The stiffness of a carton is its resistance to bending, which shows how hard or soft the carton board is, or how rigid or flexible it is. Rheological properties of the paperboard, like how much the outer layer can stretch and how much the inner layer can compress when the paperboard is bent, are related to stiffness. The ability of the paperboard to hold its own weight is one way to measure stiffness.
The paper stiffness tester can be used to find out how strong paper and paperboard are when they are bent. The tool can be used to find out how stiff paper and paperboard are. It works especially well for measuring the stiffness of paper and paperboard with a thinness of less than 1 mm and a low weight.
Why test the bending stiffness and crease stiffness of paperboard?
On the high-speed automatic packaging line, there are often cartons that don’t meet the standards (they are the wrong shape, are bent, or don’t stick well), which slows down production. The reason for the above effect is that the ratio between how stiff the paperboard is and how much force it takes to fold after being indented is wrong. Research shows that the ratio between the stiffness of the fold and the stiffness of the paperboard in the same direction is the most important thing that affects how well paperboard can be folded into cartons.
The paper stiffness tester can simulate the conditions of the packaging production process, measure the folding force and bending stiffness of the paperboard, and calculate the stiffness folding force ratio based on the measurement results. This allows the folding force of the carton needed by the packaging machine during the actual packaging process to be accurately determined, and the carton’s tendency to bend and stick poorly can be avoided.
For example, the method of increasing the depth of the indentation is often used to reduce the folding force and the tension of the carton going outward at the same time. Choosing the right indentation width can also keep the crease from getting damaged. All tests are done at a certain temperature and level of moisture in the air.
How to improve the stiffness of paperboard?
When measuring the stiffness of paperboard with white paper, the bending force distance is measured in millinewtons.
The main things that affect how stiff white paperboard is are the thickness of the base paper and how well the fibers stick together. When all the numbers are the same, the stiffness is directly related to the square root of the thickness. The type of fiber and how well the fibers stick together have a big effect on how stiff something is. Paper made from hardwood short fibers and mechanical wood pulp is stiffer than conifer long fiber paper.
High-lignin pulp is hard to beat, doesn’t stick together well, isn’t very tight, and isn’t very strong. On the other hand, lignin can make fibers less able to expand and thus increase the stiffness of paper.
The traditional idea that lignin makes paper less strong is being called into question. Some people think that the acidity of paper, not lignin, is the main reason why it breaks down.
Use good chemical additives to make the fibers stick together better and make white paperboard stiffer. The paper stiffening agent makes the paper stiffer, which is a good thing. Using spray starch between layers, in particular, can not only make the layers stick together better but also make the cardboard stiffer. By spraying starch on the layer and the layer between the cardboard, you can increase the paper layer’s binding force by 25%. You can’t get this effect by adding pulp.
In the process of making white paperboard, stiffness and thickness can be improved by choosing the right wood and pulp, making sure the slurry ratio and beating conditions are right, using chemical additives to strengthen the bonds between fibers, adjusting how the paper machine works, lowering the linear pressure of the press and calendar, and lowering the amount of water in the paper.
It also makes the surface layer more opaque and able to cover more. It has a clear effect on making products better and lowering the cost of making them. Experiments show that slurry and interlayer spray starch can be added to white boards to make them stiffer.
Paper cup stiffness tester
A paper cup is a type of paper container that is made by cutting and gluing the chemical wood pulp base paper (white paperboard) together. It looks like a cup for your mouth. The waxed paper cup that is used for frozen food can hold ice cream, jam, or butter. There are three types of paper cups, each used for a different thing: cold drink cups, hot drink cups, and ice cream cups.
The stiffness of the paper cup is not less than the average stiffness. This means that the stiffness of the paper cup won’t change much when it’s used. The stiffness of the cup’s body is high, and the wall is too thick, which will raise the cost of making the cup. So, testing how stiff paper cups are has become one of the most important ways to measure the quality of a product.
The paper cup body stiffness tester (dual probe) can measure the stiffness of paper cups, paper bowls, plastic cups, and other products with different capacities. A high-quality sensor and a double-probe test structure are used, and the test results are stable and reliable.
The user only has to put the sample in the fixture position, and the paper cup body stiffness tester will do the rest of the testing on its own. It is easy to use and can prevent mistakes made by people. It has become one of the testing tools that quality control centers, factories that make paper cups, companies that make food, and other places need.
How to use
Place the sample cup on the stiffness tester‘s movable bench so that the sensor probe just touches the side wall of the cup. Then, move the bench so that the distance between the sensor probe and the bottom of the cup is about two-thirds of the cup’s height. After a certain distance has been moved forward, the instrument automatically measures how stiff the paper cup is.
