Code Inspection Machine

I. Project Equipment Overview

1. Project Name: PET Bottle Cap, Anti-theft Ring, Liquid Level, and Inkjet Printing Inspection System

2. Project Description:
This system performs comprehensive online inspection of PET bottles, including cap integrity, anti-theft ring condition, liquid level accuracy, and inkjet printing quality. Any defective bottles identified are automatically rejected.

3. Maximum Throughput: 60,000 bottles/hour

4. Applicable Container Type: PET bottles

5. Product Capacity Range: 200 mL – 2 L

II. Environmental Requirements

1. Installation Altitude: 5 – 3000 m above sea level

2. Operating Temperature Range: 5°C – 40°C

3. Recommended Relative Humidity: 50% – 65% RH

4. Factory Conditions: Floor flatness, load-bearing capacity, and other parameters must comply with relevant national standards to ensure stable and reliable operation.

5. Storage Conditions: Upon delivery, all components and equipment should be stored in facilities that meet national standards. During storage, regular lubrication and preventive maintenance are required to prevent surface damage, corrosion, or deformation that may affect installation, commissioning, and subsequent operation.

III. Operating Conditions

1. Power Supply: 220V AC, 50 Hz, single-phase (to be provided by the customer).
   Note: Special voltage requirements must be communicated in advance, as they may affect specifications, delivery schedule, and pricing.

2. Total Power Consumption: Approx. 2.4 kW

3. Control Voltage: 24 VDC

4. Compressed Air: 4 Pa – 12 Pa (customer to provide pipeline connection from air source to the equipment).

IV. Equipment Introduction

1. Installation Position

The inspection system is installed on the conveyor line at a suitable point downstream of the filler to ensure stable bottle movement and accurate detection.

2. Inspection Scope

• Missing cap

• Improperly seated (high) cap

• Tilted (crooked) cap

• Broken or damaged anti-theft ring

• Low liquid level

• Absence of inkjet printing

• Excessive or incorrect inkjet printing

3. Detection Principle

1. Bottle Identification:
   As each PET bottle passes the positioning sensor, the sensor detects its presence and signals the control unit. The control unit assigns a unique bottle ID and synchronizes the encoder signal.

2. Image Capture & Processing:
   The positioning sensor simultaneously triggers the cameras to capture images of three inspection zones: the bottle cap, the liquid level, and the inkjet marking. The captured images are processed by the image processor, which evaluates conformity. The results are transmitted both to the HMI (for real-time visual monitoring) and to the PLC (for quality control logic).

3. Rejection Mechanism:
   When a non-conforming result is confirmed, the control unit associates the defect with the corresponding bottle ID and sends a command to the rejection system. The rejector then removes the defective bottle from the production line with high precision.

4. Equipment mechanical components

5. Electrical composition of the equipment

6. Testing cabinet structure diagram

Capping liquid level detection

Capping liquid level detection

7. Cap Inspection

This module uses three CCD cameras to capture images of bottles from different angles, reducing blind spots. Special optical lenses filter light from all directions to ensure efficient image acquisition. Its primary function is to detect defective bottles such as missing caps, overhanging caps, crooked caps, and broken caps.

PET bottle capping images captured by CCD camera

8. Liquid Level Detection
        This module employs a CCD camera to capture frontal images of the bottle’s liquid level. When the bottle is stationary, the liquid surface is expected to remain nearly horizontal. Through image processing, the area below the liquid surface is displayed in black, while the empty region above appears white. By applying this method, the system effectively distinguishes whether the liquid level falls above or below the preset threshold.

9. Inkjet Printing Inspection
        A CCD camera is used to acquire images of inkjet markings on both the bottle and cap. The images are digitally analyzed, enabling precise identification of defective printing. Bottles with unqualified inkjet results are automatically rejected. The system supports inspection of both black text on yellow caps and white text on black caps.

Sample image recognition processing effect

10. Detection accuracy