Abstract:
A container design process. The process involves receiving container design specifications, receiving readings from a first scan of a container taken before the container has been exposed to expected conditions of use, receiving readings from a second scan of the container taken after the container has been exposed to the expected conditions of use, applying finite element analysis to the container using measurements obtained by comparing the first scan and the second scan, and recommending design changes that will enable the container to meet the container design specifications based on the finite element analysis.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates generally to container manufacturing methods and, more particularly, relates to a container design process.  
         BACKGROUND OF THE INVENTION  
         [0002]    In the typical container design process, a graphic artist first sketches a container concept. Using CAD/CAM software, an engineer may then translate those sketches into a container design drawing that indicates actual container measurements. In a manner well known to those skilled in the art, the engineer may then prepare a mold corresponding to the container design drawings. The engineer may then form the container using the mold so as to test the container under the expected conditions of use.  
           [0003]    Typically, early prototypes of the container do not meet the design specifications or the objective for handling the expected conditions of use. For example, exposing the container to these expected conditions of use may deform the container. Several rounds of failure may be expected until the container design is optimized.  
           [0004]    If the container does not meet the design specifications for handling the expected conditions of use, the engineer may then visually examine the container. The engineer may make an educated guess about how to modify the container design drawings in order to produce a container that meets, or more closely meets, the design specifications. The engineer also may turn to finite element analysis to determine how to modify the container geometry and drawings. Although the engineer may at this point use finite element analysis, to date there has been no simple method by which the engineer can obtain the actual measurements to use in the finite element analysis equations. Rather, the engineer often just estimates these numbers.  
           [0005]    The engineer may then repeat the process of producing a mold (this time corresponding to the modified container design drawings), making the container using the mold, and then testing the container under the expected conditions of use to determine if the container meets the design specifications. Because of the inefficiency in this trial and error process of designing a container and resolving geometry failures, producing a container that meets the design specifications often requires many iterations of this process.  
           [0006]    Because of the many iterations typically required to produce a container meeting the given design specifications, the current container design process is time consuming. Because the process is time consuming, the process is also costly because the company developing the new container design must retain the engineers for their participation in the design process. Therefore, there is a need in the art for an improved container design process.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention meets the needs described above in a new container design process. As a result of the increased accuracy of this new container design process, fewer prototypes are created and tested. This in turn provides the container design process with the advantages of being faster and cheaper than previous container design processes.  
           [0008]    In the new container design process, an engineer prepares container design drawings, typically using CAD/CAM software. The engineer then prepares a unit cavity mold corresponding to the container design drawings. From the unit cavity mold, the engineer then creates a container. Next, the engineer completes a first scan of the container with a scanning device. After the first scan, the engineer subjects the container to expected conditions of use. The engineer then completes a second scan of the container with the scanning device. By comparing the first scan and the second scan, a computer can predict appropriate changes to make to the container design drawings in order to produce a container meeting given design specifications concerning how the container may respond to expected conditions of use.  
           [0009]    The comparison between the first scan and the second scan involves calculating changes in wall thickness of the container and changes in container geometry from the first scan to the second scan. Typical scanning devices include magnetic resonance imaging devices, optical scanning devices, and other electromagnetic scanning devices. To use such scanning devices, the engineer may first have to cover the container with a substance detectable by the scanning device. By covering the container surface with microdots of the substance that a computer can separately track from the first scan to the second scan, the computer can calculate the geometric changes in the container resulting from exposure of the container to expected conditions of use.  
           [0010]    Generally described, the present invention comprises a method for designing a container. An engineer prepares container design drawings, preferably with CAD/CAM software. The engineer then creates the container from the container design drawings. After completing a first scan of the container with a scanning device, the engineer exposes the container to expected conditions of use. The engineer then completes a second scan of the container with the scanning device. A computer then compares the first scan and the second scan.  
           [0011]    By comparing the first scan and the second scan, the computer may determine if the container meets design specifications. If the container does not meet design specifications, the computer may apply finite element analysis to the container using measurements obtained by comparing the first scan and the second scan. Based upon that finite element analysis, the computer may then suggest refinements to the container design drawings that are calculated to produce a container meeting the design specifications. Comparing the first scan and the second scan could also involve calculating location changes, from the first scan to the second scan, of microdots of substance that are placed onto the container and are detectable by the scanning device.  
           [0012]    Using the revised container design drawings, the process may be reiterated. Multiple iterations may be necessary to finally produce container design drawings for containers that meet the design specifications.  
           [0013]    In one embodiment of the process, the computer determines if measurements of the container obtained from the first scan conform to the container design drawings. If the measurements of the container obtained from the first scan do not conform to the container design drawings, then the process continues by attempting to produce a container that does conform to the container design drawings.  
