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来源:https://www.gtmfpack.com 发布时间:2022-01-15

Thickness of corrugated board
The thickness of cardboard is also one of the inspection items of carton appearance defects. The thickness index of paperboard directly affects the edge pressing strength, puncture strength and compressive strength of paperboard. There are many reasons affecting the thickness index of paperboard, such as low wear at the tooth tip (top) of corrugating roller, poor adjustment of paper guide, too fast speed of single-sided machine, too high external pressure and low temperature of corrugating roller. If the thickness of corrugated board is too thin, its edge compressive strength, puncture strength and compressive strength will also decrease accordingly. Corrugated board has different corrugated type and thickness.
Corrugated board thickness refers to the vertical distance between the top and bottom of corrugated board under certain pressure. Corrugated board thickness gauge is usually used in the laboratory to detect the thickness of corrugated board. During measurement, several parts on the board without damage, indentation and tile collapse (not less than 50mm from the edge) are selected as detection points and placed between the measuring head and anvil for measurement, And read the measured value of the dial indicator respectively. The number of samples is generally 10, and the average value is the inspection result. The thickness of paperboard is large, and the vertical and plane compressive properties of carton are correspondingly high. Therefore, the thickness index of corrugated board is a test item that can not be ignored in the production process.
3、 Edge pressure strength
一定宽度的试样,单位长度所能承受的压力叫边压强度,它是指承受平行于瓦楞方向压力的能力。按照有关的标准,边压强度的试样从3个杆箱中,每个分别切取3块无机械压痕、无印刷痕迹和损坏的试样,试样的瓦楞方向应为短边,试样规格为25mm x100mm,误差±0.5mm。这就要求取样器的刀口应保持的锋利,并且刀架上的刀片,安装位置要合适,刀刃口与刀槽所成角度可调整至45°为适。
The pressure that a specimen with a certain width can bear per unit length is called edge compression strength, which refers to the ability to bear the pressure parallel to the corrugation direction. According to relevant standards, three samples without mechanical indentation, printing trace and damage shall be cut from each of the three rod boxes for the sample of edge compression strength. The corrugated direction of the sample shall be the short side, and the sample specification shall be 25mm x100mm, with an error of ± 0.5mm. This requires that the knife edge of the sampler should be kept sharp, and the blade on the tool holder should be installed in an appropriate position, and the angle between the blade edge and the tool slot can be adjusted to 45 °.
此外,刀尖不可碰擦到刀槽底部,防止刀口弯曲变形,使切取出来的试样边缘瓦楞容易出现损坏和起毛现象,影响检测的准确性。边压强度的换算公式为:R= F/L x 103。式中:R为瓦楞纸板试样边缘的抗压强度,用N/m表示:F是试样压溃时读取的力值;L是试样长边的尺寸,单位是mm。原纸的环压强度和纸板的粘合强度如何,很大程度上决定着纸板的边压强度。
In addition, the knife tip shall not touch the bottom of the knife groove to prevent the bending and deformation of the knife edge, so that the corrugated edge of the cut sample is prone to damage and fuzzing, which affects the accuracy of detection. The conversion formula of boundary pressure strength is: r = f / L x 103. Where: R is the compressive strength of the edge of the corrugated board sample, expressed in N / M; F is the force value read when the sample is crushed; L is the dimension of the long side of the specimen, in mm. The edge pressing strength of paperboard is largely determined by the ring pressing strength of base paper and the bonding strength of paperboard.
4、 Adhesive strength
The peak adhesion degree of face paper, inner paper, core paper and corrugated paper of corrugated board is called the adhesion strength of corrugated board. The test of adhesive strength is mainly to test the mounting fastness of corrugated board. For the test of type a corrugated board, the pin of stripping frame should be medium 3mm, while the corrugated residue l of type B and C corrugated board is thin, and the pin of stripping frame should be ① 2mm. Each pin on the stripping frame shall be aligned with the corrugated notch, and after the spacing is adjusted to be equal, tighten and fix each screw. For the test sample blocks of adhesive strength, it is required to take 12 pieces, that is, 4 pieces from each of the three sample boxes. The corrugated direction is short side (i.e. 25mm), and the material is intact without degumming and blistering.
样块规格为25mm x 80mm,误差±1.0mm,这样可较好地保证检测的准确性。粘合强度的换算公式为:P F/L。式中:P为瓦楞纸板试样的粘合强度,用N/m表示;F是试样分离时读取的力值,单位是N;L是试样长边的尺寸,单位是m。粘合剂的质量、配方以及设备、操作工艺等因素的合适与否,决定着纸板的粘合强度,而纸板的粘合强度好坏,在很大程度上影响着纸箱的抗压力强度、耐破强度和戳穿强度等性能。
The sample block specification is 25mm x 80mm with an error of ± 1.0mm, which can better ensure the accuracy of detection. The conversion formula of adhesive strength is: PF / L. Where: P is the bonding strength of corrugated board sample, expressed in N / M; F is the force value read during sample separation, in N; L is the dimension of the long side of the sample, in M. The quality, formula, equipment, operation process and other factors of the adhesive determine the adhesive strength of the paperboard, and the adhesive strength of the paperboard greatly affects the performance of the carton, such as pressure strength, burst strength and puncture strength.
5、 Puncture strength
以一定形状的角锥穿过瓦楞纸板所做的功,所显示的称为瓦楞纸板的戳穿强度,它的单位是:J。戳穿强度指标是采用戳穿强度测定仪进行检验的,检测时,挑选3个外观较好的样箱,从每个样箱的箱壁上各取4块无破坏、无水印、无折痕和无其他外观缺陷的纸板,规格为175mm x 175mm的检测样12块。分切试样时应注意起始线与瓦楞成平行状态。在每次检测之前应对仪器调零校准,其方法是:
The work done by a certain shaped pyramid passing through the corrugated board is called the puncture strength of the corrugated board, and its unit is J. The puncture strength index is tested by the puncture strength tester. During the test, select 3 sample boxes with good appearance, take 4 pieces of paperboard without damage, watermark, crease and other appearance defects from the box wall of each sample box, and 12 test samples with the specification of 175mm x 175mm. When cutting the sample, it shall be noted that the starting line is parallel to the corrugated. Before each test, the instrument shall be zeroed and calibrated by:
1. After removing the heavy hammer and sample splint, turn the pointer to the larger value and place the pendulum at the starting position of the test. After pressing the release device of the lower pendulum, the swinging pendulum shall make the pointer point to "0", otherwise, it is necessary to screw the adjusting screw for adjustment;
2. According to the general strength of the sample, select an appropriate heavy hammer to make the measured value between 20% ~ 80% of the measurement range;
3. Clamp the sample firmly in the middle of the test plate, turn the pointer to a higher scale value, put the friction ring behind the corner cone, and lock the pendulum to the starting position during the test,
4. Press the release device to make the swing arm push the corner cone to penetrate the sample, and then read the test value;
5. Calculate the arithmetic mean of the detected values of front, rear, vertical and horizontal, and keep 3 digits.