Patent Publication Number: US-2021163166-A1

Title: System and method for the measurement of stretch film

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Patent Application No. 62,656,683, filed Apr. 12, 2018, which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     Stretch film is typically a plastic-based film that can be stretched and applied to or wrapped around one or more items. Stretch film is typically fabricated from linear low-density polyethylene (LLDPE). Stretch film can also be manufactured from or include other materials and layers while maintaining an ability to stretch. Once manufactured, stretch film is wound around a cylindrical core to produce a supply roll. Most stretch film can stretch between 50% and 500% of the manufactured length of stretch film originally wound around the core. 
     Stretch film is commonly applied as a wrap around one or more items in order to tightly bind the item(s). The binding of the item(s) occurs as a result of elastic recovery from the stretch film being stretched at one or more steps of a wrapping cycle. The wrapping cycle can be manual, semi-automated, or automated. The semi-automated and automated processes often include a stretch film machine. These machines typically include a platform or a conveyor on which the item(s) to be wrapped can be placed. A stretch film dispenser then automatically wraps the stretch film around the item(s) on the platform or conveyor. The stretch film dispenser can consist of one or more rollers on which the core of the supply roll of stretch film can be coupled. The supply roll coupled to the roller can be horizontal or at an angle or variable angle as required by the stretch film machine. Some stretch film machines move the roller to which the stretch film is mounted so that the item(s) to be wrapped can maintain position. Other stretch film machines maintain the location of the roller and spin or move the item(s) to be wrapped during the wrapping cycle. Further, a combination of moving or rotating both the roller and the item(s) can be used in a stretch film machine to complete the selected wrapping cycle. 
     The stretch film machine can also include an additional series of rollers over which the unwound stretch film passes and can be stretched. The additional series of rollers are calibrated to apply a specific force to the stretch film in order to obtain a desired elastic tension and stretch film thickness for the wrapping cycle. Stretch film stretches as soon as it leaves the core which makes determining how much stretch film is unwound from the core challenging. The amount of stretch film unwound from the core is a useful measurement in cost analysis and allows for adjustments to be made to wrap cycle settings. Knowing the amount of stretch film unwound from the core of a supply roll also allows a user to determine the amount of stretch film still wound around the core. The amount of stretch film that remains on the core of a supply roll allows a user to reduce waste and maintain the quality of the wrap. For example, if the supply rolls runs out of stretch film during the wrap cycle, it is likely the wrap cycle will have to start again from the beginning with a new roll of stretch film. Likewise, if the supply roll is near the end of the stretch film, there is often a difference in the quality of the stretch film resulting in an undesirable wrap of the item(s). If a user is informed that the stretch film on the core is too low to adequately complete the selected wrap cycle, the stretch film left on the core can be recycled instead of used for a partial wrap or a wrap of undesired quality. Often, the entire wrap cycle is repeated over or in place of a partial wrap or a wrap of undesired quality. Having to repeatedly run the machine to wrap the same item(s) consumes additional stretch film, energy and time. 
     It is known to measure the amount of unwound stretch film using a variety of sensors to count the number of rotations of one or more rollers or one or more roller shafts. However, the supply roll or stretch film can slip on the rollers; introducing error to the measurement. It is also known to use weight sensors and rotary sensors that engage the stretch film or the roller to measure the amount of stretch film unwound from the core of the supply roll. However, sensors that require direct contact to obtain a measurement can experience greater wear, are more subject to damage, and are subject to disengagement, introducing errors into measurements. It is also known to use optical or ultrasonic sensors to detect breaks in the stretch wrap, measure dimensions of the load to be wrapped, or measure a distance to an outside surface of a stretch wrap on a supply roll to calculate an amount of time until the supply roll is empty. See, for example, JPH01110467. 
     BRIEF DESCRIPTION 
     In one aspect, the present disclosure relates to a system for determining an amount of stretch film unwound from a stretch film dispensing apparatus. The stretch film dispensing apparatus includes a roller, one or more supply roll sensors, and a controller. The stretch film can be rotated about a longitudinal axis and unwound from a core of a supply roll that is placed onto or otherwise coupled to the roller. The one or more supply roll sensors are positioned relative to the roller to measure a distance from the one or more supply roll sensors to an outside face of the wound stretch film on the supply roll. The one or more supply roll sensors are configured to take a first measure of the distance and, after stretch film is unwound from the core of the supply roll, take a second measure of the distance, and send signals representative of the first and second distances to the controller. A core sensor is positioned relative to the roller to measure a core distance from the core sensor to an outside face of the core and send a signal representative of the core distance to the controller. The controller is configured to determine the amount of stretch film unwound based on the one or more signals from the one or more supply roll sensors and the core distance. 
     Another aspect of the present disclosure relates to a method of measuring an amount of stretch film unwound from a supply roll about a longitudinal axis. The method can begin with measuring one or more distances from one or more points radially away from the supply roll to an outside face of the supply roll. Alternatively or additionally, a second distance can be measured one or more times from one or more points radially away from the supply roll to the outside face of the supply roll after stretch film has been unwound from the supply roll. A third distance can be measured one or more times from one or more points radially away from the supply roll to the outside face of the core. The amount of stretch film unwound from the supply roll can then be determined based on the one or more first and second distances, and a third distance between the longitudinal axis and at least one of the first or second measures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1A  is a schematic, cross-sectional view of a system for determining an amount of stretch film unwound from a stretch film dispensing apparatus. 
         FIG. 1B  is a schematic, cross-sectional view of a stretch film supply roll. 
         FIG. 1C  is a schematic, cross-sectional view of the stretch film supply roll coupled to the system for determining an amount of stretch film unwound from a stretch film dispensing apparatus. 
         FIG. 2  is a schematic, top view of the stretch film supply roll coupled the system for determining the amount of stretch film unwound from the stretch film dispensing apparatus of  FIG. 1C . 
         FIG. 3  is a schematic view of a controller of the system for determining the amount of stretch film unwound from the stretch film dispensing apparatus of  FIG. 1A ,  FIG. 1B ,  FIG. 1C , and  FIG. 2 . 
         FIG. 4  is a flow chart showing a method for determining an amount of stretch film unwound from a stretch film dispensing apparatus using the system of  FIG. 1A ,  FIG. 1B ,  FIG. 1C ,  FIG. 2 , and  FIG. 3 . 
     
