Patent Grant
8568127
This application is the U.S. national phase, pursuant to 35 U.S.C. §371, of PCT international application Ser. No. PCT/EP2007/062734, filed Nov. 23, 2007, designating the United States and published in German on May 29, 2008 as publication WO 2008/062054 A2, which claims priority to European application Ser. No. 06024452.2, filed Nov. 24, 2006. The entire contents of the aforementioned patent applications are incorporated herein by this reference.
The present invention relates to a device for forming moldings from a moldable material. The device comprises a die grid, in which there is formed at least one receiving space, and comprises at least one tool, with which the moldable material in the receiving space can be compressed. Furthermore, the invention relates to a method for forming moldings in which a moldable material is formed, fed to at least one receiving space of a die grid and then compressed by at least one tool.
Various devices and methods for producing tablets are known from the pharmaceutical industry. In the case of so-called rotary table tableting machines, for example, the material to be molded, which is in the form of bulk material, is fed by way of a fixed filling device into a likewise fixed die table, the receiving spaces (dies) of which are filled with the bulk material. Arranged above and below the receiving space are punches, which are guided by way of an upper and a lower compression roll for compressing the bulk material. The compression rolls have the effect that the punches are moved toward one another, whereby initially a rising pressure and, once the vertex point has been passed, a falling pressure is exerted on the bulk material, whereby it is compressed to form a tablet. A conventional rotary table tableting machine is described, for example, in DE 37 14 031 A1.
A disadvantage of known tableting machines is that the time interval during which the pressure required for compressing is exerted on the moldable material is limited. For many applications, it is desirable to prolong the so-called holding pressure time. With conventional tableting machines, this is only possible with a small time window.
EP 0 358 107 A2 discloses a method for producing pharmaceutical tablets in which the pharmaceutical mixture is extruded and the still plastic material is processed in a conventional tableting machine to form solid pharmaceutical moldings. In the case of this method, although an extruder can be advantageously used for forming and feeding in the moldable material, the disadvantages accompanying conventional tableting machines cannot be overcome. In addition, cost-effective feeding of the material would not be sufficiently possible.
U.S. Pat. No. 2,829,756 discloses a device in which an extruded plastic strand is cut up into elongate, cylindrical forms by co-running molding punches. A disadvantage of this device, and of the method put into operation on this device, is that the extruded plastic strand is not processed completely and a relatively high proportion of scrap, or of material which has to be re-processed, is produced. Working up pharmaceutical materials for renewed processing, and consequently feeding, into a sales product entails the risk of a change in the efficacy of the formulation occurring, whereby scrap is in turn produced.
Furthermore, it is known from EP 240 906 B1 to extrude polymer melts and deform them by injection molding or calendering. A disadvantage of the injection molding process is that it is not fully continuous, but works with operations recurring in a cycle, which cannot be speeded up to the extent required for mass production because of the cooling times required. Moreover, the temperature and pressure also disadvantageously change internal structures of the materials, and consequently the properties. Even when calendering with two rolls, the production rate is limited, because the rolls are only in contact along a line, with the result that only slowly running rolls allow adequate cooling time to cool the hot, still plastic strand to the extent that the moldings obtained are dimensionally stable. Furthermore, even when calendering with two rolls, the holding pressure times that can be realized are not obtained because of the linear contact of the rolls.
The calendering method with two calender rolls is developed by adding a so-called chain calender, as described in EP 0 358 105 B1. In the case of this chain calender, the still deformable strand of the extruder is compressed between two belts which are in contact in sections on the lateral surface, rotate in opposite directions and run parallel over the contact section or between a roller and a belt which rests on a segment of the roller shell and runs in a rotational manner along with the latter, to form tablets. In this case, the shaping depressions are provided in both or only in one of the rotating shaping elements. However, this method of production has the disadvantage that no specific adaptations of the material can be made without the individual doses becoming considerably misshapen, because here there are no lateral surrounding guides. Furthermore, it is necessary for the moldings obtained to undergo secondary finishing, in particular smoothing and flash removal. Furthermore, corrections of the mass are only possible on the moldings to a very limited extent, as a result of which it is not possible to change the format to produce heavier or lighter moldings.
The object of the present invention is to provide a device and a method for forming moldings from a moldable material by means of which the holding pressure time while compressing the moldings can be extended.
