Sensor system and method for web manufacturing

Abstract

The present invention provides a sensing system and method adapted for use in monitoring and detecting features of a web for manufacturing. The sensing system has an energy source adapted to project an energy beam onto the web and a sensor positioned relative to the web and the energy source to sense attenuation of the energy beam from the energy source to detect, locate, identify, or measure the web or its features. The method includes passing the web through a light from a light source, measuring attenuation of the light from the light source with an optical sensor, and identifying an optical signature as a function of attenuation for characterizing the web and/or its feature.

1 . A sensing system adapted for use in monitoring and detecting features of a web for manufacturing, the sensing system comprising:
 an energy source adapted to project an energy beam onto the web; and   a sensor positioned relative to the web and the energy source to sense attenuation of the energy beam from the energy source to detect, locate or measure the web and/or features of the web.   
   
   
       2 . The sensing system of  claim 1  wherein the energy source comprises a light source and the energy beam comprises a light beam. 
   
   
       3 . The sensing system of  claim 1  wherein the energy source is positioned on one side of the web and the sensor is aligned with the energy source on an opposite side of the web, the web passing between the energy source and the sensor. 
   
   
       4 . The sensing system of  claim 3  wherein at least a portion of the energy beam is transmitted through the web, the portion of the energy beam passing through the web is sensed by the sensor. 
   
   
       5 . The sensing system of  claim 4  further comprising a comparator in data communication with the sensor to measure a difference in energy between the energy beam and the portion of the energy beam that passes through the web. 
   
   
       6 . The sensing system of  claim 5  wherein the difference comprises an energy signature for the web and/or a feature of the web. 
   
   
       7 . The sensing system of  claim 6  wherein the feature comprises:
 a) a perforation of the web;   b) a seal of the web;   c) a timing mark of the web;   d) a skirt length of the web; or   e) any part, alteration or dimension of the plastic bag web ascertainable by measuring attenuation of the energy beam.   
   
   
       8 . The sensing system of  claim 1  wherein the energy source and the sensor are positioned on one side of the web, the sensor positioned relative the energy source and the web on the one side to sense at least a portion of the energy beam reflected off of the web. 
   
   
       9 . The sensing system of  claim 1  in combination with a machine for manufacturing plastic bags. 
   
   
       10 . The sensing system of  claim 1  in combination with a plastic bag winding machine. 
   
   
       11 . The sensing system of  claim 1  in combination with a plastic bag counter machine. 
   
   
       12 . The sensing system of  claim 1  wherein the web comprises:
 a) a paper web;   b) a plastic web; or   c) a metal web.   
   
   
       13 . A plastic bag manufacturing machine adapted to detect the existence and/or location of one or more features in the bag, the machine comprising:
 a machine frame with one or more components for supporting and handling a plastic bag web;   an energy source on the machine proximate the plastic bag web to project an energy beam onto the plastic bag web; and   a sensor on the machine proximate the plastic bag web and the energy source to sense attenuation of the energy beam projected onto the plastic bag web from the energy source.   
   
   
       14 . The machine of  claim 13  wherein the energy source comprises a light source and the energy beam comprises a light beam. 
   
   
       15 . The machine of  claim 14  wherein the light source is adjustable in intensity or frequency to be tuned each specific plastic bag web or to filter out background light. 
   
   
       16 . The machine of  claim 13  wherein:
 a) the energy source is positioned on the machine on one side of the plastic bag web and the sensor is aligned with the energy source on the machine on an opposite side of the plastic bag web to sense at least a portion of the energy beam passing through the plastic bag web; or   b) the energy source and the sensor are positioned on the machine on one side of the plastic bag web, the sensor positioned relative the energy source and the plastic bag web on the machine on the one side to sense at least a portion of the energy beam reflected off of the plastic bag web.   
   
   
       17 . The machine of  claim 13  further comprising a comparator to measure an energy difference between the energy beam and the portion of the energy beam reflected off of and/or transmitted through the plastic bag web. 
   
