1. Project Overview

This scheme deploys a high-precision machine vision inspection system in the post-printing stage for finished single-piece hang tags after printing. High-speed industrial cameras capture real-time images, paired with professional intelligent inspection software to intelligently detect various defects generated during hang tag production. Covered common quality issues include printing defects, barcode quality problems, variable data errors, surface stains, missing prints, die-cut misalignment, gold and silver hot stamping process defects, and mixed or wrong serial numbers.

The system can automatically identify, judge and intelligently reject hang tags with wrong information, missing content, flaws or defects. It comprehensively controls the production quality of finished hang tags and effectively avoids batch quality accidents and customer complaint risks.

2. Inspection Requirements and Performance Indicators

To meet full-range quality inspection demands for hang tags made of diverse materials and with different processes, and eliminate missing and false detections, the system’s core inspection indicators are designed with high standards to fit high-speed mass production inspection scenarios. Specific parameters are as follows:

Inspection Mode: Offline inspection after printing

Applicable Materials: Coated art paper, white cardboard, grey cardboard, gold and silver cardboard

Inspection Width: 300~350 mm

Operating Speed: The equipment can run continuously and stably for inspection, with a maximum inspection speed of 120 meters per minute, matching the production rhythm of mass hang tag manufacturing

Inspection Precision:

① Minimum detectable area for defects such as missing prints and dirt spots: Front side ≥0.2 mm²;

② Overprint deviation inspection: ≥0.2 mm

③ Die-cut deviation inspection: ≥0.2 mm

④ Scratches: Horizontal or vertical scratches with vertical width over 0.2 mm, horizontal width over 0.15 mm, length over 15 mm and contrast above Grade 20 can be detected;

⑤ Partial color difference inspection: ΔE≥2.5 ΔELab

3. Full-Range Core Inspection Functions

3.1 Printing and Appearance Defect Inspection (Standard Fixed Content Tags)

The system compares samples with templates to identify surface physical and printing defects in real time:

Printed Texts & Patterns: Missing print, blocked printing plates, dirt spots, ink specks, scratches, ink splashes, knife lines.

Color Control: Supports online color difference monitoring and quantitative inspection of overall or local printing color deviation.

Post-Processing Structures: Die-cut misalignment, glue overflow, missing tags (broken strips).

Special Processes: Misaligned or missing gold/silver hot stamping, uneven varnish coating or surface scratches.

3.2 Variable Data and Barcode Compliance Inspection (Intelligent Variable Content Tags)

Conduct data comparison for high-standard tags applied in pharmaceutical, food, electronics and other industries;

First-level quality grading for barcodes and QR codes;

Real-time reading of 1D barcodes and 2D QR codes;

Real-time online quality grading of barcode indicators including contrast, modulation ratio and decodeability. Automatic rejection and alarm will be triggered if the grading result is lower than the preset standard.

3.3 Text Inspection and Error Code Prevention Control

The system can automatically identify standard text on hang tag templates, and compare various variable text contents including production batch numbers, production dates, shelf lives, product serial numbers, specification parameters and brand information. It effectively verifies the integrity, clarity and readability of texts to eliminate text defects such as incomplete characters, broken lines, wrong prints and missing prints.

Duplicate and Missing Code Prevention Control: The system dynamically connects to exclusive hang tag code packages and code pool databases to compare variable codes of mass-produced products in real time. Once severe problems such as duplicate codes, skipped serial numbers, missing codes and mixed serial numbers are detected, the equipment will trigger alarms and perform interception and rejection to solve the disorder of hang tag serial numbers.

4. Hardware System Architecture

Facing harsh production environments featuring diverse hang tag materials, high reflectivity of partially laminated or hot-stamped materials, and high-speed mass production, the system adopts high-end industrial hardware architecture to guarantee stable high-speed and high-precision inspection. Hardware configurations can be flexibly adjusted according to customers’ hang tag processes, materials and output requirements.

4.1 Industrial Cameras

① Line Scan Camera: Suitable for continuous high-speed wide-width hang tag production lines. It forms images through continuous scanning to realize blind-spot-free inspection for high-volume mass production.

② Area Scan Camera: Suitable for accurate fixed-position inspection of finished single hang tags or low-speed fixed stations.

Matching of Color / Monochrome Cameras: High-definition color cameras are standard for hang tags with color patterns, color difference detection and colored processes; high-definition monochrome cameras are adopted for scenarios only requiring structural defect detection and barcode reading, further improving imaging resolution and inspection precision.

4.2 Light Source System

Light sources are matched to meet imaging requirements of various hang tag materials. Dome shadowless light sources are used for high-reflective hang tags with lamination, hot stamping and high-gloss special finishes to completely eliminate interference from surface reflection, light spots and shadows. Strip lights and ring lights are equipped for ordinary paper hang tags to ensure defect features are clearly highlighted and provide high-quality images for inspection.

4.3 Image Capture Card and Processing Host

Equipped with high-speed image capture cards and special industrial processing hosts, the system ensures real-time image data collection, high-speed transmission and millisecond-level arithmetic processing during high-speed hang tag production. It solves issues including data delay, picture stuttering and lagged inspection, and guarantees real-time performance and stability of the whole inspection process.

5. Closed-Loop Control and Defective Product Disposal Mechanism

Accurate detection and efficient interception are core priorities of post-production hang tag quality inspection. The system is equipped with a fully automatic closed-loop defective product disposal mechanism that perfectly matches the operating logic of hang tag inspection machines. After detecting defective cut single hang tags, the system can quickly link pneumatic blow-off valves and mechanical push rods of the equipment to accurately reject defective hang tags into exclusive waste areas, realizing full closed-loop operation of automatic detection, intelligent judgment, direct rejection and waste isolation.

6. Data Management and Upstream Process Tracing

The system supports intelligent defect classification statistics and process tracing functions. It automatically sorts and summarizes all types of hang tag defects, accurately calculates the proportion of various defects such as dirt spots, knife lines, color differences, unqualified barcodes, wrong/missing codes and die-cut misalignment, and automatically generates visual pie charts and defect trend analysis graphs to intuitively display production quality problems.

All inspection data and defect records are automatically archived to realize traceability of quality problems, optimization of production processes and review of batch quality. It helps enterprises standardize production and inspection workflows and achieve standardized and data-based quality control for hang tag manufacturing.