    
    
     DESCRIPTION 
     Herein, unless otherwise noted, the term “stretch film” applies to a film having the capability to stretch from an original manufactured length. Stretch film can be manufactured in a variety of ways; non-limiting examples include being cast or blown. The primary material used to manufacture stretch film is typically linear low-density polyethylene (LLDPE); however, the term stretch film is not limited to a LLDPE base and can include multiple layers and varieties of plastics or other materials in combination with or in place of LLDPE. Stretch film has a manufactured thickness; also known as a gauge. Since the thickness of the stretch film changes as the stretch film is stretched, herein, the “thickness of the wound stretch film” will pertain, unless otherwise noted, to the thickness of the stretch film after manufacturing and prior to being stretched. 
     Herein, unless otherwise noted, the term “core” refers to a shaft on which stretch film can be wound. The core can be constructed from a variety of materials. Non-limiting examples include cardboard, plastic, metal, glass, or paper. The core is often in the shape of a hollow cylindrical shaft, but can, in some circumstances, be formed in different shapes. The core can be a variety of lengths compared to the wound stretch film. The core can protrude from the wound stretch film on one or more sides; it can be the same length as an aspect of the wound stretch film, or it can be shorter than an aspect of the wound stretch film. Once the stretch film is wound around the core, the core can remain in at least partial contact with the wound stretch film or the core can be removed. 
     Herein, unless otherwise noted, the term “supply roll” will refer to stretch film that is wound around a core. 
     All directional references (e.g., radial, axial, proximal, distal, upper, lower, upward, downward, left, right, lateral, front, back, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise, upstream, downstream, forward, aft, etc.) are only used for identification purposes to aid the reader&#39;s understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of aspects of the disclosure described herein. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and can include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to one another. The exemplary drawings are for purposes of illustration only and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto can vary. 
     As illustrated in  FIG. 1A ,  FIG. 1C  and  FIG. 2 , a system  10  includes, at a minimum, a roller  12  mounted to a support structure, at least one supply roll sensor  50 , and a controller  80 . The system  10  can optionally include a core sensor  24 , a rotation sensor  26 , and a user interface  28 . 
     While shown vertically in  FIG. 1A ,  FIG. 1B , and  FIG. 1C , the roller  12  can be horizontal or at an angle or variable angle as required by the stretch film dispensing apparatus. The roller  12  is illustrated as a solid cylindrical shaft with a longitudinal axis  14  and a roller radius (RR)  16 ; however, the roller can be any shape or have one or more portions that are hollow. The roller  12  can be mounted to a support structure of a stretch film machine. The support structure can include, but is not limited to; a platform or frame. The support structure of the roller  12  can, in any combination or singularity; rotate, move, or remain stationary relative to the ground before, during, or at the conclusion of a wrapping cycle. Likewise, the roller  12 , relative to the support structure, can, in any combination or singularity; rotate, move, or remain stationary before, during, or at the conclusion of a wrapping cycle. Non-limiting examples of the motion of the roller  12  can include one or more of: the rotation of roller  12  driven by a motor, belt, or other external drive force; or the roller  12  can be mounted with bearings and allowed to freely rotate around the longitudinal axis  14  at an angle relative to the support structure. 
     As illustrated in  FIG. 1B ,  FIG. 1C , and  FIG. 2 , a supply roll  20  includes a core  30  on which is a supply of wound stretch film  40 . The supply roll  20  can be coupled to the roller  12 . Non-limiting examples of how the supply roll  20  can be coupled to the roller  12  include: a lock or clasp mechanism to secure the supply roll  20  and the roller  12 ; a press fit of the roller  12  through the core  30  of the supply roll  20 ; a loose fit of the roller  12  through the core  30  of the supply roll  20 ; an adhesive applied between the supply roll  20  and the roller  12 ; a magnetic force between the supply roll  20  and the roller  12 ; or a static force between the supply roll  20  and the roller  12 . 
