A processing method for a milling skin mold with chemical treatment

Abstract

The present invention belongs to the technical field of sheet metal tooling manufacturing, and relates to a processing method for a mold with chemical milling skin. The feature of the present invention is that the material thickness dimension (the thickness of the chemical milling template) is first reserved to complete the CNC processing (initial processing) of the chemical milling skin profile; then, after the skin mold is stretched and formed to complete the chemical milling skin, the skin mold is aligned for a second time, and then it is CNC processed to remove the reserved margin again, that is, the theoretical mold profile, and the skin mold is used again to complete the manufacture of aircraft skin parts. By aligning the skin mold for a second time, the manufacture of chemical milling templates and the manufacture of aircraft skin parts are realized at the same time, and the process of manufacturing standard templates and manual manufacturing of chemical milling templates is abandoned. A simple, fast and accurate processing method for a mold with chemical milling skin is provided.

Description

Technical Field

[0001] The invention belongs to the technical field of sheet metal tooling manufacturing, and relates to a method for processing a skinning mold with chemical milling. Background Art

[0002] During the processing of the mold with chemical milling skin, the mold is subjected to secondary CNC processing by setting the material thickness relationship, so as to obtain the mold molding surface of the chemical milling sample and the mold molding surface of the standard skin respectively, and then the molding production tasks of the chemical milling sample and the standard skin are realized through the corresponding surfaces.

[0003] The current manufacturing process of chemical milling skins for large aircraft is as follows: first, the skin is manufactured by stretching the mold, and then the skin is positioned through the chemical milling template to produce the chemical milling area, and chemical milling is performed to complete the aircraft chemical milling skin manufacturing. During the use of the molding mold, two sheet metal skins need to be formed, one of which is a standard template for making chemical milling templates; the other skin is an aircraft skin part, which is directly delivered to relevant downstream units for aircraft assembly after chemical milling and other processes.

[0004] The present invention processes the skin forming mold twice, thereby realizing that the same tool can process the milling sample skin and the aircraft skin parts separately.

[0005] The difference between this invention and conventional milling skin mold processing is:

[0006] 1. The present invention processes the skin mold twice to respectively realize the manufacture of the chemical milling sample and the manufacture of the aircraft skin parts.

[0007] 2. The present invention simplifies the manufacturing process of the milling template, and directly uses a skin mold to form the milling template; it abandons the method of using a skin mold to make a standard template, and then manually manufacturing the milling template based on the standard template.

[0008] 3. The skin mold in the present invention needs a secondary alignment function; the mold surface needs to have reference holes, lines, and surfaces that can meet the secondary alignment requirements. Summary of the invention

[0009] The present invention realizes the manufacture of chemical milling templates and aircraft skin parts by performing secondary alignment on the skin mold, abandons the process of manufacturing standard templates and manual manufacturing of chemical milling templates, and provides a simple, fast and accurate processing method of a mold with chemical milling skin.

[0010] The characteristic of the present invention is that the material thickness dimension (the thickness of the chemical milling sample) is reserved first to complete the CNC machining (initial machining) of the chemical milling skin surface; then, after the skin mold is stretched and formed to complete the chemical milling skin, the skin mold is aligned for a second time, and then it is subjected to CNC machining to remove the reserved margin again, that is, the theoretical mold surface, and the skin mold is used again to complete the manufacture of the aircraft skin parts.

[0011] Technical Solution

[0012] A method for processing a skin mold with chemical milling, comprising the following steps:

[0013] 1) Perform the initial CNC machining and reserve the corresponding material thickness size during programming, i.e. the working surface of the milled skin. After the CNC machining is completed, 3 to 4 reference holes, reference surfaces, or related reference lines are made at the corresponding positions of the skin mold, which are used as the alignment reference during the secondary machining.

[0014] 2) Based on the skin mold that has completed the initial CNC processing, the stretching process of the milling sample skin is carried out.

[0015] 3) The skin mold is aligned again according to the secondary alignment reference, and CNC machining is performed again to remove the thickness of the milling sample preset during the initial machining, and the skin surface is machined to its theoretical working surface.

