SMC-material-based powder spraying method

Abstract

Provided in the present invention is an SMC-material-based powder spraying method. The method comprises: bringing the side, away from a spraying surface, of a workpiece to be spray-coated that is made of an SMC material into contact with an electrically and thermally conductive material; preheating said workpiece that is in contact with the electrically and thermally conductive material; and spraying powder onto the spraying surface of said workpiece that has been preheated and is in contact with the electrically and thermally conductive material, and performing baking and curing at a preset temperature to complete a powder spraying process. Specifically, since a workpiece to be spray-coated that is made of an SMC material is in contact with an electrically and thermally conductive material, the stability of the overall surface temperature after preheating can be ensured; moreover, during a subsequent powder spraying process, the electrostatic adsorption characteristic of the electrically and thermally conductive material is used, such that powder can adhere better to the surface of the SMC material, and in combination with a baking and curing process, a finally obtained product has a high level of overall structural strength and excellent wear resistance, and the product sprayed with powder is also more aesthetically pleasing.

Description

A powder spraying method based on SMC material TECHNICAL FIELD

[0001] The present application belongs to the technical field of powder spraying based on SMC material, and particularly relates to a powder spraying method based on SMC material. BACKGROUND

[0002] At present, most of the automobile bodies are made of metal materials, and the metal materials have the advantages that the safety is guaranteed to a certain extent, and the appearance is more beautiful after the metal materials are painted.

[0003] With the development of society, under the premise of ensuring the safety of vehicles, lightweight and detachable design also arises, for example, the roof of some vehicles can be detached, and the material of the roof also uses lightweight non-metallic materials.

[0004] Sheet molding compound (SMC) is a sheet-shaped compound composed of thickenable resin, short-cut (and / or continuous) glass fiber reinforced material, filler, additive, etc. The upper and lower surfaces are covered with a bearing film. Commonly used is a molding compound made of unsaturated polyester resin as the resin matrix. Add thickeners, inorganic fillers, initiators, additives and pigments to the unsaturated polyester resin to make a resin mixture, impregnate short-cut fibers or felt sheets, cover the upper and lower surfaces with PE film, and prepare a sheet-shaped molding compound after thickening. It should be noted that there is currently no good method to apply SMC material to vehicles. The reason is that although the SMC material is lighter in quality than the metal material, the strength of the vehicle body made of pure SMC material is insufficient, and it cannot meet people's requirements for aesthetics. SUMMARY

[0005] Therefore, the present application provides a powder spraying method based on SMC material, which aims to improve the strength of SMC material for application in vehicles while meeting people's requirements for aesthetics.

[0006] The present application provides a powder spraying method based on SMC material, which includes the following steps:

[0007] Prepare a workpiece to be sprayed, the material of the workpiece to be sprayed is SMC material, and the spraying surface and / or the side away from the spraying surface of the workpiece to be sprayed are in contact with a conductive and heat-conductive material;

[0008] Preheat the workpiece to be sprayed in contact with the conductive and heat-conductive material;

[0009] The spraying surface of the preheating treated workpiece to be sprayed which is in contact with the electrically conductive and thermally conductive material is treated by powder spraying, and is baked and solidified at a preset temperature to complete the powder spraying process.

[0010] Further, the electrically conductive and thermally conductive material is a metal material.

[0011] Further, the metal material is one or an alloy of several of copper, aluminum, iron, silver, and gold.

[0012] Further, the electrically conductive and thermally conductive material is an electrically conductive liquid.

[0013] Further, the electrically conductive and thermally conductive material is an electrically conductive paint.

[0014] Further, in the step of preheating the workpiece to be sprayed which is in contact with the electrically conductive and thermally conductive material, the preheating temperature is 60-160°C, and the preheating time is 5-15 minutes.

[0015] Further, the step of treating the spraying surface of the preheating treated workpiece to be sprayed which is in contact with the electrically conductive and thermally conductive material by powder spraying includes:

[0016] testing the surface temperature of the spraying surface of the preheating treated workpiece to be sprayed which is in contact with the electrically conductive and thermally conductive material, and determining whether the difference between the maximum and minimum surface temperatures is less than a threshold value;

[0017] if the difference between the maximum and minimum surface temperatures is less than the threshold value, then treating the spraying surface by powder spraying.

[0018] Further, the step of treating the spraying surface of the preheating treated workpiece to be sprayed which is in contact with the electrically conductive and thermally conductive material by powder spraying includes:

[0019] controlling the distance between the nozzle of the spray gun and the spraying surface to be a preset distance;

[0020] controlling the spray gun to perform reciprocating operation to spray powder on the spraying surface layer by layer.

