Method and apparatus for shaping a glass workpiece with minimal lubrication

Abstract

An apparatus for shaping a workpiece made of glass using minimum lubrication is provided. The apparatus includes device for heating the workpiece, a shaping station with at least one forming tool for shaping the workpiece, and at least one spray nozzle for applying an oil as a lubricant onto the surface of the forming tool. The forming tool exhibits heat dissipation such that the temperature on the contact surface of the forming tool during the shaping process is kept below 300° C. The amount of oil dispensed by the spray nozzle per forming step and application instance is less than 0.1 g.

Claims

1. An apparatus for shaping a workpiece made of glass, comprising: a heating device configured to heat the workpiece; a shaping station with a forming tool, the forming tool having a contact surface that is configured to shape the workpiece, the forming tool is configured with a heat dissipation such that a temperature of the contact surface during shaping of the workpiece is below 300° C.; and a spray nozzle configured to apply an oil as a lubricant onto the contact surface of the forming tool, wherein the spray nozzle provides a jacket gas spray emitted from the spray nozzle parallel to an oil-gas jet, and is configured and controlled, to dispense an amount of the oil that is less than 0.1 grams and provide a full-surface covering layer on the contact surface.

2. The apparatus of claim 1, wherein the forming tool comprises an inner forming tool and an outer forming tool, the inner forming tool having an inner contact surface configured to shape an inner lateral surface of the workpiece, and the outer forming tool having an outer lateral surface configured to shape an outer lateral surface of the workpiece.

3. The apparatus of claim 2, wherein the inner forming tool is a mandrel.

4. The apparatus of claim 1, wherein the spray nozzle is configured and controlled to apply the oil to the contact surface in intermediate clock cycles of the shaping process.

5. The apparatus of claim 1, wherein the spray nozzle is configured and controlled so as to provide a characteristic selected from a group consisting of: a directionally stable oil-gas jet, a vertical angle γ with the contact surface in a range from 0 to 60°, a horizontal angle α with the contact surface in a range from −85° to 85°, and any combinations thereof.

6. The apparatus of claim 5, wherein the directionally stable oil-gas jet has an opening angle selected from a group consisting of: greater than 1°, in a range from 2 to 10°, and in a range from 2 to 6°.

7. The apparatus of claim 1, wherein the heating device, shaping station, and spray nozzle are configured for the workpiece shaped as a tubular workpiece.

8. The apparatus of claim 1, comprising a lateral spacing between the spray nozzle and the contact surface of 1 to 50 mm.

9. The apparatus of claim 1, wherein the spray nozzle is a coaxial spray nozzle.

10. The apparatus of claim 1, wherein the spray nozzle comprises a plurality of spray nozzles per forming tool.

11. The apparatus of claim 1, wherein the spray nozzle is installed in the shaping station in a stationary manner or is installed in the shaping station a non-stationary manner so that the spray nozzle is driven towards or close to the forming tool in an intermediate clock cycle of the shaping process.

12. The apparatus of claim 1, wherein the amount of oil is less than 0.01 grams.

13. The apparatus of claim 1, wherein the spray nozzle is configured to apply the oil in a spraying process with a duration of less than 0.5 seconds.

14. The apparatus of claim 1, wherein the temperature is below 250° C.

15. The apparatus of claim 1, wherein the temperature is lower than an evaporation temperature and/or a flash point of the oil.

16. The apparatus of claim 1, wherein the forming tool comprises a material exhibiting a thermal conductivity of at least 400 W/mK.

17. The apparatus of claim 1, wherein the forming tool comprises copper.

18. The apparatus of claim 1, further comprising a seat that holds the forming tool such that heat can be removed therefrom and/or supplied thereto through a heat exchange surface of the forming tool that is in direct mechanical contact with an associated heat exchange surface of the seat.

19. The apparatus of claim 18, wherein the forming tool is releasably supported on the seat by a locking device.

20. The apparatus of claim 1, wherein the forming tool comprises two pieces, and wherein the forming tool has an effective outer diameter that is adjustable by relative movement of the two pieces.

21. The apparatus of claim 1, wherein the forming tool comprises a coolant passage configured to receive a cooling medium to cool the forming tool.

22. The apparatus of claim 1, wherein the full-surface covering layer of the oil on the contact surface has a thickness of less than 750 μm.

23. The apparatus of claim 1, wherein the full-surface covering layer of the oil on the contact surface has from one up to ten molecular monolayers of the oil.