[0016] 4) The skin mold after secondary processing is subjected to subsequent surface engraving, grinding, repairing and streamlining processes, thereby completing the manufacture of the mold with chemically milled skin. After the secondary processing of the mold is completed, it is used to form aircraft skin parts.

[0017] Furthermore, the secondary alignment reference in step 3) is specifically: secondary alignment is performed by using X, Y reference engraved lines that have a positional dimension relationship with the lower die processing coordinate system.

[0018] Furthermore, in the step 3), the secondary alignment reference is replaced by 3 to 4 blind holes made at the four corners of the lower die, and the blind holes are specifically φ8 mm in diameter and 15 mm in depth.

[0019] Furthermore, in the step 3), the reference is aligned twice or replaced by using an X, Y plane having a positional dimension relationship with the lower die processing coordinate system.

[0020] Furthermore, the secondary alignment inspection method in the step 3) is specifically as follows: the alignment inspection can be performed by using the X, Y reference lines that have a positional dimensional relationship with the lower die processing coordinate system, the secondary alignment reference using 3 to 4 blind holes made at the four corners of the lower die, and the X, Y plane that has a positional dimensional relationship with the lower die processing coordinate system.

[0021] Furthermore, before the step 2), when the skin mold is initially CNC machined, tooling lines must be produced for subsequent milling sample molding inspection.

[0022] Furthermore, after the skin mold processing in step (4) is completed, the material used to repair the surface defects.

[0023] Furthermore, in the previous step, a resin material having the same quality as the mold surface is selected to repair the surface defects.

[0024] Furthermore, in the previous step, the corresponding position should be roughened before rework to ensure the bonding performance.

[0025] Furthermore, the thickness of the mold surface layer for CNC machining must be able to satisfy the margin for two CNC machining operations.

[0026] Furthermore, in the previous step, the thickness of the mold surface layer is specifically 60 mm-70 mm;

[0027] Furthermore, it also includes completing the appearance modification of the tooling after the secondary processing of the skin mold is completed, including making rounded corners, painting the tooling surface, and adding tooling signs.

[0028] Furthermore, in the previous step, the specific setting rules for the fillet values ​​are as follows: the fillet in the tooling stretching direction is R50mm, and the fillet in the non-stretching direction is set to R20mm.

[0029] Technical Effects

[0030] Compared with the conventional skin mold manufacturing method, the invention has the following beneficial effects:

[0031] 1. Through two CNC machining of the skin mold, different surface shapes are obtained, so as to realize the skin stretching manufacturing of the corresponding surface layer, that is, the chemical milling template and aircraft skin parts.

[0032] 2. In the two CNC machining processes, the milling template surface and the skin part surface are directly formed, eliminating the intermediate transition of the standard template, reducing the labor intensity of workers and shortening the manufacturing cycle of the milling template.

[0033] 3. This processing method realizes the use of the same tooling with different profiles and shapes, and realizes the manufacture of milling templates and aircraft skin parts. It provides a simpler idea for the manufacture of non-metallic material tooling, which can be expanded and applied to the manufacture of the same type of tooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the original technical solution, and also illustrates the relative position relationship between the skin mold profile and the thickness of the sheet metal skin (chemical milling sample, aircraft skin parts);

[0035] Figure 2 This is a schematic diagram of the processing of the skin mold of the present invention;

[0036] Figure 3 This is a detailed diagram of the processing method of the lower mold and the two processing steps.

[0037] Among them: 1-aircraft skin parts, 2-milling template, 3-skin mold, 4-primary surface, 5-secondary surface. DETAILED DESCRIPTION

[0038] The processing method of the strip milling skin mold comprises:

[0039] 1. Perform the initial CNC machining and reserve the corresponding material thickness size during programming, i.e. the working surface of the milled skin. After the CNC machining is completed, 3 to 4 reference holes, reference surfaces, or related reference lines are made at the corresponding positions of the skin mold, which are used as the alignment reference during the secondary machining.

[0040] 2. Based on the skin mold that has completed the initial CNC processing, the stretching process of the milling sample skin is carried out.

[0041] 3. Align the skin mold again according to the secondary alignment reference, perform CNC machining again, remove the preset thickness of the milling sample during the initial machining, and machine the skin surface to its theoretical working surface.

