PET full bottle inspection machine

I. Project Equipment Overview

• Project Name: PET Bottle Inspection System for Caps, Anti-theft Rings, Liquid Levels, and Inkjet Printing

• Description: The system automatically inspects PET bottles for defects in the cap, anti-theft ring, liquid level, and inkjet print quality, and rejects non-compliant bottles.

• Maximum Capacity: Up to 60,000 bottles per hour

• Applicable Bottle Type: PET bottles

• Product Volume Range: 200 mL – 2 L

II. Environmental Specifications

• Operating Altitude: 5–3000 m above sea level

• Ambient Temperature: 5°C – 40°C

• Relative Humidity: 50% – 65% RH

• Factory Conditions: Floor levelness, load-bearing strength, and related parameters must comply with national standards to ensure stable equipment operation.

• Storage Conditions: After delivery, equipment and components must be stored in facilities that meet national standards. During storage, proper lubrication and maintenance are required to avoid corrosion, damage, or deformation that could impact installation, commissioning, and performance.

III. Equipment Operating Parameters

• Power Supply: 220 V, 50 Hz, single-phase (provided by customer). For non-standard voltages, advance notice is required as this may influence specifications, delivery schedule, and cost.

• Total Power Consumption: ~2.4 kW

• Control Voltage: 24 VDC

• Compressed Air Requirement: 4–12 Pa (customer is responsible for connecting the air supply from the source to the equipment).

IV. Equipment Description

• Installation Position: Installed on the production line at the designated inspection point.

• Inspection Items:

• Missing cap

• Over-height cap

• Misaligned/tilted cap

• Damaged or broken anti-theft ring

• Insufficient liquid level

• Missing inkjet code

• Excessive or irregular inkjet code

• Detection Principle:

1. As each PET bottle passes the positioning sensor, the control unit records the bottle ID and the corresponding encoder value.

2. The sensor activates the camera system, which captures images of the cap, liquid level, and inkjet code. The image processor analyzes the captured data and transmits results to both the HMI for real-time display and the PLC for defect rejection preparation.

3. If a defect is detected, the control unit signals the reject mechanism to remove the defective bottle identified by the recorded ID.

4. Equipment mechanical components

5. Electrical composition of the equipment

6. Testing cabinet structure diagram

Capping liquid level detection (capping liquid level detection at stations one and three)

Inkjet printing inspection (station 2, single-camera inkjet printing inspection)

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.

8. Liquid Level Detection

This module uses a CCD camera to capture liquid level images from the front, ensuring that the liquid level in the bottle is nearly horizontal when the bottle is stationary. This module employs image processing principles that render the portion below the liquid level black in the image and the portion above the empty bottle white. A special method is used to distinguish between levels below and above the specified liquid level.

9. Inkjet Printing Inspection

This module employs a CCD camera to capture frontal images of inkjet printing on both bottles and caps. The acquired images are then processed through digital analysis to identify defects, enabling the system to automatically and reliably reject bottles with improper or missing inkjet codes. The inspection system supports multiple color schemes, including black ink on yellow caps and white ink on black caps.

10. Detection accuracy