Abstract:
A control system for a corrugating machine and a method for determining a length of paper web in a corrugating machine having a bridge are disclosed, the method including the steps of calculating an approximate length of the paper web on the bridge using photoelectric detectors, applying a liquid pattern on a portion of the paper web for a short duration, initiating a count at the application of the liquid pattern, detecting the liquid pattern with a moisture detector, terminating the count at the detection of the liquid pattern, calculating a determined length of the paper web based on the count and the detection of the liquid pattern, comparing the determined length to the approximate length, and adjusting the approximate length to equal the determined length.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional Application Serial No. 60/403,147, filed on Aug. 13, 2002, entitled CONTROLLER FOR CORRUGATING MACHINE AND METHOD. 
     
    
     
       TECHNICAL FIELD  
         [0002]    This invention relates generally to a controller for a corrugating machine for producing corrugated paperboard and methods for using the same. In particular, the controller for a corrugating machine and methods relate to generating a synchronized splice by comparing a plurality of variables for automatically determining the length of the web material in the bridge of the machine.  
         BACKGROUND OF THE INVENTION  
         [0003]    Conventional corrugating machines produce single-wall, double-wall and triple-wall corrugated board from multiple continuous webs of flat paper and an additional continuous web of corrugated paper. The prior art has produced a corrugating machine where a pair of corrugating rollers corrugates a web of paper and glues it to a web of flat paper in order to produce a single-faced corrugated web, which is supplied to the bridge of the corrugating machine.  
           [0004]    Each of the paper webs employed to form the single-faced corrugated web is fed from a large roll of paper, which periodically runs out. As one of the paper rolls runs out of paper, a paper web from a new roll is spliced onto the paper web from the old roll via a conventional splicer. A new roll may also be spliced in when the corrugator has produced the required quantity of corrugated board with the current paper composition and it is desired to start producing board of a new paper composition (known as a paper change).  
           [0005]    In order to accommodate the splicing of the new roll to the old roll, the portion of the corrugating machine which produces single-faced corrugated board may be slowed somewhat; consequently, the single-faced corrugated web is provided to the bridge at a speed that is variable. The single-faced corrugated web is drawn from the bridge of the corrugating machine and is bonded to a third web of paper to produce single-wall corrugated web, which is then supplied to a conventional cutter which cuts the single-wall corrugated web into the desired sizes.  
           [0006]    When one of the paper webs forming the single-faced corrugated board is spliced by one of the splicers, the web portion in which the splice is made is often twice as thick as usual (due to overlap of the original paper web with the new paper web) and contains tape to hold the new paper web to the original paper web. This extra-thick, taped web portion is undesirable and may be automatically cut out by the cutter (which may be the main cutter or an auxiliary cutter) after the single-wall corrugated web is produced. If a paper change is in progress then it is desirable to synchronize the changing of the paper webs with each other and with the cutter so as to provide an efficient transition between orders with a minimum amount of wasted paper.  
           [0007]    The prior art corrugating machine described above incorporates a method of automatically cutting out the extra-thick, taped web portion based upon a procedure that periodically determines the length of the web that was in the bridge portion of the corrugating machine. As the single-faced corrugated web was supplied to the bridge at a variable rate and thereby removed from the bridge at a variable rate, the length of the web in the bridge at any time was also variable.  
           [0008]    In the prior art method, the length of the web in the bridge was determined, and then the total length of the web from one of the splicers to the cutter was determined based thereon (the length of the web from one of the splicers to the bridge was a known constant, and the length of the web from the bridge to the cutter was a known constant). As soon as a splice was made, the corrugating machine would start measuring the web length from the splicer to the cutter. When the machine had measured a web length that was slightly less than the total web length, the cutter would make a first cut, wait for a predetermined period of time or a distance, and then make a second cut. This resulted in the extra-thick spliced portion of the web would be cut out from the web.  
