat surface 45 »the has a smaller diameter than the drawing surface 18 of the mold 14 and is axially aligned with this. A spacer plate 46 is inserted between the mold 14 and the mold 45. Through the downward movement of the punch 20 v. becomes the tinned Side wall of the cup-shaped object on the Fltl-tt- " ■ surface 45 is pre-pressed, thereby reducing the thickness of the side wall 4p and extended it.

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Fahrend. this flattening operation serves both the soft metal layer as well as the oily lubricant with which they im- " The steel side wall during the cold reduction is also impregnated * to lubricate. The oil absorbed by the matt finish plate remains tougher than a conventional flow-gloss treated one Tin plate and has better lubricating effect under the extreme pressures during plating. That inside and on the The oil on the tin surface lubricates during flattening and the soft layer itself becomes on top of the during flattening

Polished and machined on the outside and on the Stretched inside »*

A second platform 48 with a platform 49 is in the same way in the mold holder 12 below the platform 44 attached. One arranged between the platforms 44 and 48 Spacer 50 creates between their respective plate surfaces 45 and 49 a certain distance. During its downward movement, the punch 20 brings the cup-shaped object to the platen surface 49 »while the side wall is still in engagement with the plateau surface 45 of the first plat form 44. Depending on the The side wall can also still be spaced between the respective platelet surfaces with the drawing surface 18 of the drawing die 14 are in engagement when they · to the flat surface 49 of the second

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Platform 48 arrives. On the downward movement, the side releases itself from the pulling surface 18, but still acts with the. Plättflächen or 45 ', 49 of the platforms 46 and 48 together m _ge 5). -

The side wall is further smoothed by the flat surface 49, so that its land thickness is reduced and its length is increased. The end 42 of the finished molded, deep-drawn and smoothed container 52 is as thick as that of the blank 8 and its side wall 54 is considerably thinner than that Blank 8. While only two platforms are shown in the drawing are ,, are to achieve any desired sidewall length and thickness other platforms can be used.

The production of the coated container from a flat, round blank is described as a one-step operation; however, the blank can first be in the form of a shallow, seamless container and this then another machine be presented with one or more platforms, where the cup is then passed through the plat form or forms ", to thin and lengthen its sidewall. '

After passing through the second platform 48 becomes the molded one Container 52 due to the continuous downward movement of the

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J-t

The punch 20 is guided by a conventional stripper, generally designated 56 ″, the latter consists of a flat segment ring 58 with a row of segments 60 _t which are radially displaceable in a recess 62 in the underside of the mold holder 12. The segments 60 are supported by springs 64 Pressed radially inward and held in the recess 62 by a flat locking ring 66, which is attached to the form holder 12 by means of "screws .68". In the extreme inner position of the segments 60, the segment ring 58 has an almost cylindrical inside 70, with a diameter that is slightly smaller than that of the punch 20, as well as with a smoothly rounded upper edge 72 and a sharp lower edge 74.

While the molded container 52 (Fig. 6) through the The punch 20 is moved towards the stripper 56., It arrives with it the rounded upper edge 72 of the Segnientring 58 in contact and pushes the segments 60 outward, so that the Stesipel and the container can pass through the ring. After the container 52 passes through the ring 58, the springs press segments 60 inwardly on ram 20. By suitable means (not shown) the ram 20 is moved upward emotional. During the upward deflection of the punch 20, the

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over edge 76 of the molded container 52 into the sharp bottom cold74 of the segment ring 58. 'This .will-each additional Upward movement of the container is prevented and this from the punch 2Ö stripped.

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From the above description it can be seen that the soft rivet layers on the surface of the inner and outer side wall of the drawn and smoothed container are subjected to different mechanical sin effects. the inner side wall surface is around with a bending force of 90 ° pressed around a curved drawing shape and during plating exposed to a tension force, while the outer side wall surface during the deep-drawing by a bending pressure by 90 ° press-bent and then an extrusion or "squeezing" - ' , Is subjected to operation as it passes through the platforms. On the other hand, the lower end of the container was not deformed much.

Vfeiterbin can be seen that the outer layer 7a of the container 52 has deformed and changed differently than the interior Metal layer 7b. With each flattening operation, the layer 7a strongly deformed if they are between the respective plate surface and is pressed through the mandrel. During this "squeezing through" causes the Cl with which the soft metal layer 7 on the container

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outer was impregnated, some lubrication of the flattening work sgangs.

On the other hand, the soft metal layer on the container * outside in the flowing state and is through each 'subsequent Platform that reduces the thickness of the side wall 54 and its length increased, thinned. Due to the hard mechanical processing and polishing the layer 7a, it is not only thinned and lubrication for flattening but also the same Mirror gloss increases until it is shinier than one of the usual Flow-gloss treated tinplate manufactured conventionally Can. Of course, this coating differs from conventional tin plating in that it is not was really made liquid and therefore no tin-iron alloy is present between the tin layer and the steel base metal, as is the case with the conventional flow-gloss treated or hot-dipped tin plate is the case.

This is the case with the quasi-deposited tin layer in comparison with a tin plate treated with a flow-gloss finish due to its softness and their ability to apply that to their surface Absorb lubricating oil, better; Lubrication during the Flattening achieved.

909084 / 0aS8.

The tin layer 7b on the inside of the container wall has not been polished and therefore does not have the properties a shiny surface like the outer layer Ta. As above mentioned, the inner side wall layer was only subjected to a bending pressure of 90 ° during pulling and a subsequent stretching or subjected to stretching while flattening. Since it was not machined or polished during flattening, it has 'They generally have the same luster as the Eohling, albeit due to the stretching and elongation of the side wall is much thinner.

Both the inside and the outside of the lower end 42 of the container, which was neither drawn nor flattened, hold the almost deposited layer of alight metal that neither shines the outer layer 7a still has the stretched state of the inner Layer 7b has. \ -

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Claims (6)

Claims ϊ 1. Method of forming a cup-shaped container made of a metal with relatively poor drawability by deep drawing a flat blank into the Shape of a cup with a bottom wall and a cylindrical one Side wall, the thickness of which corresponds almost to that of the bottom wall and by subsequent, at least one-time flattening of the cup for thinning and lengthening the side wall, characterized in that at least that of the outside of the finished container corresponding surface of the blank is provided with a thin layer of a metal, its drawability is much higher than that of the base metal. - 2. The method according to claim 1, characterized in that that the metal layer applied to the blank consists of a non-glossy, matt layer. 3. The method according to any one of claims 1 and 2, characterized characterized in that both surfaces of the blank are stranded with a thin metal layer. 4. The method according to any one of claims 1 to 3, characterized 909884/0088 characterized in that the Eohling is made of one with the metal sheet metal coated for better drawability will. 5- The method according to any one of claims 1 to 4, characterized 'marked' that the metal is relatively poor Drawability consists of steel. 6. The method according to claim 5, characterized in that the metal forming the coating is made of tin, brass, Lead, copper, zinc, silver or cadmium. 7 · The method according to any one of claims 1 to 6, characterized characterized in that the metal coating is by an electroplating process is achieved. b. Deep-soaked and smoothed steel container with a cylindrical body closed by a bottom, which is manufactured according to the method according to one of claims 1 to 7, characterized in that the metal layer on the outside of the cylindrical body is thinner and more shiny than the layer on the inside of the Body and on both sides of the floor. 909884/0088