Comparison between the Martindale flat grinding method and the Taber wear resistance method
Leather’s ability to hold up against wear is its wear resistance. Leather damage is often caused by wear and tear. To figure out how good leather is, you have to test how well it wears. There are two common methods based on the different tools used in the experiment: the Martindale flat grinding method and the Taber wear resistance method.
- Martindale abrasion method (10000 times)
- Instrument for testing: There are a lot of different kinds of tools for flat grinding fabric. The Martindale wear tester is now the one that testing professionals use most often. So, the flat grinding method is often called the Martindale friction experimental machine method.
- Experimental principle: The circular sample in the sample fixture of the Martindale wear resistance tester rubs against the abrasive (i.e., standard fabric) with the plane motion of the Lissajous figure under the specified load, and the sample fixture can freely rotate around its axis perpendicular to the horizontal plane. The wear resistance of leather is based on how long each sample has been in contact with the ground.)
- Experimental method: During the experiment, the test sample of a certain scale is contacted with the standard abrasive under the specified pressure, and the sample moves relative to the abrasive along a lisaaru trajectory so that the test sample is subjected to uniform wear in multiple directions.
- Taber abrasion method (1000 times)
- Experimental tool: Taber wear resistancetesting machine
- The experimental principle is to first grind the sample for 25 turns and then rotate it in the horizontal channel of the Taber wear-resistant testing machine. Two grinding wheels are put on the test piece with a certain amount of force. The center of the grinding wheel is in the same plane as the horizontal. One wheel grinds toward the outside, and the other grinds toward the inside. In a certain amount of time, write down any changes to the test piece.
- Experimental method: To do the experiment, cut the sample so that it has an outside diameter of 108 mm and an inside diameter of 8 mm. Then, put the same scale on a hard sticker and stick it to the back of the sample. Place the sample’s central hole on the rubber pad of the screw, cover the gasket, and use a compression nut to hold the sample in place. Then, cover the fixing ring and use a wrench to lock the fixing ring screw. Put two H18 grinding wheels on the arm that holds the support. So that the side with the label is on the outside, each grinding wheel applies a force of 250 10g to the sample being tested. This makes the grinding wheel load 500 g.
Connect the vacuum cleaner, connect the vacuum cleaner’s tube to the joint on the left side of the machine, and turn on the vacuum cleaner. Set the test times to what the instructions say, and set the speed of rotation to 72 revolutions per minute. Then, press the start key, turn the instrument on at a speed of 60 5 times per minute, turn it horizontally, and test it the number of times specified. In the experiment, they use a brush to remove the attachment from the surface of the sample, watch how the experiment wears, grind the leather to a certain point, and write down the last revolution.
From the two tests above, you can see that the results of the tests for wear resistance of different materials are expressed in different ways. With the Martindale friction testing machine method, the wear resistance is shown by the change in the end point and the way the material looks. With the Taber abrasion testing machine method, the wear resistance index is based on how long it takes for friction to happen.
It doesn’t mean much to compare test results from different materials that were done with the same method, but the conclusions that can be drawn from these results are consistent. So, any method that can evaluate the wear resistance of a material on its own can do so quantitatively. By looking at the results of the above tests, it is clear that natural leather is usually made of soft materials that don’t hold up well to wear. The coating is hard leather that doesn’t wear down easily, so it can take a lot of wear and tear.
For leather products, the wear resistance is also affected by the size, shape, test environment, wearing environment, subjective error, instrument accuracy, etc. So, when we think about how resistant leather is to wear, we need to think about as many things as we can to get a more accurate answer.
The method for testing the wear resistance of fabrics by the Martindale wear test
- Wear of textile products
Wear resistance is an important measure of the quality of textile products because it directly affects how long they last and how well they work. Most of the wear on textiles can be seen in the following five ways:
1) During the process of friction, the fibers are always touching each other. Because of wear and tear, the fibers in the yarn break, which in turn breaks the yarn.
2) The fiber is pulled out of the fabric, which makes the yarn and the structure of the fabric less tight. When the fiber is pulled on over and over again, it can be completely pulled out. This can make the yarn thinner, the fabric thinner, or even cause it to fall apart.
3) The fibers are cut and broken, which makes the yarn break.
4) The surface of the fiber is worn and there are pieces of dirt on it.
5) Friction creates high temperatures, which makes the fiber melt or deform like plastic. This changes the fiber’s structure and how it works.
Wear is shown by changes in the way the fabric looks. These changes include damage, loss of quality, and change in color, fuzzing, and pilling.
There are many ways to test the wear resistance of textile products, such as flat grinding, curved grinding, folding grinding, and compound grinding. The Martindale method is a type of flat grinding that is often used to test the wear resistance of clothes, household textiles, decorative fabrics, and furniture fabrics.
- Evaluation method of wear resistance of fabrics
At least two separate yarns in a woven fabric must be completely broken for a sample to be considered broken. If a single yarn in a knitted fabric is broken, a hole will appear in the fabric. The pile or cut fabric’s surface fluff has worn down to the bottom, or pile clusters have fallen off. Holes in nonwoven fabric with a diameter of less than 0.5 mm are caused by friction. The coating part of the coated fabric is damaged enough to show the base cloth or flake coating that fell off. Most of the time, the wear resistance of a fabric is measured and evaluated from three different points of view: the sample damage, the mass loss, and the change in appearance.