           [0009]    In the prior art method of determining the length of the web in the bridge, an ink or other liquid mark was sprayed onto a portion of the single-faced corrugated web just prior to its entry into the bridge. An ink mark or other reflectance detector was positioned at the exit of the bridge, and a measuring wheel that abutted against the single-face top liner or medium web generated a plurality of counts in direct proportion to the travel of the single-faced corrugated web. The length of the single-faced web in the bridge was determined based on the number of pulses that were generated by the measuring wheel as well as any movement by the dancer rollers or preheater or preconditioner wrap arms between the time the ink or other liquid mark was sprayed and the time the ink or other liquid mark was later detected by the detector. This manner of determining the length of the single-faced corrugated web in the bridge is generally advantageous in that it allows the splice to be more precisely cut out, without the need to cut out larger adjacent portions of the web that are acceptable for use.  
           [0010]    Other methods of determining the length of the web in the bridge, such as the use of metal foil pieces that are adhesively applied to the web, are relatively expensive and have other disadvantages including maintenance problems.  
           [0011]    In addition, none of the prior art corrugating machines includes control mechanisms that can compare a plurality of variables to automatically and more accurately determine the length of the web material in the corrugating machine in order to create a synchronous splice of all paper webs. Such variables include the position of the pre-heater arms, the dancer roll position, and moisture content of the web. Thus, there exists a need for a controller for corrugating machines that can compare a plurality of variables to automatically and more accurately and cost-effectively determine the length of the web material in the corrugating machine in order to create a synchronous splice of all paper webs.  
         SUMMARY OF THE INVENTION  
         [0012]    The present invention provides a controller for corrugating machines that can compare a plurality of variables and a method for accurately determining the length of the web material in the corrugating machine in order to create a synchronous splice. Such variables can include the position of the pre-heater arms and the dancer roll position within the splicer.  
           [0013]    In accordance with the present invention, there is provided a control system for a corrugating machine, including a first positionable dancer roll for manipulating a first paper web operatively engaged to a controller, a first positionable pre-heater wraparm for adjusting an amount of the first paper web in contact with the positionable pre-heater operatively engaged to the controller, a second positionable dancer roll for manipulating a second paper web operatively engaged to the controller, a second positionable pre-heater wraparm for adjusting an amount of the second paper web in contact with the positionable pre-heater operatively engaged to the controller, a roller assembly for corrugating the second paper web and adhering the first paper web to the second paper web to form layered paper web, a moisture applicator for applying moisture to the first paper web and operatively engaged to the controller, a bridge for temporarily storing the layered paper web, a plurality of photoelectric detectors positioned on the bridge of the corrugating machine and operatively engaged to the controller, a moisture detector to detect the presence of moisture of the first paper web and operatively engaged to the controller, wherein the moisture detector adjusts the plurality of photoelectric detectors, at least one splicer operatively engaged to the controller for cutting out a portion of the layered paper web at a synchronized splice point, wherein the synchronized splice point is determined by correlating said plurality of photoelectric detectors with the moisture detector.  
           [0014]    The present invention is further directed to a method for determining a length of paper web in a corrugating machine having a bridge, the method including the steps of calculating an approximate length of the paper web on the bridge using photoelectric detectors, applying a liquid pattern on a portion of the paper web for a short duration, initiating a count at the application of the liquid pattern, detecting the liquid pattern with a moisture detector, terminating the count at the detection of the liquid pattern, calculating a determined length of the paper web based on the count and the detection of the liquid pattern, comparing the determined length to the approximate length, and adjusting the approximate length to equal the determined length.  
           [0015]    The present invention is additionally directed to a moisture detector for a control system for a corrugating machine, including a lamp for emitting light towards a paper web, a detector for detecting wavelengths of the light reflected off of the paper web, the detector generating an electrical signal indicative of the wavelengths of the reflected light, an amplifier in electrical communication with the detector, the amplifier amplifying the electrical signal, a differential amplifier in electrical communication with the amplifier, the differential amplifier receiving the electrical signal and differentially amplifying the electrical signal, an analog-to-digital converter in electrical communication with the differential amplifier, the analog-to-digital converter converting the differentially amplified electrical signal to a digital signal indicative of the wavelengths of the reflected light, a central processing unit in electrical communication with the analog-to-digital converter, the central processing unit receiving the digital signal and containing software to maintain a fluid offset and identifying the digital signal indicative of the wavelengths of the reflected light, and wherein the central processing unit includes an output to transmit the digital signal indicative of the wavelengths of the reflected light to a controller. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1A is a schematic side view of a first portion of the preferred embodiment of the present invention.  
