Hot press forming die and device for small glass tube

Abstract

The utility model relates to the technical field of glass forming, in particular to a hot press forming die and device for a small glass tube. At present, small glass tubes for earphones are mainly processed by CNC (computer numerical control) processing, and the processing of single products is long in time consumption, low in efficiency and incapable of batch production. The utility model provides a hot-press forming die and device for a small glass tube, the hot-press forming die comprises a male die and a female die, the hot-press forming device comprises a heating furnace, a die base for placing the hot-press forming die and a pressing plate, and a flat glass sheet and the hot-press forming die are heated to a specified temperature during hot-press forming; and then a power device is used for driving the pressing plate to slowly press downwards, and then the male die and the female die are driven to slowly close, so that the flat glass sheet is slowly subjected to plastic deformation in the forming cavity, and the glass tube is jacked by the top plate to demold after cooling. The batch production of small glass tubes is realized, and the production efficiency is greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of glass forming technology, and in particular to a hot pressing mold and device for forming small glass tubes. Background Technology

[0002] Miniature glass tubes are commonly used components in headphones, serving various purposes including: sound guides, resonant cavity components, mounting fiber optic and proximity sensors, and encapsulating antennas. In terms of dimensional accuracy, the diameter of miniature glass tubes used in headphones is typically 1 to 5 millimeters, and the length is 5 to 20 millimeters. Regarding material properties, miniature glass tubes must possess good optical, physical, and chemical stability, such as high light transmittance, suitable hardness, and resistance to acids and alkalis. In terms of manufacturing processes, miniature glass tubes require a smooth and flat surface, finely processed tube openings, and rigorous cleaning to ensure the absence of impurities. The quality of the miniature glass tube directly affects the headphone user experience. Currently, miniature glass tubes used in headphones are generally formed using CNC machining. Specifically, the inner and outer contours of the glass tube are sculpted from a glass block blank using CNC machining, and then the surface of the glass tube is polished. The material utilization rate of CNC machining is only 15%, and tool marks are easily left on the material surface. Polishing is required to remove the tool marks. Since the glass tubes of this type are small in size, polishing is difficult and time-consuming. This makes it very time-consuming to process a small glass tube, which cannot meet the needs of daily production. Therefore, there is an urgent need to design a new small glass tube forming technology, mold and device to process small glass tubes in large quantities quickly. Utility Model Content

[0003] Based on this, it is necessary to address the above-mentioned shortcomings by providing a hot-press forming mold for small glass tubes, comprising: a punch and a die, wherein a punch protrudes from the lower surface of the punch, and a top plate with a central opening is movably fitted onto the punch; the upper surface of the die is recessed to form a forming cavity matching the punch, and the opening of the forming cavity forms a first placement position matching a glass sheet and used for placing the glass sheet; the punch forms a punch shoulder around the lower surface of the punch, and at least two spring cavities are recessed at intervals around the punch on the punch shoulder; each spring cavity is provided with a spring that extends and retracts in the vertical direction, one end of the spring is fixedly connected to the top wall of the spring cavity, and the other end of the spring is fixedly connected to the upper surface of the top plate; the top plate is used for demolding after the small glass tube is hot-pressed.

[0004] Preferably, one set of sidewalls of the punch are provided with a first guide strip and a second guide strip extending in the vertical direction, and the other set of sidewalls of the punch are provided with a first positioning block and a second positioning block, and the upper surface of the die extends upward to form a first guide groove matching the first guide strip, a second guide groove matching the second guide strip, a first positioning groove matching the first positioning block, and a second positioning groove matching the second positioning block.

[0005] Preferably, the number of spring cavities is two, three, or four.

[0006] This utility model also provides a hot pressing forming device for small glass tubes, including any of the hot pressing forming molds described above, and further including: a heating furnace, a lower heating plate disposed on the bottom wall of the furnace cavity, a lower heat spreader plate fixedly connected to and in contact with the lower heating plate, a mold base disposed on the lower heat spreader plate, and a pressure plate disposed above the base and driven by a power device. The pressure plate includes an upper heating plate and an upper heat spreader plate arranged sequentially from top to bottom and in contact with each other. The mold base has a plurality of second placement positions for placing the hot pressing forming mold. The pressure plate is used to heat the furnace cavity and drive the punch to press down.