     The core  30  has core edges  31 ,  32  that define a core inside face  33  and a core outside face  34 . The core  30  has a core inner radius (CIR)  36  measured from the longitudinal axis  14  to the core inside face  33 . The core  30  also has a core outside radius (COR)  38  measured from the longitudinal axis  14  to the core outside face  34 . 
     The wound stretch film  40  has film edges  41 ,  42  that define a stretch film inside face  43  and a stretch film outside face  44 . The wound stretch film  40  has a stretch film inside radius that can be equal to the core outside radius (COR)  38  measured from the longitudinal axis  14  to the stretch film inside face  43 . The wound stretch film  40  also has a stretch film outside radius (SFOR)  47  measured from the longitudinal axis  14  to the stretch film outside face  44 . The stretch film outside face  44  is an outside face of the supply roll. A remaining stretch film depth (RSFD)  46  is the distance from stretch film inside face  43  to the stretch film outside face  44 . The remaining stretch film depth (RSFD)  46  can also be calculated by subtracting the core outside radius (COR)  38  from the stretch film outside radius (SFOR)  47 . 
     The supply roll  20  can include an information label  22 . The information label  22  can be located, but is not limited to, the core inside face  33 , the core outside face  34 , the stretch film inside face  43 , the stretch film outside face  44 , or anywhere on the supply roll  20  packaging. Information label  22  can be a barcode, a Quick Response code, a color or numeric indicator, Radio Frequency Identification circuit or chip, a Near Field Communication circuit or chip, one or more magnets, patterned gaps, one or more images, or any other known art of communicating or storing data. Information label  22  can include, but is not limited to, information about the supply roll  20 . Non-limiting examples of information about the supply roll  20  include: data regarding a thickness or gauge of the wound stretch film  40 ; an amount of the wound stretch film  40 ; a dimension of the core  30 ; a dimension of the wound stretch film  40  on the core  30 ; one or more elastic properties of the wound stretch film  40 ; one or more chemical properties of the wound stretch film  40 ; or one or more manufacturing properties of the supply roll  20 . 
     The at least one supply roll sensor  50  of the system  10  is positioned relative to the roller  12  to sense a wrap distance (WD)  52  from the at least one supply roll sensor  50  to a stretch film outside face  44 . Preferably, as illustrated in  FIG. 1C , and  FIG. 2 , the position of the at least one supply roll sensor  50  can be a first radial distance (1RD)  54  from the longitudinal axis  14  of the supply roll  20  on roller  12 , so that the at least one supply roll sensor  50  is not in physical contact with the wound stretch film  40 . 
     When the supply roll  20  is coupled to the roller  12  in the vertical position as illustrated in  FIG. 1C , the at least one supply roll sensor  50  is preferably positioned to sense the wrap distance (WD)  52  from the at least one supply roll sensor  50  to a lower portion  48  of the stretch film outside face  44 . The lower portion  48  of stretch film outside face  44  can be, but is not limited to, a location that is closer to edge  42  than edge  41 . When the wrap distance (WD)  52  is measured from the at least one supply roll sensor  50  to a lower portion  48  of the stretch film outside face  44 ; supply rolls with a variety of core lengths can be coupled to the roller  12  without having to change the location of the at least one supply roll sensor  50 . 
     The at least one supply roll sensor  50  can communicate with the controller  80 . Communication with the controller  80  can be, but is not limited to, electrical signal, optical signal, sonic signal, electromagnetic signal, any other wireless signal processes, induction, or user input of data read from the at least one supply roll sensor  50 . 
     The at least one supply roll sensor  50  can communicate one or more signals representative of the sensed wrap distance (WD)  52  to the controller  80 . The controller  80 , in turn, can, among other things, analyze the signal(s) to identify possible outliers; determine an average value related to the signal(s); or analyze the signal(s) to determine possible obstructions to one or more of the at least one supply roll sensor  50 . Further, while  FIG. 1A ,  FIG. 1C ,  FIG. 2 , and  FIG. 3  demonstrate the at least one supply roll sensor  50  as a single sensor, it is also understood that the more than one signal representative of the wrap distance (WD)  52  can be communicated to the controller  80  by more than one supply roll sensor  50 . 