24. An apparatus for shaping a workpiece made of glass, comprising: a heating device configured to heat the workpiece; a shaping station with a forming tool having a contact surface that is configured to shape the workpiece, the forming tool has a heat dissipation such that a temperature of the contact surface is below 300° C. during shaping of the workpiece; and a spray nozzle configured to apply an oil onto the contact surface, the spray nozzle comprises a center with an oil supply line and air supply passages that generate an oil-air jet and comprises air jets external to the center that emit air in parallel to each other and to the oil and that impart directional stability to the oil so as to provide a full-surface covering layer of the oil on the contact surface with an amount of the oil that is less than 0.1 grams.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be described in more detail with reference to FIGS. 1 through 12, wherein:

(2) FIG. 1 is a schematic side view of the arrangement of a spray nozzle relative to a mandrel as the inner forming tool;

(3) FIG. 2a is a schematic side view of a preferred embodiment of the apparatus, which furthermore shows further forming tools, in particular outer forming tools that are used for shaping an outer contour of the workpiece to be formed;

(4) FIG. 2b is a top plan view of the embodiment illustrated in FIG. 2a, i.e. in a direction opposite to that of the arrow 7 shown in FIG. 2a;

(5) FIG. 3 is a schematic cross-sectional view of a forming tool in the form of a mandrel having a copper core, with the sectional plane extending along the sectional plane A-A as shown in FIG. 2b;

(6) FIG. 4 is a schematic cross-sectional view of an actively cooled mandrel, with the sectional plane extending along the sectional plane A-A as shown in FIG. 2b;

(7) FIG. 5 is a schematic cross-sectional view of a spray nozzle illustrating the spray pattern of this coaxial spray nozzle, with the sectional plane extending through the longitudinal and symmetry axis of the spray nozzle;

(8) FIG. 6 is a perspective view of an embodiment of an inner forming tool, in particular a mandrel, in which the inner forming tool is supported in its operational position on an associated seat of the shaping station by a locking device, and is passively cooled;

(9) FIG. 7 is a view of the seat of the inner forming tool or mandrel as seen from below, illustrating coolant passages extending within the seat;

(10) FIG. 8 is a perspective view of a further embodiment of an inner forming tool, in particular a mandrel, in which the inner forming tool in held in its operational position on an associated seat of the shaping station by a locking device, and is passively cooled, and in which the inner forming tool, in particular the mandrel, consists of two pieces;

(11) FIG. 9 is a view of the seat of the inner forming tool or mandrel of the further embodiment as seen from below, illustrating coolant passages extending within the seat; and

(12) FIG. 10 is an enlarged perspective view of a detail, in particular of the upper portion of the further embodiment of the inner forming tool, in particular the mandrel, shown in FIG. 8.

DETAILED DESCRIPTION

(13) In the description of preferred and particularly preferred embodiments that follows, reference is made to the accompanying figures which are not drawn to scale, for the sake of clarity.

(14) Furthermore, throughout the various disclosed embodiments, the same reference numerals designate the same or equivalent characteristics or features.

(15) In the description of the method, the terms shaping, shaping process and forming or reshaping are used in the context of this disclosure as follows. Shaping describes the shape-defining operation for the workpiece 6, which is performed during the shaping process. Forming may in this case comprise one or more forming steps, each one achieving an at least partial shaping of the workpiece made of glass. If this shaping process is carried out until its completion, in particular until the final desired shape of the workpiece 6 is achieved, it is also referred to as forming or reshaping.

(16) FIG. 1 schematically illustrates the arrangement of a spray nozzle 2 relative to the mandrel 1 as an inner forming tool. Mandrel 1 has a substantially cylindrical shape which tapers in frustoconical manner towards the upper end thereof. Here, the respective outer cylindrical lateral surfaces provide shaping or contact surfaces 18 for shaping the heated glass of the workpiece 6. The contact surface 18 of the mandrel 1 may have a length from 5 to 20 mm in the y-direction and a diameter D from 5 to 20 mm in its cylindrical portion. For certain embodiments of the workpiece 6 to be shaped, this diameter D may as well be only about 1 mm or even smaller. The mandrel 1 as shown in FIG. 1 is preferably made of a HSS steel, i.e. a high-speed steel. According to this embodiment, the spray nozzle 2 may be installed stationarily in the shaping station which is overall designated by reference numeral 100, and/or on the roller fixture 22, each of which supports the outer forming tools 5a, 5b for rotation but fixed in the axial direction, or may alternatively, in a non-stationary configuration, be driven by any appropriate movable device to approach the mandrel.

