GB2406817A - Moulding Device - Google Patents

Abstract

A press-moulding device (1) comprises a tool (3) generating at least a part of the geometry of an article to be moulded and optionally having at least one pressure measuring means (5) and/or at least one pressure chamber (4) directly below a surface (3.3) associated with the article. The device further comprises a die (2) co-operable with the tool. In another form, the tool selectably comprises a tool mask generating the shape of the article, a base body and a measuring film between the mask and the body. The measuring film can instead be an elastic intermediate layer with a smaller modulus of elasticity than the base body. At least one of the tool or corresponding die having at or under their respective surface means to cause or allow displacement of at least a portion of the surface.

Description

MOULDING DEVICE

The present invention relates to a moulding device, especially a pressmoulding device such as a deep-drawing mould for moulding articles of metallic material.

There is known from DE 199 25 458 A1 a press-moulding device comprising at least one tool, which generates at least a part of the workplace geometry and with which a tool die corresponding with at least a part of the workplace geometry is associated.

A method of high-pressure shaping of sheet-metal parts is described in DE 44 17 460 A1.

A device with an intermediate plate, which receives the sheet-metal parts to be shaped, with drawing rings bearing against the intermediate plate at both sides, is used for the method. The drawing rings serve for fixing and sealing the sheet-metal parts to the intermediate plate. A shaping space formed by the drawing rings is bounded towards the end face by a die, which is flexible, in order to positively influence the shaping process.

A device for measuring the retaining force exerted on the pressure ring of a press is disclosed in DE 693 31 016 T2. The device is arranged in front of an installation of punching ram and pressure elements in order to ascertain the holding force to be later applied.

A shaping tool consisting of a double-layer composite body is disclosed in DE 198 55 407 A1. One of the layers is made of metal and electrolytically applied to a synthetic material support structure.

There remains a need for a moulding device in which process stability and process reliability are optimised or at least improved.

According to a first aspect of the present invention there is provided a press-moulding device comprising at least one tool, which generates at least a part of the workplace geometry and with which a tool die corresponding with at least a part of the workplace geometry is associated, wherein the tool and/or the tool die optionally has or have a pressure-measuring means directly in the region of its or their surface associated with the workpiece, characterized in that the tool and/or the tool die has or have at least one actuator below the surface.

Preferably, the tool and/or the die has or have at least one pressure measuring means and/or at least one actuator, which is below the surface and formed as a hydraulic pocket, directly in the region of its or their surface associated with the tool.

In the case of a device embodying the invention the stress distribution need not be influenced by a bending line emanating from the tool. The desired stress distribution can be applied over an area and detected by the pressure measuring means and/or optimised by the actuator or actuators.

For this purpose it is advantageous if the pressure measuring means and/or the actuator constructed as a hydraulic pocket or cell or as a pressure chamber is or are arranged with respect to the surface and the spacing between the pressure chamber and the surface is between 0.5 mm and 3 mm, particularly 1 mm. Thus, compensation for the bending line, which negatively influences the shaping process, of the tool can be provided by varying the pressure in the hydraulic cell. The orientation of the hydraulic cell towards the surface favours a compensating movement.

In a development the pressure measuring means is a piezo pick-up and/or a measuring film and is arranged flush with or at the height of the surface or directly below the surface, wherein several pressure measuring means and/or pressure chambers can be provided in distribution with respect to the surface. Thus, local pressure relationships, formation of folds and/or thinned zones of a sheet can be measured during the reshaping or in situ and regulated out by the actuators or further method parameters. A spot-grinding process for working-in the tool parts is no longer necessary.

According to a second aspect of the invention there is provided a pressmoulding device comprising at least one tool, which generates at least a part of the workplace geometry and with which a tool die corresponding with at least a part of the workplace geometry is associated, characterized in that the tool and/or the die has or have at least one first part, which is constructed as a tool mask forming the shape of the workpiece, and a second part, which receives the tool mask and forms the base body, wherein an active intermediate layer for measuring the contact stress and for breaking down local stress peaks is provided between the tool mask and the base body.

The intermediate layer enables dynamic measuring of the contact stress during the shaping or moulding process and the contact relationships between the tool and the workplace are not falsified. The tool mask preferably has a thickness between 0.5 mm and 4 mm, especially between 1 mm and 2 mm.

Preferably, the mask is detachably connectible with the base body and/or with the intermediate layer and is Delectably arranged at the intermediate layer or at the base body.

The mask can thus be arranged directly at the base body without the intermediate layer.

The intermediate layer is exchangeable. It is also envisaged to arrange several intermediate layers which are appropriate for various tasks, such as measurement of the contact stress and/or breaking-down local stress peaks.

Of particular significance is that the intermediate layer can be constructed as a measuring film with at least one sensor and/or as a resilient intermediate layer, wherein the sensor can be a dye sensor and/or a piezo element. A suitable intermediate layer can be used in correspondence with the conditions of the reshaping process.

Moreover7 it is advantageous if the base body has a greater modulus of elasticity than the elastic intermediate layer. Thus, the elasticity is concentrated in the intermediate layer.

