Measurement and calculation method of the weight o

2022-09-21
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The measurement and calculation method of carton weight

the measurement of carton weight is an important work in the carton factory. The carton factory needs to measure the carton weight during export customs declaration and statistical output. Not only for example, but for the experimental belt with different belt length, it is necessary to prepare planetary gear train shells with different diameters and gears with different tooth numbers. Some customers even take the box weight as one of the standards for the incoming inspection of cartons. Although the carton weight test method is very simple, it is easy to be affected by moisture, resulting in the deviation of the measured value of carton weight from the true value. In addition to providing the measurement method of carton weight, this paper also focuses on two calculation methods of carton weight, which can greatly facilitate the carton factory to control the carton weight

box weight measurement method

measuring tool

electronic balance with an accuracy of more than 1 gram, the weighing range should be in kilograms

selection of samples

three samples are randomly selected from the same batch of cartons for testing

treatment of the sample

the surface of the projection screen at the sample can be wiped off with absorbent cotton dipped in glass cleaner. According to the gb/t 10739 standard, that is, balance for more than 24 hours under the environment of relative humidity (50 ± 2)% and temperature 23 ± 1 ℃, and then weigh. The temperature and humidity balance treatment of the sample is very important to obtain an objective and consistent box weight. For the sample without temperature and humidity balance treatment, the measured box weight error can reach more than 15%. For example, if the weight of a carton after temperature and humidity balance treatment is measured to be 1kg, it will not be treated in a temperature and humidity environment. Even if it is the same carton, its weight may be between 960g and 1150G

test results:

test the box weight of three samples respectively, and calculate the average value of the three weight values, that is, the single box weight of this batch of cartons

calculation formula:

3 carton weight = m1+m2+m3

carton weight unit is expressed in grams

method of rapid test of box weight

box weight measurement is the most difficult to give full play to the carbonization characteristics of thermosetting polyurethane. The disturbing factor is the moisture content of the carton. Many carton factories or carton customers are limited by the delivery time or test conditions, and weigh the carton without temperature and humidity balance treatment, resulting in a significant deviation from the true value. Here, we will provide you with a method to accurately test the weight of the box without temperature and humidity balance

principle of rapid measurement of carton weight:

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%, while the dry weight of the carton is unchanged. Therefore, as long as we measure the weight and moisture content of the carton without temperature and humidity balance, we can calculate the real weight of the carton

measuring tools:

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

measurement method:

n three cartons are randomly selected from a batch of cartons as test samples

n weigh the box weight of three samples respectively and take the average value. The measured value is the reference weight, expressed in MC, in grams

n measure the moisture content of three samples respectively, take the average value, and the measured value is expressed in W, with the unit of "%"

n finally, substitute the measured MC value and W value into the formula to calculate the standard value after temperature humidity balance, which is expressed in M

calculation formula of standard container weight:

m= MC × (1-W)

92%

example:

take three samples from a batch of cartons, the average measured box weight is 1285g, and the average measured water content is 13%. Try to calculate the box weight after temperature and humidity balance treatment

substitute the above value into the formula:

m= MC × (1-w) = 1285 × (%) =1215g

92% 92%

calculation method of carton weight

the calculation method of carton weight is actually relatively simple, that is, add the weight of each layer of base paper that makes up the corrugated board respectively, plus the weight of the adhesive in the board, and then you can get the weight of carton 1. The force value of the tensile testing machine is measured through the force measuring sensor, expander and data processing system. Among them, the weight of face, septum and lining paper is the area of corrugated board multiplied by the gram weight of base paper, and the weight of pit paper is the product of corrugated board area, corrugated elongation coefficient and gram weight of base paper. The weight of the adhesive can be obtained from the parameter table

carton weight calculation formula

single pit paperboard weight: ws=s* (g1+g2+r*gm+g1)

double pit paperboard weight: wd=s* (g1+g2+g3+r*gm+r1*gm1+g2)

three pit paperboard weight: wt=s* (g1+g2+g3+g4+r*gm+r1*gm1+r2*gm2+g3)

where:

ws, WD and WT represent the weight of single pit, double pit and three pit cardboard respectively

g1, G2, G3 and G4 are the gram weight of corrugated board surface paper, lining paper and spacer paper per unit area (g/m2)

r, R1, R2 represent corrugation elongation coefficient

gm, GM1 and GM2 respectively represent the gram weight of core paper (g/m2)

g1, G2 and G3 respectively represent the gram weight of corrugated board adhesive (g/m2)

s refers to the area of corrugated board

note

l the area of corrugated board can be obtained by actual measurement or calculation

l the width of adhesive strip is 40mm by default, except in special cases

l the weight of slotting and material removal of cartons can be ignored, and the bumps added at the shaking part of cartons can basically offset it

l the accuracy of this calculation method is within ± 5%

attached table: corrugated elongation coefficient and adhesive weight table

examples

there is an ordinary flat lap carton with paper configuration of 250k/112f/112f/112f/250k and external dimension of 56cm × 40cm × 13cm, try to calculate the customs declaration weight

problem solution:

the area of the ordinary box s= (w+h) *2 (l+w) + adhesive strip area = (40+13) cm*2*96cm+4cm*13=1.02m2

according to the table, the elongation coefficient of a ridge is r=1.53, and the elongation coefficient of b ridge is r1=1.40, The amount of adhesive per square meter g=15+20=35g/m2

is substituted into 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 lap carton (i.e. the width of the upper and lower swing cover is 1/2 carton width of carton):

example: estimated length 600mm × 450mm wide × Area of 400mm high carton

s= (w+h) × 2 (l+w) + nail (adhesive) strip area

=850 × two × 1050+40 × 400

=1.801m2

2. Half lap carton (that is, compared with ordinary flat lap carton, there is only one side of the carton with swing cover at the upper or lower end):

example: the estimated length is 600mm × 450mm wide × Area of 400mm high half lap carton

s= (1/2w+h) × two × (l+w) + nail (adhesive) strip area

=625 × two × 1050+40 × 400

=1.328 m2

3. Full lap carton (that is, the carton with the width of the up and down flap equal to the width of the carton):

example: the estimated length is 600mm × 450mm wide × Area of 400mm high full lap carton

s= (2w+h) × (l+w) × 2 + nail (adhesive) strip area

=1300 × one thousand and fifty × 2+40 × 400

=2.746 m2

4. Heaven and earth box:

example: estimated length 600mm × 450mm wide × Height 100mm day box area

s= (1+2h) × (w+2h)

=800 × 650

=0.52 M2

tolerance standard of carton weight

generally, the tolerance standard of carton weight should be set within the range of ± 4%, because the tolerance of the base paper and adhesive itself constituting the carton is also within the range of ± 4%. Some carton customers do not understand this rule and set the carton weight tolerance within ± 2%, which is difficult to achieve

reprinted from: Industry Technology (carton)

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