(17) The shaping station 100 with its respective sensor and/or actuator modules is connected to a programmable logic controller 30, known as PLC, which stores tables and corresponding programs for sequence control, in particular of the described method steps. For the sake of simplicity of presentation, however, the respective connections between the PLC and the respective sensor and actuator modules are not explicitly shown, but will be obvious for a person skilled in the art.

(18) During the spraying operation, the spray nozzle 2 has a distance 4 by which it is spaced from the surface, in particular the contact surface 18 of the mandrel 1, and this spacing 4 is measured from the opening 23 at the head of spray nozzle 2 during the spraying operation to the contact surface 18 in the lateral direction, i.e. in the direction opposite to the arrow designated x, and is also referred to as a lateral spacing. Lateral spacings between the opening of spray nozzle 2 and the contact surface 18 in a range from 1 to 50 mm, in particular in the range from 10 to 30 mm have been found to be particularly advantageous here. In y-direction, the height level of the respective nozzle 2, 2a, 2b can be chosen such that the opening 23 of the respective nozzle 2, 2a, 2b is slightly above or within the range of the respective contact surface 18 of the mandrel 1, so that a full-surface application of oil at least onto the respective contact surface 18 and the areas 47 is ensured.

(19) Depending on the structural dimensions, the respective nozzle 2, 2a, 2b may as well be arranged below the respective contact surface 18 as seen in the x-direction, in particular if negative angles α are used.

(20) The angle α describes the angle of the spray nozzle's orientation horizontally to the mandrel's surface, i.e. relative to the axis designated by x and represented by an arrow x. The spray nozzle's orientation can be seen more easily in the more detailed view of FIG. 5 and substantially corresponds to the direction of the arrows shown in FIG. 5 and thus essentially to the longitudinal orientation of the air passages 11a, 11b, oil supply line 12, and air passages 13a, 13b, which are aligned in parallel to each other all extending to the exit direction of the resulting oil-air jet 14.

(21) According to a preferred embodiment, angle α is from 0 to 85°, preferably from 30 to 50°, most preferably 45°. Such an arrangement of the spray nozzle 2, 2a, 2b during the spraying operation also allows, by using the small quantities of oil according to the invention, to uniformly and completely wet or cover the surface of the mandrel by the spray jet 3. Depending on the structural dimensions of the shaping station 100, it is even possible to set a negative angle α, which may, for example, be up to −85°, when the nozzle 2, 2a, 2b is arranged below the inner forming tool 1.

(22) In all preferred embodiments, the spray jet 3 is always adjusted, in particular aligned such that preferably each spray burst and preferably using spray air sprayed after each spray burst achieve full-surface wetting or covering by the applied oil of at least the respective forming tool surfaces, in particular contact surfaces 18, and preferably of the area 47 of the frustoconical portion 46 of the inner forming tool or mandrel 1 that will be described in more detail below.

(23) FIGS. 2a and 2b schematically illustrate an embodiment of the shaping station. FIG. 2a shows a side view of the apparatus. In addition to the mandrel 1 as an inner forming tool, the apparatus comprises the two outer forming tools 5a and 5b which are configured as shaping rollers.

(24) Each of shaping rollers 5a, 5b preferably is a cylindrically symmetrical disk having the shaping surface 21 in the region of the lateral surface thereof, which is adapted for contacting the glass. The contour of the shaping surface typically corresponds to a section of the contour of the glass workpiece 6 to be produced, in particular a glass container. Each of shaping rollers 5a, 5b is typically made of a highly heat-resistant material such as steel, at least in the area of the shaping surface, while portions thereof may as well be made of aluminum, and is supported for rotation about its respective axis of symmetry, i.e. the axis of cylindrical symmetry.

(25) In the embodiment shown, two spray nozzles 2a and 2b are fixedly attached to the roller fixtures 22 of outer forming tools 5a, 5b. Spray nozzles 2a and 2b are used to wet and so lubricate, with a thin oil film, the surface, in particular contact surface 18 of the mandrel 1 in the intermediate clock cycles, i.e. between two reshaping operations. By using two spray nozzles 2a and 2b, particularly uniform wetting of the surface of the mandrel is achieved. Following the minimum lubrication, a previously heated workpiece 6 is introduced into the shaping station. The heating device 20 may comprise a burner powered with a fossil fuel, the flame 24 of which is moved over the outer surface of the workpiece 6 until the latter has the desired temperature.