         [0017]    [0017]FIG. 1B is a schematic side view of a second portion of the present invention of FIG. 1A.  
         [0018]    [0018]FIG. 2 is a flow chart of the method of determining the length of the web in the bridge of the corrugating machine of FIGS. 1A and 1B.  
         [0019]    [0019]FIG. 3 is a flow chart of the method of determining the synchronous splice point in accordance with the method of FIG. 3.  
         [0020]    [0020]FIG. 4 is a component diagram of a moisture detector in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0021]    [0021]FIG. 1A illustrates a first portion of a preferred embodiment of a corrugating machine  10  in accordance with the present invention. Referring to FIG. 1A, corrugating machine  10  includes a conventional splicer  12  that supplies a paper web  14  from a paper roll to cylindrical idler roller  18  rotatably supported by a support member attached to a frame portion. The average size of paper roll is approximately 25,000 lineal feet, having a width of about 48 inches to about 108 inches. Paper web  14  passes through splicer  12 , then further passes through positionable dancer roll  16 , positionable dancer roll  16  for providing constant tension of the paper roll so that paper rolls can be properly adhered together under measuring wheel  71   a , then underneath a pair of positionable cylindrical rollers  22 , positionable cylindrical rollers  22  for adjusting the amount of paper on a wraparm and over a portion of a pre-heating roller  24  supported by a frame portion  26 . For example, by adjusting the position of positionable cylindrical rollers  22  relative to pre-heating roller  24 , web  14  can be heated to different degrees. By increasing the amount of web  14  that passes over pre-heating roller  24 , positionable cylindrical rollers  22  cause web  14  to be heated to a higher temperature. Similarly, by decreasing the amount of web  14  that passes over pre-heating roller  24 , positionable cylindrical rollers  22  cause web  14  to be heated less. Web  14  passes through roller assembly  28  for bonding to a corrugated web, such as paper web  32  described below. Computer-operated controller  64  tracks the paper moving under measuring wheel  71 . Controller  64  also tracks the position of dancer roll  16 , either via a pulse wheel, analog signal from a potentiometer, or load cell that changes proportionally with the position of the dancer roll. Controller  64  is also capable of tracking the position of cylindrical rollers  22  via an analog signal from a potentiometer that changes proportionally with the roller position.  
         [0022]    Corrugating machine  10 , illustrated in FIG. 1B, includes a second conventional splicer  41  that supplies a second paper web  32  from another paper roll to another cylindrical idler roller also rotatably supported by a support member attached to the frame portion. As with paper web  14 , paper web  32  passes through splicer  41  then further passes through positionable dancer roll  44 , under measuring wheel  71   b , then underneath a pair of positionable cylindrical rollers  50  and  52 , and over a portion of a pre-heating roller  48  supported by a frame portion  46 . Web  32  passes between a pair of corrugating rollers  29 , each of which has a corrugating surface to corrugate web  32 , as is known in the art. An adhesive, such as glue, including but not limited to, corn starch and potato starch is applied to the top portions of corrugated web  32  via a conventional apparatus in the form of a pair of adhesive applicator rollers  30 .  
