Syringe Needle Shield Inspection

Identify problems with the shield protecting the needle

Defects detected on a syringe needle shield

After the syringe needle is staked in the tip of the syringe, it is covered with a needle shield, or needle safety guard, to prevent accidental needle sticks. This shield is typically injection molded and can be either soft or rigid.

The needle shield must be placed in a precise location, so the angle between the shield and the syringe cone can only vary a slight amount before the assembly is rejected. If the shield is misplaced or bent, it can also bend the needle. Likewise, if the shield is pushed down too far, the needle may protrude from the end of the shield. In additional to these common defects, other manufacturing and handling processes can cause surface contamination on the shield or needle. Needle safety guard inspection is a key safety step.

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Machine vision systems, such as the In-Sight 8505P, are commonly used to inspect and measure needle safety guard location, straightness, and other features. However, needle protrusion or dark material contamination may require more sophisticated deep learning technology, because of the wide range of subtle variations that may indicate a defect.

The Cognex AI-based defect detection tool learns the normal appearance of the needle shield by training on a small set of sample images. It is then able to spot even small variations in needle shields that indicate the tip is protruding, while accepting cosmetic variations in the shield’s surface.

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