(26) At the temperature to which the workpiece 6 was heated, viscosity is from 10.sup.3.5 to 10.sup.5.5 dPa.Math.s.

(27) A preferred glass of which the workpiece 6 is made or of which the workpiece 6 consists, is a borosilicate glass, in particular a type 1 borosilicate glass according to USP and EP, without however limiting the method which is suitable for many, even most hot-formable glasses, or the apparatus which is suitable for many, even most hot-formable glasses.

(28) The workpiece 6 is in the form of a glass tube. For forming or shaping, the mandrel 1 is introduced into the workpiece 6 in the direction shown by arrow 7, so that the contours of the mandrel 1 are transferred to the inner lateral surfaces 25 of workpiece 6, while the workpiece 6 rotates and the contours of the outer forming tools 5a and 5b are transferred to the outer lateral surfaces of the workpiece. In this case, the contact surfaces 18 of the mandrel 1 come into direct mechanical contact with the inner lateral surfaces or inner lateral surface 25 of the workpiece 6, while they are caused to rotate relative to the stationary mandrel 1. The velocities of the here resulting relative movements of the forming tools, in particular the inner forming tool or mandrel 1, relative to the workpiece 6 substantially correspond to the velocities conventional in hot forming and known to a person skilled in the art and did not have to be modified or specially adapted for the purposes of the invention.

(29) Mandrel 1 as the inner forming tool is supported in or on seat 26 such that heat can be dissipated therefrom and/or, in some embodiments, even supplied thereto to accelerate heating thereof.

(30) For mandrels 1 which do not have internal coolant passages and so are referred to as passively cooled, this can be accomplished through a heat exchange surface 27 of the mandrel 1, which is in direct mechanical contact with an associated heat exchange surface 28 of the seat 26. Through these heat exchange surfaces 27, 28, heat can be removed from and/or supplied to the mandrel 1, in particular by adjusting the temperature of the heat exchange surface 28, so that the mandrel's temperature is thereby adjustable in defined manner, in particular under control of the PLC.

(31) The size of the respective heat exchange surfaces 27, 28 corresponded approximately to the size of the respective contact surfaces 18 and was about 0.1 to 5 cm.sup.2, see FIG. 2a, for example.

(32) The movements of mandrel 1 are indicated by arrow 7, and the movement of workpiece 6 is indicated by arrow 8. Here, arrows 7 and 8 each indicate the relative movement of mandrel 1 relative to workpiece 6.

(33) FIG. 2b shows the apparatus described above in a top plan view, i.e. from above. Spray nozzles 2a and 2b are shown by dashed lines here, since the spray nozzles 2a and 2b are located below forming tools 5a and 5b.

(34) As can be seen from FIG. 2a by way of example, nozzles 2, 2a, 2b each were connected to a respectively associated oil and air supply device 52, via oil and air supply lines 50, 51 which are shown only schematically in this figure. By means of electrically controllable valves 53, 54 it was possible to control both the supply of air, in particular compressed air, and of oil in time-defined manner, by programmable logic controller 30. Only for the sake of ease of understanding, not every one of the respective supply lines is shown individually, rather they will be obvious from the view of FIG. 5, for example, in which the respective air passages 11a, 11b, 13a, 13b and the oil supply line 12 connected to such supply lines can be seen in more detail. Each of these lines has a respective valve associated therewith, which is controlled by the programmable logic controller 30, but for the sake of clarity they are not explicitly shown but symbolically represented by valves 53 and 54.

(35) Supply of the air channels 11a, 11b, 13a, 13b for the nozzle 2 as shown in FIG. 5 and for nozzles 2a, 2b was achieved with a pressure of 1 to 6 bar and did not exceed an air volume of 100 l/min. In preferred embodiments it was even possible to use air volumes of less than 10 l/min. In preferred embodiments, the effective diameter of the nozzle for the exit of air was between 0.5 mm and 3 mm. Effective diameter herein refers to the hydraulically equivalent diameter effective for the exit of the air, which in its effect corresponded in total to the air supply lines 11a, 11b, 13a, 13b. The diameter of the oil supply line 12 and the feeding pressure of the oil were each set so that the desired amount of oil could be reliably emitted during an application instance or spray burst.

(36) With this arrangement controlled by the programmable logic controller it was possible to control, in an adjustable manner, at least one spray nozzle 2, 2a, 2b or more of these spray nozzles for applying the oil as a lubricant to the surface of the forming tool 1, with an adjustable amount of oil dispensed per forming step and application instance, i.e. per spray burst, of less than 0.1 g. For the sake of brevity and ease of readability, the spray nozzles 2, 2a, 2b are also simply referred to as nozzles in the context of this disclosure.

