Rejection System: What You Need To Know

Last updated May 29, 2024

bottle production line

In modern production environments, a rejection system is indispensable for maintaining high standards of product quality and operational efficiency. This system, typically integrated into assembly lines, automatically identifies and removes defective products that fail to meet quality specifications.

Understanding the mechanisms, applications, and benefits of these systems is crucial for industries ranging from pharmaceuticals to food and beverage, where compliance with safety standards is mandatory.

Overview of rejection systems

A rejection system functions by detecting and removing products that do not adhere to the set quality criteria. These systems are equipped with various sensors and detection mechanisms that scan each item for defects. Upon detection, the system activates a mechanism to discard the defective item, ensuring that only products meeting the quality standards proceed further in the production line.

rejection system

Types of rejection systems

  • Mechanical rejection: Utilizes physical devices like pushers or arms to remove defective products from the conveyor belt.
  • Pneumatic rejection: Employs compressed air to gently blow faulty items off the line, ideal for delicate products.
  • Optoelectronic rejection: Uses cameras and light sensors to identify inconsistencies in products and initiates rejection through precise mechanical or pneumatic mechanisms.

Applications in various industries

  • Food and beverage: Ensure the safety and quality of food products by removing those with improper seals, incorrect weights, or visual defects.
  • Pharmaceuticals: Critical for removing products that could compromise patient safety, such as vials with incorrect labels or missing caps.
  • Electronics: Detects and rejects components with physical damage or assembly flaws, ensuring the reliability of electronic devices.
rejection system application

Technical requirements for rejection systems

  • Accuracy: High precision in detecting defects is crucial to avoid false rejections and ensure no defective product is overlooked.
  • Speed: Must keep up with the production line speeds without causing bottlenecks.
  • Reliability: Should perform consistently over long periods with minimal maintenance.

Integration and optimization

  • Seamless integration: Rejection systems must be integrated into existing production lines without significant disruptions.
  • Data-driven optimization: Leveraging production data to refine rejection algorithms and settings can enhance the system’s effectiveness and reduce wastage.

Challenges faced by rejection systems

  • High-Speed production lines: Maintaining accuracy at high speeds is a significant challenge.
  • Product diversity: Adapting to different product types and sizes on the same production line can complicate the setup and calibration of rejection systems.
  • Environmental factors: Dust, humidity, and temperature variations can affect the sensitivity and accuracy of sensors used in rejection systems.
high speed production line

Future trends

  • Smart technologies: Incorporation of AI and machine learning to predict and automatically adjust to changes in product specifications or production conditions.
  • Sustainability: Advances in technology that allow for energy-efficient and less wasteful rejection systems.


The effectiveness of a rejection system in a production line directly correlates with enhanced product quality, reduced waste, and improved consumer satisfaction. As technology evolves, these systems are becoming more integrated and intelligent, capable of handling higher throughput with greater precision.

For manufacturers, investing in advanced rejection systems means stepping towards more automated, efficient, and error-free production processes, ensuring that only products meeting the strictest quality standards reach the market.

Our pharmaceutical labeling machines (e.g. vial labeling machines, syringe labeling machines, tube labeling machines, etc.) All use rejection systems to increase productivity for screening the right products ……

Table of Contents