           [0014]    To complete the first scan of the container with the scanning device, an engineer may first coat the container with a substance detectable by the scanning device. The engineer may then scan the container with the scanning device to collect information about wall thickness and container geometry. To coat the container with the substance detectable by the scanning device, the engineer may coat the inside and the outside of the container with the substance. To coat the container with the substance detectable by the scanning device, the engineer may additionally or alternatively coat the container with microdots of the substance that can be separately tracked from the first scan to the second scan.  
           [0015]    The present invention also comprises a method for improving a container design. A computer receives container design specifications. The computer also receives readings from a first scan of a container taken before the container has been exposed to expected conditions of use. The computer further receives readings from a second scan of the container taken after the container has been exposed to the expected conditions of use. Using measurements obtained by comparing the first scan and the second scan, the computer applies finite element analysis to the container. Based on the finite element analysis, the computer recommends design changes that will enable the container to meet the container design specifications.  
           [0016]    The various aspects of the present invention may be more clearly understood and appreciated from a review of the following detailed description of the disclosed embodiments and by reference to the appended drawings and claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    [0017]FIG. 1 is a logical flow diagram for a container design process in accordance with an exemplary embodiment of the present invention.  
         [0018]    [0018]FIG. 2 is a plan view of the container with the layer and the small dots thereon.  
         [0019]    [0019]FIG. 3 is a plan view of the mold cavities.  
         [0020]    [0020]FIG. 4 is a schematic view of the computer, the ring scanner, and the wand scanner. 
     
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0021]    The present invention is typically embodied in a container design process. Specifically, an engineer may prepare initial container design drawings, typically using CAD/CAM software and a “best estimate” finite element analysis. The engineer then may prepare a unit cavity mold corresponding to the container design drawings. From the unit cavity mold, the engineer then may create a container. Next, the engineer may complete a first scan of the container with a scanning device. After the first scan, the engineer may subject the container to the expected conditions of use. The engineer then may complete a second scan of the container with the scanning device. By comparing the first scan and the second scan, actual physical measurements of wall surfaces and thicknesses may be provided. A computer then may predict appropriate changes to make to the container design drawings so as to produce a container meeting the given design specifications concerning how the container may respond to the expected conditions of use.  
         [0022]    The comparison between the first scan and the second scan involves calculating the changes in the wall thickness of the container and the changes in the container geometry. Typical scanning devices include magnetic resonance imaging devices, optical scanning devices, and other electromagnetic scanning devices. To use such scanning devices, the engineer may first have to cover the container with a substance detectable by the scanning device. By covering the container surface with, for example, small dots of a substance that a computer can track separately from the first scan to the second scan, the computer can calculate the geometric changes in the container resulting from the exposure of the container to the expected conditions of use.  
         [0023]    Container Design Process  
         [0024]    [0024]FIG. 1 is a flow chart illustrating the steps in a typical container design process  100  to develop a container  10  with the use of a computer  15 . FIGS.  2 - 4  show the container  10  and the elements used to design the container  10 . The container design process  100  begins with step  110 .  
         [0025]    In step  110 , an engineer prepares container design drawings, preferably using CAD/CAM software. In step  115 , the engineer also prepares, based upon the drawings, an estimated finite element analysis which describes the expected geometry of the container under its intended use conditions. As is well known, finite element analysis is a method for solving an equation by approximating continuous quantities as a set of quantities at discrete points, often regularly spaced into a so-called grid or mesh. Because finite element analysis can be adapted to problems of great complexity and unusual geometry, it is useful in the solution of fluid mechanics and mechanical systems issues. Finite element analysis is described in detail in, for example, Spyrakos, C., FINITE ELEMENT MODELING, published by Algor, Inc. of Pittsburgh, Pa., incorporated herein by reference. Numerous Finite Element Analysis software packages also are commercially available. Examples include several packages sold by Algor, Inc. of Pittsburgh, Pa. and Adina R &amp; D, Inc. of Watertown, Mass.  
         [0026]    In step  120 , the engineer prepares a unit cavity mold  20  that corresponds to the container design drawings. Methods for preparing the unit cavity mold  20  from the container design drawings are well known to those skilled in the art. In step  130 , the engineer creates the container  10  using the unit cavity mold  20  by blow molding or other manufacturing means known to those skilled in the art.  
         [0027]    In step  140 , the engineer coats an inside surface  30  and an outside surface  40  of the container  10  with a coating  55  of a substance  60  detectable by a scanning device  70 . Although the scanning device  70  may not be able to detect directly the surfaces  30 ,  40  of the container  10 , the scanning device  70  can detect the locations of the substance  60  chosen to coat the inside  30  and the outside surface  40  of the container  10 . From this information, the scanning device  70  can indirectly determine the locations of the container surfaces  30 ,  40  and the thickness of the container wall, i.e., the difference between the locations of the container surfaces  30 ,  40 . Selection of the appropriate substance  60  for the coating  55  on the container  10  will therefore depend on the scanning device  70  to be used in the process.  
         [0028]    Those skilled in the art should be familiar with a multitude of scanning devices  70  appropriate for the purposes of the present invention. Such scanning devices  70  include, but are not limited to, magnetic resonance imaging (MRI) devices, other electromagnetic scanning devices, and optical scanning devices.  
         [0029]    The scanning device  70  may include a wand scanner  75 . The scanning device  70  alternatively may include a ring scanner  80 . A combination of scanning devices  70  may be used to complete a scan of the container  10 . For example, the wand scanner  75  inserted into the container  10  can detect the coating  55  of the substance  60  on the inside surface  30  of the container  10  and the ring scanner  80  surrounding the outside surface  40  of the container  10  can detect the substance  60  on the outside surface  40  of the container  10 . However, a single scanning device  70  could detect the coating  55  of the substance  60  on both the inside surface  30  and the outside surface  40  of the container  10 .  
         [0030]    Those skilled in the art also should be familiar with the appropriate substances  60 , which, if needed, are available for use with a particular scanning device  70 . If the scanning device  70  includes a magnetic resonance imaging device, for example, then the substance  60  may include magnetic particles such as iron ions. If the scanning device  70  includes an optical or a laser-scanning device, then the substance  60  may be reflective or refractive coating detectable by the particular optical scanning device  70 . Some optical scanning devices  70  may not require that the container  10  be coated with any particular substance  60  in order to be successfully scanned.  
         [0031]    After the engineer coats the inside surface  30  and the outside surface  40  of the container  10  with the substance  60  detectable by the scanning device  70 , step  150  is executed. In step  150 , the engineer places a grid of the small dots  90  on the outside surface  40  of the container  10 . These small dots  90  are preferably individually distinguishable from the coating  55  of the substance  60 , which may be more uniform and uninterrupted, of step  140 . Preferably, these small dots  90  comprise an increased amount or concentration of the substance  60  used in step  140 . To help distinguish the small dots  90  from the coating  55  of the substance  60  of step  140 , however, the small dots  90  may instead include a different substance  60  detectable by the scanning device  70  than the substance  60  applied in step  140 .  
         [0032]    The engineer affixes the small dots  90  to the container  10  such that the engineer may arrange the small dots  90  sequentially in a manner that renders, but is not limited to, a grid or a mesh  95 . The grid or the mesh  95  therefore corresponds to the grid or the mesh system that is integral to conventional finite element analysis. Because the engineer can repeat identical sequential traversal of the small dots  90  or the mesh  95  at a later time, these small dots  90  or the mesh  95  allow the engineer to track the locations of specific points on the container  10  from scan to scan, even though the container  10  may have become deformed in the interim. The small dots  90  or the mesh  95  therefore may enable the engineer to track deformities in the container  10  occurring between scans from exposure of the container  10  to the expected conditions of use.  
         [0033]    In step  160 , the engineer completes a first scan of the container  10  with the scanning device  70 . The data recorded during this first scan can be digitally stored in the computer  15 . The computer  15  may calculate the wall thickness of the container  10  in various locations using the data recorded during the first scan. This may be done, for example, by calculating the difference between the nearest point on the coating  55  on the outer surface  40  to a fixed point of the scanning device  70  and the nearest point on the coating  55  of the inner surface  30  to the fixed point of the scanning device  70 .  
         [0034]    From the data recorded during the first scan, the computer  15  also can determine the initial geometry of the container  10 . In other words, the computer  15  may determine the initial locations of each of the small dots  90  or the mesh  95  relative to the scanning device  70 .  
         [0035]    In step  165 , the computer compares the container wall thickness calculations and the container wall geometry to the CAD/CAM drawings to determine if the drawings have been accurately embodied in the container  10 . If the container  10  does not match the CAD/CAM drawings, then the “NO” branch is followed to step  120  to attempt again to reproduce accurately the CAD/CAM drawings in a prototypical container. Referring still to step  165 , if the container  10  does match the CAD/CAM drawings, then the “YES” branch is followed to step  170 .  
         [0036]    In step  170 , the engineer exposes the container  10  to the expected conditions of use for the container  10 . To replicate the expected conditions of use, the engineer may, for example, fill the container  10  with a carbonated liquid at a known pressure, expose the container  10  to an internal vacuum, expose the container  10  to temperature extremes, or simulate the handling that the container  10  would experience during shipment to a consumer. The pressure may be greater than atmospheric. During extensive testing, the engineer may subject the container  10  to combinations of these and other expected conditions of use.  
         [0037]    In step  180 , the engineer completes a second scan of the container  10  with the scanning device  70 . The data recorded during this second scan also can be digitally stored in the computer  15 . Using the data recorded during the second scan, the computer  15  again can calculate the wall thickness of the container  10  in various locations and the new container geometry (i.e., the new locations of the small dots  90 , or the new locations of the nodes that make up the mesh  95 ). Because of the exposure of the container  10  to the expected conditions of use in step  170 , the wall thickness of the container  10  and the new container geometry are likely to be different from that found in step  160 .  
         [0038]    In step  185 , the computer  15  examines the wall thickness of the container  10  determined by the second scan and the new locations of the small dots  90 , or the new locations of the nodes of the mesh  95 , relative to the initial locations of the small dots  90  or the nodes of the mesh  95 . Also, the engineer may make visual observations to determine the cause of the failure, if any, of the container  10 . From this examination, the computer  15  may be used to determine if the container  10  meets the predetermined design specifications, including performance requirements. If the container  10  meets the predetermined design specifications, then the “YES” branch is followed to step  195 , and the container design process  100  ends because the container design drawings are now optimized. If the computer  15  determines in step  185  that the container  10  does not meet the predetermined design specifications, then the “NO” branch is followed to step  190 .  
         [0039]    In step  190 , the computer  15  may make improvements to the initial finite element analysis of the container  10 . The calculations may be based upon the commercially available Finite Element Analysis software described in detail above. The use of such software is considered to be with the ability of one of ordinary skill in the art. The actual finite element analysis techniques embodied in the software is not considered essential to the present invention. The computer  15  may do this initial analysis by using computations derived from the two scans of the container  10  as the input into the finite element analysis equations. These computations may include the wall thickness computations and the movement of the small dots  90  or the nodes of the mesh  95  from their initial locations (as determined by the first scan) to their new locations (as determined by the second scan). The actual physical measurements and the location changes of the small dots  90  or nodes of the mesh  95  of the container  10  after it has been exposed to its intended use may be used. This information may correspond to the nodes of the mathematical mesh of the finite element analysis. The computer  15  may then generate an improved finite element analysis by having verified dimensions for the equations that describe the container geometry and the dimensional behavior that could be expected when the container  10  is put under the expected conditions.  
         [0040]    In Step  200 , after running the improved finite element analysis, the computer  15  may then recommend changes to the container geometry and the associated design drawings that should enable the container  10  produced from those drawings to meet design specifications. The computer  15  may automatically make those changes to the container design drawings.  
         [0041]    The process then repeats from step  120 , where the engineer prepares a unit cavity mold  20 , or modifies the previous mold  20 , that corresponds to the refined container design drawings. The procedures and the provisions of the above process thus provides the physical verifications for the improvement of the initial finite element analysis that is used to describe the geometry and the behavior of the geometry of the container after exposing the container to its intended use.  
         [0042]    Automation of the Container Design Process  
         [0043]    The steps of the container design process  100  may be automated under the control of the computer  15 . Alternatively, a human may perform some steps and leave other steps, such as digitally storing the information from the two scans of the container  10  and performing calculations on that information, to the computer  15 .  
         [0044]    The computer  15  may have typical features of a computer system, such as a processing unit, a system memory containing random access memory (RAM) and read only memory (ROM), and a system bus that couples the system memory to the processing unit. The computer  15  also may include various memory storage devices, such as a hard disk drive, a magnetic disk drive (e.g., to read from or write to a removable magnetic disk), and an optical disk drive (e.g., to read from or write to optical media such as a CD-ROM).  
         [0045]    A number of program modules may be stored in the drives and RAM of the computer  15 . Program modules control how the computer  15  functions and interacts with the user, with input/output devices, or with other computers  15 . Program modules include routines, an operating system, application program modules, data structures, browsers, and other software or firmware components. The present invention may conveniently be implemented in various program modules that are stored on the drives of the computer  15  and implement the methods described in the detailed description.  
         [0046]    No particular programming language will be described for carrying out the various procedures described in the detailed description because it is considered that the operations, steps, and procedures described and illustrated in the accompanying drawings are sufficiently disclosed to permit one of ordinary skill in the art to practice an exemplary embodiment of the present invention. Moreover, there are many computers and operating systems that may be used in practicing an exemplary embodiment, and therefore no detailed computer program could be provided which would be applicable to all of these many different systems. Each user of a particular computer  15  will be aware of the language and tools which are most useful for that user&#39;s needs and purposes.  
         [0047]    Conclusion  
         [0048]    The detailed description has described a container design process. Other alternative embodiments will become apparent to those skilled in the art to which an exemplary embodiment pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description.