(37) FIG. 3 is a schematic view of a mandrel 1 as an inner forming tool, which has an inner core 6a made of copper. Here, the copper core 6a allows for fast and effective heat dissipation. Alternatively, core 6a may also be made of other materials exhibiting high thermal conductivity, such as copper alloys, silver, or silver-containing alloys. This type of cooling through thermal conduction in the solid body of mandrel 1 is generally referred to as passive cooling in the context of this disclosure.

(38) The further portion 29 of mandrel 1 surrounding the copper core 6a is also made of a HSS steel. The thickness Ds of this further portion 29 is less than 1 mm within the area below contact surfaces 18, see for example FIG. 3, in preferred embodiments less than 0.5 mm, and preferably more than 0.2 mm.

(39) In the described embodiments with passive cooling, the forming tool fixtures or seats of the forming tools, in particular of the inner and outer forming tools, are cooled.

(40) As a result, the cooling circuit remains closed at all times and leaking of coolant is prevented. Indirect or passive cooling is designed such that minimal amounts of oil do not evaporate on the forming tools, and so adequate lubrication is guaranteed for separating the hot glass from the forming tools. Due to the use of minimal amounts of oil, deposits on the forming tools are reduced, which increases the forming tool's service life from 2 h to 8 h and reduces production interruptions. This moreover results in less startup losses. The reduction of deposits also leads to a lower spread of dimensional deviations or product contamination.

(41) For cleaning purposes, the forming tools can be exchanged using a quick-release pin, as illustrated by way of example in FIGS. 6 and 9 and 10, and as will be described in more detail below, so that machine downtime is reduced.

(42) The passively cooled system is configured such that no pneumatic hoses or coolant hoses need to be disassembled.

(43) In mandrel 1, the heat is dissipated through a copper core 6a, for example, or through another material of good thermal conductivity in the interior of mandrel 1. In this case, the inner forming tool, in particular the mandrel 1, preferably has a core 6a which comprises a material exhibiting a thermal conductivity of at least 400 W/mK, and/or copper.

(44) In preferred embodiments which will be described in more detail further below, the forming tool 1 is easily disconnected from its seat 26 which also serves as a heat sink. The indirect cooling thereby allows easy removal and replacement of the respective tool, in particular the mandrel 1, especially since no cooling ports are directly attached thereto.

(45) FIG. 4 schematically illustrates an alternative embodiment of mandrel 1. The mandrel 1 shown in FIG. 4 features active cooling. For this purpose, mandrel 1 comprises a coolant passage 9a inside, through which a cooling medium flows, for example a cooling liquid. The direction of movement of the cooling medium is symbolized by arrow 9. For example water, air, an aerosol, or an oil can be used as the cooling medium. The active cooling allows the heat emitted by the hot glass of the workpiece 6 to be removed particularly effectively, and thus mandrel temperatures of less than 250° C. or even less than 200° C. can be achieved.

(46) FIG. 5 shows a schematic view of the spray pattern of a coaxial spray nozzle 10 as used in one embodiment in the apparatus of the invention. Coaxial spray nozzles have been found to be particularly advantageous here, because the spray pattern can be significantly influenced by adjusting the jacket air that is emitted.

(47) In addition to an oil supply line 12, the coaxial nozzle 10 as shown in FIG. 5 has four air channels 11a, 11b, and 13a, and 13b. Thus, not only oil particles 16 are emitted from the oil supply line 12 in a spraying operation, but at the same time spray air is emitted from air channels 11a, 11b, 13a, and 13b. The direction of movement during the spraying process is symbolized by the arrows. The spray air emitted from air passages 11a and 11b together with the oil dispensed from oil supply line 12 form an aerosol in the form of an oil-air jet 14.

(48) The jacket spray air emitted from air passages 13a and 13b forms the spray air jets 15a and 15b which impart directional stability to the oil-air jet 14 emitted from the center of the nozzle and thus provide for a precise oil-air jet. The oil-air jet or spray jet 3, 3a, 3b emitted upon a spray has an opening angle β of >1° in this case. An opening angle β in a range from 3 to 6° has been found to be particularly advantageous in view of the local distribution of the oil on the mandrel, see e.g. the view of FIG. 2a with respect to the opening angle β. According to a preferred embodiment, the opening angle is 5°.

