Graphene    Continuous Improvement, Reliability and Quality for Manufacturing and Logistics

 A common PET bottle as visible with (right side) and without (left side) polarising filtering.  At right side, cellophane in the stripes around the bottle rotates the light polarization vector (   C. López-Mariscal/US Naval Research Labs./2014)

Introduction

Polariser filters were first developed long time ago.  They became rapidly a standard for nearly all Military and Scientific applications, but not in the Civil Industrial applications like those of the Food and Beverage Industry.    Why polarised light ?     The answer lies in the solution of a key problem.   One affecting all imaging, included the human visual imaging, is that most sources of light are classified as incoherent and unpolarized (or only “partially polarized”) because they consist of a random mixture of waves having different:

1.  spatial characteristics, 
2.  frequencies, 
3.  phases, 
4.  polarization states.   

Photons later superimposing themselves in the photo-detectors giving rise to destructive interference.    

 Constructive and destructive interferences fringes markedly visible in this thin plastic tape, illuminated and observed with polarised light (  Katy Wood/Maryland Institute College of Art/ 2014)

As an example, imagine to illuminate a photo-detector with 1 joule of radiant energy, later discovering that the Signal at the detector outfeed shall be represented by only a small fraction of the non-negligible amount of energy which entered the detector.  Semitransparent and transparent foreign bodies are much more difficult to detect than opaque and yet this basic observation pave the way to special measures when trying to detect them.   Plastic foils like those folding packs of cigarettes, are often encountered in the base of RGBs (Returnable Glass Bottles).   Plastic foils rotate in a fixed direction the spin angle of the polarized light.   Then, to detect plastic foils, light is forced to pass thru an additional delay filter, whose delay is related to the angle with whom all plastics rotate the plane of polarization.    Finally, a separate base camera detects these images.   To detect the truly difficult completely transparent cigarette plastic foils, it is not as efficient as the Inner Sidewall inspection.

  The impressive increase of the Signal-to-Noise ratio felt when circularly polarised light is emitted  through a polariser filter and later detected again filtered by a second polariser, depends by a non-classic quantum feature of the photon named “spin”.  In the example depicted here, shown left-handed clockwise circularly polarised light, propagating along the z axis. Integrating several of these waves in a photo-detector let them interfere destructively.  Meaning less photons detected with the same spin and phase angle, each one of them contributing to form the Signal

(continued)  

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Classification on base of the kind of container Empty Bottle Inspectors (EBIs) and the related measurements whose goal is a binary classification (collectively named inspections), are a category making a particularly sensitive activity: to protect final consumers' health, assuring beverages' safety in the Food and Beverage Packaging Lines. …

Rotary-Linear EBI ComparisonRotary EBIThe Empty Bottle Inspectors of the past were always and only Rotary Machines. The industries which first started to design and produce them and those which adopted them, were all US-based and specialized in the production of glass bottles. …

Introduction When discussing elsewhere the High Frequency fill level inspection, we also examined the complex mechanism of interaction between the High Frequency (HF) electromagnetic waves (3 - 30 MHz) and polar liquids like water. …

Introduction It is a fact: when bottles are urgently needed, also glass returnable bottles born to host beer or mineral water, can fulfill their basic purpose of container for liquids of completely different nature. …

Introduction Base inspection is the most important at all and also the first historically created for EBIs. In the start, it was applied to small inspectors used by glass bottles Producers. It is always present in the Empty Bottle Inspectors, as a minimum standard, jointly with a few others like the High Frequency Residual Liquid control and the Finish inspection.

A common PET bottle as visible with (right side) and without (left side) polarising filtering. At right side, cellophane in the stripes around the bottle rotates the light polarization vector (  …

Introduction The term “finish” originates with the mouth-blown bottle production process where the last step in completing a finished bottle was to finish its lip. Today, the lip or finish is the first forming step in the bottle making process. …

Operative principleThe operative principle of the Finish inspection is applied, in a similar way, to the more complex case of check of the status of the glass threads. In this case, light is generated by an illuminator on top of the finish. …

In the Linear Glass Returnable Empty Bottle Inspectors, External Sidewall Inspection may be performed adopting one or two CCD-cameras. We’ll treat in the following the application with two CCD-cameras: single-camera applications are not satisfactory, covering only < 80 % of the external surface of the bottles.

Why Inner Sidewall InspectionThe inner surface of the bottle may host larvae, insects and other low-contrast foreign objects whose detection, as seen by the External Sidewall is nearly impossible. …

IntroductionThey exist defects no Bottle Washer shall never remove, whatever the duration of its cycles, the amount of caustic soda or temperature of the water. Between these:Paint, internal or external;…

IntroductionScuffing is a memory of the many passages of the returnable bottle thru the Bottling Line, mainly of the wearing of its external sidewalls after friction with other adiacent bottles. …

Infeed ChecksEmpty Bottle Inspectors always need to be protected by prior controls and rejector, to prevent damages implicit in their operation. Dammages originated by: fallen bottles, inclined bottles, …

IntroductionTo perceive the rationale for the inspection of the bottles’ colour, we recommended to take a look at the figure on right side. That is what a Customer considered “a bottle format”. …

Closure inspection by digital Photoscanners(to be continued)Links to other pages: 

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