CN104816837A - Aluminum alloy skin digital assembly method - Google Patents

Abstract

The invention relates to a digital assembly method of an aluminum alloy skin, which belongs to the field of aircraft manufacturing. In the prior art, for the assembly of the skin, the position is adjusted based on the experience of the workers, and the assembly accuracy is low; the inaccurate position of the skin will cause the misalignment of the shape of the skin and the shape of the skeleton, and the shape error of the skin itself will cause large riveting deformation. The appearance quality of the fuselage is poor; the quality of the skin butt joints is poor; the manual marking error is large, the repeatability is low, and the efficiency is low; in the absence of tooling, the riveting site manually grinds the allowance, the efficiency is low, the quality is poor, and the noise is large. The invention adopts the positioning technology of the digitized process lugs, and the skin can be clamped in place at one time without repeated adjustments; except for the process lugs, the edges of the skin are clean edges, and no on-site grinding allowance is required; the assembly efficiency and assembly efficiency can be greatly improved. quality.

Description

A digital assembly method of aluminum alloy skin

technical field

The invention belongs to the field of aircraft manufacturing, and in particular relates to a digital assembly method of an aluminum alloy skin.

Background technique

Before the use of digital manufacturing technology, the aluminum alloy skin did not have positioning holes for process lugs; a certain width margin was reserved outside the edge of the skin; at the riveting assembly site, the aluminum skin was not positioned accurately on the assembly tooling, and workers adjusted the mask based on experience. After confirming the adjusted position, fasten the skin and the fuselage frame with clamps, tensioning ropes, and clamps, drill rivet holes, and insert spring pins for positioning; manually draw the edge line, and determine the remainder to be removed. Measure, then remove the skin, and manually polish off the skin margin on site.

If the skin is not positioned accurately, adjust the position according to the experience of the workers, and the assembly accuracy will be low; if the skin position is not accurate, it will cause the shape of the skin and the shape of the skeleton to be misaligned, and the shape error of the skin itself will cause large riveting deformation and the appearance of the fuselage The quality is poor; the quality of the skin butt joint is poor; the manual marking error is large, the repeatability is low, and the efficiency is low; in the absence of tooling, the riveting site manually grinds the allowance, the efficiency is low, the quality is poor, and the noise is large.

Contents of the invention

The invention adopts the positioning technology of the digitized process lugs, and the skin can be clamped in place at one time, without repeated adjustment; except for the process lugs, the edges of the skin are clean edges, and no on-site grinding allowance is required; the assembly efficiency and assembly efficiency can be greatly improved. quality.

Two or more positioning holes are made on the skin, and these positioning holes are used to accurately position the skin on the riveting assembly jig, so that it is not necessary to repeatedly adjust the position of the skin at the riveting site; the skin clamped to the jig does not need With margin. However, it is not allowed to add positioning holes casually within the edge line of the skin. It is therefore conceivable to provide positioning holes in the margin area.

Specific steps are as follows:

Step 1. Use digital technology to manufacture stretch tires and riveting assembly fixtures. On the stretch tires, use a glass fiber reinforced plastic plate to drill molds in the skin margin area to drill the positioning holes for the process lugs. The positioning holes for the process lugs are selected in the skin Stretch forming a symmetrical area with small deformation and small curvature change, the number of the positioning holes is at least two;

Step 2. Position the skin on the stretch tire through the positioning hole, cut the skin to the net edge size according to the skin cutting line (EOP) on the stretch tire, but keep the craft lugs; place the skin through the positioning hole Locate on the riveting assembly jig, drill out the rivet holes between the skin and the frame beam, and position with spring pins;

Step 3. Remove the skin and cut off the ears;

Step 4. Reinstall it on the fixture, and use the spring pin to locate the rivet hole;

Step five, install the rivets and complete the riveting assembly.

The old method requires manual scribing, which has low scribing accuracy and low repeatability; the new method does not have a scribing step; the old method manually grinds the skin margin without tooling at the riveting site; the new method only needs to polish off the craft lugs , the grinding workload is less than 1% of the old method.

The assembling efficiency and assembling quality are improved through the assembling method of the invention. It can realize the exchange of skin production and use. It provides a reliable positioning system for digital automatic drilling and riveting assembly of skins.

Description of drawings

Figure 1 is a schematic diagram of the relative positional relationship between the aluminum alloy skin, the stretch tire and the FRP pressure plate;

Fig. 2 is the drilling state of the skin on the stretched tire;

Fig. 3 is to drill the positioning hole of the skin craft lug on the stretched tire;

Fig. 4 is the state after the skin blank is drilled (the margin area is not all shown);

Figure 5 is the state after trimming the skin;

Fig. 6 is the positioning state of the skin on the assembly fixture;

Fig. 7 is a detailed diagram of the positioning of the skinning lugs.