[0021] Further, the preset distance is 15-30 cm.

[0022] Further, in the step of controlling the spray gun to perform reciprocating operation to spray powder on the spraying surface layer by layer, the angle between the spray gun and the spraying surface is controlled to be 85-95°, the moving speed of the spray gun is controlled to be 2-4 m / min, the powder spraying amount of the spray gun is controlled to be 50-250 g / min, and the reciprocating times of each layer are controlled to be 3-5 times.

[0023] Further, in the step of baking and solidifying at a preset temperature, the preset temperature is 150-200°C, and the baking time is 10-30 minutes.

[0024] Further, in the step of performing powder spraying treatment on the spraying surface of the preheating treated SMC material workpiece in contact with the electrically conductive and thermally conductive material, the material of the sprayed powder is polyurethane resin or polyester resin.

[0025] Compared with the prior art, the implementation of the present application has the following beneficial effects:

[0026] By contacting the side of the SMC material workpiece away from the spraying surface with the electrically conductive and thermally conductive material, preheating the SMC material workpiece in contact with the electrically conductive and thermally conductive material, and performing powder spraying treatment on the spraying surface of the preheating treated SMC material workpiece in contact with the electrically conductive and thermally conductive material and baking and curing at a preset temperature to complete the powder spraying process, specifically, since the SMC material workpiece is in contact with the electrically conductive and thermally conductive material, the stability of the overall surface temperature after preheating can be ensured, and in the subsequent powder spraying process, the electrostatic adsorption property of the electrically conductive and thermally conductive material is utilized, so that the powder can better adhere to the surface of the SMC material, and then the baking and curing process is used, so that the finally prepared product has high overall structural strength and good wear resistance, can be applied to vehicles, and the product after powder spraying is more beautiful.

[0027] BRIEF DESCRIPTION OF DRAWINGS

[0028] Fig. 1 is an implementation flowchart of a powder spraying method based on SMC material provided by the present application.

[0029] The following specific embodiments will be further described in conjunction with the above-mentioned drawings.

[0030] DETAILED DESCRIPTION

[0031] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the related drawings. The drawings show several embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0033] Please refer to Fig. 1, which is an implementation flowchart of a powder spraying method based on SMC material provided by the present application. The preparation method specifically includes the following steps:

[0034] Step S01, a to-be-sprayed workpiece is prepared, the material of the to-be-sprayed workpiece is SMC material, and the spraying surface of the to-be-sprayed workpiece and / or a side away from the spraying surface is in contact with a conductive and heat-conductive material.

[0035] In the embodiment, first, the SMC material is processed into a to-be-sprayed workpiece with a specific shape by a common technical means, that is, the mixed SMC slurry is placed in a pre-designed mold for curing. It can be understood that if a detachable roof of a car needs to be prepared, a to-be-sprayed workpiece with a specific shape is processed according to the needs of the customer for the detachable roof.

[0036] After the to-be-sprayed workpiece is obtained, the surface of the to-be-sprayed workpiece generally needs to be pretreated. For example, the surface of the to-be-sprayed workpiece can be wiped with an organic solvent such as alcohol by manual means. After the pretreatment, part of the area of the spraying surface of the to-be-sprayed workpiece is shielded. The shielded area will not be attached with powder. Generally, the shielded area is a sealed area and a glued area. It needs to be noted that the shielded area is determined according to the design. If the entire spraying surface needs to be sprayed with powder, the shielding treatment is not needed. In the embodiment, the shielding treatment can be performed by covering the shielded area with adhesive tape and shielding film.

[0037] In the embodiment, the to-be-sprayed workpiece can be positioned by a tooling and then fixed by a high-temperature adhesive tape. It can be understood that when the spraying surface of the to-be-sprayed workpiece is in contact with the conductive and heat-conductive material, a metal material that is adapted to the shape of the spraying surface of the to-be-sprayed workpiece or a conductive liquid or conductive paint is sprayed on the spraying surface of the to-be-sprayed workpiece. When the side away from the spraying surface of the to-be-sprayed workpiece is in contact with the conductive and heat-conductive material, a metal material that is adapted to the shape of the side away from the spraying surface of the to-be-sprayed workpiece is prepared or a conductive liquid or conductive paint is sprayed on the side away from the spraying surface of the to-be-sprayed workpiece, so that the contact is more close. The conductive and heat-conductive material is a metal material, for example, one or several kinds of alloys composed of copper, aluminum, iron, silver and gold. More specifically, in order to achieve better powder spraying effect, the attached area of the conductive and heat-conductive material to the side away from the spraying surface of the to-be-sprayed workpiece is at least 85%, and the thickness of the conductive and heat-conductive material is 0.1mm-2mm.

