Sheet preheating mechanism of thermoforming machine

Abstract

The utility model discloses a sheet preheating and heating mechanism of a thermoforming machine, which comprises a rack and a heating device, the heating device is arranged on the rack, and the sheet preheating and heating mechanism is characterized in that the heating device is provided with a sheet preheating area and a sheet heating area positioned behind the sheet preheating area; the sheet preheating area comprises a plurality of first heating units, the sheet heating area comprises a plurality of second heating units, and gaps between the first heating units in the sheet preheating area correspond to the positions of the second heating units in the sheet heating area. The sheet preheating and heating mechanism can heat each position of a sheet to reach the temperature required by forming.

Description

Technical Field

[0001] The utility model relates to the technical field of thermoforming machines, in particular to a sheet material preheating and heating mechanism of a thermoforming machine. Background Art

[0002] During the operation of a thermoforming machine, sheet heating is crucial, and its effectiveness directly impacts the quality of the final product. Currently, thermoforming machines generally utilize a heating mechanism to heat the sheet to the desired forming temperature. This heating mechanism typically consists of multiple heating units (e.g., arranged in a matrix of multiple rows and columns), which work together to achieve comprehensive heating of the sheet.

[0003] However, in practice, due to installation and structural design requirements, gaps between the heating units are inevitably created, creating areas with lower temperatures than the heating units. As the sheet passes through the heating mechanism, the areas of the sheet corresponding to these gaps are not heated as fully by the heating units as the rest of the sheet. This results in lower temperatures in these areas than in the rest of the sheet, preventing them from reaching the required forming temperature. This, in turn, causes uneven heating across the sheet.

[0004] In the subsequent molding process, the parts that are not heated enough have poor plasticity and are difficult to deform in coordination with other parts, resulting in uneven thickness of the molded product. It may also cause defects such as blemishes and wrinkles on the product surface, seriously affecting the appearance quality of the product and reducing the product's market competitiveness. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a sheet preheating and heating mechanism for a thermoforming machine, which can heat various positions of the sheet to the temperature required for forming.

[0006] In order to solve the above technical problems, the technical solutions adopted are as follows:

[0007] The sheet preheating mechanism of the thermoforming machine includes a frame and a heating device, which is installed on the frame. The characteristics are: the heating device has a sheet preheating zone and a sheet heating zone located behind the sheet preheating zone; the sheet preheating zone includes multiple first heating units, and the sheet heating zone includes multiple second heating units. The gap between each first heating unit in the sheet preheating zone corresponds to the position of the second heating unit in the sheet heating zone.

[0008] The sheet conveying mechanism of a thermoforming machine typically conveys the sheet in a step-by-step manner. During preheating, the sheet is first conveyed to a position corresponding to the sheet preheating zone for preheating. The sheet is then conveyed to a position corresponding to the sheet heating zone for heating to the required thermoforming temperature. Finally, the sheet is conveyed to the rear thermoforming mold for forming. In the sheet heating zone, the low-heated areas of the sheet corresponding to the gaps between the first heating units in the sheet preheating zone are aligned with the positions of the second heating units upon entering the sheet heating zone and heated by the second heating units, ensuring that all areas of the sheet are adequately heated. This sheet preheating mechanism, by arranging the second heating units in the sheet heating zone, achieves high-intensity heating of the low-heated areas of the sheet after preheating. Even if there is some overlap between the sheet preheating zone and the sheet heating zone at the gap, the overlap is minimal and essentially negligible, ensuring that all areas of the sheet are fully heated, reaching the required forming temperature.

[0009] Typically, the lengths of the sheet preheating and heating zones are determined based on the sheet length required for each forming cycle in the thermoforming mold (i.e., the length in the front-to-back direction, where the front-to-back direction refers to the sheet conveying direction). The gaps between the first heating units in the preheating zone correspond to the positions of the second heating units in the heating zone. This means that the areas of the sheet corresponding to the gaps between the first heating units during preheating will be located in the corresponding positions of the second heating units upon reaching the heating zone.