         [0023]    Paper web  14  is adhesively bonded to the corrugated web  32  when the webs  14  and  32  come into contact together at the junction of the rollers in roller assembly  28  so that a single-faced corrugated web  34  is formed. Web  34  is transported to a bridge  42  via a conveyor mechanism  36  composed of a pair of conveyors, each of which has a pair of rollers  38  which support a respective conveyor belt  37 , with the web  34  passing between the conveyor belts  37  through an aperture  39  formed in the bridge  42 . Conveyor mechanism  36  supplies web  34  to bridge  42  at a rate which may be many times greater than the speed at which web  34  is conveyed along bridge  42  by a number of bridge conveyor belts (not shown). When supplied to bridge  42 , a portion of web  34  often automatically folds over itself a number of times as shown in FIG. 1A. The purpose of bridge  42  is to store and create a buffer of excess single face web in the system  
         [0024]    Single-faced corrugated web  34  may be selectively sprayed with water at a spot or location on the web  34  via a spraying apparatus with a spray nozzle  72  upon the receipt of an electrical spray signal generated by controller  64 . Duration of a spray is between one-tenth and one-half of a second, and preferably approximately one-sixth of a second. In the preferred embodiment of the present invention, there is a plurality of sprays of such duration, with a predetermination period of time between sprays, in combination with the known speed of the web, yields a determinable distance between sprays. The duration of the sprays in the present invention are of much shorter duration than the sprays in the prior art, resulting in less water spray volume, and thereby preserve product quality by preventing warping and delamination of the web due to the presence of excess water. Moisture detectors  55  or  57  sense the presence of the sprayed water on web  34  as web  34  is pulled past them. Prior art detection systems utilize temperature sensors to detect a large-volume water spray. The difficulties that arise from the temperature sensing systems of the prior art are numerous. For example, water sprayed on the web has a temperature approximately equivalent to the temperature of the web, due to the water stored near the system. The resulting lack of temperature difference makes the water difficult to detect, and often results in the need to dump the standing water and refill the water supply with cooler water. Moreover, the prior art system requires significantly more water to be sprayed on the web in order to be detected, since water is typically not sprayed on the side that the temperature sensor views or senses. The excess water results in warping and/or delamination  
         [0025]    Moisture detectors  55  and  57  of the present invention perform a spectral analysis of web  34 . Light emitted by moisture detectors  55  and  57  is reflected off of web  34  and analyzed by one or both of moisture detectors  55  or  57  for the wavelengths of light reflected. For example, light reflected off of a dry web has different wavelength components that light reflected off of a web that is moist with water provided by nozzle  72 . By providing sprays of short duration and low water volume, the present invention reduces the frequency of detecting false positives and missing false negatives that are replete in the prior art. False positive detections result from changes in paper type, condensation dripping on the web, as well as a multitude of other factors. False negatives typically result from having to lower the detection threshold of a temperature sensor or other prior art detector.  
         [0026]    As illustrated in FIG. 4, a component diagram of a moisture detector is shown. Moisture detectors  55  and  57  includes a lamp  300 , a detector  302 , an amplifier  304 , a differential amplifier  306 , an analog-to-digital converter  308 , a microprocessor or central processing unit  310 , a digital-to-analog converter  312 , and an output  314 .  
         [0027]    As described above, lamp  300  emits light that strikes a web, the light then reflecting off of the web and to detector  302 . Detector  302  detects the reflected light, such as infrared light, and generates a signal indicative of wavelengths of light detected that is forwarded to amplifier  304 . Once the signal is amplified, it is sent to differential amplifier  306 . An offset voltage is applied to differential amplifier  306  to produce a differential signal on an input to differential amplifier  306 . This signal is amplified and output to analog-to-digital converter  308 . Once the signal is converted to digital, it is output to central processing unit  310 . Central processing unit  310  contains normalizing software to maintain a fluid offset (reference point or baseline), thereby accounting for variables such as paper change. For example, if the digital signal is recalculated by central processing until  310  every two seconds, and the minimum value of the amplified signal is ten percent different from the previous minimum value, then the offset is changed. The offset signal is preferably just below the value of the amplified signal to permit the system to focus on small changes. Central processing unit  310  also identifies signals indicative of changes in wavelengths of reflected light off of a paper web, such as web  34 . Such signals are transmitted via output  314  to a controller, such as controller  64 .  