This object is achieved by a device with the features of claim 1 and a method with the features of claim 11. Advantageous forms and developments are provided by the subclaims.
The device according to the invention is characterized in that the tool is movable along a guideway, which has a molding portion in which a constant pressure is exerted over a section of the way by the tools on the portion of moldable material that is located in the receiving space. The device according to the invention allows very high pressures to be exerted on the material to be molded for very long periods of time. The device according to the invention can therefore be used inter alia in particular for molding materials which require a long holding pressure time. This is so because the maximum pressure of the tools can be exerted over the entire section of the molding portion of the guideway. Depending on the speed at which the tool carrier moves on the guideway, this molding portion may be chosen to be long enough for any desired holding pressure times to be realized. The dwell time of the material in the portion in which it is compressed can, moreover, consequently be set.
According to a development of the device according to the invention, the tool is mounted in a tool carrier. The tool carrier is preferably held in the guideway by way of a slotted guide. In this case, at least one tool carrier may run along the guideway on guide rollers, at least in certain portions, the guide rollers being adjustable with respect to their distance from another tool carrier, at least in the molding portion of the guideway. As a result, a molding pressure can be set according to the properties of the material to be molded. The volumes to be set of the different materials to be compressed are adjusted by means of the height adjustable die grid. In this way, the volume to be compressed in the receiving space of the die grid can be set very easily. In the case of the method according to the invention, consequently, an online change of the forms of administration with regard to the dosage can be realized. Furthermore, it is possible to compensate for tolerances of the guideway in the molding portion.
Preferably, the molding portion of the guideway runs in a straight line. Particularly high compression pressures can be realized in this way.
According to a development of the device according to the invention, a further, second tool for the at least one receiving space can be guided into the receiving space from the opposite side of the first tool. In this way, the moldable material in this receiving space can be compressed from two sides.
In particular, a multiplicity of receiving spaces are formed in the die grid and are respectively assigned a first tool and a second tool. In this case, the first tools and/or the second tools may each be mounted in a tool carrier. They are, in particular, secured in the tool carrier in a floating manner. The tools may, in particular, be coolable and/or heatable for specific moldable materials.
According to a development of the device according to the invention, a separate guideway is provided for the tool carrier of the first tools and for the tool carrier of the second tools.
In the case of the device according to the invention, a cooling portion of the guideway, in which the compressed moldings in the die grid cool down, may be formed downstream of the molding portion in the direction of processing. The cooling portion is preferably also formed by a straight section of the guideway. In the case of the device according to the invention, this allows the cooling time to be set. A very long cooling time can be chosen, so that moldings with complicated geometries can also be demolded well when carrying out thermal processes. Furthermore, in the case of pharmaceutical moldings, it is often necessary for long cooling-down times to be realized, in order to counteract any residual stresses in the moldings.
A sampling station for removing one or more moldings, which may be passed on for quality control, may be arranged downstream of the molding portion or downstream of the cooling portion. Following that there may be arranged a removal and camera inspection station for removing and examining the moldings, a cleaning station and, finally, a molding space coating device, in which the parts of the device which come into contact with the moldable material are cleaned and coated to avoid adhesive attachments.
The tool cleaning and the molding space coating can be carried out continuously while the production process is in progress. Furthermore, an online inspection and online mass correction of the moldings is possible while the production process is in progress. Furthermore, an online 100% visual inspection by means of a camera and online NIR for various analytical data acquisitions are possible.
According to a preferred form of the device according to the invention, the tool carrier is coupled with a rotatable drive unit by way of a telescopic arm, so that the tool carrier can be guided over a closed curve. The drive unit may be the only driven unit of the device according to the invention. A telescopic arm is preferably provided for the tool carrier of the first tools and for the tool carrier of the second tools. The telescopic arm or telescopic arms may be pivotably mounted, in particular about a tangential axis with regard to the rotation of the drive unit. Furthermore, the length of the telescopic arm is variable. The tool carrier is in this case coupled with the telescopic arm by way of a horizontal/vertical two-axis fork joint. In this way, the tool carrier can on the one hand be moved along the guideway radially toward the drive unit and radially away from the drive unit. On the other hand, the tool carrier can be pivoted upward and downward with a horizontal pivoting plane.