     The at least one supply roll sensor  50  can be, although is not limited to, one of an optical sensor, a sonic sensor, or a magnetic field sensor. A non-limiting example of an optical sensor is the Wenglor Photoelectronic Sensor part number OCP662X0080. A non-limiting example of a sonic sensor is the Wenglor Ultra Sonic detector part number UMF402U035. 
     The system  10  can also include a core sensor  60  that is positioned relative to the roller  12  to sense a core distance (CD)  62  between the core sensor  60  and the core outside face  34 . Preferably, the position of the core sensor  60  can be a second radial distance (2RD)  64  from the longitudinal axis  14 , so that the core sensor  60  is not in physical contact with the supply roll  20 . The second radial distance (2RD)  64  may be the same or different than the first radial distance (1RD)  54 . 
     The core sensor  60  can communicate with the controller  80 . Communication with the controller  80  can be, but is not limited to, electrical signal, optical signal, sonic signal, electromagnetic signal, any other wireless signal processes, induction, or user input of data read from the core sensor  60 . The core sensor  60  can communicate one or more signals representative of the sensed core distance (CD)  62  to the controller  80 , which can, among other things, analyze the signal(s) to identify possible outliers; or determine an average value related to the signal(s) to determine the best approximation of the core distance (CD)  62 . Further, while  FIG. 1A ,  FIG. 1C ,  FIG. 2 , and  FIG. 3  demonstrate the core sensor  60  as a single sensor, it is also understood that the more than one signal representative of the core distance (CD)  62  can be communicated to the controller  80  by more than one core sensor  60 . 
     The core sensor  60  can be, although is not limited to, one of an optical sensor, a sonic sensor, or a magnetic field sensor. A non-limiting example of an optical sensor is the Wenglor Photoelectronic Sensor part number OCP662X0080. A non-limiting example of a sonic sensor is the Wenglor Ultra Sonic detector part number UMF402U035. Additionally or alternatively, the core sensor  60  can communicate information from the information label  22  to the controller  80 . A non-limiting example of a communicating scanner is the Wenglor Barcode Reader part number FIS-0003-0103. 
     The system  10  can also include a rotation sensor  70  that is positioned relative to the roller  12  to sense a number of rotations of the core  30 . The rotation sensor  70  may be positioned a third radial distance (3RD)  72  from the longitudinal axis  14 , or it may be positioned in any other location consistent with well-known techniques to sense a number of rotations of the supply roll  20 . 
     The rotation sensor  70  can communicate with the controller  80 . Communication with the controller  80  can be, but is not limited to, electrical signal, optical signal, sonic signal, electromagnetic signal, any other wireless signal processes, induction, or user input of data read from the rotation sensor  70 . The rotation sensor  70  can communicate one or more signals representative of the number of core rotations to the controller  80 , which can, among other things, analyze the signal(s) to identify possible outliers; or determine an average value related to the signal(s) to determine a best approximation of the number of core rotations. Further, while  FIG. 1A ,  FIG. 1C ,  FIG. 2 , and  FIG. 3  demonstrate the rotation sensor  70  as a single sensor, it is also understood that the more than one signal representative of the number of core rotations can be communicated to the controller  80  by more than one rotation sensor. 
     The rotation sensor  70  can be, although is not limited to, one of an optical sensor, a sonic sensor, an encoder, a barcode scanner, or a magnetic field sensor. A non-limiting example of an optical sensor is the Wenglor Photoelectronic Sensor part number OCP662X0080. A non-limiting example of a sonic sensor is the Wenglor Ultra Sonic detector part number UMF402U035. A non-limiting example of a barcode scanner is the Wenglor Barcode Reader part number FIS-0003-0103. Additionally or alternatively, the rotation sensor  70  can communicate information from the information label  22  to the controller  80 . 
