Using Vision to Your Advantage
Tue, 12/16/2008 - 6:02am
Vision sensors can prove particularly useful for inspecting and tracking pharmaceutical products to improve product integrity and satisfy industry quality standards.
To meet ever-increasing industry regulations, pharmaceutical companies need to employ strict inspection and verification tools during product manufacturing and packaging processes. While simple sensors can be used for presence detection on the automated production line, to achieve accurate results in more sophisticated pharmaceutical applications—such as those requiring analysis of more than one product feature at a time—vision sensors can deliver a more comprehensive and cost-effective solution.
Determining whether a vision sensor is required for the application at hand involves several decision criteria. First, if the application requires sensing a larger area—such as a blister pack, a label, or a date code, rather than a single point, vision generally provides a more complete solution. Vision sensors are additionally helpful when more than one feature must be inspected on a single part. For example, while a photoelectric sensor may be able to determine vial fill level, a vision sensor can confirm that both the level and vial stopper alignment are correct. Some vision sensors also prove advantageous on high-speed production lines and for identifying color, translucency or other traits of the feature of interest.
The following scenarios are a few examples of how the appropriate vision system can be used to efficiently and effectively solve common pharmaceutical applications.
Inspect for complete blister packs
Vision sensors serve multiple purposes when used for verifying blister pack contents and packaging integrity. Vision inspection tools allow users to set parameters for the inspection and specify which features of interest within the blister pack must be identified. This teaches the sensor to inspect the packs for tablet presence, verify that no tablets are broken, and alert operators of any blisters that are empty or contain foreign, unwanted debris.
To perform this task, the vision sensor is taught to identify a known "good" reference part—a correctly filled blister pack—from a "bad" part, rejecting all defective packaging and product. Once the inspection region and features of interest have been properly illuminated to create the highest contrast possible, the sensor acquires the image by a 2-dimensional CMOS or CCD imager chip. Next, the vision sensor compares this acquired image to the stored "good" part and notes any discrepancies between the two, thereby allowing users to quickly identify rejects and divert them from the production line.
Accurate, efficient vial inspection
Another common use for color vision sensors is in vial packaging, in cases where the vials' cap color must be verified. Once all the vials are placed into a tray based upon the vials' color-coded lids, a color vision sensor "sees" the color pattern of each, allowing the sensor to identify each vial's cap color and verify that they are correctly placed.
To verify vial fill level as well as stopper seal and alignment, a high-speed vision sensor can deliver results rapidly, right on the production line. The sensor captures the image of each conveyed vial, then compares it to the image of a good part—a correctly filled and capped vial—that is taught to the sensor. This comparison allows the vision sensor to identify improperly filled or capped vials and reject them.
Read, verify, and grade bar codes for product traceability
The vision-based Bar Code Reader (BCR) tool is particularly useful for identifying and tracking pharmaceutical products. Since bar codes are comprised of light and dark patterns, a vision sensor with the BCR tool can scan a bar code pattern as an image, then compare it to the taught good bar codes stored in the sensor. In this way, the sensor can determine if the bar code read is legitimate and, if so, "translate" the symbol into encoded information—generally a string of numbers or letters.
Simplify inserts and outserts verification
Along with confirming product integrity and quality control, vision sensors can verify that a product insert is included with each unit. The sensor is mounted above a pharmaceutical packaging line and checks each passing package for the information leaflet, using the Geometric Find vision tool to look for the insert within a defined search area. This tool allows the sensor to identify the insert despite its orientation, and any packages that do not contain the leaflet are diverted from the production line.
A similar method is used to ensure that an outsert is included with each package. The vision sensor can be taught to let only bottles with an outsert attached to the cap pass the inspection. As each bottle passes on the production line, the vision sensor captures and analyzes an image of the bottle cap to verify the outsert's presence. This vision sensor capability, combined with the aforementioned tools for image acquisition and analysis, allows these sensors to deliver a comprehensive inspection and verification solution for a broad range of pharmaceutical industry applications.