         [0028]    It is preferred that moisture detectors  55  and  57  be positioned between 0.1 inches and 15 inches away from web  34 . More preferably, moisture detectors  55  and  57  should be positioned 7 inches away from web  34 .  
         [0029]    The paper on the bridge  42  is removed at a rate that is correlated directly to the amount of bottom liner web  50  that is pulled through the gluing machine  65 . Measuring wheel  71  in FIG. 1B makes non-slip contact with bottom liner web  50  and measures the rate that paper is removed from bridge  42 . Therefore controller  64  can keep track of the bottom liner paper  50  from the time the web  34  is sprayed at nozzle  72  until the SPRAY is detected at moisture detectors  55  or  57 , to determine the quantity of web in the variable-storage bridge  42 . Controller  64  adjusts its measurement of the paper in the machine based upon the relative quantities of paper entering the bridge (moving under measuring wheel  71   a ) and being removed from the bridge (moving under measuring wheel  71   c ). Controller  64  also adjusts its measurement of the paper in the machine based upon changes in the dancer roll positions  16 ,  44  and  53  as well as the wrap arm positions  52 ,  22 ,  56 ,  49   a  and  49   b . A second portion of the corrugating machine  10  is illustrated in FIG. 1B. Referring to FIG. 1B, single-faced corrugated web  34  passes from the bridge  42  to an alignment mechanism  45  and then to gluing machine  65 . Gluing machine  65  is conventional and may include a pair of adhesive applicator rollers like the rollers  30  which apply adhesive to the corrugated portions of single-faced web  34  and a pair of rollers through which web  34  passes along with a third web after adhesive is applied.  
         [0030]    Third splicer  51  supplies a third paper web  50  from a paper roll to a cylindrical roller rotatably supported by a support member attached to a frame portion. Paper web  50  passes through splicer  51  then further passes through positionable dancer roll  53 , underneath a pair of positionable cylindrical rollers  56 , and over a portion of a pre-heating roller  58  supported by a frame portion. Paper web  50  passes on to bonder  60  where it is bonded to single-faced corrugated web  34  to form single-wall corrugated web  62 .  
         [0031]    Controller  64  is electronically connected to receive the electrical pulses generated by measuring wheel  71 , as well as electrical signals generated by a series of conventional photoelectric detectors  43  disposed on bridge  42  to detect folds  40 . By detecting folds  40  on bridge  42 , the approximate amount of web  34  present on bridge  42  can be determined. A reflectance detector, such as moisture detectors  55  or  57 , can be used to check and refine the readings provided by photoelectric detectors  43  and adjust the readings of photoelectric detectors  43 , if required. As discussed above, reflectance detectors, such as moisture detectors  55  or  57 , identify the portion of web  34  that was previously sprayed with a water pattern via nozzle  72  by projecting a beam of white light on to web  34 . Portions of the visible light spectrum comprising the white light subsequently reflect off of web  34  and are analyzed by detectors  55  or  57 . A dry portion of web  34  will have a particular spectral reading different than that of a moistened portion of web  34 , since the light reflects differently off of dry and moist paper webs.  
         [0032]    The readings taken from photoelectric detectors  43  and reflectance or moisture detectors  55  or  57  are correlated by controller  64  to determine the length of web  34  on bridge  42 . By doing so, controller  64  can determine a synchronous splice point so that splicers  12 ,  41 , and  51  can form a synchronous splice. A synchronous splice exists where all three splices are in close proximity to one another, thereby reducing paper waste by requiring fewer cuts to remove the splices from the final product.  
         [0033]    The operation of corrugating machine  10  is described below in connection with FIGS. 2 and 3, which illustrate a portion of the operation of controller  64 . Controller  64  may be composed of one or more conventional programmable logic controllers or a conventional computer system, such as a personal computer. Moreover, controller  64  can be networkable, so that it can be accessed and manipulated in real-time over a computer network.  