For the purposes of the invention, a moldable material is understood as meaning any material which changes its shape under the effects of a force. Powdered bulk materials may be fed to the die grid as moldable material. The bulk material is filled into the receiving spaces of the die grid for example by means of a filling device known per se. The filling device may be, for example, a powder distributing installation for uniformly discharging flowable, moldable, powdered bulk materials, in the case of which the bulk materials can be fed in continuously. The device according to the invention allows, in particular, highly resilient polymer granules to be compressed to form moldings. The settable molding time for the molding operation means that the device according to the invention can preferably be used for processing flowable and moldable powdered bulk materials, for example in the pharmaceutical, food, cosmetics and hygiene industries.
Furthermore, the moldable material may be a ribbon of melt. To form the ribbon of melt, the device may comprise in particular an extruder, it being possible for the ribbon of melt to be fed continuously to the die grid. A molding station for smoothing and aligning a strand of melt discharged by the extruder to form the ribbon of melt is preferably arranged between the extruder and the die grid. In this way, the width of the ribbon of melt can be formed such that it corresponds to the width of the die grid. As a result, the thickness of the ribbon of melt can be set such that the weight of the individual portions of the material is set.
If required, the ribbon of melt may comprise a number of layers of different compositions. The extruder may, in particular, be designed for two-component or three-component extrusion, it being possible for the different components to lie against one another in different sequences. For example, films and moldings with a product sequence ABA or ABCBA can be formed. Such product sequences may be used for the production of medical products, for example in the production of lingual and sublingual films/tablets and transdermal plasters. Such products can be easily produced on the device according to the invention.
Equally, applications from the food industry can be realized by means of coextrusion. In this case, softer elements of moldings, for example confections, can be superposed with layers which have a more viscous consistency in various product sequences, in order in this way to allow previously poorly processable foods to be handled and confected better. Furthermore, a number of layers of extremely varied flavored melts may be produced to form a confection.
The device according to the invention may furthermore comprise a displacement partition which can be moved toward the die grid for portioning the moldable material, the displacement partition comprising lateral limiting elements which correspond to lateral limiting elements which form the receiving spaces of the die grid. The moldable material is displaced by the displacement partition into the receiving space of the die grid and is thereby simultaneously portioned, so that the material can then be compressed in mold with a settable volume. In this way it is possible to produce moldings which have no peripheral flash and no distortion, so that there is no need for any further, secondary finishing. Furthermore, smooth surface structures and complicated geometries of the moldings can be realized.
The lateral limiting elements of the displacement partition are preferably in line with the lateral limiting elements of the die grid. The thickness of the lateral limiting elements of the die grid corresponds in particular to the thickness of the lateral limiting elements of the displacement partition. The lateral limiting elements of the displacement partition and the lateral limiting elements of the die grid may have end faces which at least partly meet when the displacement partition and the die grid are moved completely toward one another. In particular, the respective end faces have the same geometry. For example, the die grid may comprise a square, rectangular, rhomboidal or circular grid pattern. The same grid pattern is then formed by the lateral limiting elements of the displacement partition, so that the end faces respectively match one another. The transition from the end faces to the lateral limiting elements of the die grid and/or of the displacement partition may be, in particular, rounded or beveled. As a result, the displacement of the materials when the displacement partition is lowered is made easier and the direction of the material to be displaced is predetermined in the direction of the receiving spaces of the die grid, whereby the amount of scrap from the materials to be molded is reduced to virtually nothing.
According to a configuration of the device according to the invention, the tool can be guided into the receiving space by the lateral limiting elements of the displacement partition. The displacement partition can consequently perform a dual function. On the one hand, it serves for the portioning of the moldable material. On the other hand, it serves as a guide for the tool.
The displacement partition may be coupled with the tool carrier for the first tools. In this case, the displacement partition is, in particular, movable with respect to the tool carrier against the force of at least one spring.
In the case of the method according to the invention for forming moldings, a moldable material is formed and fed to at least one receiving space of a die grid. At least one tool then compresses a portion of the moldable material in the receiving space, in that the tool is moved on a guideway, which has a molding portion in which a constant pressure is exerted over a section of the way by the tool on the portion of moldable material that is located in the receiving space. The section is, in particular, a straight section.