[0038] In some other embodiments of the application, the conductive and heat-conductive material can also be a conductive liquid or conductive paint, which is sprayed on the side away from the spraying surface of the to-be-sprayed workpiece by a spray gun. The area of the sprayed conductive liquid or conductive paint is at least 85% of the area of the side away from the spraying surface of the to-be-sprayed workpiece, and the thickness after curing is 15μm-20μm.

[0039] Step S02, the to-be-sprayed workpiece in contact with the conductive and heat-conductive material is preheated.

[0040] Specifically, the material is brought into contact with conductive and thermally conductive materials at a preheating temperature of 60℃~160℃ for 5min~15min to complete the preheating process.

[0041] Step S03: The coating surface of the workpiece to be coated, which is in contact with the conductive and thermally conductive material after preheating treatment, is powder coated and then baked and cured at a preset temperature to complete the powder coating process.

[0042] To ensure the uniformity and stability of the powder coating process, the surface temperature of the coating surface of the workpiece in contact with the conductive and thermally conductive material after preheating is first tested, and it is determined whether the difference between the maximum and minimum surface temperatures is less than the threshold.

[0043] If the difference between the maximum and minimum surface temperatures is less than a threshold, then powder coating is performed.

[0044] It should be noted that the surface temperature test can be performed at least at five points on the surface, including the center point and the points around the perimeter. The difference between the maximum and minimum surface temperatures should be less than 12°C.

[0045] In this embodiment, the powder material used is polyurethane resin or polyester resin, which can be appropriately formulated according to customer needs, and different colors can also be formulated to meet the appearance requirements, with the same effect as traditional spray painting.

[0046] Furthermore, during the powder coating process, the nozzle of the spray gun is kept at a preset distance from the surface to be coated, which is 15cm to 30cm. The spray gun is controlled to reciprocate, coating the surface layer by layer. The angle between the spray gun and the surface is controlled to be 85° to 95°. For example, when the angle between the spray gun and the surface is 85°, it means that the nozzle is tilted upward and the acute angle formed with the surface is 85°. When the angle between the spray gun and the surface is 95°, it means that the nozzle is tilted downward and the obtuse angle formed with the surface is 95°. When the angle between the spray gun and the surface is 90°, it means that the nozzle is perpendicular to the surface. The moving speed of the spray gun is 2m / min to 4m / min, the powder spraying rate is 50g / min to 250g / min, and the number of reciprocations for each layer is 3 to 5 times.

[0047] Furthermore, in the step of baking and curing at a preset temperature, the preset temperature is 150℃~200℃ and the baking time is 10min~30min.

[0048] In summary, the SMC material-based powder spraying method provided in the embodiments of the present application contacts the side away from the spraying surface of the SMC material workpiece to be sprayed with the electrically-conductive and thermally-conductive material, preheats the workpiece to be sprayed in contact with the electrically-conductive and thermally-conductive material, sprays the spraying surface of the workpiece to be sprayed in contact with the electrically-conductive and thermally-conductive material after preheating, and bakes and cures at a preset temperature to complete the powder spraying process. Specifically, because the side of the SMC material workpiece to be sprayed is in contact with the electrically-conductive and thermally-conductive material, the heat preservation property of the electrically-conductive and thermally-conductive material can ensure the stability of the overall surface temperature after preheating. Meanwhile, in the subsequent powder spraying process, the electrostatic adsorption property of the electrically-conductive and thermally-conductive material enables the powder to better adhere to the SMC material surface. In combination with the baking and curing process, the final product has high overall structural strength, good wear resistance, and a more beautiful appearance after powder spraying.

[0049] In order to make the present application more comprehensively and thoroughly understood, several embodiments of the present application will be given below. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more comprehensive and thorough.

[0050] Embodiment 1

[0051] In the embodiment 1 of the present application, a SMC material-based powder spraying method is provided. Specifically, a workpiece to be sprayed is prepared, the material of the workpiece to be sprayed is SMC material, and an aluminum film is attached to the side away from the spraying surface of the workpiece to be sprayed. The attachment area of the aluminum film to the side away from the spraying surface of the workpiece to be sprayed is 85%, and the thickness of the aluminum film is 0.1 mm.

