Method for rapid hot press forming and punching composite board

Abstract

The application provides a method for rapid hot-press forming and punching of a composite board, which is applied to a mold with a rapid temperature rising and falling mold pipeline system and an in-mold cutting mechanism, and the method comprises the following steps: placing the board; adjusting the mold temperature; making the mold temperature reach between the Tg and the Tm of the thermoplastic plastic in the composite board; first-stage mold closing; heating the composite board; second-stage mold closing; heating and pressing the composite board to be formed; first-stage temperature falling; after the mold temperature is lowered to below the HDT of the composite board, punching the product head; second-stage temperature falling; cooling and pressing the composite board to be formed; and taking out the finished product after the mold is lowered to normal temperature and the mold is opened. The application can save work sections, reduce the defective rate, avoid the diffusion of harmful gas and smoke, and rapidly and stably perform hot-press forming and punching on the composite board.

Description

[Technical Field]

[0001] This invention relates to the field of composite sheet forming technology, and in particular to a method for rapid hot pressing and punching of composite sheets. [Background Technology]

[0002] The hot pressing and die-cutting process of composite panels generally involves heating the material outside the mold in an external furnace before placing it into the mold, or using an infrared heating plate inserted into the hot pressing mold for heating before hot pressing. Afterward, the hot-pressed product is transferred to the die-cutting section for die-cutting to obtain the finished product. However, using an external furnace to heat the composite panel before placing it into the mold for hot pressing will cause the following problems:

[0003] 1. Difficult to clamp and position: When the heating furnace heats the composite material to above Tg (glass transition temperature), the material softens, making clamping and positioning difficult and unsuitable for more precise products;

[0004] 2. Poor temperature reproducibility: The temperature of the heated composite board continuously drops during the process of moving it from the heating furnace to the mold, and it is easily affected by the external environment, resulting in large temperature variations of the board during hot pressing. In particular, the heat loss of thinner composite boards is faster, and the impact on hot pressing is greater.

[0005] 3. Decreased product quality: When high Tg (glass transition temperature) composite boards are heated to high temperatures, the resin and additives in the boards will volatilize, resulting in resin loss, which in turn leads to a decrease in the mechanical properties and surface appearance quality of the hot-pressed products.

[0006] 4. Environmental pollution: When high-Tg (glass transition temperature) composite boards are heated to high temperatures, the resin and additives that volatilize will produce dense smoke, polluting the production environment.

[0007] The method of using an infrared baking pan inserted into the hot pressing mold for heating avoids the problem of difficulty in clamping and positioning, but all the other problems mentioned above still exist. When the hot-pressed composite material is moved to the punching section for punching, if the product has high dimensional accuracy, it is difficult for the punching section to accurately position the hot-pressed composite material.

[0008] In view of this, the present invention provides a method for rapid hot pressing and punching of composite sheets to solve the above problems. [Summary of the Invention]

[0009] The technical problem to be solved by this invention is: in order to solve the problems that occur when hot-pressing composite boards by heating them externally and then placing them into a mold or by inserting an infrared baking pan into the mold, it is difficult to clamp and position the products, the temperature reproducibility is poor, the product quality is reduced and the environment is polluted, and the composite boards after hot pressing are difficult to accurately position when they are moved to the punching section of the punching section. This invention provides a method for rapidly hot-pressing and punching composite boards to solve the above problems.

[0010] The solution to the technical problem of this invention is: a method for rapid hot pressing and punching of composite sheets, applied to a mold with a rapid heating and cooling mold piping system and an in-mold cutting mechanism, comprising the following steps:

[0011] S1: Inserting the board material: Place the cut composite board material into the mold;

[0012] S2: Adjust mold temperature: Select the corresponding medium to enter the mold pipeline to adjust the mold temperature. The mold temperature depends on factors such as the Tg (glass transition temperature) and Tm (melting temperature) of the thermoplastic in the composite board and the product pressing shape, so that the mold temperature reaches between the Tg (glass transition temperature) and Tm (melting temperature) of the thermoplastic in the composite board.