[0007] The aforementioned hot-press forming mold and apparatus for small glass tubes includes a punch and a die. During hot pressing, the mold containing a glass sheet is placed in the second position on the mold base. An upper heating plate and a lower heating plate heat the mold and the glass sheet, softening the glass sheet. A power device then drives a pressure plate to slowly press down, which in turn drives the punch and die to slowly close, allowing the glass sheet to slowly deform in the forming cavity, ultimately forming a glass tube. After cooling, the punch spring is lifted, releasing its elastic potential energy to push the top plate, which ejects the glass tube, achieving demolding. The hot-press forming mold and apparatus for small glass tubes provided by this invention not only significantly improves material utilization but also greatly reduces processing time, effectively increasing the production efficiency of small glass tubes. Small glass tubes produced using the hot-press forming mold and apparatus provided by this invention have precise dimensional control, a smooth and flat surface, and stable optical, physical, and chemical properties, meeting all requirements for small glass tubes used in headphones. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the structure of a hot pressing mold for small glass tubes in one embodiment of the present invention;

[0009] Figure 2 This is a schematic diagram of the combined state structure of a thermoforming mold for small glass tubes in one embodiment of the present invention;

[0010] Figure 3This is a top view of the combined state of a thermoforming mold for small glass tubes in one embodiment of the present invention;

[0011] Figure 4 This is a cross-sectional view of position AA, showing the combined state of a thermoforming mold for a small glass tube in one embodiment of the present invention.

[0012] Figure 5 This is a schematic diagram of a hot pressing device for forming small glass tubes in one embodiment of the present invention (the heating furnace and power unit are not shown).

[0013] Explanation of reference numerals in the attached drawings: 10-Hot pressing mold, 100-Punch, 110-Punch head, 120-Top plate, 130-Punch shoulder, 130a-Spring cavity, 140-Spring, 150-First guide bar, 160-Second guide bar, 170-First positioning block, 180-Second positioning block, 200-Die, 200a-Forming cavity, 200b-First placement position, 200c-First guide groove, 200d-Second guide groove, 200e-First positioning groove, 200f-Second positioning groove, 300-Lower heating plate, 400-Lower heat spreader plate, 500-Mold base, 500a-Second placement position, 600-Pressure plate, 610-Upper heating plate, 620-Upper heat spreader plate, 700-Glass sheet. Detailed Implementation

[0014] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below. In this utility model, the terms "upper," "lower," "left," "right," "inner," "outer," "top," and "bottom" are all based on the normal placement of the hot-pressing mold and device.

[0015] This utility model discloses a hot pressing mold and device for small glass tubes, such as Figure 1-4As shown, the hot pressing mold includes a punch 100 and a die 200. The lower surface of the punch 100 is provided with a punch 110. The shape of the punch 110 is selected according to the shape of the glass tube. It also includes a top plate 120 with a central opening. The shape of the opening is the same as the cross-sectional shape of the punch 100. The top plate 120 is movably fitted on the punch 110. The upper surface of the die 200 (i.e. the surface opposite to the punch of the punch 100) is recessed to form a forming cavity 200a that matches the punch 110. When the punch 100 and the die 200 are closed, there is a gap between the punch 100 and the wall of the forming cavity 200a, forming a space for forming glass flat sheets. The opening of the forming cavity 200a also forms a first placement position 200b for placing glass flat sheets. The punch 100 forms a punch shoulder 130 around the lower surface of the punch 110. The punch shoulder 130 has at least two spring cavities 130a recessed at intervals around the punch 110. In this embodiment, there are two spring cavities 130a. Each spring cavity 130a is provided with a spring 140 that extends and retracts in the vertical direction. One end of the spring 140 is fixed to the top wall of the spring cavity (130a), and the other end of the spring 140 is fixed to the upper surface of the top plate 120 (i.e., the surface of the top plate 120 facing the punch shoulder 130). The top plate 120 is used for demolding small glass tubes after hot pressing. Before stamping, the spring 140 is in normal condition. During stamping, the top plate 120 is pressed against the opening of the forming cavity 200a and cannot move further. The punch 110 enters the forming cavity 200a to hot press the glass flat sheet. The spring 140 in the spring cavity 130a is continuously compressed and accumulates elastic potential energy. After hot pressing, the punch 100 is lifted upward, and at the same time, the spring 140 gradually releases elastic potential energy until the small glass tube attached to the punch 110 and the top plate 120 is demolded.