In the case of the method according to the invention, a further second tool for the at least one receiving space is preferably guided into the receiving space from the opposite side of the first tool. The pressure in the receiving space of the die grid is then exerted by the first tool and the second tool. For the first tools and the second tools there may be respectively provided a tool carrier, which is in each case guided on a separate guideway.
According to a development of the method according to the invention, after compression, the moldings cool down in the die grid. After cooling, a molding or a number of moldings may be removed for inspection.
The invention is now explained in detail on the basis of exemplary embodiments with reference to the drawings:
With reference to
The device comprises an extruder 1, with which a moldable material can be formed. The moldable material is transferred from the die of the extruder 1 into a rotating mechanical system in which the moldings are formed. The basic setup of this rotating mechanical system is explained below.
A rotatable drive unit 2 is provided and has radially outwardly extending telescopic arms 5 fastened to it. Molding units 4 are fastened to the radially outer ends of the telescopic arms 5. As explained later, a molding unit is made up of an upper part 4A and a lower part 4B. A telescopic arm 5A or 5B is respectively provided both for the upper part 4A and for the upper part 4B. The telescopic arm 5A for the upper part 4A and the telescopic arm 5B for the lower part 4B of the molding unit 4 are arranged parallel, lying vertically one above the other. The drive unit 2 consequently comprises the telescopic arms 5A for the upper part 4A of the molding unit 4 in an upper horizontal plane and the telescopic arms 5B for the lower part 4B of the molding unit 4 in a lower horizontal plane. The telescopic arms 5 with the molding units 4 are consequently moved by the drive unit 2 substantially in an upper and a lower horizontal plane.
The molding units 4 are guided on a guideway 3. The guideway 3 describes a closed curve with straight portions A and B (
The various portions which the guide path runs through are described with reference to
The die of the extruder 1 is followed directly by a molding portion A, in which the guideway 3 runs over a straight section. The molding portion A is followed by a cooling portion B, which may also run over a straight section. Downstream of the cooling portion B, the guideway 3 changes its direction in a 90° bend and feeds the molding units 4 to a sampling station 6 at the portion C. After the portion C, the guideway 3 describes a semicircle, in which the molding units 4 are fed to a molding removal and camera inspection station 7 at the portion D, a cleaning station 8 at the portion E and a molding space coating device 9 at the portion F. The individual stations and devices of these portions are described in detail later.
Once the molding units 4 have left the molding space coating device 9, they are returned to the molding portion A by way of a 90° bend. Since the closely arranged molding units 4 in this constellation cannot carry out a curved movement beyond their diagonal, diversionary traveling curves are formed for the guideway and are explained below with reference to
The extruder 1 is described with reference to
In the device according to the invention, an extruder 1 that is known per se can be used. The configuration of the extruder 1 depends on the material that is to be processed in the extruder 1. The materials to be processed may, for example, be intended for use in the pharmaceutical industry, in the food industry and in the cosmetics and hygiene industries. A plastic melt is produced and discharged from the extruder die 10 as a strand of melt 11. The strand of melt 11 may be formed by just one melt. However, as shown in
As shown in
Consequently, the thickness and the width of the ribbon of melt from which the moldings are formed are exactly set by the molding station. The setting ensures that the masses of the individual moldings are always the same. Furthermore, the height, and consequently the mass, of the molding to be formed, can be set by way of the thickness of the ribbon of melt 14. In the molding station, a pre-compaction of the moldable material takes place, leading to greater stability of the ribbon of melt 14. The thickness of the ribbon of melt 14 in this case depends on the consistency of the melt, its density and the desired individual weights of the moldings to be produced from it.
As can be further seen from
The molding unit 4 is described in detail below with reference to
The molding unit 4 comprises a tool carrier 15, which is divided into an upper tool carrier 15A and a lower tool carrier 15B. The upper tool carrier 15A is fastened to an upper telescopic arm 5A, the lower tool carrier 15B is fastened to a lower telescopic arm 5B. The telescopic arms 5A and 5B are arranged parallel to one another in a vertical plane. As already described with reference to
The upper and lower tool carriers 15A and 15B in each case comprise a number of guide pins 16A and 16B, respectively, which hold and guide the upper tool carrier 15A in two upper guideways 3A. The two upper guideways 3A are arranged at the same level, with different radii with regard to the rotational movement of the drive unit 2. The lower guide pins 16B correspondingly hold and guide the lower tool carrier 15B in lower guideways 3B. In the present exemplary embodiment, three guide pins 16A and 16B are respectively provided for the upper and lower tool carriers 15A and 15B. They respectively hold the two tool carrier parts 15A and 15B in a horizontal position. Of the three guide pins 16A and three guide pins 16B, two guide pins 15A and two guide pins 15B are arranged for the outer guideway 3A and 3B, respectively, and the individual guide pins 16A and 16B are arranged for the inner guideway 3A and 3B, respectively, in order to obtain dependable curving behavior of the tool carrier 15.
