COBB-01 COBB Tester

1. Introduction of COBB Tester

COBB Tester is used for assessing the water absorption of paper and paperboard through the cobb test method. It proves effective in sizing paper and determining water absorption on cardboard surfaces, but it is not recommended for use on basic paper or embossed paper with a basis weight below 50g/m², having low sizing degree, or exhibiting numerous pinholes. Additionally, it is not suitable for assessing unsized paper and cardboard accurately, nor does it provide an accurate evaluation of the writing performance of paper or cardboard.

The Cobb tester evaluates the water absorption capability of paper or cardboard surfaces. The Cobb value represents, under specific conditions and within a specified timeframe, the mass of water absorbed by the carton board surface per unit area, expressed in grams per square meter (g/m²).

The total recommended test time by international standards for the removal of excess water and the execution of water absorption is as follows:

2. What is COBB sample cutter?

The COBB sample cutter is an essential tool for absorption testing, swiftly and accurately cutting a sample with a specified area of φ125mm.It’s a stamping type sampler and proves to be an ideal apparatus for corrugated board and carton production, research, quality supervision, inspections, and various other departments.

3. Why do you need a COBB Tester?

Paper and cardboard are common materials used for printed content, and their water absorption properties can impact print quality. Knowing the Cobb value helps ensure that the selected materials are suitable for printing, minimizing issues related to ink smudging or poor print quality.

Cobb testing is a quality control measure to ensure that the materials meet industry standards. Material scientists use this data to optimize the composition of paper and cardboard, tailoring it for specific uses based on its water absorption characteristics.

4. Advantages of COBB Tester

Stainless steel made

Standard conformed metal roller

5. Test Principle of COBB Tester

Before conducting the test, weigh the sample. When one side of the sample comes into contact with water for a specified duration, remove the excess moisture from the dried sample and immediately weigh it. Express the results by the increase in mass per unit area of the sample, measured in grams per square meter (g/m²).

6. Application of COBB Tester

The Cobb tester is commonly used to measure the water absorption capacity of porous materials, particularly paper and cardboard. It is crucial for assessing the ability of these materials to absorb water, which can impact various applications, such as printing, packaging, and paper-based products. The Cobb tester is particularly relevant for materials where water absorption characteristics are significant, and maintaining specific standards is essential for quality control and performance optimization.

7. Specifications of COBB Tester

8. Standards of COBB Tester

GB/T1540, ISO 535, QB/T1668, TAPPI T441

9. Configuration of COBB Tester:

a) Standard configuration: COBB-01 COBB Tester, Metal Roller, manual

b) Optional configuration: Blotting paper, COBB sample cutter

10. FAQs of COBB Tester

What is the COBB value?
Cobb value is the calculated mass of water absorbed in a specified time by 1 m² of paper or board under specified conditions

What is absorption time?
The time from the beginning of contact between water and sample to the end of water absorption.

Why is the COBB test important for paper quality?
The COBB test is crucial for assessing the water absorption properties of paper. This information is vital for maintaining print quality, preventing issues like ink smudging, or compromised print standards, which is especially important in the production of high-quality printed materials.

What is the metal roller used in COBB testing? 
Metal roller used in COBB test is a stainless steel roller, having a smooth face 20 cm wide and eighing 10.0 ± 0.5 kg (22 ± 1.1 lb).

If you have purchase needs, please contact us and COBB Tester manufacturer – Cell Instruments will give you satisfactory products.

Hvis du ønsker mer informasjon om dette produktet, er du velkommen til å kontakte oss. Anbefaler andre populære produkter for deg: Paper Dirt Tester supplier