[0010] The heating unit is usually a ceramic heating plate or an infrared heating plate composed of infrared heating tubes.

[0011] In one preferred embodiment, the first and second heating units are both rectangular in shape, with the long sides of the first heating units arranged in a front-to-back direction, and the first heating units arranged in a matrix; the long sides of the second heating units are arranged in a left-to-right direction, and the second heating units arranged in a matrix. The rectangular first and second heating units are arranged in a matrix with multiple rows and columns, and the long sides are arranged in perpendicular directions to achieve staggered gaps between the heating units in the sheet preheating zone and the sheet heating zone.

[0012] In another preferred embodiment, the first and second heating units are both rectangular, with the long sides of the first heating units arranged in the left-right direction, and the first heating units arranged in a matrix; the long sides of the second heating units are arranged in the front-to-back direction, and the second heating units arranged in a matrix. The rectangular first and second heating units are arranged in a matrix with multiple rows and columns, and the long sides are arranged in perpendicular directions to achieve staggered gaps between the heating units in the sheet preheating zone and the sheet heating zone.

[0013] In a further preferred embodiment, the first heating unit and the second heating unit are of the same size. Generally, to reduce manufacturing costs, the first heating unit and the second heating unit are usually of the same size, and by arranging the long sides in different directions, the gap between the first heating units corresponds to the position of the second heating units. Of course, the first heating unit and the second heating unit can also be of different sizes.

[0014] In a further preferred embodiment, the aspect ratio of the first heating unit and the second heating unit is 3:2. Arranging the heating units with this aspect ratio and number ensures that the gaps between the first heating units in the sheet preheating zone correspond to the positions of the second heating units in the sheet heating zone, and the gaps between the second heating units in the sheet heating zone correspond to the positions of the second heating units in the sheet preheating zone.

[0015] The beneficial effect of the utility model is that the sheet preheating and heating mechanism can heat various positions of the sheet to the temperature required for forming, which is beneficial to improving the quality of the thermoformed product. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a structural diagram of the sheet preheating and heating mechanism in an embodiment of the present utility model;

[0017] Figure 2 This is the distribution of heated areas on the sheet after the sheet is preheated in the sheet preheating zone in the embodiment of the present invention. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0019] like Figure 1 The sheet preheating mechanism of the thermoforming machine shown includes a frame 1 and a heating device 2. The heating device 2 is installed on the frame 1. The heating device 2 has a sheet preheating zone 201 and a sheet heating zone 202 located behind the sheet preheating zone 201; the sheet preheating zone 201 includes a plurality of first heating units 2011, and the sheet heating zone 202 includes a plurality of second heating units 2021. The gaps between the first heating units 2011 in the sheet preheating zone 201 correspond to the positions of the second heating units 2021 in the sheet heating zone 202.

[0020] The sheet conveying mechanism of the thermoforming machine usually conveys the sheet 3 in a step-by-step manner. When preheating, the sheet 3 is first conveyed to the position corresponding to the sheet preheating zone 201 for preheating (after the sheet 3 is preheated in the sheet preheating zone, the heated areas on the sheet 3 are distributed as follows Figure 2As shown, the heated area corresponding to the first heating unit 2011 is 301, and the low-heated area corresponding to the gaps between the first heating units 2011 is 302). The sheet 3 is then transported to a position corresponding to the sheet heating zone 202 and heated to the required temperature for thermoforming. Finally, the sheet 3 is transported to the rear thermoforming mold for forming. In the sheet heating zone 202, the low-heated area 302 of the sheet 3 corresponding to the gaps between the first heating units 2011 in the sheet preheating zone 201 can correspond to the position of the second heating unit 2021 when entering the sheet heating zone 202 and be heated by the second heating unit 2021, thereby ensuring that all positions on the sheet 3 are fully heated. This sheet preheating mechanism can achieve high-intensity heating of the low-heating area 302 of the sheet 3 after preheating by arranging the position of the second heating unit 2021 in the sheet heating zone 202. Even if the sheet preheating zone 201 and the sheet heating zone 202 partially overlap at the gap position, the area is small and can basically be ignored, thereby achieving the purpose of fully heating each position of the sheet 3 and heating each position of the sheet 3 to the temperature required for molding.

