Injection molding method of jute fiber board or jute fiber felt

Abstract

The invention discloses an injection molding method for a jute fiber board or jute fiber felt. The injection molding method comprises the following steps that S1, the jute fiber board or jute fiber felt is put into heating equipment to be baked and heated; s2, the heated jute fiber board or jute fiber felt is put into an injection mold to be subjected to forming and punching treatment, and a primary finished product is generated; s3, a melt raw material is injected into the injection mold, the structure of the back of the primary finished product is subjected to injection molding, pressure maintaining and cooling are conducted, and a finished product is generated; and S4, ejecting a finished product by the injection mold, and demolding the finished product. According to the method, hot pressing, injection molding and punching are combined, and the jute fiber board or the jute fiber felt can be integrally subjected to hot pressing injection molding to obtain a finished product without special equipment for combining hot pressing and injection molding, so that the production cost is reduced, and the production period is shortened.

Description

Technical Field

[0001] The invention relates to the technical field of fiberboard injection molding, in particular to an injection molding method for a hemp fiberboard or a hemp fiber felt. Background Art

[0003] In the field of automobile manufacturing, many automobile parts must be lightweight and environmentally friendly. Therefore, some OEMs have proposed that natural fibers such as hemp can be used to replace plastic parts for some automobile interior parts, so as to adapt to the current trend of lightweight and environmentally friendly automobiles.

[0004] In the prior art, the first method of forming a hemp fiberboard or hemp fiber felt is to first hot press the hemp fiberboard or hemp fiber felt, cut it, and then place it in an injection mold as an insert for injection molding. The second method is to use a dedicated hot pressing and injection molding equipment, that is, hot pressing and injection molding of the hemp fiberboard and its upper skin layer.

[0005] However, the first method has the disadvantage of adding molds, and the multiple processes also increase production costs and extend the production cycle. The second method has the disadvantage of expensive equipment and high implementation difficulty, and many details need to be controlled in mold design. Summary of the invention

[0006] The purpose of the present invention is to provide an injection molding method for hemp fiberboard or hemp fiber felt, which can reduce the difficulty of manufacturing the injection-molded finished products of hemp fiberboard or fiber felt, improve the qualified rate of the injection-molded finished products of hemp fiberboard or fiber felt, and greatly save costs.

[0007] A method for injection molding of a hemp fiberboard or hemp fiber felt, the key of which is that it comprises the following steps:

[0008] S1: placing the hemp fiberboard or hemp fiber felt into a heating device for baking and heating;

[0009] S2: placing the heated hemp fiberboard or hemp fiber felt into an injection mold for molding and punching to generate a primary finished product;

[0010] S3: Injecting molten raw materials into the injection mold to form the structure on the back of the primary finished product, and cooling under pressure to form a finished product;

[0011] S4: The injection mold ejects the finished product and demoulds the finished product.

[0012] The above method combines hot pressing, injection molding and punching, and can form the hemp fiber board or hemp fiber felt into a finished product by integrated hot pressing and injection molding without using special hot pressing and injection molding equipment, thereby reducing production costs and shortening production cycles.

[0013] Furthermore, the specific steps of step S2 are as follows:

[0014] S21: opening the injection mold, immediately placing the heated hemp fiberboard or hemp fiber felt into the injection mold, and fixing the heated hemp fiberboard or hemp fiber felt in the injection mold;

[0015] S22: A floating frame in the injection mold presses the heated hemp fiber board or hemp fiber felt;

[0016] S23: The injection mold is closed, and a closing force is applied to form the heated hemp fiber board or hemp fiber felt;

[0017] S24: The blade on the floating frame punches the formed hemp fiberboard or hemp fiber felt by using the clamping force and the cylinder force, and cuts off the excess hemp fiberboard or hemp fiber felt to generate a primary finished product.

[0018] The floating frame presses the hemp fiberboard or hemp fiber felt, which can ensure that the hemp fiberboard or hemp fiber felt can deform freely during stretching and prevent movement obstruction or tearing. At the same time, by adjusting the position of the floating frame, finished products with different thickness requirements can be made according to actual needs, thereby improving the practicality of the injection mold and further reducing production costs.

[0019] Furthermore, in step S1, the heating device is a baking oven, and at least one infrared heating block is arranged in the baking oven, and each infrared heating block can be individually temperature-controlled.

[0020] Furthermore, the infrared heating block bakes and heats the hemp fiber board or hemp fiber felt, and the baking temperature is 250±20°C.

[0021] After the infrared heating block bakes and heats the hemp fiber board or hemp fiber felt, the injection mold does not need to be heated separately, which simplifies the operation steps and reduces the production cost.

[0022] Furthermore, in step S2, a positioning pin is provided in the injection mold, and the positioning pin passes through the hemp fiber board or the hemp fiber felt, so that the hemp fiber board or the hemp fiber felt is unfolded and fixed in the injection mold.

[0023] The hemp fiberboard or hemp fiber felt is unfolded and fixed in the injection mold, which makes it convenient for the floating frame to press the hemp fiberboard or hemp fiber felt, ensures the free deformation of the hemp fiberboard or hemp fiber felt during the mold closing process, prevents movement obstruction or tearing, thereby improving the molding effect of the hemp fiberboard or hemp fiber felt, generates high-quality primary products, and facilitates the injection molding of the structure on the back of the primary product, thereby improving the quality of the finished product.

[0024] Furthermore, the injection mold is an inverted mold structure, wherein the cavity is in the movable mold and the core is in the fixed mold.

