Gram weight, test method, unit conversion and impact on Gift Paper Boxes printing

Gram weight, test method, unit conversion and impact on Gift Paper Boxes printing

Quantitative commonly known as gram weight, known as basis weight in Hong Kong and Taiwan, refers to the weight of paper per unit area, generally expressed in grams per square meter. Quantity is the most basic physical index of paper, its level and its uniformity affect all physical, mechanical, optical and printing properties of paper.

Various performance indicators of general printing paper, such as thickness, tensile strength, bursting strength, opacity, etc., are closely related to quantification. If the basis weight of the paper is significantly lower than the standard, it will not only be prone to printing failures, but also break due to insufficient mechanical strength. On the contrary, if the basis weight is too high, pulp will be wasted in production, and the user's practical area per ton of web paper cannot be guaranteed. When the quantitative weight of a piece of paper is not uniform, inaccurate overprinting, unclear writing and inconsistent picture color and luster will occur.

Quantitative units and conversion methods

The common unit of quantification is expressed in gsm, which is the international common unit. But there are two other notations (commonly used) for basis weights (both kraft and kraft) in the United States: lbs/1000 sq. ft. (LBS/1000ft2) and lbs/3000 sq. ft. Cardboard; the latter is used for thin cardboard.

If you convert from the imperial system to the metric system, you can multiply it by the coefficient: grams/square meter = (pounds/1000 square feet) x 4.888; grams/square meter = (pounds/3000 square feet) x 1.627

The unit we commonly use is correctly GSM (Gram Square Meter), which is g/㎡, which is calculated on a single sheet of paper.

Conversion algorithm for pounds and GSM:

Pounds = Grams Inches (the length and width of the paper are converted into English) / 1406

Determination of the grammage of corrugated cardboard in each layer

In corrugated cardboard, because each layer of paper is glued together, it is difficult to know its gram weight by directly weighing a 100-square-centimeter sample like the base paper. Here, the "Packaging Zone" micro-editing recommends two methods for you:

1. Intuitive method

If you have samples of each layer of corrugated cardboard at hand, gently peel off each layer of corrugated cardboard, feel the thickness with your hands, and use the naked eye to identify the texture and color of the paper to judge the brand specification of the base paper. This method is only for experienced and professional testers.

2. Baidu test volume

Usually, especially for the base paper of the same brand, the thickness of the base paper of the same gram weight is the same. Therefore, the paper layer can be gently peeled off, and the grammage can be judged by measuring the thickness of the base paper.

3. Accurate test volume

Take a 2020CM square corrugated cardboard, soak it in water for about half an hour, and then gently peel off each layer of paper by hand. After finishing, it is best to scrape off the glue at the paste line with a knife. Then put the peeled base paper in a standard constant humidity and constant humidity environment for 48 hours to equilibrate. Finally, the quantitative measurement of each layer of paper can be measured according to the method of testing the quantitative measurement of base paper.

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