1-stretch tire; 2-aluminum alloy skin; 3-glass fiber reinforced plastic pressure plate; 4-drilling mold for positioning hole positioning hole of the process lug on the pressure plate; 5-positioning hole; 6-skin margin area; 7-process lug; 8-Craft lug hole locator

Detailed ways

A kind of aluminum alloy skin digital assembly method of the present invention, its specific process is as follows:

Step 1: Drill holes for positioning the craft lugs on the stretch tire

Using digital technology to manufacture stretching tires and riveting assembly fixtures, on the stretching tires, use a glass fiber reinforced plastic plate to drill molds in the skin margin area to drill the positioning holes for the process lugs, and the positioning holes for the process lugs are selected in the skin stretching The symmetrical area with small deformation and small curvature change provides accurate processing and assembly positioning references for the subsequent processing of the skin; in addition, because the stretch tire and the pressure plate drilling jig use digital manufacturing methods, the positioning of the process lugs is guaranteed. Holes are highly coordinated with skin geometry, as shown in Figures 1, 2, 3, and 4;

Step 2: Position the cut edge of the skin

Position the skin on the digital stretch tire through the positioning hole, cut the skin to the net size according to the edge of the glass fiber reinforced plastic plate, and leave the craft lug; as shown in Figure 4; check according to the skin cutting line on the stretch tire Skinned edges. Other product holes can be drilled according to the stretched tire and the FRP platen.

The present invention utilizes the skin cutting line (EOP) and the pressing plate on the stretch tire to ensure the coordination of the skin edge and the positioning hole.

Step 3: Skin Assembly Positioning

The aluminum alloy skin with craft lug holes is positioned on the riveted digital assembly fixture through the positioning holes, and the rivet holes between the skin and the frame beam are drilled and positioned with spring pins.

The present invention utilizes the assembly positioning reference (also the processing reference) obtained in the forming stage to accurately clamp the skin to the riveting assembly fixture under the premise that the reference remains unchanged, thereby ensuring the shape, edge, hole and other structural features of the skin The relative position of the frame and beam of the machine body is highly coordinated, which ensures the production interchange of the skin from forming, trimming and drilling to assembly, and finally ensures the interchangeability of the skin; as shown in Figure 5;

Step 4: Cut off the Craft Ears

Remove the skin and cut off the craft lugs; as shown in Figure 6;

Step 5: Skin riveted assembly

Reinstall the skin with the craft lugs removed on the body structure, position it with spring pins, drive rivets, and complete the riveted assembly.

In addition, the material of the stretched tire is cast iron or epoxy plastic, which is processed by numerical control; the manufacturing method of the glass fiber reinforced plastic plate of the stretched tire: a thick skin material (lead skin) is placed on the molded tire, and a wet paste is used on the pad. FRP template; after the FRP template is solidified, drill a large hole for the positioning hole drill sleeve of the mosaic process lug on it; fill the drill sleeve (with ring) according to the corresponding positioning hole (NC boring) on the stretched tire Oxygen resin); the edge of the platen is made according to the cut line of the skin of the stretched tire. See Figure 3.

The positioning holes of the process lugs should be selected in the symmetrical middle area where the stretching deformation of the skin is small, and the area where the curvature changes are small, and the number of positioning holes should be at least two. In order to avoid large changes in the relative position of the axis of the positioning hole due to the deformation of the skin, resulting in difficulty in positioning. The positioning hole bushing on the locator of the assembly tool can be selected as a normal aperture, the second positioning hole bushing is a long round bushing, and the third bushing (if any) is a large hole bushing. Positioning difficulties can be avoided.

In addition, the position of the positioning hole of the process lug should be determined and proposed by the designer of the assembly tooling, and the hole position data should be submitted to the designer of the stretch tire tooling. To ensure that the positioning holes are coordinated.

Claims (1)

1. A digital assembly method for aluminum alloy skin, characterized in that, comprising the following steps: Step 1. Use digital technology to manufacture stretch tires and riveting assembly fixtures. On the stretch tires, use glass fiber reinforced plastic platen drilling molds to drill process lug positioning holes in the skin margin area. The process lug positioning holes are selected in the skin Stretch forming a symmetrical area with small deformation and small curvature change, the number of the positioning holes is at least two; Step 2. Position the skin on the stretch tire through the positioning hole, cut the skin to the net edge size according to the skin cutting line on the stretch tire, but keep the craft lugs; position the skin to the riveting through the positioning hole On the assembly fixture, the rivet holes between the skin and the frame beam are drilled and positioned with spring pins; Step 3. Remove the skin and cut off the ears; Step 4. Reinstall it on the fixture, and use the spring pin to locate the rivet hole; Step five, install the rivets and complete the riveting assembly.