[0042] 4. The skin mold after secondary processing is subjected to subsequent surface engraving, grinding, repairing and streamlining processes, thereby completing the manufacture of the mold with chemically milled skin. After the secondary processing of the mold is completed, it is used to form aircraft skin parts.

[0043] In steps 1 to 4:

[0044] 1) The secondary alignment datum is specifically: secondary alignment is performed by using X, Y datum lines that have a positional dimension relationship with the lower die processing coordinate system.

[0045] The secondary alignment reference is replaced by 3 to 4 blind holes made at the four corners of the lower die, wherein the blind holes have a diameter of φ8 mm and a depth of 15 mm.

[0046] Secondary alignment of the datum or replacement using the X, Y plane method that has a positional dimensional relationship with the lower die machining coordinate system.

[0047] Secondary alignment inspection method: Alignment inspection can be performed by using the X, Y reference engraved lines that have a positional dimension relationship with the lower die processing coordinate system, the secondary alignment reference using 3 to 4 blind holes made at the four corners of the lower die, or the X, Y plane method that has a positional dimension relationship with the lower die processing coordinate system.

[0048] 2) When the skin mold is undergoing the initial CNC processing, the tooling lines must be made for subsequent milling sample molding inspection.

[0049] 3) After the skin mold is processed, the material used to repair the surface defects;

[0050] In the step (3), the resin material of the same quality as the mold surface is selected to repair the surface defects. Before the step (3) is repaired, the corresponding position should be roughened to ensure the bonding performance.

[0051] 4) The thickness of the mold surface layer for CNC machining must be able to meet the margin for two CNC machining operations.

[0052] The thickness of the mold surface layer is specifically 60mm-70mm;

[0053] 5) After the secondary processing of the skin mold is completed, the appearance of the tooling is modified (rounded corners, paint the surface of the tooling, and add tooling signs);

[0054] The specific setting rules of the fillet value in step (5) are as follows: the fillet in the stretching direction of the tooling is R50mm, and the fillet in the non-stretching direction is set to R20mm.

[0055] 6) The skin mold made by this method can directly form the milling template and aircraft skin parts without making a standard template (for manual forming of milling template), thus ensuring accuracy and reducing the labor intensity of workers.

[0056] First, let's introduce the conventional manufacturing method: Figure 1 , indicating the relative position relationship between "aircraft skin part 1", "chemical milling sample 2" and "skin mold 3". The "aircraft skin part 1" and the standard sample are processed and formed at one time, and then the "chemical milling sample" is manufactured based on the standard sample.

[0057] The specific implementation methods of the present invention are as follows:

[0058] 1. As Figure 2 First, include the "aircraft skin part 1" in the "skin mold 3" surface in the initial CNC processing, and then perform CNC processing to produce the "primary processing surface 4", in which the surface contains the "aircraft skin part 1", and the surface marking lines on the "skin mold 3" must be processed for manufacturing and inspecting the chemical milling skin.

[0059] 2. According to the state of the "skin mold 3" at this time, the "milling template 2" is processed and manufactured.

[0060] 3. Align the "skin mold 3" again for use. After the second alignment, perform CNC processing on the "skin mold 3" again to produce the following Figure 3 "Secondary machining surface 5" in.

[0061] 4. According to the state of the "skin mold 3" at this time, the "aircraft skin part 1" is processed and manufactured.

[0062] 6. Repair and polish the surface and CNC processing defects of "Skin Mold 3", and polish the overall surface to make it smooth and streamlined. Modify the appearance of "Skin Mold 3", paint, mark, etc., and make R50 and R20 fillets. The specific setting rules of the fillet value are as follows: the fillet in the tooling stretching direction is R50mm, and the fillet in the non-stretching direction is set to R20mm.

[0063] The following is a brief summary of the present invention for a specific example of a certain model.

[0064] 1. The mold base after pouring is processed for the first time. During processing, the corresponding material thickness size is reserved, that is, the working profile of the milling skin. After the profile processing is completed, the reference hole, reference surface and part line shape are made. At this time, the mold state is used to stretch the sheet metal skin.

[0065] 2. After the skin is drawn, the mold is aligned again on the CNC machine tool, the drawn skin is placed on the mold surface, and the skin is tightened and fixed with a tensioning belt.

