Patent Publication Number: US-2013234358-A1

Title: Method for manufacturing profiled strips and hollow profiled bodies and a device for implementing the method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to German Patent Application No. 10 2012 004 826.2, filed Mar. 8, 2012, which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     Described is a method for manufacturing profiled strips and hollow profiled bodies, in particular a method for manufacturing profiled strips and hollow profiled bodies for vehicles, and a device for implementing the method. 
     BACKGROUND 
     Known from publication DE 196 35 357 A1 is a method and a tool system for manufacturing profiles reinforced with continuous filaments. The known method is used to manufacture fiber-reinforced extruded profiles from a plastic matrix with embedded aluminum fibers. Extrusion already yields the profile comprised of a plastic material, preferably a thermoplastic, and longitudinal fibers are then fused into the extruded profile with the extrusion process still ongoing. 
     Known from publication DE/EP 0 093 748 T1 is a method and device for manufacturing profiles out of fiber-reinforced, thermoplastic resin and profiles manufactured in this way. To this end, the publication discloses a method for manufacturing thin profiled parts comprised of continuously unidirectional fibers, which are embedded in a thermoplastic resin, in which a web of parallel fibers is impregnated with resin particles, after which the resin is melted, and the profiled part is formed and cooled. 
     For this purpose, the fiber web is immersed in a bath comprised of resin particles, and the particles are mechanically induced to penetrate into the web, wherein the excess particles are removed to achieve the desired percentage of resin in relation to the fibers. Cylinders or rollers are used to mechanically press the resin particles into a web comprised of fibers, and the rolled-in resin is melted, after which the fiber-reinforced plastic band is formed into a band between two cooled cylinders. 
     At least one object herein is to provide a method and device for cost-effectively manufacturing profiled strips and hollow profiled bodies for vehicles out of a fiber-reinforced plastic band. In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background. 
     SUMMARY 
     An example for implementing the method for manufacturing profiled strips exhibits the following steps. An organic sheet band is first prepared. The organic sheet band is then heated to a deformation temperature while being fed through. The organic sheet band is thereafter profiled by means of profiling rollers while being fed through. The roller-profiled organic sheet band can finally be cut to a specified profiled strip length. 
     Organic sheet denotes a fiber-reinforced plastic, which is shaped like a sheet due to its dimensions. 
     With this method, nearly any number of profiled strips can be cost-effectively manufactured while being processed. However, a plurality of roller stages in corresponding profile roller chambers is used for roller profiling. But the method makes it possible to fabricate any number of varying cross sectional profiles. Several possible cross sectional profiles will be described in more detail in the attached figures. To this end, profiling takes place in several roller profiling stages until such profiles have been fabricated. 
     In an exemplary embodiment, in order to fabricate profiled components in any embodiment desired and in any cross sectional profile out of organic sheet, roller forming tools are incorporated into the profiling chambers, and a heating furnace is connected upstream at least in a first heating chamber, wherein additional intermediate heating chambers with corresponding heating furnaces can be interspersed, depending on the length of the necessary roller forming tools or number of necessary roller profiling stages. 
     During roller profiling, the organic sheet bands, which are films comprised of thermoplastic continuously fiber-reinforced with carbon, glass or aramite fibers, are kept in a softening temperature range of the thermoplastic, for example, lying in a range of from about 150° C. to about 350° C., so that a suitable deformation temperature range measures from about 200° C. to about 300° C. 
     Another embodiment provides that a partially roller-profiled organic sheet band is intermediately heated between the roller profiling stages once a prescribed deformation temperature threshold has been reached during the multistage roller profiling process. The deformation temperature threshold for intermediate heating is about 5° C. higher than the lower softening temperature of the organic sheet band. 
     In another embodiment, the organic sheet band is wound onto an organic sheet band coil as a prepreg semi-finished product, and is unwound from such an organic sheet band coil during the continuous process. 
     Another embodiment provides that reinforcement ribbing initially is incorporated into the organic sheet band after heating and before multistage roller profiling, so as to elevate the dimensional stability of the profiled strip. 
     The profiles comprised of organic sheet bands fabricated with the roller forming method exhibit a flexible shaping at a high stiffness. In addition, it is possible to fabricate a respectively closed profiled box for hollow profiled bodies or hollow profiled beams for vehicle bodies out of two organic sheet profiled bands via welding. To this end, known welding procedures like friction welding, vibration welding and/or electromechanical powder welding can be used. This makes it possible to cost-effectively prepare hollow profiles for vehicle construction. 
     One basic advantage to using organic sheets as profiled strips or hollow profiles in motor vehicle construction lies in the reduced weight, which advantageously brings with it a decreased fuel consumption for motor vehicle operation. Also advantageous is that fabrication is more cost-effective by comparison to the previously used deep-drawing methods for generating profiled strips for motor vehicle construction. 
     In an exemplary embodiment, a device for implementing a method for manufacturing profiled strips or hollow profiled bodies for vehicles of the kind described above exhibits at least one heating chamber with an area for receiving an organic sheet band from an organic sheet band coil. The device further exhibits at least one profiling chamber with at least one roller profiling stage. Finally, a cutter is built onto the device for cutting a roller-profiled extruded profile to a prescribed profiled strip length while removing the extruded profile from the profiling chamber. 
     With such a device, a plurality of profiled strips can be manufactured as they are fed through the device, without requiring dies or extrusion dies. 
     In addition, the device can exhibit a first roller profiling chamber and a second roller profiling chamber, between which is situated an intermediate heating chamber to ensure that the deformation temperature does not drop below a threshold deformation temperature. This threshold deformation temperature depends on the lowest softening temperature of the organic sheet band, and, in an embodiment, is at least about 5° C. higher than this lower softening temperature TuE. 
     In another embodiment, instead of a first and second profiling chamber, the device can exhibit as many profiling chambers are desired, which each have arranged between them an intermediate heating chamber, so as to keep the organic sheet temperature within the required deformation temperature range during roller deformation, for example, at about 150° C.—TV—350° C., such as about 200°≦TV≦300° C. 
     In order to test, determine and regulate the temperature, each of the chambers can exhibit corresponding temperature sensors, so that the organic sheet remains within the softening temperature range of the thermoplastic while being processed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The various embodiments will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein: 
         FIG. 1  is a schematic diagram of the method for manufacturing profiled strips out of an organic sheet band, in accordance with an exemplary embodiment; 
         FIG. 2  is a schematic, perspective view of a device for manufacturing profiled strips out of an organic sheet band, in accordance with an exemplary embodiment; 
         FIG. 3  includes  FIGS. 3   a  and  3   b , which are schematic views an organic sheet band with an organic sheet band width roller profiled into a profiled strip with a profile circumference, in accordance with exemplary embodiments; 
         FIG. 4  includes  FIGS. 4   a  to  4   f , which are schematic cross sections of roller profiled profiles strips, in accordance with exemplary embodiments; and 
         FIG. 5  includes  FIGS. 5   a  and  5   b,  which are cross-sectional views of hollow profiled bodies manufactured out of roller profiled strips, in accordance with exemplary embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is merely exemplary in nature and is not intended to limit the various embodiments or the application and uses thereof. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description. 
       FIG. 1  presents a schematic diagram of a method for manufacturing profiled strips  50  out of an organic sheet band  1  in accordance with an exemplary embodiment. The organic strip band  1  is a semi-finished product of continuous strand-reinforced thermoplastic with an organic sheet band width s, which corresponds to the profile circumference of the profiled strip  50 , and an organic sheet band thickness d, as depicted in the following figures. While the organic sheet band width s depends on the profile circumference of the profiled strip  50  to be manufactured or a hollow profiled body to be manufactured, the organic sheet band thickness d ranges from about 0.5 mm to about 3 mm. Such an organic sheet band  1  can be deformed at a temperature TV in the range of about 150° C. to about 350° C. To this end, the organic sheet band  1  is passed through a heating chamber  6  while being processed, and heated to the required deformation temperature. The heated organic sheet band then passes through roller tools in a profiling chamber  30 , which can comprise several profiling stages  3 , until the at least partially roller profiled organic sheet band  8  has dropped to a threshold deformation temperature TS at least about 5° C. higher than the lowest softening temperature TuE of the thermoplastic of the organic sheet band at T&gt;TS=TuE+about 5° C. 
     In an embodiment, if the profile has already been completely roller profiled before this threshold deformation temperature TS has been reached, the roller-profiled extruded profile  2  is separated into profiled strips already after a single roller profiling chamber  7 . However, if additional roller profiling tools or roller profiling stages  4  are needed, the partially roller-profiled extruded profile  8  is heated in an intermediate heating chamber  9  to the deformation temperature TV in the aforementioned temperature range, and passed through the other roller profiling stages  4  in another, second roller profiling chamber  40 . 
     In another embodiment, if the end profile of the profiled strip  50  is reached after the second roller profiling chamber  40 , the roller-profiled organic sheet band  2  is cut in an adjoining cutting device  10  to the profiled strip lengths  1 , and the profiled strip  50  can be cooled down to room temperature T=TR. The organic sheet band  1  can continue to be fed through and formed into the roller-profiled organic sheet band  2  until the organic sheet band coil  5  has been completely unwound. 
       FIG. 2  presents a schematic, perspective view of a device  100  for manufacturing profiled strips  50  out of an organic sheet band  1 , which is wound off of an organic sheet band roller  5  and fed to the first heating chamber  6  of the housing 
     In accordance with an exemplary embodiment, in order to economize on energy in this device  100 , the heating chambers  6  and  9  along with the profiling chambers  30  and  40  are accommodated in a single housing with the adjacent cutting device  10 . Each heating chamber  6  or  9  can incorporate thermocouples, so as to maintain a constant prescribed deformation temperature of the heating chambers. In addition, temperature sensors are provided inside the profiling chambers  30  and  40 , and respectively monitor the temperature of the organic sheet band during roller profiling. Cutting to the corresponding length  1  of the profiled strips  50  for a vehicle can only take place once the temperature in the cutting device has dropped below the lower softening temperature value of TuE at T&lt;TuE. 
       FIGS. 3   a  and  3   b  of  FIG. 3  present a schematic view of how an organic sheet band  1  with an organic sheet band width s is roller profiled into a profiled strip with a profile circumference s. The organic sheet band is wound onto an organic sheet band coil  5  in organic sheet band width s, and is wound off of the latter for roller profiling as depicted on  FIG. 3   a.    
       FIG. 3   b  shows the profile of the roller profiled organic sheet band  2  generated via roller profiling, wherein the profile circumference s is equal to the organic sheet band width s, and the organic sheet has a thickness d in the range of about 0.5 mm to about 3 mm. 
       FIGS. 4   a  to  4   f  of  FIG. 4  present schematic cross sections of roller profiled strips  50   a  to  50   f,  according to various embodiments. 
     The profile of the profiled strip  50   a  on  FIG. 4   a  can already be achieved with only a single roller profiling stage by drawing the heated organic sheet band between two corresponding profile rollers. The profile on  FIG. 4   a  can simultaneously be used as a half profile for a hollow profiled body by integrally joining two of these profiles depicted on  FIG. 4   a  with their flange surfaces  11  and  12 . Such an integral bond can be achieved by welding or adhesively joining the flange surfaces  11  and  12  of two profiled strips  50   a.    
     The profile of the profiled strip  50   b  on  FIG. 4   b  can be realized in three roller profiling stages, wherein a U-shaped area  13  with a short leg  14  and a long leg  15  are created in a first roller profiling stage. The long leg  15  is subsequently chamfered in a second roller profiling stage at a first chamfering angle α of about 90°, and the second chamfering angle β is then also realized in a third roller profiling stage at about 90°. 
     Distinctly more roller profiling stages are required for the profile of a profiled strip  50   c  shown on  FIG. 4   c , while the profile of a profiled strip  50   d  depicted on  FIG. 4   d  can practically be realized in a single roller profile stage. The profile of the profiled strip  50   e  on  FIG. 4   e  can also be realized using three roller profiling stages. 
     While the profile of a profiled strip  50   f  depicted on  FIG. 4   f  can in turn be realized with just a single roller profiling stage, a significantly wider organic sheet band  1  is here suitable to provide a profile for a profiled strip  50   f  that can simultaneously also serve as a semi-finished product for manufacturing three hollow body profiles with three different cross sections for the hollow body. In this case as well, the flange surfaces  11  and  12  can be used to generate a correspondingly adjusted second profiled strip for integrally joining the flange surfaces  11  and  12  in order to manufacture hollow profiled strips or hollow profiled beams with the strip  50   f  depicted on  FIG. 4   f.    
       FIGS. 5   a  and  5   b  of  FIG. 5  show how hollow profiled bodies  60  are manufactured out of roller profiled strips  50  in an exemplary embodiment. 
     Fabricated to this end as shown on  FIG. 5   a  is a first profiled strip  50   f  with three U-shaped areas, and a uniform profiled strip  50   g  also with three U-shaped bulges, wherein each of the profiled strips  50   f  and  50   g  exhibits flange surfaces  11  and  12  that are integrally joined together to form the hollow profiled bodies  60   a,    60   b  and  60   c  depicted on  FIG. 5   b . This integral bond can be a welded or adhesive bond, wherein the three hollow profiled bodies  60   a,    60   b  and  60   c  can subsequently be formed by dividing up the hollow body  60  depicted on  FIG. 5   a  to form individual hollow profiled bodies, e.g., for hollow profiled beams in vehicle construction. 
     While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims and their legal equivalents.