[0013] S3: First stage mold closing: Control the distance between the mold and the composite material. This distance depends on factors such as the product pressing shape. Utilize the temperature of the mold to heat the composite material through thermal radiation and convection.

[0014] S4: Second stage mold closing: The mold closing speed in this stage is adjusted according to the thickness of the composite material and the shape of the product. The mold closes while simultaneously heating the composite material using heat conduction and pressing it into shape.

[0015] S5: First stage cooling: Select the corresponding medium to enter the mold pipeline and start the first stage cooling. When the mold temperature drops below the HDT (heat distortion temperature) of the composite board, use the in-mold cutting mechanism to punch the product head.

[0016] S6: Second stage cooling: The mold continues to cool down and cool the composite material until the mold closing pressure slowly decreases to zero. The composite material cools in the mold and is pressed and shaped under the mold pressure.

[0017] S7: Remove the finished product: After the mold has cooled to room temperature, open the mold and remove the finished product.

[0018] Preferably, the thermoplastic in the composite sheet is PC (polycarbonate), with a Tg (glass transition temperature) of 100-150°C and a Tm (melting temperature) of 220°C. The medium passing through the mold pipeline in S2 is water vapor at 160-170°C, and the medium passing through the mold pipeline in S5 is water at 15-30°C.

[0019] Preferably, the thermoplastic in the composite board is PSU (polysulfone), with a Tg (glass transition temperature) of 190°C and a Tm (melting temperature) of 288°C. In S2, the mold pipeline can first pass water vapor at 160-170°C. When the mold temperature rises to 150°C, hot kerosene at 250-280°C is then used to pass through the mold pipeline to achieve rapid heating. In S5, the medium passing through the mold pipeline is water at 15-30°C.

[0020] Preferably, the distance between the mold and the composite material in S3 is 1mm to 5mm.

[0021] Preferably, the mold closing speed in S4 is 0.1 mm / sec to 3 mm / sec.

[0022] Preferably, in step S5, when the mold is cooled to HDT-50 to HDT-30℃, the punching effect on the product material head is better.

[0023] Preferably, before changing the medium in the mold pipeline, the mold pipeline can be dried with air to drain the medium from the mold pipeline, so as to prevent the mold pipeline from bursting due to the reaction between different media when changing the medium in the mold pipeline.

[0024] The beneficial effects of this invention are that it saves processing steps, avoids defective products caused by poor positioning accuracy when transferring the hot-pressed composite sheet to the punching section, and can quickly and stably process thin parts and composite sheets with high surface precision requirements, while preventing harmful gases and dust from spreading into the production environment. [Attached Image Description]

[0025] Figure 1 This is a flowchart of the steps of a method for rapid hot pressing and punching of composite sheet metal according to the present invention.

[0026] Figure 2 This is a flowchart of the steps in Embodiment 1 of the present invention.

[0027] Figure 3 This is a flowchart of the steps in Embodiment 2 of the present invention.

[0028] Figure 4 This is a schematic diagram of the composite board placed in a mold and awaiting hot pressing.

[0029] Figure 5 This is a schematic diagram of the composite board being hot-pressed and shaped in a mold.

[0030] Figure 6 This is a schematic diagram of the in-mold cutting mechanism punching composite sheet material.

[0031] Figure 7 This is a schematic diagram of the finished product after hot pressing and punching.

Detailed Implementation Methods

[0032] To further illustrate the technical means and effects of the present invention, the following detailed description is provided in conjunction with the embodiments of the present invention and their accompanying drawings.

[0033] This invention provides a method for rapid hot pressing and punching of composite sheet metal, applied to a mold 1 having a rapid heating and cooling mold piping system and an in-mold cutting mechanism 5. The rapid heating and cooling mold piping system connects to the inlet 20 and outlet 21 of the original mold piping 2 with a pipe (not shown in the figure) through which the medium entering the mold piping 2 can be controlled by a valve (not shown in the figure). According to the required temperature of the mold 1, the medium entering the mold piping 2, such as steam, hot kerosene, air or water, is controlled by the valve (not shown in the figure) to achieve rapid heating and cooling of the mold temperature, thereby achieving the purpose of rapidly heating and cooling the mold 1. The in-mold cutting mechanism 5 can punch the material head inside the mold 1 after the composite sheet metal 3 is cooled to below the HDT (heat distortion temperature) to obtain a finished product 4 that meets the finished product size.