[0052] The workpiece to be sprayed in contact with the electrically-conductive and thermally-conductive material is preheated, wherein the preheating temperature is 160℃, and the preheating time is 10 min.

[0053] The surface temperature of the spraying surface of the workpiece to be sprayed in contact with the electrically-conductive and thermally-conductive material after preheating is tested, and the difference between the maximum value and the minimum value of the surface temperature is 12℃.

[0054] The spraying surface of the workpiece to be sprayed in contact with the electrically-conductive and thermally-conductive material after preheating is sprayed, and baking and curing are performed at a preset temperature. Specifically, the spraying gun is controlled to be perpendicular to the spraying surface, the nozzle of the spraying gun is controlled to be at a preset distance of 30 cm from the spraying surface, the spraying gun is controlled to perform reciprocating operation, and the spraying surface is sprayed layer by layer. Specifically, the angle between the spraying gun and the spraying surface is controlled to be 90°, the moving speed of the spraying gun is controlled to be 3 m / min, the powder spraying amount of the spraying gun is controlled to be 200 g / min, and the reciprocating frequency of each layer is controlled to be 4 times. In addition, in the step of baking and curing at a preset temperature, the preset temperature is 180℃, and the baking time is 15 min. Embodiment

[0055] The powder spraying method based on SMC material in the embodiment 2 of the present application also provides a powder spraying method, which is different from the embodiment 1 of the present application in that the thickness of the aluminum plate is 0.3 mm, the surface temperature of the spraying surface of the workpiece to be sprayed after preheating is tested, and the difference between the maximum value and the minimum value of the surface temperature is 10℃. Embodiment

[0056] The powder spraying method based on SMC material in the embodiment 3 of the present application also provides a powder spraying method, which is different from the embodiment 1 of the present application in that the thickness of the aluminum plate is 1 mm, the surface temperature of the spraying surface of the workpiece to be sprayed after preheating is tested, and the difference between the maximum value and the minimum value of the surface temperature is 6℃.

[0057] Embodiment 4

[0058] The powder spraying method based on SMC material in the embodiment 4 of the present application also provides a powder spraying method, which is different from the embodiment 1 of the present application in that the thickness of the aluminum plate is 2 mm, the surface temperature of the spraying surface of the workpiece to be sprayed after preheating is tested, and the difference between the maximum value and the minimum value of the surface temperature is 6℃. Embodiment

[0059] The powder spraying method based on SMC material in the embodiment 5 of the present application also provides a powder spraying method, which is different from the embodiment 4 of the present application in that the preheating temperature is 60℃. Embodiment

[0060] The powder spraying method based on SMC material in the embodiment 6 of the present application also provides a powder spraying method, which is different from the embodiment 4 of the present application in that the preheating temperature is 100℃. Embodiment

[0061] The powder spraying method based on SMC material in the embodiment 7 of the present application also provides a powder spraying method, which is different from the embodiment 4 of the present application in that the preset distance is 15 cm. Embodiment

[0062] The powder spraying method based on SMC material in the embodiment 8 of the present application also provides a powder spraying method, which is different from the embodiment 4 of the present application in that the preset distance is 20 cm. Embodiment

[0063] The powder spraying method based on SMC material in the embodiment 9 of the present application also provides a powder spraying method, which is different from the embodiment 4 of the present application in that the preset distance is 25 cm. Embodiment

[0064] The powder spraying method based on SMC material in the embodiment 10 of the present application also provides a powder spraying method, which is different from the embodiment 4 of the present application in that the angle between the spraying gun and the spraying surface is controlled to be 85°. Embodiment

[0065] The embodiment 11 of the present application also provides a powder spraying method based on SMC material, and the difference from the embodiment 4 of the present application is that the angle between the spray gun and the spraying surface is 95°. Embodiment

[0066] The embodiment 12 of the present application also provides a powder spraying method based on SMC material, and the difference from the embodiment 4 of the present application is that the preset temperature is 150℃. Embodiment

[0067] The embodiment 13 of the present application also provides a powder spraying method based on SMC material, and the difference from the embodiment 4 of the present application is that the preset temperature is 200℃. Embodiment

[0068] The embodiment 14 of the present application also provides a powder spraying method based on SMC material, and the difference from the embodiment 4 of the present application is that the conductive and heat-conductive material is copper.