The different materials for the base body and the intermediate layer can be selected.

Preferably, the intermediate layer is formed from synthetic material and the mask from wear-resistant material. The mask can be constructed to be substantially stiffer so that wear-resistance and shape accuracy are guaranteed.

Embodiments of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a schematic sectional view of part of a pressmoulding device with tool die, tool and pressure recording means; and Fig. 2 is a schematic sectional view of part of a second press-moulding device with tool die, tool, tool mask and intermediate layer.

The press-moulding device 1 according to Fig. 1 consists of a co-operable tool die 2 and tool 3. The die 2 and the tool 3 in that case have complementary surface shapes to enable deep-draw moulding of a component (not illustrated), particularly an article of metallic sheet material.

The tool 3, in particular a body thereof, has directly in the region of a surface 3.3 of the tool 3 different actuators 4, 5 formed as pressure-measuring means or as a pressure chamber or hydraulic pocket or cell.

Arranged at each of the two angled surfaces is a respective pressuremeasuring means 5, 5', oriented towards the surface 3.3, directly below the surface 3.3 or at the level of the surface 3.3. The pressure-measuring means 5, 5' is in that case arranged in a recess (not illustrated) and cast in place.

A hydraulic pocket or cell 4 is provided in the central region below the surface 3.3. Not only the pressure measuring means 5, 5', but also the cell 4 is disposed in operative connection by way of connecting elements, which are not illustrated, with a process control device (not illustrated) .

In the device of Fig. 2 the tool 3 is formed from a first part 3.1 and a second part 3.2. The second part 3.2 represents a base body and the first part 3.1 has the form of a tool mask covering the base body 3.1. The mask in that case has a thickness between 0.5 mm and 4 mm, particularly between 1 mm and 2 mm. An intermediate layer 6 is provided between the mask 3.1 and the base body 3.2. The intermediate layer 6 can be constructed as an elastic layer with a smaller modulus of elasticity than the base body 3.2. It is also possible to construct the intermediate layer 6 as a measuring film in order to detect different deformation forces on the surface 3.3 or on the junction surface between the tool 3 and tool die 2. s

Claims (18)

1. A moulding device comprising a tool having a surface defining part of the geometry of an article to be formed and a die co-operable with the tool and having a surface defining another part of the geometry of such article, at least one of the tool and the die being provided at or under the respective surface with means for causing or allowing displacement of at least a portion of that surface in response to pressure exerted on the surface portion during moulding of the article and optionally also for measuring that pressure.

2. A device as claimed in claim 1, wherein the means comprises a pressuremeasuring element disposed below or forming a part of the said respective surface.

3. A device as claimed in claim 1, wherein the means comprises a measuring film disposed below or forming the said respective surface and following the contour thereof.

4. A device as claimed in claim 1, wherein the means comprises a fluidoperable expansion/retraction element.

5. A device as claimed in claim 4, wherein the element comprises a hydraulic cell.

6. A device as claimed in claim 1, wherein the means comprises a resilient zone disposed below or forming the said respective surface and following the contour thereof.

7. A moulding device comprising a tool defining at least a part of the geometry of an article to be formed and a tool die associated with the tool and corresponding with at least a part of the geometry of the article, wherein at least one of the tool and the die is provided directly in the region of a surface thereof for imparting shape to the article with optional pressure-measuring means and at least one of the tool and the die is provided underneath the surface with actuator means.

8. A device as claimed in claim 7, wherein at least one of the pressuremeasuring means and the actuator means is formed as a hydraulic cell or pressure chamber and disposed at a spacing from the surface.

9. A device as claimed in claim 8, wherein the spacing is 0.5 to 3 millimetres.

10. A device as claimed in claim 9, wherein the spacing is substantially 1 millimetre.

11. A device as claimed in any one of claims 7 to 10, wherein the pressure-measuring means comprises one of a piezo pick-up and a measuring film and is disposed flush with or directly under the surface.

12. A device as claimed in any one of claims 7 to 10, comprising a plurality of such pressure-measuring means and/or a plurality of such actuator means in spaced-apart arrangement.

13. A moulding device comprising a tool defining at least a part of the geometry of an article to be formed and a tool die associated with the tool and corresponding with at least a part of the geometry of the article, wherein at least one of the tool and the die comprises a mask defining the shape of the article, a base member supporting the mask and an intermediate layer between the mask and the base member, the layer comprising at least one of a measuring film with sensor means and a layer of resilient material.

14. A device as claimed in claim 13, wherein the mask is detachably connectible with at least one of the base member and the intermediate layer and is selectably arranged at the member or the layer.

15. A device as claimed in claim 13 or claim 14, wherein the sensor means comprises at least one of a dye sensor and a piezo element.

16. A device as claimed in claim 15, wherein the modulus of elasticity of the base member is higher than that of the intermediate layer.

17. A device as claimed in any one of claims 13 to 16, wherein the mask is made of wear-resistant material and the intermediate layer of plastics material.

18. A device as claimed in any one of the preceding claims, wherein the device is a deep-drawing mould for moulding articles of metallic material.