(49) Although the oil-gas jet 14 comprises finely dispersed oil particles 16, the jacket spray air 15a and 15b at the same time prevents the aerosol from spreading in space and allows for the formation of a stable oil-air jet 14 or spray jet 3, 3a, 3b. Thus, even with small amounts of oil, precise, uniform and complete wetting of the forming tool such as a mandrel's surface, in particular of the contact surface 18, with oil is feasible. This makes it possible to reduce the amount of oil that is applied per spray stroke and forming step to less than 2 mg, without adversely affecting the lubricating effect during the reshaping process. This corresponds to a reduction of the amount of oil dispensed per forming step by more than two orders of magnitude compared to the prior art. In addition to the savings of oil, this leads to less contamination of the products and the processing equipment, which in turn implies less downtime as caused by necessary cleaning of the equipment, for example.

(50) The distribution of the oil on the forming tool 1 can be further improved if pure spray air is sprayed subsequently to the emission of the defined amount of oil. A preferred embodiment therefore contemplates that after each completion of oil supply, the spray nozzle 2, 2a, 2b sprays pure spray air.

(51) According to one exemplary embodiment, vials of a volume of 15 ml were continuously made on a rotary machine. The machine included a plurality of forming tools, which could be used, inter alia, for producing an inner notch of the vials, which is also referred to as a groove in the present disclosure. The oil used for minimum lubrication had a viscosity, at 40° C., of 200 to 240 mm/s and a flash point of >246° C. Each mandrel was lubricated using two fixedly installed circular spray nozzles, with a fixed horizontal spray-application or spray angle α of about 20° with a mandrel surface-to-nozzle tip spacing of 15 mm. The amounts of oil applied to the mandrels per clock cycle and spray burst were between 0.002 and 0.0002 g, with a spray duration of 0.14 s. The mandrels were actively and passively cooled to surface temperatures between 190 and 280° C. during the process.

(52) In this case, the spray nozzles 2, 2a, 2b are preferably calibrated to a fixed flow rate, with a correction factor that takes into account the room and/or nozzle temperature, and this flow rate was always less than 0.5 g/s, although dependent on the selected machine clock cycle.

(53) By sensing the temperature near the nozzles, for example using thermocouple 17, it is possible even during operation to calculate a correction at elevated temperature for the spray nozzles and to implement it in the associated programmable logic controller PLC. In this case, a temperature-dependent adaptation of the spray duration is effected, which ensures that in each case only the specified amounts of oil are spray-applied onto the inner forming tool 1, in particular onto the shaping or contact surfaces 18 and preferably the area 47. The method can be applied to various lubricants and is not limited to a particular oil.

(54) Surprisingly, it has been found that a variety of oils can be used for the purposes of the invention without thereby incurring any limitation to the success of the invention.

(55) Examples of such oils and their properties are shown in Table 1 below:

(56) TABLE-US-00001 TABLE 1 Density @ 15° C. Viscosity [mm.sup.2/s] Flash point Oil [g/cm.sup.3] @ 40° C. @ 100° C. [° C.] Type 1 0.892 150.5 15.3 235 Type 2 0.843 155.6 20 252 Type 3 0.83 200-240 20-30 260

(57) Here, the oil available under the trade name Panolin HVP was used as type 1, Panolin Orcon Vitra as type 2, and GTI as type 3.

(58) In this case, a thickness of the oil or lubricant covering layer on at least the surfaces having glass contact, i.e. contact surface 18 and preferably the area 47, of <750 μm has proven to be advantageous.

(59) In one of the embodiments described above, this corresponded to about 0.1 g of Panolin HVP.

(60) In this case, the inner forming tool, in particular the mandrel 1, has a contact surface 18 of a size of typically about 0.1 cm.sup.2 to 5 cm.sup.2.

(61) The inventors even assume that at least one molecular monolayer of the employed oil is sufficient to achieve the effects described herein.

(62) In general, and independently of the respective forming tool, a most favorably adjusted spray quantity corresponded to a thickness of the covering layer of <75 μm. By way of example, this thickness of the covering layer corresponded to about 1 mg of oil per spray burst for the mandrels 1 described herein.

(63) In further preferred embodiments, the preferred thicknesses of the covering layer for all of the forming tools used, in particular the inner forming tool, i.e. mandrel 1, included even layer thicknesses of only one or preferably only up to 10 monolayers of the molecules of the applied oil.

(64) In further embodiments, the thickness of the covering layer was up to <750 μm, preferably up to <75 μm.

