Carton weight measurement and calculation method

The measurement of the carton weight is an important task in the carton factory. The carton factory needs to measure the weight of the carton both when exporting customs declarations and during statistical output. Not only that, there are some customers who even use box weight as one of the standards for carton incoming inspection. Although the carton box weight test method is extremely simple, it is easily affected by moisture and causes the box weight measurement value to deviate from the true value. In addition to providing a measurement method for the weight of the box, this article also focuses on the two methods of calculating the box weight, which can greatly facilitate the control of the weight of the box by the carton factory.

Box weight measurement method

Measuring tools

For electronic balances with an accuracy of 1 gram or more, the weighing range should be 0-5 kilograms.

Sample selection

Three samples were randomly selected from the same batch of cartons for testing.

Sample processing

Sample treatment according to GB/T 10739 standard, that is, in the relative humidity (50 ± 2)% and temperature 23 ± 1 °C environment balanced more than 24 hours, and then weighed. The temperature-humidity balance of the sample is very important for obtaining an objectively consistent box weight. Without the sample subjected to temperature-humidity balance, the measured weight of the box can reach over 15%. For example, a carton that has undergone a thermo-humidity balance treatment, if measured to have a weight of 1 kilogram, will not be treated in a warm and humid environment. Even if it is the same carton, the weight of the carton may be between 960 g and 1150 g.

Test Results:

The box weights of the three specimens were tested separately and the average of the three weight values ​​was calculated, ie the individual box weights for this batch of cartons.

Calculation formula:

3 Carton weight = m1+m2+m3

Box weight units are expressed in grams.

Quick test box weight method

The most troublesome factor in box weight measurement is the water content of the carton. Many carton manufacturers or carton customers are limited by the delivery time or test conditions, and are weighed without temperature-humidity balance. As a result, the box is greatly deviated from the true value. . Here, we provide you with a method for accurately measuring the weight of a box without temperature and humidity balance.

The principle of rapid measurement of the weight of the box:

A large number of experimental data show that after the carton is fully balanced in the standard temperature and humidity environment, the moisture content is about 8%, and the dry weight of the carton is constant. Therefore, we only need to measure the weight and water of the unbalanced carton without temperature and humidity. Content, you can calculate the true weight of the carton.

Measuring tools:

Accuracy of more than 1 gram of electronic balance, oven or digital red line external moisture tester. The oven can be used to test the water content of the carton, but it still takes 1 hour to test. Digital infrared moisture tester can instantly read the moisture content of the carton, and its accuracy can reach more than 1%, fully meet the needs of accurate testing of water.

Measurement methods:

n Select three cartons randomly from a batch of cartons as test specimens.

n Weigh the box weights of the three samples and average them. The measured value is the reference weight, expressed in Mc, in units of grams.

n The moisture of the three specimens was measured separately, and the average was taken. The measured value was expressed as W and the unit was “%”.

n Finally, by substituting the measured Mc and W values ​​into the formula, the standard value after temperature and humidity balance can be calculated and expressed as M.

The formula for estimating the weight of a standard box:

M= Mc×(1-w)

92%

For example:

Three samples were withdrawn from a batch of cartons. The average value of the measured weight of the box was 1285 grams. The average moisture content was 13%. The weight of the box after temperature and humidity balance was calculated.

Substitute the above values ​​into the formula:

M= Mc×(1-w) = 1285×(1-13%)=1215g

92% 92%

Box weight calculation method

The calculation method of the weight of the carton is relatively simple, that is, the weights of the base papers of the respective layers constituting the corrugated cardboard are added together, and the weight of the adhesive in the cardboard is added to obtain the weight of the carton. The weight of the surface, septum, and paper is the corrugated board area multiplied by the base paper weight, the weight of the pit paper is the product of the corrugated board area, the corrugation elongation coefficient, and the basis weight of the base paper. The weight of the adhesive can be obtained from the parameter list.

Carton weight calculation formula

Single pit cardboard weight: Ws=S*(G1+G2+R*Gm+g1)

Double pit cardboard weight: Wd=S*(G1+G2+G3+R*Gm+R1*Gm1+g2)

Three-dump cardboard weight: Wt=S*(G1+G2+G3+G4+R*Gm+R1*Gm1+R2*Gm2+g3)

In the formula:

Ws, Wd, Wt represent the weight of the single pit, double pit, and triple pit cardboard, respectively;

G1, G2, G3, and G4 are the weights (g/m2) of corrugated cardboard, paper, and septum in unit area;

R, R1, R2 represent the corrugation elongation coefficient;

Gm, Gm1, Gm2 respectively represent the weight (g/m2) of the core paper;

G1, g2, g3 respectively represent the weight of the corrugated board adhesive (g/m2);

S represents the area of ​​corrugated cardboard.

Notes

l The corrugated board area can be obtained through actual measurement, and can also be derived through calculation.

l The default width of adhesive strip is 40mm, except in special cases.

l The weight of carton slotted material is not taken into account, and the bumps added to the carton flap cover can basically cancel out.

l The accuracy of this calculation method is within ±5%.

Schedule: Corrugated Elongation Coefficient and Adhesive Weight Table

Examples

There is an ordinary flat-top carton, the paper configuration is 250K/112F/112F/112F/250K, the external size is 56cm×40cm×13cm, and the weight of the declaration is calculated.

answer:

The area of ​​the common box S = (w + h) * 2 (l + w) + sticky area = (40 + 13) cm * 2 * 96cm + 4cm * 13 = 1.02m2

Check the table to obtain A楞 elongation coefficient is R=1.53, B extension coefficient is R1=1.40, binder usage per square meter g=15+20=35g/m2

Substituting the formula Wd=S*(G1+G2+G3+R*Gm+R1*Gm1+g2)

=1.02 *(250+11 2+250+1.53 *112+1.40*112+35)

= 1.02 * 940

=959g

Common carton area algorithm

1. Ordinary flat-top carton (that is, a carton with a width of 1/2 carton width):

Example: Calculate the area of ​​a 600mm long × 450mm wide × 400mm high carton

S = (w + h) × 2 (l + w) + nail (stick) area

=850 × 2 × 1050 + 40 × 400

=1.801m2

2, half-lapboard carton (that is, compared with the ordinary flat-mouth box, the upper or lower side only one side of the carton with a flap cover):

Example: Calculating the area of ​​a 600mm long × 450mm wide × 400mm high half-lapboard carton

S = (1/2w + h) × 2 × (l + w) + nail (stick) area

=625×2×1050+40×400

=1.328 m2

3, full-lap-top carton (that is, the carton width width of the carton box):

Example: Calculate the area of ​​a 600mm long × 450mm wide 400mm high-span cardboard box

S = (2w + h) × (l + w) × 2 nail (stick) area

=1300×1050×2+40×400

=2.746 m2

4, World Box:

Example: Calculate the area of ​​a box with a length of 600mm × width 450mm × height 100mm

S=(1+2h) ×(w+2h)

=800×650

=0.52 m2

Carton weight tolerance standard

The standard tolerance of the general box weight should be set within ±4%, because the tolerances of the paper and the binder that make up the carton itself are within ±4%. Some carton customers do not understand this rule and set the box weight tolerance within ±2%, which is very difficult to achieve.

Reprinted from: Industry Technology (Carton)