CN104400987A - Vacuum plastic-suction forming technology for special-shape folded core material - Google Patents

Abstract

The invention discloses a vacuum suction molding process for a special-shaped wrinkled core material, which belongs to the technical field of wrinkled core material forming. The special-shaped wrinkled core material is obtained by adopting the vacuum suction method, and the required special-shaped wrinkled core material is obtained according to the sequence of manufacturing the vacuum suction mold for the special-shaped core material, heating the plastic sheet, vacuuming with a vacuum pump, demoulding and stripping. The effects and benefits of the invention include utilizing the plastic sheet to enter a high-elastic state after being heated, and being adsorbed on the surface of a mold under the power of a vacuum pump, so as to solve the problem of difficult processing and forming of a special-shaped wrinkled core material. The method for manufacturing the special-shaped wrinkled core material has the advantages of short manufacturing cycle, low cost, good product integrity, wide range of processable materials, and no need for reprocessing in one-time forming. Moreover, as long as the mold design of the special-shaped wrinkled core material is reasonable, the special-shaped wrinkled core material can be formed repeatedly, and a large number of special-shaped wrinkled core materials can be produced, laying the foundation for its large-scale application.

Description

A Vacuum Blister Forming Process of Special-shaped Wrinkled Core Material

technical field

The invention belongs to the technical field of wrinkled core material forming, and relates to a vacuum suction forming process of special-shaped wrinkled core material.

Background technique

The corrugated core material has the characteristics of sound insulation, shock insulation, low density and high strength, and has been widely used in aviation and civil fields. Typical corrugated core materials include honeycomb core material, foam core material, rectangular core material, circular core material, shaped core material, etc. At present, the honeycomb core material has been widely used in the production of aircraft wings and fairings due to its high specific stiffness and high strength. However, when an aircraft flies at high altitudes, condensation slowly accumulates in the closed honeycomb core, resulting in increased airframe mass and reduced structural performance. The special-shaped wrinkled profile refers to a three-dimensional structure formed by folding a plane along a certain fold line. The more common special-shaped wrinkled profiles include V-shaped core material, M-shaped core material, and U-shaped core material. They all have good air permeability and processing Continuity has great application prospects.

At present, the development of special-shaped core materials is still in the research stage, and its forming methods and forming materials are various. The main processing methods include discontinuous forming methods and continuous forming methods. The discontinuous forming method includes: (1) Relying on the expansion and folding of the mold to form a special-shaped core material. The mold is movable, and each unit of the mold is connected by a cylindrical hinge or an elastic plate. Although this forming method is simple, the movable range of the mold is limited. Limited, low production efficiency; (2) punch some small holes on the metal sheet folding line, and then place the metal sheet on the separator for folding to complete the manufacture of the special-shaped core material, but this method destroys the special-shaped core material The continuity, the processing process is cumbersome. The continuous forming method includes rolling forming. The specific method is that the metal sheet is rolled by two rollers to leave the folding line of the special-shaped core material, and then the metal sheet is mechanically extruded to complete the manufacture of the special-shaped core material. However, this method forms The height of the special-shaped core material is uncontrollable, and it is prone to local over-extrusion. At present, the forming methods of special-shaped profiles have certain limitations. If a simple, feasible, high-efficiency, and low-cost forming process can be found, its application prospects must be great.

Contents of the invention

The purpose of the present invention is to simplify the cumbersome process in the manufacturing process of the special-shaped core material, ensure the continuity and strength requirements of the special-shaped core material, and at the same time reduce the investment and production cost.

There are various geometric forms of shaped corrugated core materials, among which the most basic geometric forms are zigzag and V-shaped corrugated core materials, both of which have convex and concave fold lines. We call the convex fold line of the profiled wrinkled core material ridges, and the concave fold line is called the valley, and the design of the shaped wrinkled profile mold does not allow sharp corners, and the ridges and valleys need to be chamfered. At the same time, due to the , the plastic sheet is not easy to fill the valley on the mold, so the air extraction holes are designed in the valley to ensure the forming quality, and the number of air extraction holes is designed according to the plastic mold design manual.

The present invention provides a vacuum blister forming process for special-shaped wrinkled core materials, the specific steps are as follows:

(1) Manufacture of special-shaped wrinkled core material vacuum blister mold

According to the structure of the special-shaped wrinkled core material, the mold of the special-shaped wrinkled core material is designed, and the vacuum plastic mold is processed by a numerical control machining center. There are air holes on the valley of the vacuum plastic mold to ensure that the plastic sheet is tightly adhered when forming. For the valley of the vacuum plastic mold, the specific number of vent holes can be according to the design manual of the vacuum plastic mold. Choose metal or gypsum as the material of vacuum blister mould. During the forming process, the vacuum blister mold needs to withstand a lot of pressure, so heat treatment can be considered to improve its mechanical properties.

(2) Plastic sheet heating

Cut out a suitable size plastic sheet according to the size of the vacuum blister mold, place the cut plastic sheet on the platform of the vacuum blister machine and clamp it, and the plastic sheet is driven by the guide rail on the vacuum blister machine under the action of the motor Send it over the resistance wire for heating, and after the plastic sheet is heated to soften, send the plastic sheet above the vacuum blister mould.

