Non-contact colorimeter detects color differences of irregular metal parts on production lines

Despite all the advancements in color measurement and management, one challenge remains: how to accurately measure color without making the instrument touch the sample, which has always been a persistent problem troubling customers. 

Background and Needs

A metal parts manufacturing enterprise faces challenges in managing product appearance color consistency during multi-supplier collaborative production. Due to the irregular shapes and complex surface reflection characteristics of the parts, traditional contact colorimeters are prone to instrument contamination and fail to ensure measurement accuracy. There is a need for non-contact color measurement technology to achieve precise measurement of the metal parts' Lab values and ensure cross-supply chain color uniformity.

Instrument Configuration and Core Functions

Brand: 3nh ThreeNH
Model: TS7708L Online Non-Contact Colorimeter

Key Technologies

1. Non-Contact Measurement Port Design: Prevents sample contamination of the integrating sphere.

2. Lab Color Space Analysis: Quantifies lightness (L value), red-green axis (a value), and yellow-blue axis (b value).

3. Standard Sample Measurement Bracket: Ensures precise control of the measurement distance (0.7±0.1mm) and maintains a parallelism of 0.2 degrees between the sample's measured surface and the measurement port.

Operation Process and Key Points

1. Calibration and Initialization

• Calibration: Perform black-and-white calibration first after power-up to reduce measurement errors.

• Bracket Installation: Fix irregular metal parts on the measurement bracket and adjust them to maintain a standard 0.7mm distance from the measurement port (see figure).

  
  

  
  

2. Measurement Execution

• Light Leakage Prevention: Fully cover the measurement port to prevent ambient light from affecting data accuracy.

• Multi-Area Sampling: For uneven surfaces, select multiple representative areas for measurement and take averages to reduce errors.

3. Data Management and Analysis

• Data Export: Supports connection to a computer to retrieve measurement results and generate color difference reports (ΔE values).

• Naming Convention: For the same sample, use numerical or alphabetical suffixes (e.g., "A-1, A-2") instead of descriptive terms like "upper/lower" to facilitate batch data management.

Problems and Solutions

Recommended Online Non-Contact Colorimeters

The need for non-contact color measurement comes from enterprises across various industries. For example, in the food, beverage, and cosmetics industries, there are often samples that cannot come into contact with measurement equipment. To address this challenge, Threenh has developed the TS7708L, a non-contact imaging spectrophotometer that brings breakthrough versatility and accuracy to the measurement of wet and dry paints, plastics, cosmetics, as well as small and irregularly shaped samples. The Threenh TS7708L can accelerate color formulation, in-production color inspection, and quality control, reducing waste and rework while shortening cycle times.

TS7708L Online Non-Contact Spectrophotometer

• Technology: Features a 1000-line precision grating, dual-column 40-group silicon photodiode sensors, and a long-life full-spectrum LED light source.

• Performance: Repeatability ΔE*ab < 0.03, optical resolution < 10nm.

• Applications: Non-contact measurement of liquids, pastes, powders, etc. Suitable for automated production lines in industries such as plastics & electronics, paints & coatings, textiles printing&dyeing，printing paper, automotive, metal, medical, cosmetics, and food, enabling standardized color management.

This solution addresses the challenges of color consistency in complex metal parts production, providing high-precision, contamination-free measurement and efficient data management for cross-supplier quality control.