     The system  10  can further include a user interface  28  that can communicate with the controller  80 . Communication with the controller  80  can be, but is not limited to, electrical signal, optical signal, sonic signal, electromagnetic signal, any other wireless signal processes, induction, or user input. Non-limiting examples of the user interface  28  can include one or more of: a mobile device, a touch screen, a keyboard, a monitor, a light emitting diode or other light source, a speaker, or a microphone. Examples of information that can be communicated to the controller  80  via the user interface  28  can include, but are not limited to: the thickness of the wound stretch film  40 ; a length of the wound stretch film  40 ; the wrap distance (WD)  52 ; a core radius including: the core inside radius (CIR)  36  and/or the core outside radius (COR)  38 ; the core distance (CD)  62 ; one or more dimensions of the core  30 ; the length of the core  30 ; one or more dimensions of the wound stretch film  40 ; one or more elastic properties of the wound stretch film  40 ; one or more chemical properties of the wound stretch film  40 ; one or more manufacturing properties of the supply roll  20 ; the number of rotations of the core  30 ; and/or a programmed sequence of steps for operation of the system, such a start and stop times, sensor sampling rates, acceptable tolerances in measure, etc. Additionally or alternatively, the user interface  28  can be used to communicate data to a user. Non-limiting examples of data that can be communicated to the user via the user interface  28  include: the amount of stretch film unwound from the supply roll  20 ; an indication to change the supply roll  20 ; the thickness of the wound stretch film  40 ; a length of the wound stretch film  40 ; the wrap distance (WD)  52 ; the core outside radius (COR)  38 ; the core inside radius (CIR)  36 ; the core distance (CD)  62 ; one or more dimensions of the core  30 ; the length of the core  30 ; one or more dimensions of the wound stretch film  40 ; one or more elastic properties of the wound stretch film  40 ; one or more chemical properties of the wound stretch film  40 ; or one or more manufacturing properties of the supply roll  20 ; or the number of rotations of the core  30 . 
       FIG. 3  schematically illustrates the controller  80  that can be provided with a memory  82  and a central processing unit (CPU)  84 . The memory  82  can be used for storing control software that can be executed by the CPU  84  that among other things, is configured to calculate amounts based on measurement signals, operate a stretch film wrapping cycle, and to perform a variety of other functions. The memory  82  can also be used to store information, such as, but not limited to, a look up table or a database. The look up table or the database can be used to store data received from one or more components of the system  10  that can be communicably coupled with the controller  80 . The look up table or database can be used to store the various operating parameters for the one or more cycles of operation, including factory default values for the operating parameters and any adjustments to them by sensed measurements or by user input. 
     The controller  80  can be operably coupled with one or more components of the system  10  for communicating with and/or controlling the operation of the components to sense a measurement or participate in a stretch film wrapping cycle. The controller  80  can communicate with the at least one supply roll sensor  50  to receive one or more signals representative of the wrap distance (WD)  52 . Optionally, the controller  80  can control the at least one supply roll sensor  50 . The controller  80  can, but is not limited to, activating the at least one supply roll sensor  50  and/or establishing a sampling rate at which is the at least one supply roll sensor  50  communicates a signal representative of the wrap distance (WD)  52  to the controller  80 . 
     Additionally, the controller  80  can communicate with the core sensor  60  and/or the rotation sensor  70  to receive one or more signals representative of the core distance (CD)  62  and/or the number of core rotations, respectively. Optionally, the controller  80  can control the core sensor  60  and/or the rotation sensor  70 . The controller  80  can, but is not limited to, activating the core sensor  60  and/or the rotation sensor  70  and/or establishing a sampling rate at which the core sensor  60  and/or the rotation sensor  70  communicates a signal representative of the core distance (CD)  62  and/or the number of core rotations, respectively, to the controller  80 . 
