The invention relates to the field of manufacturing aircraft parts, in particular to a manufacturing method of aircraft wing tip cover mirror parts using a drawing die and a processing method for deep drawing. Including the following steps: Mechanically polish the skin material, customize a blank material with an irregular elliptical shape according to the size of the concave die opening contour line of the drawing die uniformly offset outwardly by a predetermined value; uniformly apply lubricating oil on the concave die fillet part of the drawing die, the pressing surface and the inside and outside the mold cavity of the drawing die composed of a concave die and a convex die, and on the surface of the blank material in contact with the blank material; place the blank material in the drawing die with the fiber direction along the length direction of the blank material; cover a layer of rubber material between the concave die and the blank material; Carry out deep drawing, the drawing pressure is 3~ 5Mpa, and the blank holder pressure is 3~ 5Mpa; hold for 5~10 seconds after the drawing is completed; remove the pressure and take out the parts. The surface of the mirror part obtained in this way has no slip lines and coarse grains, and the surface is smooth and free from scratches, meeting the quality requirements of the mirror part.
The difficulty in manufacturing wing tip cover mirror parts is that during the drawing process, the mirror surface is easy to be scratched in the mold cavity; the shape of the wing tip part changes greatly, and the material formed by one-time drawing is easy to break or coarse crystal phenomenon (Also called "orange peel phenomenon"). If secondary drawing is used, the mirror surface is difficult to ensure; female die round grooves are easy to occur at the junction of the part rounded corners and the straight wall section; the precision requirements of the part are high, and the overall size tolerance is 0.25mm. This patented technology uses a special drawing die to deeply draw the mechanically polished skin material to achieve left-right symmetry and can be cut into two wing tip cover mirror parts, and can ensure that the mirror parts do not appear after one molding. phenomenon.
The main characteristics of its technical method that is different from traditional deep drawing methods are:

1. High surface quality of parts. During the part forming process, taking into account the surface quality requirements of mirror parts, appropriate protection and lubrication are used for mirror parts. The material can flow smoothly during the drawing process, so that the surface cannot have slip lines, coarse grains and scratches.
2. Forming it once, no correction is needed. By analyzing the mechanical properties of the material, adopting a reasonable calendering plan and formulating various process parameters such as the shape size of the blank, the mirror drawn parts can be drawn and formed in one step without needing to calibrate the parts. requirements.
3. The forming adopts the method of pressing two pieces one by one to realize that the left and right parts are formed together, which shortens the part manufacturing cycle and improves production efficiency.
   Through the above technical methods, the surface of the mirror part after drawing remains thin and wrinkled; by determining the blank holder force and the selection of mirror material protection, the appearance quality such as grooves and mirror scratches caused by friction between the surface of the part and the interior of the mold is solved. The traditional drawing method is generally aimed at ordinary aluminum alloy plates, which can be drawn multiple times and corrected before finally meeting the drawings and customer requirements. The appearance quality is not high, the actual application effect is not ideal, the production cycle is long, and the manufacturing cost is high.
   The wingtip cover parts products of the Boeing 737 horizontal tail project produced using this patent have produced a total of 2995 aircraft since 2009, of which 1278 aircraft were produced from 2013 to 2015, with an added output value of 69.5831 million yuan, an added profit of 75.9089 million yuan, and generated foreign exchange revenue of US$217.0405 million. In addition, with the development of the national civil aircraft industry, this patent has also been used in the manufacturing of wing tip parts on the new ARJ21 regional aircraft. Currently, the production of parts for 20 aircraft has been completed. Although it is now in the airworthiness approval stage and there is no sales, the total number of orders has reached 258 aircraft, which will bring greater economic benefits in the future.