There are five items in corrugated cardboard and corrugated boxes and performance tests. Is the side pressure strength, burst strength, puncture strength and compression test.
Performance tests must be performed on all specimens. The test was performed after the sample was treated for 24 hours in a constant temperature and humidity environment at a temperature of 23°C ± 2°C and a humidity of 50% ± 5%.
First, the side pressure strength test
In the corrugated direction, a certain thickness (25mm) of corrugated cardboard, the unit of length can withstand the vertical and uniform increase in force, called the corrugated cardboard side pressure strength.
The unit of side pressure strength is: N/m.
Three specimens from each of the three specimens were measured to have a size of 100 mm ± 0.5 mm × 25 mm ± 0.5 mm. A total of nine specimens with no printing, no mechanical indentation, and damage were obtained.
The side pressure strength test instrument is a compressive strength tester (Figure 26).
The main parameters of the compressive strength tester are:
Measuring range: 0-3000N
Accuracy: ±1%
Relative change in display value: <1%
Minimum reading: 1N
Upper plate lowering speed: 12.5mm<min
Pressure plate surface size: 120mm × 120mm
The side pressure strength test method is to place the sample in the middle of the pressure plate under the tester so that the corrugation direction of the sample is perpendicular to the two pressure plates. The sample is supported by the guide block so that the surface of the sample is perpendicular to the platen and the tester is started. pressure. When the pressure is close to 50N, remove the guide block until the sample is crushed and record the maximum pressure that the sample can withstand. Readings are accurate to 1N.
For the test results, find the arithmetic mean and calculate the edge pressure strength according to the following formula.
R=F×103÷L
In the formula: R-side pressure strength unit N/m;
F-sample withstand maximum pressure N;
L-sample long dimension mm.
The unit of side pressure strength is N/m, and the length of the long side of the sample is 100 mm, which requires data processing. First convert 100mm to 0.1m and calculate according to the above formula. Assume that the arithmetic average pressure of the sample under test is 680N. After data processing, it is:
680N/0.1m=6800N/m
Then, according to the above formula, the edge pressure intensity value of the sample is:
6.80×103N/m
The side pressure of the corrugated board directly affects the supporting strength of the corrugated box. The corrugated board production process, the structure of the corrugated board, the shape of the crucible, the quality of the adhesive and other factors can all affect the side pressure strength of the corrugated board.
Second, the burst strength test
The maximum pressure that a corrugated board can withstand evenly per unit area is the burst strength of corrugated board.
The burst strength unit is: KPa.
From each of the three sample boxes, four blocks of 140mm×140mm each with no printing, no watermark, no crease or obvious damage were taken.
The burst strength test instrument is a burst resistance meter (Figure 27).
The main technical parameters of the burst resistance meter are:
Measuring range: 0-6000KPa
Accuracy: ±0.5%FS
Resolution: 1KPa
Sample clamp ring: 37.5±0.05mm
Lower clamp hole diameter 31.5±0.05mm
Concentricity error of inner hole of upper and lower clamp ring:<0.25mm
Pressurization speed: 170±15ml/min
Sample clamp pressure: >690KPa (adjustable)
The technical requirements for the air compressor used in conjunction with the burst tester are:
Displacement: 0.25-0.3m3/min
Rated discharge pressure: 0.5-0.8MPa
Breaking strength test method:
An old and resilient rubber membrane firmly clamped by a lower pressure ring under the action of a hydraulic force, with a certain force, the specimen tightly fixed between the upper and lower pressure rings passes through an ancient rubber membrane They burst.
The test specimens were divided into groups A and B. A group was attached to the rubber film on the front, and the B group was attached to the rubber film on the reverse side for testing. When the specimen breaks, read the displayed value. For the test results, find the arithmetic mean and keep the three significant figures.
The hydraulic rating of the burst tester is important. The hydraulic system is working properly to ensure that the hydraulic oil meets the work requirements. The main hydraulic oil must be observed and measured frequently. To observe and measure the small amount of oil, observe whether the hydraulic oil has deteriorated or become fouled by the operation.
The preparation and use of the breakage meter hydraulic oil:
1 Select a barrel-shaped measuring cup with a capacity of 1000 ml or find a beer bottle (ensure that the container has a certain height, enabling the density meter to move up and down);
2 Take proper amount of purified distilled water and 98% of glycerin reagent, shake it well or stir it to make it homogeneous after fusion;
3 After the foam has been eliminated, take a density meter to measure it;
4 Observe that the densimeter scale is guaranteed to reach 20 Baume in the liquid level of the mixture (ambient temperature 20°C);
5 The prepared mixed liquid must be placed for 24 hours and then measured with a densitometer up to 20 Baume after use;
6 Each time the amount of hydraulic oil is about 60ml, change the oil valve to use gasoline to clean the fuel tank and the oil circuit.
Third, the puncture strength test
The power of the corrugated board is made by a certain shape of the pyramid. The energy shown is called the puncture strength of the corrugated board.
The unit of puncture strength is: J.
Four specimens with a size of 175 x 175 mm were taken from the wall of each sample box of three sample boxes.
The instrument that punctures the strength test is a puncture strength tester (Figure 28).
The main technical parameters of the puncture strength tester are:
Measuring range: 0-48J
Accuracy: A scale ± 0.05J
B ruler ±0.1J
C ruler ± 0.2J
D ruler ± 0.5J
Swing arm swing times: >100 times
Friction collar resistance: >0.25J
Pyramid characteristic dimensions: 3 base length 6mm, cone height 25±0.7mm
Edge corner radius (R): 1.5mm.
The test method of puncture strength is to place the sample in the middle of the positive and negative longitudinal and lower and lateral surfaces in succession with a fixed force (250N-1000N) in the middle of the splint with a through hole, and adjust the required weight to adjust the friction ring. After the pyramid, select and test the appropriate measurement range, adjust the zero position, set the pointer to the highest scale value, and then activate the release device so that the swing arm pushes the pyramid to penetrate the specimen. Read the measured value.
For the test results, find the arithmetic mean and keep the three significant figures.