     The controller  80  can couple to the user interface  28  for receiving user selected inputs and communicating information to the user. The controller  80  can also communicate with and/or control various additional sensors  86 , which are known in the art and not shown for simplicity. Optionally, the controller  80  can couple to local or remote servers  88  to obtain or communicate data. Non-limiting examples of data communicated to or obtained from a local or remote server  88  include: the amount of stretch film unwound from a supply roll  20  during a wrapping cycle; the length of the wound stretch film  40  on the supply roll  20 ; the thickness of the wound stretch film  40 ; an indication to change the supply roll  20 ; the wrap distance (WD)  52 ; the core outside radius (COR)  38 ; the core inside radius (CIR)  36 ; the core distance (CD)  62 ; one or more dimensions of the core  30 ; the length of the core  30 ; one or more dimensions of the wound stretch film  40 ; one or more elastic properties of the wound stretch film  40 ; one or more chemical properties of the wound stretch film  40 ; or one or more manufacturing properties of the supply roll  20 ; or the number of rotations of the core  30 . 
       FIG. 4  illustrates a method  200  of measuring an amount (L) of wound stretch film  40  that is unwound from the core  30  of the supply roll  20  about a longitudinal axis  14 . While the method  200  shown in  FIG. 4  is discussed in the context of the embodiment of the system  10  and the supply roll  20  shown in  FIG. 1A ,  FIG. 1B ,  FIG. 1C ,  FIG. 2 , and  FIG. 3 , it is also understood that the method can be employed with other embodiments of the system  10  and the supply roll  20 . 
     In step  201 , the method  200  starts before an amount (L) of wound stretch film  40  is unwound from the core  30  of the supply roll  20 . In step  202 , a first distance (WD first ) is measured. The first distance (WD first ) can be measured from at least one point radially away from the supply roll  20  to the stretch film outside face  44  of the supply roll  20 . The first distance (WD first ), preferably, is measured before an amount (L) of wound stretch film  40  is unwound from the core  30  of the supply roll  20 . The first distance (WD first ) can be measured by the at least one supply roll sensor  50  and a signal representative of the first distance (WD first ) can be communicated to the controller  80 . 
     Step  203  can occur as an alternative to step  202  or in addition to step  202 . In step  203 , a second distance (WD second ) is measured. The second distance (WD second ) can be measured from at least one point radially away from the supply roll  20  to the stretch film outside face  44  of the supply roll  20 . The second distance (WD second ), preferably, is measured when an amount (L) of wound stretch film  40  has been unwound from the core  30  of the supply roll  20 . The second distance (WD second ) can be measured by the at least one supply roll sensor  50  and a signal representative of second distance (WD second ) can be communicated to the controller  80 . 
     A third distance is obtained in step  204 . The third distance can be measured from at least one point radially away from the supply roll  20  to the core outside face  44  of the supply roll  20 . The third distance can be obtained after step  201  and before step  205 . Therefore, step  204  can occur before, during, or after step  202  and/or step  203 . 
     In step  205 , the amount (L) of wound stretch film  40  that is unwound from the core  30  of the supply roll  20  can be determined. Non-limiting examples of alternative or additional dimensions that can be utilized for determining the amount of stretch film unwound from the supply roll include: the thickness of the wound stretch film  40 , the roller radius (RR)  16 , the core outside radius (COR)  38 , the core inside radius (CIR)  36 , the first radial distance (1RD)  54 , the second radial distance (2RD)  64 , or the third radial distance (3RD)  72 . Examples of how the alternative or additional dimensions can be obtained include, but are not limited to, one or more of the at least one supply roll sensor  50 , the core sensor  60 , the rotation sensor  70 , the information label  22 , the additional sensors  86 , the local or remote servers  88 , the memory  82 , calipers, or user input. A signal, representative of the alternative or additional dimension can be communicated with or recalled by the controller  80 . 
     One exemplary calculation for determining the amount (L) of wound stretch film  40  unwound from the core  30  of the supply roll  20  (L) is given in Equation (1) below: 
         L=πn (2 R+d ( n+ 1))  (1)
 