(65) By way of example, this covering layer 45 which in each case extends over the entire surface area of the respective forming tool surface, in particular contact surface 18, can be seen from FIG. 4, and it provides a closed surface layer on the respective forming tool or contact surface 18. This covering layer 45 has the above-described covering layer thickness Db which, in a preferred embodiment, was within the limits described above of one, preferably up to ten monolayers.

(66) Due to this very variable thickness range Db of the covering layers that can be used according to the invention, the inventors have found, most surprisingly, that the respective size of the forming tool surface, in particular of the contact surface 18 and the oil-covered area 47 of the frustoconical portion 46 of the inner forming tool, or mandrel 1, only played a very minor role.

(67) Advantageously, it was possible in particular in all of the embodiments described herein, to provide this covering layer 45 in the same way on at least one further area of the inner forming tool, in particular of mandrel 1, which had the above-described covering layer thickness Db, namely on the area 47 which also constitutes a forming or contact surface and extends from the respective contact surface 18 to the tip of the frustoconical portion 46 of mandrel 1, at least partially, but not necessarily reaches the tip of the mandrel 1 in all cases.

(68) This area 47 of the frustoconical portion 46 was adequately coated with oil when all its surface areas coming into contact with the glass of the workpiece 6 to be shaped just exhibited the aforementioned thickness Db of the covering layer. However, since this area 47 depends on the respective inner diameter of the workpiece 6 prior to the shaping thereof, it was consequently possible to adapt the size of these areas 47 to the workpiece to be shaped such that the workpiece 6 only came into contact with the oil-covered areas of mandrel 1.

(69) When the inner diameter of workpiece 6 prior to the shaping was only slightly smaller than the diameter D of the mandrel 1 or than the effective outer diameter of the mandrel 1, i.e. the radial spacing of the contact surfaces 18 effective during the shaping relative to each other, such areas 47 were correspondingly small.

(70) In the preferred embodiments, the areas of the respective forming tool surface, in particular of the contact surface 18 and of the area 47 of the frustoconical portion 46 of the forming tools, in particular of the inner forming tool, i.e. mandrel 1, coming into contact with the glass of the workpiece 6, were in general each provided with a full-surface covering layer 45 comprising the oil. In each case, this covering layer had the covering layer thickness as described above.

(71) Most surprisingly, the inventors found that it was essentially irrelevant which properties the lubricant had, since with the above-described temperature-dependent calibrations, the amount of oil and its density, viscosity, and volume, as well as the size of the forming tool were essentially decoupled, since, most surprisingly, already a full-surface monomolecular oil layer, in particular applied to the contact surfaces 18, was sufficient for the purposes of the invention.

(72) The PLC stores comparison tables listing for each temperature and preferably for the particular oil used, durations and/or time intervals defining the respectively sprayed amounts of oil, which result in the above-described thicknesses of the covering layer. Based on these tables, durations or time intervals are defined for the respective actual temperature as sensed in particular by temperature sensor 17, for controlling the nozzles 2, 2a, 2b, 10, which durations ensure that the correct amount of oil is applied at least onto the respective shaping or contact surfaces.

(73) Reference is now made to FIG. 6, which shows a plan view of one embodiment of an inner forming tool, in particular mandrel 1, in which the inner forming tool 1 is held on the associated seat 26 of the shaping station 100 in its operative position by means of a locking device, in particular by a quick-release pin 31, and is cooled passively.

(74) In the same manner as described above for the mandrel 1 that is cooled actively through its coolant passages 9a, it is likewise possible for the seat 26 with its coolant passage 34 to be flushed by a cooling medium, preferably a cooling liquid, and arrow 35 indicates the direction of flow of the cooling medium, preferably the cooling liquid. Coolant passage 34 is only shown in phantom in FIG. 7, since it is located in the interior of seat 26 and would normally not be visible in this view. Visible, however, are the fluid ports 36 of seat 26 associated with coolant passage 34.

(75) FIGS. 8 to 10 show a further embodiment in which the inner forming tool, in particular the mandrel 1, consists of multiple pieces, at least two pieces, and where the effective outer diameter thereof is adjustable by relative movement of at least two halves 37, 38 of the inner forming tool, in particular of mandrel 1.

(76) FIG. 8 shows a view of the further embodiment of the inner forming tool, in particular mandrel 1, in which the inner forming tool is held in its operative position on the associated seat 26 of shaping station 100 by a locking device, in particular by quick-release pin 31, and is passively cooled.