[0021] The lengths of the sheet preheating zone 201 and sheet heating zone 202 are determined based on the required length of sheet 3 per forming cycle of the thermoforming mold (i.e., the length in the front-to-back direction, where the front-to-back direction refers to the direction in which the sheet 3 is conveyed). The gaps between the first heating units 2011 in the sheet preheating zone 201 correspond to the positions of the second heating units 2021 in the sheet heating zone 202. This means that the areas of the sheet 3 corresponding to the gaps between the first heating units 2011 during preheating in the sheet preheating zone 201 will correspond to the second heating units 2021 upon arrival in the sheet heating zone 202. These heating units typically utilize ceramic heating plates or infrared heating plates comprised of infrared heating tubes.

[0022] The first heating units 2011 and second heating units 2021 are both rectangular in shape. The long sides of the first heating units 2011 are arranged in a front-to-back direction, forming a matrix. The long sides of the second heating units 2021 are arranged in a left-to-right direction, forming a matrix. The rectangular first heating units 2011 and second heating units 2021 are arranged in a matrix with multiple rows and columns. By arranging the long sides perpendicularly, the gaps between the heating units in the sheet preheating zone 201 and the sheet heating zone 202 are staggered.

[0023] The first heating unit 2011 and the second heating unit 2021 have the same size. Generally, to reduce manufacturing costs, the first heating unit 2011 and the second heating unit 2021 are typically the same size. By arranging the long sides in different directions, the gaps between the first heating units 2011 correspond to the positions of the second heating units 2021. Of course, the first heating unit 2011 and the second heating unit 2021 may also have different sizes.

[0024] The first heating unit 2011 and the second heating unit 2021 both have an aspect ratio of 3:2. This aspect ratio and number of heating units ensure that the gaps between the first heating units 2011 in the sheet preheating zone 201 correspond to the positions of the second heating units 2021 in the sheet heating zone 202, and that the gaps between the second heating units 2021 in the sheet heating zone 202 correspond to the positions of the second heating units 2021 in the sheet preheating zone 201.

Claims

1. The sheet preheating heating mechanism of the thermoforming machine includes a frame and a heating device, and the heating device is installed on the frame, and is characterized by: The heating device has a sheet preheating zone and a sheet heating zone behind the sheet preheating zone; the sheet preheating zone includes multiple first heating units, and the sheet heating zone includes multiple second heating units. The gaps between the first heating units in the sheet preheating zone correspond to the positions of the second heating units in the sheet heating zone.

2. The sheet preheating and heating mechanism of the thermoforming machine according to claim 1, characterized in that: The first heating unit and the second heating unit are both rectangular, the long sides of the first heating unit are arranged along the front-to-back direction, and the first heating units are arranged in a matrix; the long sides of the second heating unit are arranged along the left-to-right direction, and the second heating units are arranged in a matrix.

3. The sheet preheating and heating mechanism of the thermoforming machine according to claim 1, characterized in that: The first heating unit and the second heating unit are both rectangular, the long sides of the first heating unit are arranged in the left-right direction, and the first heating units are arranged in a matrix; the long sides of the second heating unit are arranged in the front-back direction, and the second heating units are arranged in a matrix.

4. The sheet preheating and heating mechanism of a thermoforming machine according to any one of claims 2 or 3, characterized in that: The first heating unit and the second heating unit have the same size.

5. The sheet preheating and heating mechanism of the thermoforming machine according to claim 4, characterized in that: The aspect ratios of the first heating unit and the second heating unit are both 3:2.

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