     where L refers to the amount of wound stretch film  40  unwound from a supply roll  20 , n refers to the number of rotations of the core  30 , R refers to the stretch film outside radius (SFOR)  47  after the amount (L) of stretch film has been unwound, and d refers to the thickness of the wound stretch film  40 . 
     An exemplary calculation for determining the stretch film outside radius (SFOR)  47  after amount L of stretch film has been unwound (R) can be shown in Equation (2): 
         R =(COR)+(CD−WD second )  (2)
 
     where COR refers to the core outside radius (COR)  38  which can be a known additional dimension or calculated using the third distance. The third distance measured in step  204  is the core distance (CD)  62  that can be measured by the core sensor  60 . WD second  refers to the second distance that can be measured in step  203 . Non-limiting examples of how the core outside radius (COR)  38  can be known include: the information label  22 , a look-up table, a direct measurement, previously stored information, or any other methods or resources known in the art. A non-limiting example of how the core outside radius (COR)  38  can be calculated using the core distance (CD)  62  includes subtracting the core distance (CD)  62  from a known distance such as, but not limited to, the second radial distance (2RD)  64 . 
     Other non-limiting examples of calculations for determining the stretch film outside radius (SFOR)  47  after amount L of stretch film has been unwound (R) are given in Equation (3) and Equation (4) below: 
         R =(1RD−WD second )  (3)
 
