The challenge
For vacuum-packed food products, the integrity of the seal is crucial for shelf life and food safety. A correctly vacuum-drawn lid exhibits measurable concavity—the slight inward curvature caused by the pressure difference between the packaging and the outside air. If this vacuum is absent, the lid will be flat or even slightly convex, and the product must be rejected.
The existing visual spot-check inspection did not provide 100% certainty and was heavily dependent on the operator’s attentiveness. A structural solution required inline 100% inspection capable of keeping pace with production speeds. Furthermore, the jar sizes in the product range varied, requiring a flexible recipe system for each product type. A 2D camera system did not provide sufficient geometric accuracy to reliably quantify the subtle lid warping.
The solution
Vision Partners integrated the Hikrobot MV-DP2120-01P 3D Laser Profiler above the conveyor belt. The sensor projects a blue-violet laser line (405 nm) onto the lid and measures the exact height for each point via laser triangulation. Due to the movement of the pot across the conveyor belt, successive profiles are stacked to create a full 3D height map of the lid. Based on this, MVTec HALCON calculates the lid depression — the degree of inward bending — and compares it with the tolerance limits of the active recipe. If there is a deviation, a GO/NO-GO signal is immediately sent to the PLC.
The system consists of:
- Hikrobot MV-DP2120-01P V2.03D laser profiler scanner with a Z-resolution of up to 3.66 µm, repeatability of 1.48 µm and a scan speed of up to 23,900 frames per second — via GigE Vision connected to an industrial PC
- HDR exposure modeMultiple exposure integration for robust measurement on glossy or reflective lids
- MVTec HALCON inspection softwareflatness analysis, depth determination, and surface matching on the 3D point cloud
- Recipe per productEach product has its own tolerance window for lid depth and flatness; recipe changeover is automatic via PLC command
- PLC integration with digital I/OGO/NO-GO signal in real-time to control the pneumatic ejection mechanism
- Traceability: per pot, the depth image, brightness image, timestamp, and inspection result can be logged
The MV-DP2120-01P is IP67 certified and suitable for direct mounting in a production environment. The reference distance of 120 mm above the lid provides an X-measuring window from 58 to 95 mm—enough to fully capture taller and shorter jars and lids.
The result
The system performs a 100% inline vacuum inspection on every jar that passes through the line. Jars without the correct vacuum are automatically ejected before the packaging station. The subtle lid warping—measured at the micrometer level—serves as an objective and repeatable quality criterion that does not depend on human judgment.
The combination of the Hikrobot MV-DP2120-01P and MVTec HALCON offers an open platform: algorithms are adaptable, recipes expandable, and the system integrates easily with existing MES or ERP environments via OPC-UA or Modbus TCP.
Vision Partners managed the entire process as an integrator for a single sensor supplier: sensor delivery from their Hikrobot distributor role, system design, software development in HALCON, mechanical integration, Factory Acceptance Test (FAT), and Site Acceptance Test (SAT) at the customer's site.