[0034] The thermoplastic in the composite sheet 3 can be PC (polycarbonate), PMMA (polymethyl methacrylate), PPS (polyphenylene sulfide), PA series such as PA6 (nylon 6) or PA66 (nylon 66) or PA12 (nylon 12)..., PSU (polysulfone) and other thermoplastics. The method of rapid hot pressing and punching composite sheet of the present invention is described below with reference to Examples 1 and 2.

[0035] Example 1

[0036] In Example 1, the thermoplastic in the composite sheet 3 is PC (polycarbonate), with a Tg (glass transition temperature) of 100-150°C and a Tm (melting temperature) of 220°C. The method for rapid hot pressing and punching of the composite sheet includes the following steps:

[0037] S110: Inserting the board material: Place the cut composite board material 3 into the mold 1;

[0038] S120: Adjust mold temperature: Use 160-170℃ water vapor to enter mold pipe 2 to adjust the mold temperature so that the mold temperature reaches between the Tg (glass transition temperature) of PC (polycarbonate) of 100-150℃ and the Tm (melting temperature) of 220℃.

[0039] S130: First stage mold closing: The distance between the composite plate 3 and the mold 1 is controlled between 1mm and 5mm. The temperature of the mold 1 is used to heat the composite plate 3 through heat radiation and convection.

[0040] S140: Second stage mold closing: The mold closing speed of the mold 1 in the second stage is controlled at 0.1mm / sec to 3mm / sec. While the mold 1 is closing, it uses heat conduction to heat the composite board 3 and press the composite board 3 into shape.

[0041] S150: First stage cooling: Water at 5-30℃ is introduced into the mold pipe 2 to start the first stage cooling. When the mold 1 is cooled to HDT-50-HDT-30℃, the product material head is punched by the in-mold cutting mechanism 5.

[0042] S160: Second stage cooling: Mold 1 continues to cool down and cool the composite board 3 until the mold closing pressure slowly decreases to zero. The composite board 3 is cooled in mold 1 and pressed and shaped under mold pressure.

[0043] S170: Remove the finished product: After the mold 1 is cooled to room temperature, open the mold and remove the finished product 4.

[0044] Example 2

[0045] In Example 2, the thermoplastic in the composite sheet 3 is PSU (polysulfone), with a Tg (glass transition temperature) of 190°C and a Tm (melting temperature) of 288°C. The method for rapid hot pressing and punching of the composite sheet includes the following steps:

[0046] S210: Inserting the board material: Place the cut composite board material 3 into the mold 1;

[0047] S220: Adjusting the mold temperature: First, use 160-170℃ steam to enter the mold pipe 2 to adjust the mold temperature and make the mold temperature rise rapidly. When the mold temperature rises to 150℃, replace it with air to blow the mold pipe 2 dry. Then replace it with hot kerosene at 250-280℃ to make the mold temperature reach between the Tg (glass transition temperature) of PSU (polysulfone) of 190℃ and the Tm (melting temperature) of 288℃.

[0048] S230: First stage mold closing: The distance between the composite plate 3 and the mold 1 is controlled between 1mm and 5mm. The temperature of the mold 1 is used to heat the composite plate 3 through heat radiation and convection.

[0049] S240: Second stage mold closing: The mold closing speed of the mold 1 in the second stage is controlled at 0.1mm / sec to 3mm / sec. While the mold 1 is closing, it uses heat conduction to heat the composite board 3 and press the composite board 3 into shape.

[0050] S250: First stage cooling: Water at 5-30℃ is introduced into the mold pipe 2 to start the first stage cooling. When the mold 1 is cooled to HDT-50-HDT-30℃, the product material head is punched by the in-mold cutting mechanism 5.

[0051] S260: Second stage cooling: Mold 1 continues to cool down and cool the composite board 3 until the mold closing pressure slowly decreases to zero. The composite board 3 is cooled in mold 1 and pressed into shape under mold pressure.

