Web inspection might sound like something conducted over the internet (the World Wide Web – as in www) and, I suppose, there could be instances where somebody is inspecting someone or something through use of the internet – even if this does sound somewhat similar to ideas put forward by today’s â€conspiracy theoristsâ€. The question is – “what is a web in the context of inspection?â€
Webs
Spiders make webs; ducks have webbed feet; a thinner piece of metal between thicker parts of machinery and fabrications is called a web and any of these could be inspected for some reason or another. However, these are not the webs that are normally associated with the term web inspection.
Using the spider analogy, a spider weaves its web and the term web is often applied to long lengths of woven material. From this point, it is not illogical to associate webs with the extremely long lengths of paper that will be fed into a printing press. The term is also applied to the endless wire mesh that transports pulp through the machinery that turns pulp into paper.
There is an industry known as “converters†that use webs in the form of long rolls of flat, thin materials such as paper, plastic film, foil and cloth and passes them through machinery that converts or changes the web of material into an intermediate form or final product. Web inspection is important for the quality of the conversion – be it adding inks and/or adhesive backing to paper or plastic or activities like slitting, laminating or coating the web.
Visual Inspection
In a majority of web processing activities, the web itself is extremely long and is running through the processing equipment or printing press at quite fast speeds (think of those fill in sequences in the movies showing a newspaper printing press in full operation). What goes in is the web of blank paper – what comes out is the complete newspaper of several pages. What would happen if there was a flaw in the web or the web becomes out of alignment with the ink applicators? The result would be, at least, a lot of paper wasted. But, how can any worker be expected to literally sit inside the machinery and keep watch over the web as it passes through? Even if that was possible, it would be impossible for the human eye to spot all the problems.
Electronic Web Inspection
Sensors and video cameras solve the problem of gaining access to the inspection point but it will still be difficult for any human to continuously monitor a screen and spot problems in order to take precautionary action. Fortunately, we live in the computer age and software has been developed that will send appropriate signals to the machine the instant the camera(s) see any problems.