[0016] This invention provides a thermoforming mold for small glass tubes. Through the cooperation of a punch 100 and a die 200, a flat glass sheet is placed on the first placement position 200b of the die 200. The punch 110 of the punch 100 applies pressure to the glass sheet, causing it to undergo plastic deformation within the forming cavity 200a, thereby stamping it into the shape of a small glass tube. Additionally, a movable top plate 120 is fitted onto the punch 110, and a spring 140 is installed in the spring cavity 130a of the punch shoulder 130, connecting to the top plate 120. After thermoforming, the elastic force of the spring 140 pushes the top plate 120 upwards, thereby pushing the formed small glass tube off the punch 110 and the top plate 130, achieving demolding. Compared to traditional CNC machining, this novel hot-press forming mold avoids tool marks on the glass tube surface through integral hot-press forming, fundamentally solving the problem of deep tool marks in small glass tubes processed by CNC. Because the hot-pressed glass tube has a high surface quality with almost no tool marks, the subsequent polishing workload and difficulty are significantly reduced. This not only reduces the time and cost of the polishing process but also lowers the scrap rate that may occur during polishing, increasing the product yield and further reducing production costs. Furthermore, the hot-press forming process can complete the forming of small glass tubes in a short time, greatly shortening production time, improving production efficiency, and reducing processing time. The hot-press forming mold has a relatively simple structure, mainly composed of a punch 100, a die 200, and a top plate 120. Each component has a clearly defined function, is easy to install and disassemble, and facilitates mold debugging, maintenance, and replacement by operators, thus improving production stability and reliability.

[0017] To ensure accurate positioning during the hot pressing process, in one embodiment, such as... Figure 1-4As shown, a first guide bar 150 and a second guide bar 160 extending vertically are protruding opposite each other on the left and right sidewalls of the punch 100, and a first positioning block 170 and a second positioning block 180 are protruding opposite each other on the front and rear sidewalls of the punch 100. The upper surface of the die 200 extends upward, and a first guide groove 200c matching the first guide bar 150 of the punch 100 and a second guide groove 200d matching the second guide bar 160 are formed on the left and right sides of the die 200. A first positioning groove 200e matching the first positioning block 170 of the punch 100 and a second positioning groove 200f matching the second positioning block 180 are formed on the front and rear sides of the die 200. The first guide bar 150 and the second guide bar 160 on the punch 100 cooperate with the first guide groove 200c and the second guide groove 200d on the die 200. During the stamping process, the guide bar can slide within the guide groove, thereby restricting the vertical movement trajectory of the punch 100. The first positioning block 170 and the second positioning block 180 match the first positioning groove 200e and the second positioning groove 200f on the die 200. Before the thermoforming mold closes, the relative positions of the punch 100 and the die 200 can be accurately determined through the cooperation of the positioning blocks and positioning grooves, ensuring that the punch 110 of the punch 100 can accurately enter the forming cavity 200a of the die 200, achieving precise thermoforming. The cooperation of the guide strip and guide groove, and the positioning block and positioning groove, can effectively prevent the punch from shifting or wobbling during the stamping process, making the cooperation between the punch 110 and the forming cavity 200a more precise, thereby improving the forming accuracy of small glass tubes, ensuring the consistency and stability of product dimensions, and reducing the scrap rate. In addition, precise positioning also reduces the probability of accidents caused by mold failure or stamping deviation, such as glass fragments flying, thereby improving the safety of the production process and protecting the safety of operators.

[0018] In one embodiment, there are two spring cavities 130a; in another embodiment, there are three spring cavities 130a; and in yet another embodiment, there are four spring cavities 130a. It should be noted that each of the above spring cavities 130a contains a spring 140 in the manner described in the previous embodiments. The number of spring cavities 130a can be selected and adjusted according to the specific size, shape, and material properties of the small glass tube. For example, for small, simple-shaped glass tubes, two spring cavities 130a may be sufficient; while for larger or specially shaped glass tubes, three or four spring cavities 130a can be selected to provide more suitable demolding force and stability, enhancing the versatility and adaptability of the mold. By rationally setting the number of spring cavities 130a, the small glass tube is subjected to uniform force during demolding, effectively avoiding problems such as deformation and breakage of the glass tube caused by uneven demolding force, thus improving product quality and yield. In addition, due to the reasonable arrangement of the number of spring cavities 130a, the top plate 120 and other components of the hot pressing mold are subjected to more uniform force during demolding, reducing wear and damage caused by excessive local force, thereby extending the service life of the hot pressing mold and reducing the maintenance and replacement costs of the hot pressing mold.

[0019] This utility model also provides a hot pressing forming device for small glass tubes using the aforementioned hot pressing forming mold, such as... Figure 5 As shown, specifically, it also includes a heating furnace, a lower heating plate 300 disposed on the bottom wall of the furnace cavity, a lower heat spreader 400 fixedly connected to the lower heating plate 300, a mold base 500 disposed on the lower heat spreader 400, and a pressure plate 600 disposed above the mold base 500 and driven by a power device. The pressure plate 600 includes an upper heating plate 610 and an upper heat spreader 620 arranged sequentially from top to bottom and in close contact with each other. The mold base 500 has several second placement positions 500a for placing the hot pressing mold. The pressure plate 500 is used to heat the furnace cavity and drive the punch 100 of the hot pressing mold to press down. In this embodiment, thermocouples are provided inside the upper heating plate 100 and the lower heating plate 500 to realize the heating function. The mold base has 15 second placement positions 500a (3×5) for placing the hot pressing mold. It should be noted that... Figure 5 The furnace body and power unit of the heating furnace are not shown in the figure. The shape of the heating furnace body can be a general heating furnace or a tunnel furnace. The power unit can be provided by hydraulic, pneumatic, electric or other means. All of the above are existing technologies.

[0020] The specific operation process of the hot pressing forming device for small glass tubes provided by this utility model is as follows: Step 1, cleaning and sampling inspection of glass flat sheets: The incoming glass flat sheets are ultrasonically cleaned and stored in a dust-free workshop before processing. 10% of each batch of incoming glass flat sheets are sampled for inspection. The inspection items include: cleanliness, appearance defects, and dimensions. If any problems are found, the sheets are isolated and screened for further inspection. Step 2, mold assembly: 15 hot pressing forming molds are placed on the second placement position 500a of the mold base 500. The contour accuracy of the hot pressing forming molds reaches 0.005mm, the roughness reaches Sa100nm, and the polishing requirement reaches Sa50nm. Step 3, preheating: The hot pressing forming molds and the mold base 500 need to be cycled twice at a temperature above 600 degrees Celsius. The purpose is to remove internal moisture and residual stress from the material and ensure the dimensional stability of the hot pressing forming molds and the mold base. After preheating, the punch 100, punch 110, and top die need to be wiped with a clean, dust-free cloth. Step 1: Wipe the surfaces of plate 120, cavity mold 200, first placement position 200b, and forming cavity once with white abrasive leather in one direction. Wipe the surfaces twice with a clean, lint-free cloth in one direction. Use a vacuum cleaner to remove dust from the surfaces. Step 4: Place the glass sheet on the first placement position 200b of cavity mold 200 after visually inspecting for defects. Step 5: Perform hot pressing. Heat the hot pressing mold and glass sheet to 700 degrees Celsius using upper and lower heating plates. Then, use a power device to drive the pressure plate 600 downwards, simultaneously driving the 15 hot pressing mold punches downwards, closing the mold. The glass slowly deforms and stretches within forming cavity 200a, ultimately forming a tubular product outline. Step 6: After cooling, remove the glass tube. After slow cooling, remove from the furnace. The upper mold opens, and spring 140 automatically ejects the product, separating it from the mold. Polish to obtain a qualified product. Compared to existing CNC-machined small glass tubes, the hot pressing forming device provided by this invention only requires a 0.06cm thick glass sheet, with a material utilization rate of 95%. Each hot pressing forming takes 60 seconds and can produce 15 small glass tubes per batch. The surface roughness reaches Sa30nm, which is much smaller than Sa150nm of CNC. The subsequent process only requires conventional light polishing, which also greatly reduces polishing time.