[0052] S270: Remove the finished product: After the mold 1 is cooled to room temperature, open the mold and remove the finished product 4.

[0053] Before changing the medium in the mold pipe 2, the mold pipe 2 can be dried with air to remove the medium from the mold pipe 2, so as to prevent the mold pipe 2 from bursting due to the reaction between different media when changing the medium in the mold pipe 2.

[0054] The beneficial effects of this invention are that it saves processing steps, avoids defective products caused by poor positioning accuracy when transferring the hot-pressed composite sheet to the punching section, and can quickly and stably process thin parts and composite sheets with high surface precision requirements, while preventing harmful gases and dust from spreading into the production environment.

[0055] It should be noted that the present invention is not limited to the above embodiments. Any simple modifications, equivalent changes and alterations made by those skilled in the art to the above embodiments based on the technical solutions of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for rapid hot pressing and punching of composite sheets, applied in a mold with a rapid heating and cooling mold piping system and an in-mold cutting mechanism, characterized in that, Includes the following steps: S1: Inserting the board material: Place the cut composite board material into the mold; S2: Adjust mold temperature: Select the appropriate medium to enter the mold pipeline to adjust the mold temperature. The factors that determine the mold temperature include the Tg (glass transition temperature) and Tm (melting temperature) of the thermoplastic in the composite sheet and the product pressing shape, so that the mold temperature reaches between the Tg (glass transition temperature) and Tm (melting temperature) of the thermoplastic in the composite sheet. S3: First stage mold closing: Controlling the distance between the mold and the composite material, which depends on factors including the product pressing shape, and using the temperature of the mold to heat the composite material through heat radiation and convection. S4: Second stage mold closing: The mold closing speed in this stage is adjusted according to the thickness of the composite material and the shape of the product. The mold closes while simultaneously heating the composite material using heat conduction and pressing it into shape. S5: First stage cooling: Select the corresponding medium to enter the mold pipeline and start the first stage cooling. When the mold temperature drops below the HDT (heat distortion temperature) of the composite board, use the in-mold cutting mechanism to punch the product head. S6: Second stage cooling: The mold continues to cool down and cool the composite material until the mold closing pressure slowly decreases to zero. The composite material cools in the mold and is pressed and shaped under the mold pressure. S7: Remove the finished product: After the mold has cooled to room temperature, open the mold and remove the finished product.

2. The method for rapid hot pressing and punching of composite sheets as described in claim 1, characterized in that: The thermoplastic in the composite sheet is PC (polycarbonate), with a Tg (glass transition temperature) of 100-150°C and a Tm (melting temperature) of 220°C. The medium passing through the mold pipeline in S2 is water vapor at 160-170°C, and the medium passing through the mold pipeline in S5 is water at 15-30°C.

3. The method for rapid hot pressing and punching of composite sheets as described in claim 1, characterized in that: The thermoplastic in the composite board is PSU (polysulfone), with a Tg (glass transition temperature) of 190°C and a Tm (melting temperature) of 288°C. In S2, the mold pipeline first passes through water vapor at 160-170°C. When the mold temperature rises to 150°C, hot kerosene at 250-280°C is then passed through the mold pipeline to achieve rapid heating. In S5, the medium passing through the mold pipeline is water at 15-30°C.

4. The method for rapid hot pressing and punching of composite sheets as described in claim 1, characterized in that: The distance between the mold and the composite plate in S3 is 1mm to 5mm.

5. The method for rapid hot pressing and punching of composite sheets as described in claim 1, characterized in that: The mold closing speed in S4 is 0.1 mm / sec to 3 mm / sec.

6. The method for rapid hot pressing and punching of composite sheets as described in claim 1, characterized in that: In step S5, when the mold is cooled to HDT-50 to HDT-30 ℃, the product head is punched.

7. A method for rapid hot pressing and punching of composite sheets as described in claim 1 or 3, characterized in that: Before changing the medium in the mold pipeline, the mold pipeline is first dried by air to drain the medium from the mold pipeline, so as to prevent the mold pipeline from bursting due to the reaction between different media when changing the medium in the mold pipeline.

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