The upper and lower tool carriers 15A and 15B respectively receive the same number of identical tools 17 and 18. Furthermore, arranged between the upper tool carrier 15A and the lower tool carrier 15B are a die grid 19 and a displacement partition 38, as explained in detail later. Both the die grid 19 and the displacement partition 38 are guided by means of the guide rods 22.
The coupling of the upper and lower tool carriers 15 to the telescopic arm 5 is described with reference to
The telescopic arm 5 comprises two parts which can be displaced in relation to one another, so that the length of the telescopic arm is variable. In this way, the radial distance of the tool carrier 15 from the drive unit 2 can be changed. At the radially outer end of the telescopic arm 5, a horizontal/vertical two-axis fork joint 23 is fastened. The two-axis fork joint 23 comprises a fastening unit 24, which is fastened to the radially outer end of the telescopic arm 5. The horizontal joint 26 of the two-axis fork joint 23 is fastened to the fastening unit 24 by way of a pin 25. The horizontal joint 26 is pivotable about the axis of the pin 25 in a first plane. In the case of the arrangement of the telescopic arm 5 in the device according to the invention, this first plane is horizontally aligned. The vertical joint 28 of the two-axis fork joint 23 is fastened to the horizontal joint 26 by way of a further pin 27. The vertical joint 28 is pivotable in a second plane, which is perpendicular to the first plane. In the case of the arrangement of the telescopic arm 5 in the device according to the invention, the vertical joint 28 is pivotable in a vertical plane. Finally, the upper tool carrier 15A or the lower tool carrier 15B is fastened to the vertical joint 28. The two-axis fork joint 23 consequently provides a firm connection between the telescopic arm 5 and the corresponding part of the tool carrier 15. In this way, the tool carrier 15 can reach all positions in all three spatial directions within the path of the guideway 3 in a trouble-free and smoothly proceeding manner.
Since the drive unit 2 represents the only motor-driven element of the device according to the invention with regard to the movement of the molding units 4, the telescopic arms 5 ensure that the force of the drive unit 2 is transmitted to the tool carriers 15 connected to them, so that said tool carriers can move on the predetermined guideway 3. The two-axis fork joint 23 and the vertical pivotability of the telescopic arm 5 thereby ensure that it is possible to compensate in a force-transmitting sense for each individual movement of the tool carriers 15 on the guideway 3.
The guidance of the lower tool carrier 15B in the guideway 3B is explained with reference to
The lower guide pins 16B comprise a mushroom head 29, which is held and guided in a slotted guide 33 in all portions of the guideway 3 apart from the molding portion A (
A separately activatable level control 31, which can move or adjust the guide roller 30 in its height, is provided for each individual guide roller 30. This allows the final deforming forces to be controlled. In this way it can be ensured that the moldings are of exactly the desired strengths. For this purpose, the level control 31 may be coupled with a weighing cell unit, which follows the camera inspection station 7. The weighing cell unit may have a stored-program controller, in order to transmit a controlled variable to the level control 31 to control the depths of penetration of the individual tools 17 and 18, whereby a change in the masses of the individual moldings is achieved, as explained later.
The mounting and guidance of the upper tool carrier 15A by way of the upper guide pins 16A in the upper guideways 3A corresponds substantially to the guidance and mounting of the lower tool carrier 15B. The mushroom head 29 of the upper guide pin 16A is received by a slotted guide 33 of the upper guideway 3A. As a difference from the guidance of the lower guide pin 16B, however, a slotted guide 33 is also provided in the molding portion A, since it is not necessary to adjust both the lower tool carrier 15B and the upper tool carrier 15A in the vertical direction.
