Safety first
The importance of label inspection and code reading have been covered in the ‘Food’ and ‘Pharmaceutical’ sections. Other packaging applications can range from checking the packaging materials and the packaging themselves for defects to checking fill levels and the integrity of the final packaging for product purity and shelf-life considerations. Examples include the orientation of bottle lids, the integrity of seams in cans and the presence of foil seals in container lids which will ultimately be heat sealed onto the neck of the container.
Developing techniques
Many emerging techniques have facilitated packaging inspection. Smart cameras can be programmed for individual inspections and decision-making anywhere on the packaging line. Thermal imaging cameras can be used to check the correct application of hot-melt glue for cardboard carton assembly. NIR imaging makes it possible to image the contents through some packaging materials at the same time as inspecting the print on the packaging itself. Hyperspectral imaging is a new technique that can inspect the contents of packaging.
The impact of 3D imaging
From its early beginnings, 3D vision required specialist programming expertise to take the raw data output and configure it for different factory control networks. Huge amounts of expensive processing power and bulky equipment were needed. Now, with advances in embedded, smart technologies, 3D is affordable and accessible to many without specialist skills. Instead of a camera or lasers that need complex configuration with a separate PC, new ‘intelligent’ sensors offer all-in one vision solutions. However, that does not mean that we have arrived at “one size fits all” in 3D vision. Instead, from high-performance cameras, advanced colour, 3D measurement and multi scanning technology through to stand-alone programmable sensors, we have reached a continuum of choice. With a solution for every application, the challenge now is to match the best technology to the process.
Applications include checking the contents, content, number and fill of a container. This is useful for products such as chocolates or biscuits in compartmented containers. Not only is the absence of an item noted, the insertion of a damaged or wrong item can also be flagged up. Overfill levels can be a problem, for example where totes, bags and tubs which must meet a safe carrying weight limit or allow safe stacking, or food products such as meat are over-height and filling would interfere with sealing the plastic film cover correctly. Checking the orientation of products like shampoo bottles prior to shrink wrapping can avoid awkward shaped packing that does not fit into outer cartons, resulting in waste and downtime.
