Process and Device for Producing a Coated Structural Component

Abstract

The present invention relates to a method of manufacturing a coated structural component (10) for a vehicle, comprising the steps of: providing a base component (11), hot forming the base component (11) into a molded component (12), electrochemically deburring the molded component (12), and electrolytically applying a corrosion protection layer (13) to the deburred molded component (12) to produce the structural component (10). The invention further relates to an apparatus for carrying out a method according to the invention for producing a deburred and coated structural component.

Claims

1. A method of manufacturing a coated structural component for a vehicle, comprising: providing a base component, hot forming of the base component into a molded component, electrochemical deburring of the molded component, and electrolytic application of a corrosion protection layer to the deburred molded component to produce the structural component.

2. The method according to claim 1, wherein the molded component has at least one forming edge produced by the hot forming and having a forming radius, wherein the electrochemical deburring for deburring at least one area section is carried out adjacent to the at least one forming edge.

3. The method according to claim 1, wherein a zinc coating is applied as corrosion protection layer.

4. The method according to claim 3, wherein after the zinc coating has been applied, a cathodic dip coating is applied to the coated molded component.

5. The method according to claim 1, wherein the cathodic dip coating is applied with a layer thickness in a range between 10 μm and 40 μm.

6. The method according to claim 2, wherein the electrochemical deburring of the molded component is performed by means of a cathode and an anode, the molded component being used as at least part of the anode and the cathode for the electrochemical deburring being positioned at a distance of less than 30 mm from the at least one forming edge.

7. The method according to claim 1, wherein the electrochemical deburring is performed with an electrolytic current density in a range between 5 A/dm.sup.2 and 15 A/dm.sup.2.

8. The method according to claim 1, wherein the electrochemical deburring is performed over a period of time in a range between 3 minutes and 12 minutes.

9. The method according to claim 1, wherein an electrolyte comprising sodium sulfate and sodium chloride is used for electrochemical deburring, wherein at least twice as much sodium sulfate as sodium chloride is used.

10. An apparatus for carrying out a method according to claim 1 for producing a deburred and coated structural component in the form of a body component for a vehicle.

Description

[0025] It is schematically shown in each case:

[0026] FIG. 1 a flow chart explaining a process according to one embodiment of the present invention,

[0027] FIG. 2 a flow chart explaining further details of the process according to the invention,

[0028] FIG. 3 a flow chart explaining an exemplary procedure for manufacturing a structural component according to the invention, and

[0029] FIG. 4 a formed structural component known in the prior art.

[0030] Elements with the same function and mode of operation are each given the same reference signs in the figures.

[0031] FIG. 1 shows the various process steps for manufacturing a structural component 10 for a motor vehicle according to a preferred embodiment. As shown in FIG. 1, base components 11 having a thickness of about 1.4 mm are first cut from a coil 18. The sheet metal components are then heated to about 900° C. in a furnace 22, and then formed into the desired shape by a forming tool 20. That is, the heated and uncoated base components 11 in the form of blanks are formed into molded components 12 by the forming tool 20. Even before the molded components are now coated, they are trimmed and then electrochemically deburred. For this purpose, the molded component 12, which forms an anode 17 via the rack for suspending the molded component 12 in the electrolyte, is positioned on a cathode 16 or on plate-shaped cathode components. More specifically, the cathode 16 or plate-shaped cathode components are positioned at a distance of about 10 mm from the molded component 12, respectively, at an area section 14 between two forming edges 15 on the surfaces to be deburred.

[0032] Electrochemical deburring is carried out with an electrolytic current density of approx. 10 A/dm.sup.2 for approx. 8 minutes. The electrolyte used is a liquid containing about 180g/I sodium sulfate and 50g/I sodium chloride at a temperature of about 40° C. Next, the electrochemically deburred molded component 12 is coated with a corrosion protection layer 13 shown in FIG. 2 to produce the structural component 10. More specifically, a zinc coating is applied to the deburred molded component 12 by moving the deburred molded component 12 through an electrolyte 19. After the application of the corrosion protection layer 13, a cathodic dip coating 21 shown in FIG. 2 is also applied to the coated molded component 12 with a coating thickness of about 20 μm over the entire surface. For this purpose, the molded component 12 or structural component 10 coated with the corrosion protection layer 13 is moved through a cathodic dip coating bath 23.

[0033] The tools and aids for carrying out the process shown in FIG. 1 may be understood as components of an apparatus for carrying out the process and thus for producing the deburred and coated structural component 10.

[0034] FIG. 2 shows the deburring and coating process in further detail. As can be seen in FIG. 2, after forming, the molded component 12 has edges and peaks that protrude more than average in the area of an area section 14 upon closer inspection. These are removed or reduced and/or smoothed by the electrochemical deburring process. Thereupon, the corrosion protection layer 13 is applied in the form of the zinc coating. Subsequently, the cathodic dip coating 21 is applied.

[0035] With reference to FIG. 3, further embodiments for manufacturing the structural component 10 are described. In a first step 51, the coil 18 is provided, from which, in a second step S2, the base component 11 is then provided in the form of a circuit board. In a direct process, the base component 11 is now heated to about 900° C. in step S3, and formed and press-hardened in step S4. In an indirect process, the base component 11 is first cold formed in step S2a, which is performed after step S2, and then trimmed to the desired shape in step S2b. In the indirect process, heating according to step S3 follows only thereafter. Step S2b can initially be omitted in the indirect process. In the direct process, press hardening or hot forming is usually carried out by means of intermediate cooling. In the direct process, step S3 is followed by trimming the molded component 12 in step S4 and cleaning the molded component 12 in step S5. In step S6, the molded component 12 is now cleaned and, in this process, electrochemically deburred as described in detail above. In the indirect process, steps S4 and S5 may be skipped. In step S7, galvanizing follows. The molded component 12 can already be considered as the structural component 10 described above. Step S7 is followed by annealing in step S8. The cleaned, galvanized and annealed structural component 10 is now oiled in step S9 to produce a transport protection. In the subsequent step S10, an assembly of possible sub-components of the structural component 10 may take place. In step S11, a further cleaning process takes place. Subsequently, the structural component 10 is coated with a cathodic dip coating 21 in step S12, which up to this point may also in principle still be regarded as a molded component 12.

[0036] FIG. 4 shows a prior art structural component 10a in which the molded component 12 has not been deburred prior to galvanizing. In this case, the edges and tips are still covered by the first corrosion protection layer 13. However, the cathodic dip coating 21 is penetrated by the anti-corrosion layer 13, as a result of which the structural component 10a has only a correspondingly lower corrosion resistance.

[0037] The invention admits of further design principles in addition to the embodiments illustrated. That is, the invention is not to be considered limited to the embodiments explained with reference to the figures.

LIST OF REFERENCE SIGNS

[0038] 10 Structural component

[0039] 10a Structural component

[0040] 11 Base component

[0041] 12 Molded component

[0042] 13 Corrosion protection layer/ zinc coating

[0043] 14 Area section

[0044] 15 Forming edge

[0045] 16 Cathode

[0046] 17 Anode

[0047] 18 Coil

[0048] 19 Electrolyte/ Zinc bath

[0049] 20 Forming tool

[0050] 21 Cathodic dip coating

[0051] 22 Furnace

[0052] 23 Cathodic dip coating bath