Various examples of tools 17, 18 and their fastening in the respective tool carriers 15A and 15B are explained with reference to
The tools 17 and 18 are formed in the manner of punches. They have an end face 35, which is chosen to correspond to the desired surface of the molding, as shown in
A special tool 36 is shown in
The parts connected to the upper tool carrier 15A are explained with reference to
The radially inner side of the upper tool carrier 15A is connected to the telescopic arm 5A by way of the two-axis fork joint 23, as explained with reference to
Finally, the displacement partition 38 is coupled with the upper tool carrier 15A by way of the connecting mechanism 41. The connecting mechanism 41 comprises a spring 42, which, in the rest position of the spring 42, holds the displacement partition 38 in such a way that the upper face of the displacement partition 38 is at a distance from the lower face of the upper tool carrier 15A. The displacement partition 38 can be moved against the force of the spring 42 vertically in the direction of the upper tool carrier 15A.
The displacement partition 38 is shown in detail in
The parts coupled with the lower tool carrier 15B are explained with reference to
The lower tool carrier 15B is coupled with the lower telescopic arm 5B by way of the two-axis fork joint 23, as explained with reference to
Finally, the die grid 19 is coupled with the lower tool carrier 15B by way of the height-adjustable connecting mechanism 46. The die grid 19 comprises receiving spaces 21, which are delimited by lateral limiting elements 20. The lower openings of the receiving spaces 21 of the die grid 19 are closed by the tools 18 protruding into the receiving spaces 21. Since the volume of the receiving space 21 determines the volume of the molding to be formed, and consequently, given a specific density, also the mass or the weight, the mass or the weight of the moldings can be set by way of the height setting of the tools 18.
A plan view of the die grid 19 is shown in
Since the tools 17 move in the displacement partition 38 and the tools 18 are in the receiving spaces 21 of the die grid 19, the tools 17 are also referred to as tools on the displacement partition side and the tools 18 are also referred to as tools on the die side.
It is explained with reference to
The molding operation takes place on the straight section of the molding portion A of the guideway 3 (
As the molding unit 4 advances further in the molding portion A, driven by the drive unit 2, the upper tool carrier 15A is lowered further with the displacement partition 38, until the lower end face 40 of the displacement partition 38 comes into contact with the upper surface of the ribbon of melt 14. With further lowering of the upper tool carrier 15A with the displacement partition 38, the portion 14A of the ribbon of melt 14 that is located between the end face 45 of the die grid 19 and the end face 40 of the displacement partition 38 is then displaced in the direction of the adjacent receiving spaces 21, as is shown in
As the upper tool carrier 15A is lowered with the displacement partition 38 during the operation of displacing the ribbon of melt 14, the distance of the displacement partition 38 from the upper tool carrier 15A is reduced, counter to the force of the springs 42. At the same time, tilting of the displacement partition 38 is prevented by the guide rods 22. The strength of the springs 42 is designed such that they allow the displacement partition 38 to sink into the ribbon of melt 14. The upper tool part 15A following thereafter thereby increases the pressure which the displacement partition 38 exerts on the ribbon of melt 14, by means of the ever more compressed springs 42. To distribute, i.e. displace, the materials of the melt 14A under the end face 40 of the displacement partition 38 in all directions during the lowering of the displacement partition 38 onto the ribbon of melt 14, the edges of the end face 40 of the displacement partition 38 are specially formed. A displacement partition 38 in which the edges of the transition from the end face 40 to the side faces of the lateral limiting elements 39 of the displacement partition 38 are rounded is shown in
The displacement partition 38 is moved toward the die grid 19 until the end face 40 of the displacement partition 38 rests on the end face 45 of the die grid 19.
As can be seen from
Once the end face 40 of the displacement partition 39 is resting on the end face 45 of the die grid 19, the upper tool carrier 15A is lowered further with the tools 17, without the vertical position of the displacement partition 38 being able to change any further, since it is resting on the die grid 19. The tools 17 are consequently moved in the openings of the displacement partition 38. The lateral limiting elements 39 of the displacement partition 38 thereby serve as a guide for the tools 17. The displacement partition 38 consequently serves as a guide chamber for the lowering tools 17 and as a pre-chamber for the material to be deformed. The lowering of the tools 17 has the effect that the part of the ribbon of melt 14 that is still located between the lateral limiting elements 39 of the displacement partition 38 above the receiving space 21 of the die grid 19 after the displacement is brought into the receiving spaces 21 of the die grid 19 by the end faces 35 of the tools 17. Finally, the portion of the ribbon of melt 14 that is entirely in the receiving space 21 is compressed in the receiving space 21.