   
       18 . The machine of  claim 17  wherein the energy difference comprises a signature for the plastic bag web and/or a feature of the plastic bag web. 
   
   
       19 . The machine of  claim 18  wherein the feature comprises:
 a) a perforation of the plastic bag web;   b) a seal of the plastic bag web;   c) a timing mark of the plastic bag web;   d) a skirt length of the plastic bag web; or   e) any part or dimension of the plastic bag web ascertainable by measuring attenuation of the energy beam.   
   
   
       20 . A sensing system for use in manufacturing plastic bags from a plastic bag web and adapted to detect the existence and/or location of one or more features of the bag and/or bag web, the sensing system comprising:
 a light source adapted to project a light onto the plastic bag web;   an optical sensor positioned relative to the plastic bag web and the light source to sense attenuation of the light from the light source by transmittance or reflectance; and   a comparator in communication with the optical sensor and the light source to measure attenuation of the light transmitted through or reflected off of the plastic bag web to provide an optical signature for the bag and/or one or more features of the plastic bag web.   
   
   
       21 . The sensing system of  claim 20  wherein the comparator comprises a phototransistor, photodiode or like device adapted to produce an electrical response for each optical signature associated with the bag and/or the features of the plastic bag web. 
   
   
       22 . The sensing system of  claim 20  further comprising a controller having a data store in communication with the comparator for storing data relating to the existence and/or location of the features of the bag and/or plastic bag web. 
   
   
       23 . The sensing system of  claim 22  wherein the controller is in communication with the sensor to detect, store, calculate, respond to, and prepare a history of attenuation versus time of attenuated light readings. 
   
   
       24 . A method for detecting, monitoring and measuring one or more features of a plastic bag web for manufacturing plastic bags, the method comprising:
 mounting an energy source and a sensor proximate each other and a plastic bag web on a machine for manufacturing plastic bags;   sensing a level of attenuation of an energy beam from the energy source transmitted through or reflected off of the plastic bag web and/or one or more features of the plastic bag web; and   associating the level of attenuation with each feature and/or the plastic bag web for monitoring, measuring and detecting the presence of each feature and/or the plastic bag web during manufacturing.   
   
   
       25 . The method of  claim 24  further comprising the step of tuning frequency and intensity of the energy source to each plastic bag web. 
   
   
       26 . The method of  claim 24  further comprising the step of creating a time record for each time the feature is detected for post-processing detections for the plastic bag web and/or the one or more features. 
   
   
       27 . The method of  claim 24  further comprising the step of measuring an energy signal for the one or more features comprising:
 a) a perforation of the plastic bag web;   b) a seal of the plastic bag web;   c) a timing mark of the plastic bag web;   d) a skirt length of the plastic bag web; or   e) any part or dimension of the plastic bag web ascertainable by measuring attenuation of the energy beam.   
   
   
       28 . The method of  claim 26  further comprising the step of substituting a missing detection for one of the features at a correct interval using the time record. 
   
   
       29 . The method of  claim 24  further comprising the step of characterizing the level of attenuation for each feature by comparing to a baseline level of attenuation for the plastic bag web. 
   
   
       30 . A method for detecting and measuring one or more features of a bag web, the method comprising:
 passing the bag web through a light from a light source;   measuring attenuation of the light from the light source with an optical sensor; and   identifying an optical signature as a function of attenuation for characterizing the bag web and/or each feature of the bag web.   
   
   
       31 . The method of  claim 30  further comprising the step of acquiring the optical signature from the optical sensor with a controller for comparing with a record describing what optical signatures should have been acquired. 
   
   
       32 . The method of  claim 31  further comprising the step of associating the line speed of the bag web with the record of detections for each optical signature for:
 a) confirming the presence of each feature of the bag web;   b) measuring one or more of the features of the bag web; and/or   c) determining false/positive readings from the optical sensor.