     where 1RD refers to the first radial distance (1RD)  54  which can be a known additional dimension or calculated using measurements from steps  202  or  204 . Non-limiting examples of how the first radial distance (1RD)  54  can be known include: a barcode, a look-up table, a direct measurement, previously stored information, or any other methods or resources known in the art. WD second  refers to the second distance measured in step  203 . 
         R =(COR)+(CD−(WD first   +dn ))  (4)
 
     where COR refers to the core outside radius (COR)  38  which can be a known additional dimension or calculated from the third distance as demonstrated in the present disclosure. The third distance measured in step  204  is the core distance (CD)  62  that can be measured by the core sensor  60 . WD first  refers to the first distance measured in step  202 , d refers to the thickness of the wound stretch film  40  and n refers to the number of rotations of the core  30 , where d and n are additional dimension known or calculated using measurements from steps  202 ,  203  or  204 . Non-limiting examples of how d and n can be known include: the information label  22 , a look-up table, a direct measurement, previously stored information, or any other methods or resources known in the art. 
     The number of core rotations (n) can be calculated using an exemplary equation (5): 
     
       
         
           
             
               
                 
                   n 
                   = 
                   
                     ( 
                     
                       
                         
                           W 
                            
                           
                             D 
                             
                               s 
                                
                               e 
                                
                               c 
                                
                               o 
                                
                               n 
                                
                               d 
                             
                           
                         
                         - 
                         
                           W 
                            
                           
                             D 
                             first 
                           
                         
                       
                       d 
                     
                     ) 
                   
                 
               
               
                 
                   ( 
                   5 
                   ) 
                 
               
             
           
         
       
     
     where WD first  refers to the first distance measured in step  202 , WD second  refers to the second distance measured in step  203 , and d refers to the thickness of the wound stretch film  40 , where d is an additional dimension that is known or calculated using measurements from steps  202 ,  203  or  204 . Examples of how d can be known include: the information label  22 , a look-up table, a direct measurement, previously stored information, or any other methods or resources known in the art. 
     Optionally, in step  207 , the number of core rotations (n) can be sensed using the core sensor  60  or the rotation sensor  70 . 
     The thickness of the wound stretch film  40  ( d ) can obtained from the information label  22  and sensed by the core sensor  60  or the rotation sensor  70 , or a look-up table, or a direct measurement, or previously stored information, or any other methods or resources known in the art. Alternatively, the thickness of the wound stretch film  40  ( d ) can be calculated using the exemplary equation (6): 
     
       
         
           
             
               
                 
                   d 
                   = 
                   
                     ( 
                     
                       
                         
                           W 
                            
                           
                             D 
                             
                               s 
                                
                               e 
                                
                               c 
                                
                               o 
                                
                               n 
                                
                               d 
                             
                           
                         
                         - 
                         
                           W 
                            
                           
                             D 
                             first 
                           
                         
                       
                       n 
                     
                     ) 
                   
                 
               
               
                 
                   ( 
                   6 
                   ) 
                 
               
             
           
         
       
     
     where WD first  refers to the first distance measured in step  202 , WD second  refers to the second distance measured in step  203 , and n refers to the number of rotations of the core  30 , where n is an additional dimension sensed in step  207  or calculated using measurements from steps  202 ,  203  or  204  as demonstrated in the present disclosure. 
     The method  200  ends in step  206  after the amount (L) of wound stretch film  40  is unwound from the core  30  of the supply roll  20  and that amount (L) has been determined. 
     Optionally, before the method  200  ends in step  206 , step  208  can provide an indication when the determined amount of stretch film unwound from the supply roll  20  is at a predetermined threshold. The indication that a predetermined threshold has been reached can be communicated to the user via the user interface  28  or other methods known in the art. 
     The measuring steps  202 ,  203  and the determining step  205  of the amount (L) of stretch film unwound from the supply roll can be done contemporaneously. The method  200  can start prior to a wrap cycle and end once the wrap cycle is complete and the amount (L) of stretch film unwound is determined. Additionally or alternatively, the method  200  can run during the wrap cycle so that between any two moments in a wrap cycle or throughout the wrap cycle, the amount (L) of wound stretch film  40  that has been unwound from the core  30  can be determined  205 . 
     To the extent not already described, the different features and structures of the present disclosure can be used in combination with each other as desired. For example, one or more of the sensors illustrated and/or described with respect to the system  10  can be used to sense one or more of the measurements discussed herein. Additionally, one or more sensors can be combined with other sensors or features to obtain one or more of the measurements discussed herein to calculate an amount of stretch film unwound from the supply roll  20 . That one feature may not be illustrated in all the embodiments and is not meant to be construed that it cannot be, but is done for brevity of description. Thus, the various features of the different embodiments can be mixed and matched as desired to form new embodiments, whether or not the new embodiments are expressly described. 
     Equations are not limited to radial measurements. Any diameter measurement can easily be processed or calculated to a radius; likewise a radial measurement can easily be converted to a diameter. The equations given as examples in the present disclosure are not limiting and a variety of sensed data can be combined using different algorithms to find the amount of stretch film unwound from a supply roll. 
     While aspects of the present disclosure have been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation. Reasonable variation and modification are possible within the scope of the forgoing disclosure and drawings without departing from the spirit of the present disclosure which is defined in the appended claims.