         [0034]    [0034]FIG. 2 illustrates a procedure  200  that is periodically performed by the controller  64  to determine the length of web  34  that is on bridge  42 . Preferably, procedure  200  is performed at predetermined intervals. Web length may be defined in a number of different ways and is not limited to the length of web  34  that physically lies on top of the bridge  42 . Procedure  200  may be performed periodically over a predetermined period.  
         [0035]    Referring now to FIG. 2, the first step in procedure  200  is photoeye step  202 . Photoeye step  202  engages photoelectric detectors  43  to determine an approximate length of web  34  on bridge  42 . Photoelectric detectors  43  make their determination of the length of web  34  on bridge  42  by subtracting the value of web  34  leaving bridge  42  from the value of web  34  coming onto bridge  42  and then adding the resulting value to a predetermined value of web  34  on bridge  42 . Once this step  202  is completed, controller  64  can engage step  204 .  
         [0036]    Step  204  sends a SPRAY command from controller  64  to nozzle  72  that causes nozzle  72  to apply a liquid pattern to a portion of web  34 , such as a web face, for a limited duration (as discussed above). In the preferred embodiment a second liquid pattern is applied to web  34  after a period predetermined by the user. A second liquid pattern is applied in an effort to prevent false readings by moisture detectors  55  and  57 , as discussed above. Once the first liquid spray of step  204  is completed, controller  64  begins a count, step  206 .  
         [0037]    As soon as SPRAY command is sent, at step  206  controller  64  begins counting the number of pulses that are being generated by measuring wheel  71   c , the pulses generated being directly proportional to the number of rotations of measuring wheel  71   c . The controller  64  continues to count the number of pulses until the reflectance or moisture detector  55  or  57  detects the liquid pattern at the spot at which the liquid was sprayed, as determined at step  208 , at which point at least one moisture detector signals controller  64  to stop counting the pulses at step  210 . Preferably, controller  64  does not stop counting pulses until the second liquid pattern is detected at the predetermined period, thereby avoiding false readings.  
         [0038]    Since the spot at which the liquid was sprayed on web  34  gives that wetted portion of the web a reflectance different than that of the dry portion of web  34 , controller  64  can determine when the spot is detected by the reflectance or moisture detector  55  or  57  by comparing the electrical signal generated by moisture detector  55  or  57  upon passage of the liquid pattern, which is representative of the moisture of the web  64 , with the baseline or offset signal indicative of the reflectance of the web. When the light sensed by moisture detector  55  or  57  falls below the threshold indicative of a moisture level for dry web  34 , the spot at which the liquid pattern was sprayed is detected.  
         [0039]    Since the detection readings from moisture detector  55  or  57  vary greatly based upon such factors as the type of paper being used, the operating speed (often over 500 feet per minute), and the rate of evaporation of the water from the web, the detection threshold required is constantly recalculated, taking into account the average reading from the detector as well as the total variation in readings from the detector over a period of time. By varying the detection threshold, the areas sprayed with water can be accurately detected. As an additional check, controller  64  only recognizes that the sprayed web has passed under detector  55  when the pattern of spray pulses matches what was sprayed (after correcting for variation in operating speed from when the web was sprayed and when the spray was detected).  
         [0040]    At step  212 , controller  64  determines the length of the web  34  in the bridge  42  by taking the reading of moisture detector  55  or  57 , in conjunction with the number of pulses from measuring wheel  71   c  counted by the controller  64  between the spraying of the liquid and the detection of the spot, and correlating the reading to the readings of photoelectric detectors  43 . That number of pulses corresponds to the current length of web  34  from nozzle  72  to the reflectance or moisture detector  55  or  57 . This determined length is compared to the length approximated by photoelectric detectors  43  on bridge  42  at step  214  and, in step  216 , controller  64  continuously adjusts photoelectric detectors  43  or the measurements taken by photoelectric detectors  43 .  