The pressure that is exerted on the portions of melt 14 by the tools 17 and 18 can be chosen according to the moldings to be formed. A special feature of the device according to the invention is that the holding pressure time, i.e. the time interval in which the maximum pressure is exerted on the material to be compressed, can be set individually for the material to be deformed and can be set appropriately for this material. The holding pressure time may be chosen to be very long, in particular in comparison with conventional tableting machines. This is so because it is determined substantially by the rotational speed of the drive unit 2 and the length of the straight molding portion A. If the molding portion A is chosen to be very long, the maximum pressure exerted on the material to be molded is maintained for a very long time.
The molding portion A is followed by the cooling portion B. In this portion B, the upper part 4A of the molding unit 4 with the upper tool carrier 15A is moved in the vertical direction away from the lower part 4B of the molding unit 4 with the lower tool carrier 15B. The compressed moldings can cool down during the dwell time in the cooling portion B. In the case of the device according to the invention, this cooling portion B can be chosen to be long enough to ensure that no undesired internal stresses remain in the moldings that are formed. The cooling portion B is followed in the portion C by the sampling station 6. In the case of this station 6, a specific number of moldings may be taken in each case by means of a randomized, memory-controlled, individually activatable vacuum molding removal unit and transferred to an inspection device. The moldings removed from the basic overall whole, or their free places on the lower tool carrier 15B, are transmitted by means of the integrated stored-program controller to the molding removal and camera inspection station 7, in order to avoid erroneous inspection messages. The task of this in-process inspection station is to inspect the quality-related operating mode of the device according to the invention, verify it or, if appropriate, intervene in a controlling manner in the method sequence by means of a stored-program controller, and correspondingly by way of the level control 31.
The portion C with the sampling station 6 is followed by the portion D with the molding removal and camera inspection station 7, which is explained with reference to
At the beginning of the portion D, the tools 18 are moved completely into the receiving space 21 of the die grid 19, so that the moldings 57 that are formed are pressed out of the die grid 19 and are ready for removal. After that, the vacuum molding removal unit 58 is pivoted between the upper tool carrier 15A and the lower tool carrier 15B, so that vacuum receiving tubes of the molding receiving head 59 are located directly above the moldings 57. The vacuum molding removal unit 58 has the same number of individually activatable vacuum tubes for receiving the moldings 57 as the number of tools 18 and receiving spaces 21 that are provided. The moldings are sucked up by the vacuum tubes and lifted off the die grid 19. After that, the molding receiving head 59 is pivoted out of the molding unit 4 by means of the motor 62 and the shaft 61, whereupon the moldings 57 are deposited on a transparent conveyor belt 63. On the conveyor belt 63, the moldings 57 are fed to a camera inspection unit with an upper camera 64 and a lower camera 65 for examining the upper side and underside as well as the side edges of the moldings 57.
By means of the cameras 64 and 65, the formed moldings 57 as a whole can be visually examined. This may involve examining the entire geometric form of the moldings 57. Furthermore, the moldings 57 may be contactlessly examined by means of infrared spectroscopy, in particular NIR spectroscopy. Since the geometric arrangement of the moldings on the conveyor belt 63 corresponds precisely to that in the die grid 19, it may be possible in the case of defective moldings 57 to draw conclusions about defective production in the die grid 19. The NIR spectroscopy operates with the aid of chemometric evaluation methods on the qualitative and quantitative analytical sorting of the acceptable production 7A.
By means of an optional weighing cell unit that follows, the individual weights of the moldings 57 can be recorded. Deviations from predetermined weight tolerances can in this way be registered and used for segregating defective moldings. Furthermore, the weighing cell unit may transmit a controlled variable to the level control 31 and/or to the guide rollers, as already explained.
