A rapid casting process for complex carbon fiber load-bearing components

Abstract

The present invention discloses a rapid casting process for complex carbon fiber load-bearing components, which relates to the technical field of light aircraft manufacturing, and specifically includes the following steps: judging whether a part is suitable for the process; designing a mold drawing for a part that meets the requirements; making a mold according to the drawing; preparing raw materials according to the part; using the raw materials to make and prepare injection molding materials; splicing the processed molds to form the left and right parts of the mold, and after injection molding and filling respectively, fixing the left and right parts of the mold together, and then filling the cavity through the overflow port; placing a tray at the bottom of the manufactured mold product; placing the tray and the mold product as a whole into a heating device for heating; taking out the heated mold product, and performing a demoulding operation after cooling; and performing a surface treatment operation on the molded part. This application adopts a simple mold method for manufacturing and shaping, and the shape is quickly engraved by an engraving machine. The manufacturing cost is ultra-low, the manufacturing efficiency is very high, and it is suitable for the manufacturing of complex carbon fiber parts.

Description

Technical Field

[0001] The invention relates to the technical field of light aircraft manufacturing, and in particular to a rapid casting process for complex carbon fiber load-bearing components. Background Art

[0002] Unmanned aerial vehicles rely on the lift provided by the wings to overcome their own gravity to achieve flight. Weight is the main factor restricting flight time. Therefore, unmanned aerial vehicles have special needs for weight reduction. Only by controlling the structural mass coefficient below 30% can sufficient mass space be left for fuel and payload. Unmanned aerial vehicles will have special requirements for the shape of some load-bearing components according to the application scenarios and the requirements of simplified structure. Such parts can be classified as special-shaped parts. Common production methods for special-shaped parts include metal CNC engraving and 3D additive printing. Special-shaped parts processed by metal CNC engraving have high precision, but the material used for the parts is metal material, and the gravity of the parts will be relatively heavy, which cannot meet the requirements of lightweight aircraft. In addition, when using metal CNC engraving processing, the parts need to be clamped and disassembled, and the clamping and disassembly of the parts takes a certain amount of time, which reduces the processing efficiency of the parts. When using 3D additive printing to produce special-shaped parts, the mechanical properties of special-shaped parts produced by materials suitable for 3D additive printing often cannot meet the load-bearing requirements, and only non-load-bearing parts can be made. For this reason, a rapid casting process for complex carbon fiber load-bearing components is proposed. Summary of the invention

[0003] The present invention provides a rapid casting process for complex carbon fiber load-bearing components, which solves the problems in the above-mentioned background technology that special-shaped parts produced by metal CNC engraving are heavy and have low production efficiency; and that load-bearing parts cannot be produced when special-shaped parts are produced by 3D additive printing.

[0004] The present invention provides the following technical solution: a rapid casting process for complex carbon fiber load-bearing components, which adopts a simple mold method for production and shaping, and uses an engraving machine to quickly carve the shape, with ultra-low production cost and high production efficiency.

[0005] A rapid casting process for complex carbon fiber load-bearing components, comprising the following steps:

[0006] Step 1: Analyze the parts to determine whether they can be made using the complex carbon fiber casting process. If the parts meet the requirements, proceed to step 2.

[0007] Step 2: Make mold drawings for parts, and the designed mold is modular;

[0008] Step 3: Use an engraving machine to produce a mold according to the drawing made in step 2;

[0009] Step 4: Perform simple processing on the produced mold and perform surface demoulding treatment;

[0010] Step 5. Prepare the raw materials for making the parts according to the volume of the parts. The raw materials used to prepare the parts include carbon fiber filaments, epoxy resin glue and epoxy resin glue adhesive. Among them, the epoxy resin glue accounts for more than 40%, and the epoxy resin glue completely wraps the carbon fiber filaments;

[0011] Step 6: Prepare the injection molding material according to the accurate raw materials in step 5. The preparation method of the injection molding material is: fully mix the epoxy resin glue and the epoxy resin glue thickener, stir until semi-viscous, add the carbon fiber filaments, and mix them evenly so that there is no dry part in the fiber filaments;

[0012] Step 7: Splice the processed mold to form the left and right parts of the mold, fill the injection molding material prepared in step 6 into the inner cavities of the left and right parts of the mold, fix the left and right parts of the mold together, and put the remaining glue-containing fiber filaments into the mold cavity through the overflow port to fill the cavity;

[0013] Step 8: Place a tray at the bottom of the molded product in step 7, and place the entire product in a heating device for heating;

[0014] Step 9: Take out the heated mold product, and after the mold cools down, perform demoulding operation and perform surface treatment on the parts.

[0015] Preferably, the features of the parts to which the carbon fiber casting process is applied are: the parts are complex and cannot be directly cut from carbon plates; the parts are non-rotating axes or long-term friction parts.

[0016] Preferably, when making the mold drawing in step 2, there should be no reverse angle on the made mold drawing, and a glue overflow port should be provided on the mold drawing.