[0069] Embodiment 15

[0070] The embodiment 15 of the present application also provides a powder spraying method based on SMC material, and the difference from the embodiment 3 of the present application is that the conductive and heat-conductive material is conductive liquid, specifically, silicone conductive spraying liquid, the conductive liquid is sprayed to the side away from the spraying surface of the workpiece to be sprayed by using a W-71 standard spray gun, the caliber of the spray gun is 1mm, the spraying pressure is 0.6MPa, the spraying thickness is 20μm, the spraying direction is horizontal and perpendicular to the spraying surface, the spraying distance is 200mm, and after the spraying is completed, sulfurization is performed at a temperature of 180℃ in a vertical oven for 25min to bake and cure. Embodiment

[0071] The embodiment 16 of the present application also provides a powder spraying method based on SMC material, and the difference from the embodiment 3 of the present application is that the conductive and heat-conductive material is conductive liquid, specifically, nano-carbon conductive liquid, the conductive liquid is sprayed to the side away from the spraying surface of the workpiece to be sprayed by using a W-71 standard spray gun, the caliber of the spray gun is 1mm, the spraying pressure is 0.6MPa, the spraying thickness is 20μm, the spraying direction is horizontal and perpendicular to the spraying surface, the spraying distance is 200mm, and after the spraying is completed, sulfurization is performed at a temperature of 180℃ in a vertical oven for 25min to bake and cure. Embodiment

[0072] The embodiment 17 of the present application also provides a powder spraying method based on SMC material, and the difference from the embodiment 16 of the present application is that the conductive liquid is sprayed to the spraying surface of the workpiece to be sprayed by using a W-71 standard spray gun. Embodiment

[0073] The embodiment 18 of the present application also provides a powder spraying method based on SMC material, and the difference from the embodiment 3 of the present application is that the conductive and heat-conductive material is conductive paint, the conductive paint is sprayed to the side away from the spraying surface of the workpiece to be sprayed by using a W-71 standard spray gun, the caliber of the spray gun is 1 mm, the spraying pressure is 0.6 MPa, the spraying thickness is 20 microns, the spraying direction is horizontal and perpendicular to the spraying surface, the spraying distance is 200 mm, and after the spraying is completed, the sulfurization is performed at a temperature of 65 DEG C for 30 min in a vertical oven for baking and curing. Embodiment

[0074] The embodiment 19 of the present application also provides a powder spraying method based on SMC material, and the difference from the embodiment 18 of the present application is that the conductive paint is sprayed to the spraying surface of the workpiece to be sprayed by using a W-71 standard spray gun. Embodiment

[0075] The embodiment 20 of the present application also provides a powder spraying method based on SMC material, and the difference from the embodiment 1 of the present application is that the spraying surface of the workpiece to be sprayed is attached with a suitable aluminum film, and then the powder spraying treatment is performed on the spraying surface attached with the aluminum film. Embodiment

[0076] The embodiment 21 of the present application also provides a powder spraying method based on SMC material, and the difference from the embodiment 4 of the present application is that on the basis of the embodiment 4 of the present application, the spraying surface of the workpiece to be sprayed is further attached with a suitable 0.1 mm aluminum film, that is, the spraying surface of the workpiece to be sprayed and the back surface of the spraying surface are both in contact with aluminum material, and then the powder spraying treatment is performed on the spraying surface attached with the aluminum film. Embodiment

[0077] The embodiment 22 of the present application also provides a powder spraying method based on SMC material, and the difference from the embodiment 4 of the present application is that on the basis of the embodiment 4 of the present application, the spraying surface of the workpiece to be sprayed is sprayed with nano-carbon conductive liquid, the spraying thickness is 20 microns, and then the powder spraying treatment is performed on the spraying surface with the cured nano-carbon conductive layer.

[0078] The comparative example 1 of the present application also provides a powder spraying method based on SMC material, and the difference from the embodiment 4 of the present application is that the angle between the spray gun and the spraying surface is 100 DEG.

[0079] The comparative example 2 of the present application also provides a powder spraying method based on SMC material, and the difference from the embodiment 4 of the present application is that the angle between the spray gun and the spraying surface is 80 DEG.

[0080] The comparative example 3 of the present application also provides a powder spraying method based on SMC material, and the difference from the embodiment 4 of the present application is that the preset distance is 35 cm.

[0081] The application comparative example 4 also provides a powder spraying method based on SMC material, and the difference from the application example 4 is that the preset temperature is 140 DEG C.

