What Is The Importance Of Conducting The Cobb Test?
The Cobb test is essential as it tests the ability of the paper to resist the penetration of water and quantity of water absorbed by the surface of fiberboard. If fiberboard absorbs too much water, the box may have difficulty maintaining strength and integrity.
How does Cobb sizing value play an important role in printing?
Cobb sizing tester measures and calculates the water or any fluid consumed by the paper, fibreboard, and paperboard in at any given point of time during varied climatic conditions. The high Cobb measure of the papers and other related materials determines the capacity of the materials to contain dampness.
What is the use of Cobb?
Cobb sizing tester determines the amount of water or any liquid absorbed by the paper, corrugated fibreboard, and paperboard in a given period of time under some conditions. Water absorptiveness is a function of various characteristics of paper or board such as porosity, sizing, etc.
What do you understand by the term Cobb value?
The Cobb value provides information about the water absorption capacity of cartonboard samples. The Cobb test determines the amount of water that is taken up by a defined area of cartonboard through one-sided contact with water, within a certain amount of time.
How Cobb test is done?
Cobb Test with ZwickRoell
Specimen and cylinder rest on a rubber mat supported on a steel plate. Approx. 100 ml of water is poured into the cylinder. After a precisely defined time the water is poured out and excess water is removed from the specimen using blotting paper and a roller.
What is a good Cobb value?
Cobb values for liner grades are typically specified as being Target 100g/m2 up to a Maximum of 150g/m2, which means they are moderately chemically sized, and this applies across a broad range of paper weights possibly from 100g/m2–440g/m2.
What is the purpose of sizing in paper making?
Sizing is used in papermaking to improve the absorption and wear characteristics of the paper. The most common materials used in sizing solutions are starch, latex, polyvinyl alcohol (PVA), and carboxymethyl cellulose (CMC).
What does the Cobb angle measurement assess?
The Cobb angle is the most widely used measurement to quantify the magnitude of spinal deformities, especially in the case of scoliosis, on plain radiographs. Scoliosis is defined as a lateral spinal curvature with a Cobb angle of >10° 4.
What Cobb angle is significant?
A Cobb angle in the range of 10 to 20 degrees is considered as mild scoliosis. Scoliosis severity is moderate when the Cobb angle ranges from 20 to 40 degrees. A Cobb angle greater than 40 degrees denotes severe scoliosis.
What is conclusion of Cobb-Douglas production function?
The conclusion of the thesis is that utilizing Cobb-Douglas production function in construction crashing cost analysis expands our understanding of crashing cost sources and the portion of each of elements.
Who invented Cobb test?
In the 1950s, the Strong-Cobb tester was introduced. It was patented by Robert Albrecht on July 21, 1953. and used an air pump.
What should be Cobb value paper?
Cobb value or water absorptiveness is counted by a 1 sq. meter sample of paper or corrugated sheet to measure the mass of water absorbed in a given time. This value helps to maintain the quality of the paper used in the packaging industry.
How do you keep Cobb in a paper?
Surface sizing with mixture of oxidized starch and AKD, at the ratio of 10 to 1, is the best method for reducing Cobb value of the papers along with preserving paper strength, which is used now in the industry for producing fluting and test-liner papers.
What is water absorption test?
Water absorption is used to determine the amount of water absorbed under specified conditions. Factors affecting water absorption include: type of plastic, additives used, temperature and length of exposure. The data sheds light on the performance of the materials in water or humid environments.
What is digital bursting strength tester?
Digital Bursting Strength Tester provides a hydraulic load under a rubber diaphragm of a specific area of the sample under test. It can be used to accurately determine the bursting strength of paper, corrugated cardboard, carton box, card board, leather, cloth or synthetic leathers.
How do you calculate the ECT of a corrugated box?
It is measured by compressing a small segment of board on edge between two rigid platens or plates perpendicular to the direction of the flutes until a peak load is established. This is measured in pounds per lineal inch of load bearing edge (lb/in), but usually reported as an ECT value (for example, 44 ECT). 40 lbs.
What is burst strength of paper?
Bursting strength or burst resistance is a property of a plastic, paper or corrugated board -used in packaging- and is general a guide to the strenght of that plastic, paper or corrugated board. With a burst tester you define the pressure needed to burst a plastic, paper or paperboard.
What is burst strength?
Burst strength is the strength of material in pounds per square inch. Burst strength can be used to monitor the quality of cold chain packaging. Often called the Mullen Burst Test, burst strength is an industry standard that measures the amount of force required to burst corrugated boxes and flexible packaging.
Does Fibreboard absorb water?
High-density fiberboard will absorb water when exposed to it.
Why is weaving sizing important?
Sizing in weaving production serves to protect the warp yarns during the weaving process. Protective sizing agents help the yarn to withstand high mechanical stress during weaving. They do this by improving the wear resistance of the warp threads and by reducing fiber abrasion.
What is sizing explain?
In textile: Singeing. Also called gassing, singeing is a process applied to both yarns and fabrics to produce an even surface by burning off projecting fibres, yarn ends, and fuzz. This is accomplished by passing the fibre or yarn over a gas flame or heated copper plates…
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