         [0041]    The length of web  34  on bridge  42  periodically calculated via the procedure illustrated in FIG. 2 and described above is used to perform a series of functions. One function being a cutting procedure  220  which controls when the cutter cuts out an extra-thick portion of the single-wall corrugated web  62  which is generated by a synchronous splice, and triggers an order change. Another reason for the synchronized splice is to reduce waste from mixing uncalled-for paper types together, a procedure that is normally unusable. Another advantage for synchronization occurs when paper widths change. Mixing unlike paper widths can cause several problems. These problems include, but are not limited to, jams at web guides, smearing glue on machinery, and jams when dry end order changes are performed.  
         [0042]    Referring to FIG. 3, when either one of the splicers  12  or  41  splices a new web onto the current web, a SPLICE signal is transmitted to the controller  64 . As soon as the SPLICE signal is received, the controller  64  starts counting the number of pulses received from the measuring wheel.  
         [0043]    It should be understood that the total length of the web from either of the two splicers  12 ,  41  to the cutter is always known with the controller of the present invention. Although the web length from one of the splicers to the bridge  42  is variable, due to the ability of controller  64  to reposition dancer rolls  16 ,  44 , and  53  as well as pre-heater arms  22  and  56 , controller  64  can determine the web length from the amount or extent that dancer rolls  16 ,  44 , and  53  and pre-heater wrap arms  22  and  56  are moved. Sensors (not shown), such as variable potentiometers, pulse wheels, or load cells, engage dancer rolls  16 ,  44 , and  53  and pre-heater wrap arms  22  and  56 . The sensors engaging dancer rolls  16 ,  44 , and  53  and preheater wrap arms  22  and  56  are used to detect, via changes in electrical potentials (as is well known in the art) in dancer rolls  16 ,  44 , and  53  and pre-heater wrap arms  22  and  56 , their respective positions in corrugating machine  10 . The values of the electrical potentials for dancer rolls  16 ,  44 , and  53  are indicative of a distance of dancer rolls  16 ,  44 , and  53  relative to their respective positions along corrugating machine  10 . Similarly, the values of the electrical potentials for pre-heater wrap arms  22  and  56  are indicative of a distance of pre-heater wrap arms  22  and  56  relative to their respective positions about preheating rollers  24  and  58 .  
         [0044]    Controller  64  is electrically engaged to the sensors as well, and is thus constantly fed position data of dancer rolls  16 ,  44 , and  53  and pre-heater wrap arms  22  and  56  from the sensors. Controller  64  uses the position data to continuously determine the amount of paper going through corrugating machine  10 . Moreover, the position data from individual sensors can be used by controller  64  to calculate the amount of paper in a particular segment of corrugating machine  10 . Additionally, by positioning a plurality measuring wheels  71  at specific segments of corrugating machine  10 , as illustrated in FIGS. 1A and 1B, controller  64  can further monitor the length of each paper web as the paper webs pass through corrugating machine  10 .  
         [0045]    By correlating the readings of photoelectric detectors  43  with the readings of the plurality of measuring wheels  71  and moisture detectors  55  and  57 , controller  64  can create a synchronous splice by adjusting the delivery of paper webs  14 ,  32 , and/or  50 . The adjustment of paper webs  14 ,  32 , and/or  50  can be accomplished by, but is not limited to manipulating the position of dancer rolls, such as dancer rolls  16 ,  44 , and/or  53 , manipulating the position of preheater arms, such as preheater roller arms  22 , and adjusting the speeds of the paper webs.  
         [0046]    At step  224 , when the number of pulses being counted at step  222  reaches a predetermined number of pulses corresponding to a length slightly shorter than the total length of the web from one of the splicers  12 ,  41  to the cutter, then at step  226  controller  64  sends a CUT signal to the cutter. In response to the CUT signal, the cutter makes a first cut in double-faced corrugated web  62 , waits a predetermined period of time and then makes a second cut in the double-faced corrugated web  62  a predetermined distance after the first cut, so that the extra-thick spliced portion is cut out of web  62 .  
         [0047]    Although only a few exemplary embodiments of the present invention have been described in detail above, those skilled in the art will readily appreciate that numerous modifications are to the exemplary embodiments are possible without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims.