Thermoforming tool for glass bottle necks

Abstract

A forming tool for forming glass, in particular for forming a bottle neck, has an axially central mounting portion provided with a flange having a forming surface on the flange, where the forming surface forms an angle with a surface perpendicular to the axial axis of the mounting portion, where the angle (X) is between 5 and 15 degrees.

Description

Technical Field

[0001] The present invention relates to a hot forming tool for glass products, especially glass products for medical use, such as vials, bottles, cartridges, etc. In particular, the present invention relates to forming glass products using cylindrical glass tubes, wherein the present invention also relates to an open end of the formed glass tube, the open end being, for example, the neck of a bottle, vial or cartridge, etc. Background Art

[0002] A known method in the prior art is to make a workpiece (also referred to as a semi-finished product) into a glass product through a forming process. Therefore, for example, a glass vial for pharmaceutical applications is made of a glass tube, wherein a short tube portion at one end is heated to the forming temperature of the glass, and a desired shape is formed in one or more forming steps by a suitable forming tool. The internal geometry is usually formed by a plug introduced into the end of the tube. The workpiece rotates during the forming process. The shape and size of the plug define the internal geometry of the glass vial. The forming is performed by an external forming mold, which squeezes the glass tube onto the plug and forms the outside of the glass tube at the same time. In the process, the glass tube and the external forming mold rotate or are indexed. The external forming mold includes a forming surface. Examples of such methods and known tools are described in U.S. Patent Application US2020 / 0354255 and European Patent Application EP 3 677 554.

[0003] In addition, such a method and tool are also described in US2021 / 0363045 A1. In this document, a portion of an intermediate glass product is heated to a predetermined temperature. The tool is in contact with the heated portion of the intermediate glass product. In a state where the tool is in contact with the heated portion, at least one of the tool and the intermediate glass product is rotated so that the tool and the intermediate glass product rotate relative to each other, wherein the portion of the tool in contact with the heated portion includes glassy carbon or is made of glassy carbon.

[0004] US2021 / 0276912A1 mentions a method for forming a mouth of a hollow precursor made of glass and the glass produced thereby. The method comprises: heating the mouth of the hollow precursor; introducing a mandrel into the mouth along a first direction while the hollow precursor rotates; and squeezing a forming roller along a second direction outside the mouth while the hollow precursor rotates with the mandrel in the mouth.

[0005] However, known tools and in particular plugs limit the geometries that can be reliably realized. In particular, for small neck geometries required for high-precision applications, such as for containers for medical purposes, existing tools are insufficient. It is therefore an object of the present invention to provide a tool that can more reliably form precise geometries. Summary of the invention

[0006] By providing a tool according to claim 1, precise geometries can be obtained. By having an inclined forming surface, the formable glass can be easily deformed and distributed in the forming space, wherein there is an angle (X) between the forming surface and the surface perpendicular to the axial axis of the mounting part, and wherein the angle (X) is between 5 and 15 degrees. In particular, glass geometries with thinner cross-sections can be formed. In addition, by providing a tool according to claim 1, the inventors found that geometries with narrower cross-sections (i.e. thinner glass walls) can be formed without the risk that the forming space will not be completely filled. As a result, the edges or contours of the produced objects can be better filled, thereby reducing the scrap rate. In addition, the inventors have also found that by using a tool according to claim 1, the forces acting on the glass can be reduced, thereby making the forming of the collar contour of the vial neck softer. In particular, the inclined molding surface, wherein the molding surface has an angle (X) with the surface perpendicular to the axial axis of the mounting part, wherein the angle (X) is between 5 and 15 degrees, and optionally the segments 64 and 63, ensure that the glass is better concentrated in the middle of the inner contour of the bottleneck surface, and fewer defects and imbalances are detectable in the obtained product. Finally, due to the inclined molding surface, wherein the molding surface has an angle (X) with the surface perpendicular to the axial axis of the mounting part, wherein the angle (X) is between 5 and 15 degrees, the demoulding agent can be better discharged, and no additional discharge opening in the form of a groove is required. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Other aspects of the present invention will be described below with reference to the accompanying drawings, in which:

[0008] Figure 1 An example of a thermoforming glass apparatus is shown;

[0009] Figure 2 An example of a thermoforming glass apparatus is shown;

[0010] Figure 3 An example of a forming tool according to the invention is shown;

[0011] Figure 4 An example of a forming tool according to the invention is shown in a top view; and

[0012] Figure 5 In accordance with Figure 4 The sectional view taken along line AA in FIG. 1 shows an example of a forming tool according to the present invention. DETAILED DESCRIPTION

[0013] Figure 1 and Figure 2A device 1 for thermoforming glass containers known from the prior art is schematically shown. In this case, Figure 1 shows a side view, Figure 2 The apparatus has an internal shaping tool 40 (also referred to in the art as a plug) for shaping the inside surface of the glass tube 30 . Figure 1 and Figure 2 The forming tool 40 in FIG. 4 is schematically represented. The external forming roller 20 is rotatably mounted on a mounting suspension 60. In addition, the apparatus also has a flame heater 70 for optionally heating the glass vial blank 30. The glass tube 30 is heated to a temperature that enables the glass material to be formed. This heating can be performed externally to the forming tool and, if necessary, can also be optionally assisted by the flame heater 70. The temperature to which the glass is heated depends on the specific type of glass used and is generally at T g +200℃ to T g +600℃ range (where T g is the transition temperature of the glass). During the forming process, the glass tube 30 rotates. The forming tools 40 and 20 move towards the glass tube blank 30 to be formed. Since the external forming tools 20 are mounted in a rotatable manner, they are also rotated by the rotational movement of the glass tube 30. Note: The forming tool 40 can be fixed in place and can also be rotated in the axial direction. In addition, during the forming of the outer surface of the glass tube 30, the entire side surface of the external forming roller 20 will be in contact with the hot glass tube 30. The interaction of the internal forming tool 40 and the external forming roller 20 with the glass tube forms the final geometry of the glass tube 30. This forms the final geometry of the opening of the tube. Note: The present invention is not limited to this implementation of the device 1, but the forming tool can also be used in other suitable forming machines in which relative rotation is achieved between the forming tool 40 and the container to be formed.

[0014] exist Figure 3 An example of a tool 40 according to the invention is shown in FIG. Figure 3 shows a three-dimensional view, in Figure 4 A top view is shown in FIG. Figure 5 The following is shown in Figure 4 A cross-sectional view of the tool 40 is shown taken along the cutting line AA.

[0015] The tool 40 has a base mounting shaft 50 that can be connected to a production machine (such as Figure 1 and Figure 2The mounting shaft 50 is firmly mounted on the production machine 1 with a corresponding coupling system. Such mounting mechanisms are known in the art. On top of the mounting shaft is a mounting ring 55. The ring 55 is provided with a cutout. The ring 55 together with the mounting shaft 50 forms a mounting system 56, which is also referred to as a mounting part. On top of the mounting ring 55, a profiled part 60 is mounted, which is therefore located on the distal side of the mounting system 56.

[0016] The molding portion 60 includes a flange 61 that contacts the glass during molding. The flange 61 has two flat molding surfaces, which are also referred to as planar end surfaces 162. The end surfaces 162 are perpendicular to the central axis of the tool 40. Adjacent to the end surfaces 162 are two molding chamfers 62. Compared with the planar end surfaces 162, the slope X of the chamfers 62 is preferably 10 degrees.

[0017] On top of the mounting ring 55 and starting from the level of the end surface 162, there is located an annular shaped portion 67. The annular shaped portion 67 is concentric with the central axis of the tool 40. The annular shaped portion 67 has cut-out portions 63 and 64.

[0018] On top of the annular forming portion 67, a top forming portion 66 is positioned, which is concentric with the central axis of the tool 40. In this example, the topmost portion of the top forming portion 66 is dome-shaped. The top forming portion 66 is provided with two cutouts 65, which extend axially in the wall portion of the top forming portion 66. The cutouts 65 have the same orientation as the corresponding cutouts 63. When in use, the glass vial 30 to be formed is heated to a temperature at which the glass can be formed, so that it is in a semi-liquid state and can be formed into a specific shape. When the tool 40 is moved into place and engaged with the opening of the glass vial, the top portion 60 is coaxially inserted into the glass vial 30. The planar forming surface 162 engages with the glass vial 30. At the same time, the forming roller 20 also engages with the vial 30 on the outside. Preferably, before or during the forming process, the surface in contact with the glass is coated or cleaned with a release agent. According to a preferred embodiment, the release agent is oil. Such oils are known to those skilled in the art and are available on the market. Due to the rotation of the glass vial 30, the formable glass of the vial 30 engages with the inclined surface 62 and the cutouts 63 and 64 under the pressure generated between the forming tool 40 and the forming roller. The inclined surface 62 pushes the now formable semi-liquid glass into the forming space formed by the forming tool 40 and the forming roller to form the glass mass. In addition, the cutouts 63 and 64 engage with the flowing glass and further guide and push the glass material through the forming space. Due to the presence of the inclined surface 62, the glass can be moved more efficiently throughout the forming space, while the cutouts 63 and 64 further help to further distribute the glass throughout the forming space. By more effectively pushing the glass into the entire forming space, it is possible to ensure that the forming space is completely filled. By using the tool according to the present invention, complex geometric shapes can be formed. In particular, geometric shapes with narrow cross-sections (i.e., thin glass walls) can be formed without the risk of the forming space not being completely filled.

[0019] The angle of surface 63 is about 60° to 70°. Surface 64 ends in the middle of the plug (angle is 20° to 30°). The inclined position of the plug and the segments 63 and 64 reduces the contact area with the forming tool. This reduces the forces acting on the glass. This makes the shaping of the contour of the bottle neck softer. The segments 64 and 63 ensure that the glass is better gathered in the middle of the inner contour of the bottle neck surface and there are fewer defects and imbalances. In this example, the slope X of the bevel 62 is 10 degrees. However, the present invention can be implemented with a slope X between 5 and 15 degrees. The angle can be selected according to the flow characteristics of the specific glass used and the required geometry. The forming tool according to claim 1 and in particular the specific geometry of the forming tool improve the production method of the glass vial, and can also improve the glass vial. Due to the specific geometry, the formable glass can be easily deformed and distributed in the forming space, thereby forming a glass geometry with a thinner cross section. By the specific geometry of the forming tool according to claim 1, the risk of the forming tool in the prior art not being able to completely fill the forming space can be reduced. Thus, the edges or contours of the produced objects can be better filled, thereby reducing the scrap rate. In addition, the inventors have found that the release agent, especially oil, can be better discharged due to the inclined molding surface, wherein the molding surface has an angle X with the surface perpendicular to the axial axis of the mounting part, and wherein the angle X is between 5 and 15 degrees. Therefore, no additional discharge outlet, such as a discharge outlet in the form of a groove, is required, which is very advantageous because such a discharge outlet can easily be blocked by glass or black carbon during the production of glass vials, resulting in expensive cleaning work and downtime. In another example of the present invention, the annular molding part 67 is concentric with the central axis of the tool 40 and does not include the cut-out parts 63 and 64. In this case, the annular molding part is cylindrical. In use, the function of the inclined surface 62 remains as described above, but the additional molding function of the parts 63 and 64 is slightly lost. The tool according to this example is easier to manufacture. In another example of the present invention, the annular molding part 67 is provided with the part 63, but the part 64 is omitted. This improves the flow effect and reduces the manufacturing cost.

[0020] In another aspect of the invention, additional heaters, such as Figure 1 The flame heater 70 shown in the figure is used to heat the glass. This can improve the temperature control of the glass during the forming process and can also make the glass flow more easily during forming.

[0021] The tool may be assembled from a number of parts, but it is preferred to form the tool from a single piece to improve strength and reliability as no parts can come loose during use. This single piece construction also has the advantage of reducing vibrations during use. For example, the plug may be made from hardened high speed steel.

[0022] Additional embodiments of the present invention:

[0023] According to a first embodiment, a forming tool for glass forming is provided, the forming tool comprising an axially central mounting portion 56, the mounting portion being provided with a flange 61, on which a forming surface 62 is provided, characterized in that the forming surface 62 forms an angle X with a surface perpendicular to the axial axis of the mounting portion. According to a second embodiment, a forming tool according to the first embodiment is provided, wherein the angle X is between 5 and 15 degrees.

[0024] According to a third embodiment, there is provided a forming tool according to the second embodiment, wherein the angle X is 10 degrees.

[0025] According to a fourth embodiment, there is provided a molding tool according to any one of embodiments 1 to 3, the molding tool further being provided with a second molding surface 63 .

[0026] According to a fifth embodiment, a molding tool according to the fourth embodiment is provided, and the molding tool is further provided with a third molding surface 64 .

[0027] According to a sixth embodiment, a forming tool according to any of the preceding embodiments is provided, wherein the tool is formed from a single piece.

[0028] According to a seventh embodiment, a molding tool for molding the internal geometry of a glass container is provided, the molding tool comprising a mounting portion, the mounting portion being provided with a molding portion, the outer surface of the molding portion being suitable for providing the internal geometry of the glass container when rotated along a vertical axis, wherein the molding portion is provided with a bevel portion, the bevel portion forming an angle between 85 and 75 with the vertical axis.

Claims

1. A molding tool for glass molding, the molding tool comprising: An axially central mounting portion (56) provided with a flange (61) having a profiled surface (62) on said flange (61), characterized in that: The molding surface (62) forms an angle (X) with a surface perpendicular to the axial axis of the mounting portion, wherein the angle (X) is between 5 and 15 degrees.

2. The molding tool according to claim 1, wherein: The angle (X) is 10 degrees.

3. The forming tool according to claim 1 or 2, further provided with a second forming surface (63).

4. The forming tool according to claim 3, further provided with a third forming surface (64).

5. The forming tool according to any one of claims 1 to 4, wherein: The tool is formed from a single workpiece.

6. A molding tool for molding the internal geometry of a glass container, the molding tool comprising a mounting portion, the mounting portion being provided with a molding portion, the outer surface of which is suitable for providing the internal geometry of the glass container when rotated along a vertical axis, wherein the molding portion is provided with a bevel portion, which forms an angle between 85 and 75 degrees with the vertical axis.

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