(77) The two halves 37, 38 of mandrel 1 are each supported on associated arms 39, 40 which are each mounted for being pivotable laterally about an associated pivot bearing 41, 42, so that the spacing between the two halves 37, 38 of mandrel 1 relative to each other can be adjusted thereby.

(78) By pivoting the arms 39 and 40 it is possible to adjust the effective outer diameter of mandrel 1, that is to say the distance, in particular the radial distance of contact surfaces 18 relative to each other with respect to the longitudinal axis can be adjusted, and thus the diameter effective for the shaping.

(79) Arm 39 includes an adjustment screw 43, see for example FIG. 10, which is preferably provided with a fine thread, and a front end thereof is abutting on an adjustment screw 44 provided in the arm 40 and preferably likewise provided with a fine thread, when the arms 39, 40 are pivoted toward each other. Adjustment screw 44 is arranged in the arm 40 in the same way as adjustment screw 43 in arm 39. These adjustment screws 43, 44 allow to adjust the outer diameters of the contact surfaces 18 that are effective during the shaping in a very precise manner and durable for continuous operation.

(80) Furthermore, a groove 49 is provided in the inner forming tool, in particular in the mandrel 1 and its two halves 37, 38, which groove can be used to formed a lip-shaped or annular peripheral elevation in the workpiece 6 to be shaped. If instead of this groove 49 an annular elevation is provided, it is possible to thereby form an annular groove in the workpiece 6. For this purpose, the two halves 37, 38 are first moved towards each other and remain in this position until the mandrel 1 consisting of these two halves has been introduced into the workpiece 6 for shaping purposes. Thereafter, the two halves 37, 38 may be slightly pivoted away from each other for shaping, so that thereby the contour of the groove 49 or of a respective elevation is transferred to the workpiece 6 to be shaped. After the forming or shaping process which may as well comprise multiple forming steps with increasing spacing of the halves 37, 38, these halves 37, 38 are pivoted back towards each other and can be removed from or retracted out of the shaped workpiece 6 without causing any damage or modification of the shaped inner surface of the workpiece 6.

(81) FIG. 9 shows a view of the seat 26 of the inner forming tool or mandrel 1 according to the further embodiment as seen from below, in which a coolant passage 34 can be seen with the fluid ports 36 thereof and extending within seat 26, as it has already substantially been explained with reference to FIG. 7.

(82) Temperature sensing was accomplished by thermocouples 17 that were soldered into the mandrels 1 near the surface thereof, as described above. Optical monitoring of the dimensions of the vial revealed stable manufacturing within the product specifications. Nearly no smoke development was visible during production, the contamination of surrounding installation areas was greatly reduced. The forming tools 1 lubricated and cooled below the flash point of the oil exhibited no residues of oil combustion or crack residues, even after a long system runtime of several hours.

(83) TABLE-US-00002 LIST OF REFERENCE NUMERALS 1 Inner forming tool/mandrel 2 Spray nozzle 2a, b Spray nozzle 3 Spray jet 3a, b Spray jet 4 Spacing 5 Forming tools 5a, b Forming tools 6 Workpiece 6a Inner core of mandrel 7 Arrow indicating movement direction 8 Arrow indicating movement of mandrel 9 Arrow indicating movement of liquid 9a Coolant passage 10 Coaxial spray nozzle 11a, b Air passages 12 Oil supply line 13a, b Air passages 14 Oil-air jet 15a, b Spray air jet 16 Oil particles 17 Thermocouple 18 Contact surface 19 Arrow indicating direction of view 20 Heating device 21 Shaping surface 22 Roller fixture 23 Opening at head of spray nozzle 2 24 Flame of device 20 25 Inner lateral surface of workpiece 6 26 Seat of inner forming tool 27 Heat exchange surface of mandrel 1 28 Heat exchange surface of seat 26 29 Further portion of mandrel 1 30 Programmable logic controller 31 Quick-release pin 34 Coolant passage 35 Arrow indicating flow direction 36 Fluid port 37 Half of two-piece mandrel 1 38 Half of two-piece mandrel 1 39 Arm for supporting half 37 40 Arm for supporting half 38 41 Pivot bearing 42 Pivot bearing 43 Adjustment screw 44 Adjustment screw 45 Covering layer 46 Frustoconical portion of forming tool 47 Oil-covered area of inner forming tool 49 Groove in inner forming tool 50 Oil and air supply line 51 Oil and air supply line 52 Supply device for supplying oil and air 53 Electrically controllable valve 54 Electrically controllable valve 56 Flattened area of inner forming tool 57 Flattened area of inner forming tool