The portion D is followed by the portion E with the cleaning station 8, which is explained with reference to
Between the upper tool carrier 15A and the lower tool carrier 15B, at least one brush head 47 is moved in by means of a brush shaft 50. Attached to the end of the brush shaft 50 is a brush head holder 49, which has cleaning brushes 48 in the direction of the upper part 4A and the lower part 4B of the molding unit 4. The brush head 47 rotates and in this way cleans all the parts that have come into contact with the moldable material. In particular, the displacement partition 38 and the tools 17 as well as the die grid 19 and the tools 18 are cleaned. After the cleaning, the brush shaft 50 is rotated out of the molding unit 4. For this purpose, it is fastened on a rotating device 51, which may comprise three brush heads 47 and corresponding numbers of brush shafts 50. The brush shafts 50 rotated out of the molding unit 4 are then cleaned by means of compressed air 52, which is fed to the compressed air nozzles 53B by way of the system of pipes 53A. The entire cleaning operation takes place fully automatically and is integrated in the guideway 3. The cleaning station 8 can operate while the operation of the continuously moving molding units 4 is in progress. The cleaning station 8 may be equipped with various brushes, compressed air and extraction devices. It is fully movable in all three coordinate directions and equipped with proximity sensors and exchanging units.
The portion E with the cleaning station 8 is followed by the portion F with the molding space coating device 9, which is explained with reference to
The molding space cleaning device 9 comprises a system of pipes 54, with which a coating fluid 56 or a coating powder (mold release agent) can be fed in. The coating fluid 56 or the coating powder emerges from the nozzles 55. The number of nozzles 55 preferably corresponds to the number of tools 17 and 18. The task of the molding space coating device 9 is to reduce or eliminate possible tendencies for the various materials that are to be processed to become adhesively attached, in order to ensure a smooth production sequence. For this purpose, the parts of the device that come into contact with the material to be processed are coated with the coating fluid 56 or the coating powder. The choice of coating fluid depends on the material to be molded and the intended field of use of the moldings 57 to be formed.
After passing the molding space coating device 9 in portion F, the molding units 4 are fed to the molding portion A on the guideway 3 for the renewed forming of moldings.
According to a second exemplary embodiment of the present invention, the moldable material from which the moldings 57 are formed is not formed by means of extrusion technology. Rather, in the case of this exemplary embodiment, the moldable material is a bulk material 14B of any desired composition. The bulk material 14B is, in particular, powdered, flowable and moldable. It may be, for example, powdered granules. The device according to the invention can be advantageously used in particular for a bulk material 14B, for example from granulating technology, which can be deformed very poorly, since the holding pressure time can be set to a very long time period in the case of the device according to the invention.
Since, in the case of the second exemplary embodiment, the bulk material 14B can be filled directly into the receiving spaces 21 of the die grid 19, the displacement partition 38 can be omitted in the case of the device of the second exemplary embodiment. However, it preferably continues to serve for guiding the tools 17. In the case of the second exemplary embodiment, the bulk material 14B is filled directly into the receiving spaces 21 by means of a device known per se, as used for example in the case of conventional tableting machines, as is represented in
In the case of the second exemplary embodiment, it is particularly important that the compressive energy produced during the molding operation is transmitted to the material to be molded over a longer time period, i.e. a high pressure is exerted on the material to be molded over a longer period of time, in order in this way to counteract the material-specific forces of resilient recovery of the materials to be deformed.
Furthermore, the pressure can also be maintained during the cooling portion B, in that the upper part 4A and the lower part 4B of the molding unit 4 only move apart after this cooling portion B. In this way, materials with increased elastic forces of resilient recovery are kept in the plastifying position until they solidify or cool down.
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| 06024452 | Nov 2006 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2007/062734 | 11/23/2007 | WO | 00 | 12/1/2009 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2008/062054 | 5/29/2008 | WO | A |
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| International Search Report for PCT/EP2007/062735, filed May 29, 2008, Abbott GmbH & Co. KG. |
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| English Translation of Written Opinion of the International Searching Authority for PCT/EP2007/062734, Abbott GmbH & Co. KG. |
| International Search Report for PCT/EP2007/062734, filed May 29, 2008, Abbott GmbH &Co. KG. |
| Written Opinion of the International Searching Authority for PCT/EP2007/062734, Abbott GmbH &Co. KG. |
| Number | Date | Country | |
|---|---|---|---|
| 20100148399 A1 | Jun 2010 | US |