[0017] Preferably, the method of simply processing the mold in step 4 is: adding a reverse angle to the mold and polishing the outer surface of the mold to ensure that the mold surface accuracy is 0.4-0.8um.

[0018] Preferably, the method for performing surface demoulding treatment on the treated mold in step 4 is: applying wax on the outer surface of the mold to perform smooth treatment.

[0019] Preferably, the epoxy resin viscosity agent includes but is not limited to white carbon black, and the mold material includes but is not limited to density board.

[0020] Preferably, the temperature of the heating device is 80-90 degrees Celsius, and the heating time is 3.8-4.2 hours.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The rapid casting process of the complex carbon fiber load-bearing components adopts a simple mold method for production and shaping, and the shape is quickly carved by an engraving machine. The production cost is ultra-low and the production efficiency is very high. It is suitable for the production of complex carbon fiber parts.

[0023] 2. The rapid casting process of the complex carbon fiber load-bearing components can greatly reduce the weight of the parts while meeting the strength of the parts through the setting of the parts raw materials, thus solving the problem of heavy weight of the parts in the prior art and facilitating the application of the parts in aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of a mold according to an embodiment of the present invention;

[0025] Figure 2 It is a schematic diagram of the process flow of the present invention.

[0026] In the figure: 1. Glue overflow port; 2. Upper die left; 3. Lower die left; 4. Lower die right; 5. Upper die right. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The present invention provides a rapid casting process for complex carbon fiber load-bearing components, comprising the following steps:

[0029] Step 1: Analyze the parts and judge whether the parts to be processed can be made by complex carbon fiber casting process according to the parts characteristics of carbon fiber casting process. If the parts meet the requirements that the parts are relatively complex and cannot be directly cut from carbon plates, and the parts are non-rotating axes or long-term friction parts, proceed to step 2;

[0030] Step 2: Make mold drawings for parts. The designed mold drawings are modular, and overflow ports should be designed on the designed mold drawings to facilitate the discharge of excess glue during the production process of parts. The mold designed on the drawing cannot have reverse angles, otherwise it will be difficult to demould. The mold must have a quick assembly groove to ensure that the mold is quickly and accurately in place, and large molds or complex molds must have multiple overflow ports;

[0031] Step 3: According to the drawing made in step 2, use an engraving machine to produce the mold. The engraving machine can be CNC opened. For complex shapes or thicker ones, splicing and bonding can be performed without affecting demoulding. The production material of the mold is mainly density board;

[0032] Step 4: Perform simple processing on the carved mold and perform surface demoulding. The simple processing method is: use a carving knife or other tools to add reverse angle edges that cannot be carved by the engraving machine to the mold and use 200-500 mesh sandpaper to polish the outer surface of the mold, polish off the carving knife marks on the mold, and ensure that the mold surface accuracy is 0.4-0.8um; the steps for surface demoulding of the polished mold are: use cotton cloth dipped in No. 8 wax to evenly apply it to the mold surface until the wood surface changes color and there is no obvious wax residue, and the demoulding process is completed;

[0033] Step 5. Prepare the raw materials. The raw materials include carbon fiber filaments, epoxy resin glue and epoxy resin glue thickener. The preferred epoxy resin glue thickener is white carbon black. Calculate the practical carbon fiber quantity according to the volume. After calculating, weigh the chopped carbon fiber. The required chopped carbon fiber length must be less than or equal to 10 mm (when casting large parts or parts with simpler shapes, the carbon fiber length can be increased as appropriate, otherwise the chopped carbon fiber length needs to be reduced). The casting process has a large glue content, which must be 65% of the calculated value of the carbon fiber (when casting complex parts, the glue content needs to be increased as appropriate, otherwise the glue content needs to be reduced to a minimum of 40%). The required epoxy resin glue ratio is calculated to be 100:36. After fully stirring, add a small amount of white carbon black to increase the viscosity of the epoxy resin and mix until it is semi-viscous. Add chopped carbon fiber filaments and mix well so that there is no dry part in the carbon fiber filaments.

[0034] Step 6: Splice the processed mold to form the left and right parts of the mold, fill the injection molding material prepared in step 5 into the inner cavities of the left and right parts of the mold, fix the left and right parts of the mold together, and put the remaining glue-containing fiber filaments into the mold cavity through the overflow port to fill the cavity;

[0035] Step 7: Place a tray at the bottom of the mold product in step 6 to prevent the mold from overflowing glue, and place the entire mold product in a heating device for heating. The temperature of the heating device is 80-90 degrees Celsius for 3.8-4.2 hours. In one embodiment of the present application, the temperature of the heating device is 85 degrees Celsius for 4 hours.

[0036] Step 8: Take out the heated mold product, cool the mold by natural cooling or other methods, then gradually open the mold, perform demoulding operation, and take out the molded parts.

[0037] Step nine, remove the burrs of the product, polish the rough surface, and paint the surface of the parts to complete the processing of the parts.