[0021] The aforementioned hot-press forming mold and apparatus for small glass tubes includes a punch and a die. During hot pressing, the mold containing a glass sheet is placed in the second position on the mold base. An upper heating plate and a lower heating plate heat the mold and the glass sheet, softening the glass sheet. A power device then drives a pressure plate to slowly press down, which in turn drives the punch and die to slowly close, allowing the glass sheet to slowly deform in the forming cavity, ultimately forming a glass tube. After cooling, the punch spring is lifted, releasing its elastic potential energy to push the top plate, which ejects the glass tube, achieving demolding. The hot-press forming mold and apparatus for small glass tubes provided by this invention not only significantly improves material utilization but also greatly reduces processing time, effectively increasing the production efficiency of small glass tubes. Small glass tubes produced using the hot-press forming mold and apparatus provided by this invention have precise dimensional control, a smooth and flat surface, and stable optical, physical, and chemical properties, meeting all requirements for small glass tubes used in headphones.

[0022] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0023] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A thermoforming mold for small glass tubes, characterized in that, include: The die includes a punch (100) and a die (200). The punch (100) has a protruding punch (110) on its lower surface. A top plate (120) with a central opening is movably fitted onto the punch (110). The die (200) has a recessed upper surface that forms a forming cavity (200a) that matches the punch. The opening of the forming cavity (200a) forms a first placement position (200b) that matches the glass sheet and is used to place the glass sheet. The punch (100) surrounds the lower surface of the punch (110). A punch shoulder (130) is formed on the punch shoulder (130), and at least two spring cavities (130a) are recessed around the punch (110) at intervals. Each spring cavity (130a) is provided with a spring (140) that extends and retracts in the vertical direction. One end of the spring (140) is fixedly connected to the top wall of the spring cavity (130a), and the other end of the spring (140) is fixedly connected to the upper surface of the top plate (120). The top plate (120) is used for demolding after hot pressing of small glass tubes.

2. The hot pressing mold for small glass tubes according to claim 1, characterized in that, The punch (100) has a set of sidewalls with a first guide bar (150) and a second guide bar (160) extending vertically. The punch (100) also has a set of sidewalls with a first positioning block (170) and a second positioning block (180) extending vertically. The upper surface of the die (200) extends upward to form a first guide groove (200c) matching the first guide bar (150), a second guide groove (200d) matching the second guide bar (160), a first positioning groove (200e) matching the first positioning block (170), and a second positioning groove (200f) matching the second positioning block (180).

3. The hot pressing mold for small glass tubes according to claim 1, characterized in that, The number of spring cavities (130a) is two, three, or four.

4. A thermoforming apparatus for small glass tubes, comprising the thermoforming mold according to any one of claims 1-3, characterized in that, Also includes: The furnace includes a lower heating plate (300) disposed on the bottom wall of the furnace cavity, a lower heat spreader (400) fixedly connected to and in contact with the lower heating plate (300), a mold base (500) disposed on the lower heat spreader (400), and a pressure plate (600) disposed above the mold base (500) and driven by a power device. The pressure plate (600) includes an upper heating plate (610) and an upper heat spreader (620) arranged sequentially from top to bottom and in contact with each other. The mold base (500) has several second placement positions (500a) for placing the hot pressing mold. The pressure plate (600) is used to heat the furnace cavity and drive the punch (100) to press down.

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