[0066] 3. Process the skin according to the CNC program to complete the manufacture of the milling template shape, milling holes, and milling positioning holes. After processing is completed, it becomes a milling template.

[0067] 4. After the chemical milling sample is processed, the sample is removed and the mold surface is processed for the second time to the theoretical shape of the skin mold. After the processing is completed, it is used for the manufacture of aircraft skin parts.

Claims

1. A method for processing a milled skin mold with a chemical treatment, characterized in that: The following steps are involved: Step 1) Performing primary CNC machining, reserving corresponding material thickness dimensions during programming, i.e., the working profile of the chemical milling skin; after the CNC machining is completed, making 3 to 4 reference holes, reference surfaces, or related reference lines at corresponding positions of the skin mold, which are used as alignment references during secondary machining; specifically, firstly including the aircraft skin parts in the skin mold profile in the primary CNC machining, and then performing CNC machining to produce a primary machining curved surface, wherein the profile includes the aircraft skin parts, and the profile lines on the skin mold must be machined, which are used to manufacture and inspect the chemical milling skin; Step 2) forming a stretching process of the milling sample skin according to the skin mold that has completed the initial CNC processing; Step 3) Aligning the skin mold again according to the secondary alignment reference, performing CNC machining again, removing the preset thickness of the milling sample during the initial machining, and machining the skin profile to its theoretical working profile; specifically, performing CNC machining on the skin mold again to produce a secondary machining surface; according to the state of the skin mold at this time, which is a skin mold including the primary machining surface and the secondary machining surface, machining and manufacturing aircraft skin parts; Step 4) The skin mold after secondary processing is subjected to subsequent surface engraving deepening, grinding, repairing and streamlining processes, thereby completing the manufacture of the mold with chemically milled skin; after the secondary processing of the mold is completed, it is used to form aircraft skin parts.

2. The method for processing a strip milling skin mold according to claim 1, characterized in that: The secondary alignment reference in step 3) is specifically: secondary alignment is performed by using X, Y reference engraved lines that have a positional dimension relationship with the lower die processing coordinate system.

3. The method for processing a strip milling skin mold according to claim 1, characterized in that: In the step 3), the secondary alignment reference is replaced by 3 to 4 blind holes made at the four corners of the lower die, wherein the blind holes have a diameter of φ8 mm and a depth of 15 mm.

4. The method for processing a strip milling skin mold according to claim 1, characterized in that: In the step 3), the secondary alignment reference is performed or the replacement is performed using an X, Y plane method that has a positional dimension relationship with the lower die processing coordinate system.

5. The method for processing a strip milling skin mold according to claim 1, characterized in that: The secondary alignment inspection method in step 3) is specifically: the alignment inspection can be performed by using the X, Y reference lines that have a positional dimensional relationship with the lower die processing coordinate system, the secondary alignment reference using 3 to 4 blind holes made at the four corners of the lower die, and the X, Y plane method that has a positional dimensional relationship with the lower die processing coordinate system.

6. The method for processing a strip milling skin mold according to claim 1, characterized in that: Before step 2), when the skin mold is initially processed by CNC, tooling lines must be produced for subsequent milling sample molding inspection.

7. The method for processing a strip milling skin mold according to claim 1, characterized in that: After the skin mold is processed in step 4), the material used to repair the surface defects is used.

8. The method for processing a strip milling skin mold according to claim 7, characterized in that: To repair surface defects, use a resin material that is the same as the mold surface, and the corresponding position should be roughened before rework.

9. The method for processing a strip milling skin mold according to claim 8, characterized in that: The thickness of the mold surface layer for CNC machining must be able to meet the margin for two CNC machinings, and the thickness of the mold surface layer is specifically 60mm-70mm.

10. The method for processing a strip milling skin mold according to claim 1, characterized in that: It also includes the completion of the tooling appearance modification work after the secondary processing of the skin mold is completed, including making rounded corners, painting the tooling surface, and adding tooling signs. The specific setting rules for the rounded corner values ​​are as follows: the rounded corners in the stretching direction of the tooling are R50mm, and the rounded corners in the non-stretching direction are set to R20mm.

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