Fabric stiffness tester
Different types of fabric have different looks, and each type of fabric has its own characteristics that are based on how it performs and what it is used for. It’s easy for morphological changes, like how the material hangs, how stiff or flexible it is, how wrinkled it gets, how fuzzy or pilled it gets, how it curves, how well it resists drawing, how well it washes, etc., to happen when conditions change. In the process of putting on clothes, these are the physical features of fabrics that can be seen from the outside. By using certain methods to test them, we can figure out how the stiffness of different materials affects the look of fabric.
A fabric stiffness tester is used to measure how well fabrics bend. It is a key physical parameter that lets us study things about fabrics like how straight they are, how well they drape, and how soft they are. Stiffness is “the ability of a fabric to resist changing its shape in the direction of bending.” The instrument uses two mechanical indexes called “bending length” and “bending stiffness” to measure “the ability of fabrics to keep their shape when bent.”
The stiffness of a fabric is how hard it is to bend and how soft it is. Flexural stiffness is the ability of a fabric to keep its shape when bent in a certain direction. The opposite of softness, flexural stiffness, is often used to measure it. The bending stiffness of a fabric depends on the bending stiffness and structure of its fibers and yarns. The bending stiffness of a fabric also increases significantly as its thickness goes up.
In general, the fabric for clothes, underwear, and other clothing needs to be soft enough to fit the human body well and keep it fit. The clothes should be made of materials that keep their shape and can be molded. In the same way, the fabric should be both stiff and flexible.
With a few simple steps and calculations, the fabric stiffness tester can figure out a fabric’s bending height, bending stiffness, and bending modulus. It can be used to measure the stiffness of woven fabrics like cotton, wool, silk, hemp, and chemical fibers. It can also be used to measure the stiffness of knitted fabrics, general non-woven fabrics, and coated fabrics. At the same time, it can also be used to measure the stiffness of materials like paper, leather, and film, which are not as hard as other materials.
How to calibrate the paper cup stiffness tester?
After some time of use, if the cup stiffness tester needs to be calibrated, the force value can be checked with calibration accessories and weights. During the inspection, be careful not to touch the measuring head too hard.
- Place the two measuring heads of the instrument at a distance of about 3 mm from the limit, and put the calibration accessories on the right measuring head.
- Put the instrument upside down at 90 degrees and place it firmly with care.
- Turn on the power, the instrument displays, and enter the function selection interface after a few seconds. Press the “calibration” key to enter the calibration interface.
- Place the standard weight on the calibration accessories (be careful and stable), (1kg = 9.81n, if hanging a 1000g weight, the standard value is 9.81mn), and the error is ± 1%.
- If the difference between the values is less than 1%, the instrument is qualified.
- If the value difference is large (more than 1%), you can correct the force value (i.e., input the weight value into the instrument). Press the “extract” stop key to lock in the force value. Press “+” “-” to modify the force value, and then press” ↙” key to confirm, and then enter the password “+” “-” test.” three keys. Press again” ↙” OK.
The measuring range of the sensor is 30 nm when the sensor is not touched (Note: the maximum measuring range is 3 kg).
What types of fabric stiffness tester are there?
A fabric stiffness tester is used to test the stiffness performance of textiles. Stiffness is one aspect of textile softness that influences textile comfort and applicability.
- Common types:
Automatic fabric stiffness tester, manual fabric stiffness tester, digital pneumatic fabric stiffness tester, and Gree fabric stiffness tester are some of the different types of testers.
What are the factors affecting fabric stiffness?
In most cases, the influencing factors of fabric stiffness include yarn diameter, twist, fabric thickness, geometric structure, and so on.
What is fabric stiffness?
One of the “individual hand-feeling values of fabric” is how stiff it feels. The ability of a fabric to resist getting bent out of shape. It is described by the fabric bending performance index, which is written as flexural stiffness. The fabric stiffness meter of the inclined plane method can be used to get the bending length value. The fabric is harder the longer it takes to bend. It is a key measure of how well a fabric will hold up over time.
What is paper stiffness?
Paper and paperboard are said to be stiff if they don’t bend easily. It shows how hard or soft the paper is, or how stiff or soft it is. The rheological properties of the paper affect how stiff it is. These properties depend on how well the outer layer can stretch and how well the inner layer can compress when the paper is bent. The ability of the paper to hold its own weight is one way to measure stiffness.
How to express the stiffness of cardboard?
The stiffness or flexural stiffness of paperboard is measured by putting a certain load on a vertically clamped sample that is 5 cm away from the fixture and looking at the bending moment, in G•cm, that is needed to bend the sample from its center line to 15°.