[0082] The powder spraying products in the application examples 1 to 14 and the comparative examples 1 to 4 are subjected to the coating adhesion test, wherein the adhesion test is carried out by using the cross-hatch method, and it is to be noted that 0 level: in the test, the coating film is not peeled off from the substrate in the cross-hatch area, indicating that the adhesion is excellent; 1 level: small pieces are peeled off at the cross-hatch intersections, but the peeled area is less than 5%; 2 level: the coating film peeled area is greater than 5% but less than or equal to 15% at the cross-hatch intersections; 3 level: the coating film peeled area is greater than 15% but less than or equal to 35%; 4 level: the coating film peeled area is greater than 35% but less than or equal to 65%; 5 level: the coating film peeled area is greater than 65%, indicating that the adhesion is poor. The specific results are shown in the following table:

[0083]

[0084] From the above table, the adhesion of the powder spraying product prepared by the application examples is at least 2 level, reaching the vehicle use standard, and it can be understood that the improvement of the adhesion reflects the improvement of the product strength to some extent, in addition, when the spray gun nozzle is inclined upward, the effect on the adhesion is slightly poor; when the powder is sprayed beyond the preset distance or the preset temperature is only 140 DEG C, the adhesion is only 3 level; there is no significant difference between the copper plate and the aluminum plate in the adhesion effect.

[0085] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0086] The above examples only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the present application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.

Claims

1. A method of powder spraying based on SMC material, characterized in that, The method comprises the following steps: preparing a workpiece to be sprayed, the material of the workpiece to be sprayed being SMC material, and contacting the spraying surface of the workpiece to be sprayed and / or the side away from the spraying surface with conductive and heat-conductive material; preheating the workpiece to be sprayed in contact with the conductive and heat-conductive material; carrying out powder spraying treatment on the spraying surface of the workpiece to be sprayed in contact with the conductive and heat-conductive material after preheating, and carrying out baking and curing at a preset temperature to complete the powder spraying process.

2. The SMC material based powder spraying method according to claim 1, characterized in that, The conductive and heat-conductive material is metal material.

3. The SMC material based powder spraying method according to claim 2, characterized in that, The metal material is one or an alloy of several of copper, aluminum, iron, silver and gold.

4. The SMC material based powder spraying method according to claim 1, characterized in that, The conductive and heat-conductive material is conductive liquid.

5. The SMC material based powder spraying method according to claim 1, characterized in that, The conductive and heat-conductive material is conductive paint.

6. The SMC material based powder spraying method according to claim 1, characterized in that, In the step of preheating the workpiece to be sprayed in contact with the conductive and heat-conductive material, the preheating temperature is 60-160°C, and the preheating time is 5-15 minutes.

7. The SMC material based powder spraying method according to claim 1, characterized in that, Before the step of carrying out powder spraying treatment on the spraying surface of the workpiece to be sprayed in contact with the conductive and heat-conductive material after preheating, the following steps are included: testing the surface temperature of the spraying surface of the workpiece to be sprayed in contact with the conductive and heat-conductive material after preheating, and determining whether the difference between the maximum value and the minimum value of the surface temperature is less than a threshold value; if the difference between the maximum value and the minimum value of the surface temperature is less than the threshold value, carrying out powder spraying treatment.

8. The SMC material based powder spraying method according to claim 7, characterized in that, The step of carrying out powder spraying treatment on the spraying surface of the workpiece to be sprayed in contact with the conductive and heat-conductive material after preheating comprises the following steps: controlling the distance between the nozzle of the spray gun and the spraying surface to be a preset distance; controlling the spray gun to carry out reciprocating operation to spray powder on the spraying surface layer by layer.

9. The SMC material based powder spraying method according to claim 8, characterized in that, The preset distance is 15-30 cm.

10. The SMC material based powder spraying method according to claim 8, characterized in that, In the step of controlling the spray gun to carry out reciprocating operation to spray powder on the spraying surface layer by layer, the angle between the spray gun and the spraying surface is controlled to be 85-95°, the moving speed of the spray gun is controlled to be 2-4 m / min, the powder spraying amount of the spray gun is controlled to be 50-250 g / min, and the reciprocating times of each layer are controlled to be 3-5 times.

11. The SMC material based powder spraying method according to claim 1, characterized in that, In the step of carrying out baking and curing at a preset temperature, the preset temperature is 150-200°C, and the baking time is 10-30 minutes.

12. The SMC material based powder spraying method according to claim 1, characterized in that, In the step of carrying out powder spraying treatment on the spraying surface of the workpiece to be sprayed in contact with the conductive and heat-conductive material after preheating, the material of the sprayed powder is polyurethane resin or polyester resin.

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