(3) Vacuum pumping

Turn on the vacuum pump to evacuate, the air between the plastic sheet and the mold is sucked away, and the plastic sheet is deformed and attached to the surface of the vacuum suction mold under atmospheric pressure.

(4) demoulding and stripping

After the plastic sheet is completely cooled, the formed plastic part is taken out, and the shaped wrinkled core material can be obtained after removing the material edge.

The effects and benefits of the present invention are: (1) The plastic sheet material enters into a high elastic state after being heated, and is adsorbed on the surface of a mold under the power of a vacuum pump, so as to solve the problem of difficulty in processing and forming a special-shaped wrinkled core material. (2) The manufacturing of special-shaped wrinkled core materials by this process has the characteristics of simple process, short manufacturing cycle, low cost, good product integrity, wide range of machinable materials, and no reprocessing is required for one-time forming. (3) As long as the mold design of the special-shaped wrinkled core material is reasonable, the special-shaped wrinkled core material can be formed repeatedly, and a large number of special-shaped wrinkled core materials can be produced, laying the foundation for its large-scale application. The main feature of the invention is that it can simply and quickly form the special-shaped wrinkled core material through the vacuum suction forming technology. Put the plastic sheet on the blister machine and heat it. After softening, the plastic sheet is adsorbed on the surface of the mold by a vacuum pump. After cooling and forming, the manufacture of the special-shaped wrinkled core material can be completed.

Description of drawings

Fig. 1 is a flow chart of the technical solution of the present invention.

Fig. 2 is a schematic diagram of the technical solution of the present invention.

In the figure: 1 plastic sheet; 2 vacuum suction mold; 3 plastic sheet after cutting and forming.

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with technical solutions and accompanying drawings.

In the present invention, the V-shaped wrinkled core material is made of PET plastic, which is heated and softened, vacuum-absorbed, cooled and shaped, and the V-shaped wrinkled core material is formed by removing the material from the mold. The specific implementation methods are as follows:

(1) Design the three-dimensional shape of the V-shaped wrinkled core material mold, select an aluminum alloy blank of 25×25×2cm, and process it on a CNC machining center after determining each process. The special-shaped wrinkled profile mold does not allow sharp corners, and the ridges and valleys need to be chamfered. In this embodiment, the ridge chamfer size of the mold is 1.5mm, and the valley chamfer size is 2mm. Finally, use a drilling machine to process the air extraction holes on the mold. Punch three 1mm diameter air extraction holes on the mold valley.

(2) Place the V-shaped vacuum plastic mold in a rectangular closed cavity, and use the resistance wire below to preheat for a period of time, so that the temperature reaches 80-100°C, so as to avoid the mold temperature being too cold when the plastic sheet is formed. Cold spots appear on the surface.

(3) Cut out 40cm×40cm PET plastic sheet according to the size of the V-shaped vacuum plastic mold, use the clamping device to clamp the plastic sheet around and fix it on the resistance wire heating furnace, and the resistance wire is heated to 110-130°C between.

(4) After the plastic is softened, through observation, it can be found that the sheet is obviously sunken under the action of gravity at this time, and it can be considered that the plastic sheet has softened to a high elastic state. At this time, the PET plastic sheet is conveyed together with the clamping device To the top of the rectangular cavity, turn on the switch of the vacuum pump, and the PET plastic sheet is quickly adsorbed on the surface of the mold under atmospheric pressure.

(5) After the PET plastic part is naturally cooled and shaped, the clamping device is lifted to separate the plastic part from the mold, and a PET plastic V-shaped wrinkled core material with edges is obtained.

(6) Use a cutter or scissors to remove the edge of the PET plastic V-shaped corrugated core material, and obtain a complete V-shaped corrugated core material.

Claims (2)

1. A vacuum-absorbing forming process of a special-shaped wrinkled core material, characterized in that the steps are as follows: (1) Manufacture of special-shaped wrinkled core material vacuum blister mold According to the structure of the special-shaped wrinkled core material, the mold of the special-shaped wrinkled core material is designed, and the vacuum plastic mold is processed. There are air holes on the valley of the vacuum plastic mold to ensure that the plastic sheet is close to the vacuum plastic mold when it is formed. valley; (2) Plastic sheet heating Cut out a suitable size plastic sheet according to the size of the vacuum blister mold, place the cut plastic sheet on the platform of the vacuum blister machine and clamp it, and the plastic sheet is driven by the guide rail on the vacuum blister machine under the action of the motor Send it to the top of the resistance wire for heating. After the plastic sheet is heated to soften, send the plastic sheet to the top of the vacuum blister mould; (3) Vacuum pumping Turn on the vacuum pump to evacuate the air between the plastic sheet and the mold, and the plastic sheet is deformed and attached to the surface of the vacuum suction mold under atmospheric pressure; (4) demoulding and stripping After the plastic sheet is completely cooled, the formed plastic part is taken out, and the shaped wrinkled core material can be obtained after removing the material edge. 2. The vacuum forming process according to claim 1, wherein the material of the vacuum forming mold is metal or gypsum.