[0025] Furthermore, the blade is made of hardened steel material with a heat treatment hardness of HRC48 or above.

[0026] Beneficial effects: 1. The present invention combines hot pressing, injection molding and punching, and can make hemp fiber board or hemp fiber felt integrated into finished products by hot pressing and injection molding without using special hot pressing and injection molding equipment, thereby reducing production costs and shortening production cycles.

[0027] 2. The floating frame presses the hemp fiberboard or hemp fiber felt, which can ensure the free deformation of the hemp fiberboard or hemp fiber felt during the mold closing process, prevent movement obstruction or tearing, thereby improving the molding effect of the hemp fiberboard or hemp fiber felt, generating high-quality primary products, and facilitating the injection molding of the structure on the back of the primary product, thereby improving the quality of the finished product.

[0028] 3. By adjusting the position of the floating frame, finished products with different thickness requirements can be made according to actual needs, thereby improving the practicality of the injection mold and further reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flow chart of the present invention;

[0030] Figure 2 Detailed flowchart for step 2;

[0031] Figure 3 This is a schematic diagram of the back of the finished product. DETAILED DESCRIPTION

[0032] The specific implementation manner and working principle of the present invention are further described in detail below with reference to the accompanying drawings.

[0033] like Figure 1 As shown, a method for injection molding a hemp fiberboard or hemp fiber felt comprises the following steps:

[0034] S1: placing the hemp fiberboard or hemp fiber felt into a heating device for baking and heating;

[0035] The heating device is a baking oven, in which at least one infrared heating block is arranged, and each infrared heating block can be individually temperature-controlled. The infrared heating block bakes and heats the hemp fiber board or hemp fiber felt, and the baking temperature is 250±20°C.

[0036] S2: forming and punching the hemp fiberboard or hemp fiber felt after heating;

[0037] S21: The injection mold is opened, and the heated hemp fiber board or hemp fiber felt is immediately placed into the injection mold. A positioning pin is provided in the injection mold, and the positioning pin passes through the hemp fiber board or hemp fiber felt, so that the heated hemp fiber board or hemp fiber felt is unfolded and fixed in the injection mold.

[0038] S22: The floating frame in the injection mold presses the heated hemp fiber board or hemp fiber felt.

[0039] S23: The injection mold is closed, and a closing force is applied to form the heated hemp fiber board or hemp fiber felt.

[0040] S24: The blade on the floating frame punches the formed hemp fiberboard or hemp fiber felt by using the clamping force and the cylinder force, and cuts off the excess hemp fiberboard or hemp fiber felt to generate a primary finished product;

[0041] The blade is made of hardened steel material with a heat treatment hardness of HRC48 or above.

[0042] S3: injecting a molten raw material into the injection mold through the gate, the molten raw material flows along the molten raw material channel in the injection mold and fills the molten raw material channel to generate guide ribs and positioning columns, and cooling under pressure to form the structure on the back of the primary finished product by injection molding to generate a finished product;

[0043] S4: The injection mold ejects the finished product and demoulds the finished product.

[0044] The above-mentioned injection mold is an inverted mold structure, wherein the cavity is in the movable mold and the core is in the fixed mold.

Claims

1. A method for injection molding of a hemp fiberboard or hemp fiber felt, characterized in that: The following steps are involved: S1: placing the hemp fiberboard or hemp fiber felt into a heating device for baking and heating; S2: placing the heated hemp fiberboard or hemp fiber felt into an injection mold for molding and punching to generate a primary finished product; S3: Injecting molten raw materials into the injection mold to form the structure on the back of the primary finished product, and cooling under pressure to form a finished product; S4: The injection mold ejects the finished product and demoulds the finished product.

2. The injection molding method of hemp fiberboard or hemp fiber felt according to claim 1, characterized in that: The specific steps of step S2 are as follows: S21: opening the injection mold, immediately placing the heated hemp fiberboard or hemp fiber felt into the injection mold, and fixing the heated hemp fiberboard or hemp fiber felt in the injection mold; S22: A floating frame in the injection mold presses the heated hemp fiber board or hemp fiber felt; S23: The injection mold is closed, and a closing force is applied to form the heated hemp fiber board or hemp fiber felt; S24: The blade on the floating frame punches the formed hemp fiber board or hemp fiber felt through the clamping force and the cylinder force, and cuts off the excess hemp fiber board or hemp fiber felt to generate a primary finished product.

3. The injection molding method of hemp fiberboard or hemp fiber felt according to claim 1, characterized in that: In step S1, the heating device is a baking oven, in which at least one infrared heating block is arranged, and each infrared heating block can be individually temperature-controlled.

4. The injection molding method of hemp fiberboard or hemp fiber felt according to claim 3, characterized in that: The infrared heating block bakes and heats the hemp fiber board or hemp fiber felt, and the baking temperature is 250±20°C.

5. The injection molding method of hemp fiberboard or hemp fiber felt according to claim 2, characterized in that: A positioning pin is arranged in the injection mold, and the positioning pin passes through the hemp fiber board or the hemp fiber felt, so that the hemp fiber board or the hemp fiber felt is unfolded and fixed in the injection mold.

6. The injection molding method of hemp fiberboard or hemp fiber felt according to claim 2, characterized in that: The injection mold is an inverted mold structure, with the cavity in the movable mold and the core in the fixed mold.

7. The injection molding method of hemp fiberboard or hemp fiber felt according to claim 2, characterized in that: The blade is made of hardened steel material with a heat treatment hardness of HRC48 or above.

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