[0038] Example

[0039] The mold made according to the part includes an upper mold left 2, a lower mold left 3, a lower mold right 4 and an upper mold right 5. The bottom of the upper mold left 2 is adapted to the top of the lower mold left 3, and the two can be connected by a snap-fitting method. The upper mold left 2 and the lower mold left 3 form a left part of the mold. The bottom of the upper mold right 5 and the top of the lower mold right 4 are connected by methods including but not limited to snap-fitting. The upper mold right 5 and the lower mold right 4 form the right part of the mold. The left and right parts of the mold can be spliced ​​into a complete mold. The cavity of the mold is adapted to the part, and a glue overflow port 1 is provided on one side of the top of the upper mold left 2, and the glue overflow port 1 is connected to the cavity.

[0040] When preparing parts, raw materials are prepared according to the volume of the parts, and the preparation materials (rubber-containing fiber filaments) of the parts are prepared with the raw materials. After the rubber-containing fiber filaments are filled into the inner cavities of the left part and the right part of the mold, the left part and the right part of the mold are fixed together, and the remaining rubber-containing fiber filaments are placed into the mold cavity through the overflow port 1, and the hollow part of the mold cavity is filled to realize the injection molding operation.

[0041] Place a tray at the bottom of the mold filled with part preparation materials, put the tray and the mold into the mold heating equipment, the heating temperature is 85 degrees Celsius, the heating time is 4 hours, so that the preparation materials can be fully integrated, take out the heated mold, wait for the mold to cool naturally, the part is formed, take out the formed part, and perform surface treatment operations such as polishing on the part.

[0042] The standard parts used in the present invention can all be purchased from the market, and special-shaped parts can be customized according to the description in the specification and the drawings. The specific connection methods of each part adopt conventional means such as mature bolts, rivets, welding, etc. in the prior art. Machinery, parts and equipment all adopt conventional models in the prior art and will not be described in detail here. The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field. Although the embodiments of the present invention have been shown and described, it can be understood by ordinary technicians in this field that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A rapid casting process for complex carbon fiber load-bearing components, characterized in that: The following steps are involved: Step 1: Analyze the parts to determine whether they can be made using the complex carbon fiber casting process. If the parts meet the requirements, proceed to step 2. Step 2: Make mold drawings for parts, and the designed mold is modular; Step 3: Use an engraving machine to produce a mold according to the drawing made in step 2; Step 4: Perform simple processing on the produced mold and perform surface demoulding treatment; Step 5. Prepare the raw materials for making the parts according to the volume of the parts. The raw materials used to prepare the parts include carbon fiber filaments, epoxy resin glue and epoxy resin glue adhesive. Among them, the epoxy resin glue accounts for more than 40%, and the epoxy resin glue completely wraps the carbon fiber filaments; Step 6: Prepare the injection molding material according to the accurate raw materials in step 5. The preparation method of the injection molding material is: fully mix the epoxy resin glue and the epoxy resin glue thickener, stir until semi-viscous, add the carbon fiber filaments, and mix them evenly so that there is no dry part in the fiber filaments; Step 7: Splice the processed mold to form the left and right parts of the mold, fill the injection molding material prepared in step 6 into the inner cavities of the left and right parts of the mold, fix the left and right parts of the mold together, and put the remaining glue-containing fiber filaments into the mold cavity through the overflow port to fill the cavity; Step 8: Place a tray at the bottom of the molded product in step 7, and place the entire product in a heating device for heating; Step 9: Take out the heated mold product, and after the mold cools down, perform demoulding operation and perform surface treatment on the parts.

2. A rapid casting process for complex carbon fiber load-bearing components according to claim 1, characterized in that: The features of the parts using the carbon fiber casting process are as follows: the parts are complex and cannot be directly cut from carbon plates; the parts are not rotating shafts or long-term friction parts.

3. A rapid casting process for complex carbon fiber load-bearing components according to claim 1, characterized in that: When making the mold drawing in the step 2, there should be no reverse angle on the mold drawing, and an overflow port should be provided on the mold drawing.

4. A rapid casting process for complex carbon fiber load-bearing components according to claim 1, characterized in that: The method for simply processing the mold in step 4 is: adding a reverse angle to the mold and grinding the outer surface of the mold to ensure that the mold surface accuracy is 0.4-0.8um.

5. The rapid casting process of complex carbon fiber load-bearing components according to claim 1, characterized in that: The method for performing surface demoulding treatment on the treated mold in step 4 is: applying wax on the outer surface of the mold to perform smooth treatment.

6. The rapid casting process of complex carbon fiber load-bearing components according to claim 1, characterized in that: The epoxy resin viscosity agent includes but is not limited to white carbon black, and the mold material includes but is not limited to density board.

7. The rapid casting process of complex carbon fiber load-bearing components according to claim 1, characterized in that: The temperature of the heating device is 80-90 degrees Celsius, and the heating time is 3.8-4.2 hours.

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