1) Measuring damage to a sample: When a certain load is put on the fixture, the sample rubs against the abrasive in a straight line, following the Lissajous curve. The total number of times the sample is damaged by friction shows how well the fabric can stand up to wear.
2) Measuring mass loss: When a certain load is put on the fixture, the sample rubs against the abrasive in a plane motion that follows the Lissajous curve. The wear resistance is based on the difference in mass between the sample before and after friction. This is done by putting the sample through a certain number of frictions.
3) Evaluating the change in appearance: When a certain load is put on the fixture, the sample rubs against the abrasive in a flat motion that matches the Lissajous curve. The wear resistance of the fabric is based on how the sample looks before and after it has been worn.
- Review of textile wear resistance testing methods
The sample breakage test can be used on all textiles but not on ones that don’t last long.
1) Selecting the abrasives to be used. Depending on what the sample is like, different standard abrasives are chosen. Woven plain wool makes up the uncoated fabric, while No. 600 water sandpaper is used to smooth out coated fabric. Wool felt separates the abrasive table from the grinding table. Check the felt’s surface after the test. If it’s dirty or worn, you should get a new one.
2) Method of collecting samples. At least three pieces of woven fabric should have different yarns in the warp and the weft. All of the parts of a complete weave should be in a jacquard or fancy weave. When a weave or pattern as a whole is big, each part can be sampled on its own.
3) Pick a gasket for the sample fixture. We measure the sample’s mass per unit area. The sample’s weight per square meter is more than 500g/m2. There is no need for foam plastic backing. The sample’s weight per square meter is about 500g/m2. The sample holder is given a foam plastic liner, which is removed and replaced after each test.
4) Determine the friction load’s effective total mass. The weight of the gripper, the stainless steel disc, and the sample hammer are all added together to get the effective mass of the friction load. According to the technical parameters of the APAC LAS m235 Martindale wear resistance and pilling tester, the mass of the gripper is (200 g), the mass of the stainless steel disc is (260 g), and the mass of the sample hammer is (395 g) or (594 g), depending on the purpose of the sample and the characteristics of the fabric. 1) 795 / 7 g: suitable for work clothes, furniture decoration, bed linen, and industrial fabrics.2) 595 – 7 g: for clothing and household textiles (decorative cloth for furniture, bed linen), non-clothing coated fabrics.3) 198 2 g: suitable for coating fabric.
5) Cycle of abrasive replacement
Standard wool fabric has been used 50,000 times, while standard water sandpaper has been used 6,000 times.
6) Interval between checks
On the basis of this, the friction times when the sample is damaged are estimated, and an appropriate inspection interval is set up to check the wear state of the surface of the sample during the sample wear resistance test. There is a certain number of friction times between checks.
7) Showing the results of a measurement
Measure the total amount of friction time until each sample is damaged. The wear time is the total amount of friction time before the sample is damaged.
The way to figure out mass loss works for all textiles, but not for those that don’t last long. In terms of abrasive choice, sampling method, sample fixture liner choice, total effective mass choice of friction load, and abrasive replacement cycle, the requirements for figuring out how much damage has been done are the same as those for figuring out how much damage has been done to a sample.
- Inspection interval
During the wear resistance test of the sample, come up with a good inspection interval to see how worn the surface is, and make sure that the inspection interval is a certain number of friction times. During the test, check how worn the sample is based on the time between inspections. The test is over when the sample is broken or when the friction times are reached.
There are two ways to measure mass loss. The first is to measure the difference between the mass of the sample before the test and the mass of the sample after the wear test at each inspection interval mi. The second is to measure the difference between the quality of the sample before the test and the quality of the sample after the wear test m when the sample reaches the wear point.
- Test results
The test results include the following data: 1) the measured mass loss at each inspection interval Δ mi； 2) The wear point of the sample is the mass loss when the test reaches the end point Δ m； 3) Mass loss Δ The relationship between MI and friction times 4) Wear resistance index AI (times / g), the calculation formula is:
Ai=N/ Δ mi
N is the total number of times friction occurs.
Appearance quality change: Determination of wear resistance of fabrics (the appearance quality change method is applicable to textile fabrics with a short wear life). The selection of abrasives, sampling methods, and the selection of sample fixture liners are consistent with the determination method of fabric sample damage.
1) Total effective mass of friction load (198 ± 2) g;
2) Abrasive replacement cycle: In each test, new foam plastics and standard abrasives are replaced.
3) Provisions for assessing the sample’s appearance change: 1) The friction times from the wear test to the surface change specified in the agreement shall be taken as the measured value of the wear resistance. Design an appropriate inspection interval as the observation point for the appearance change of the sample. 2) Wear test to the friction times specified in the agreement, and compare the sample’s surface change to an untested sample of the same fabric.
4) Test results: Changes on the surface include getting dirty, getting fuzzy, and getting holes. If the goal of the wear test is to achieve the surface change specified in the agreement, the inspection agreement must state the degree of discoloration, fuzziness, and pilling of the sample surface. The test results are given as the number of friction times when the sample reaches the degree of discoloration, fuzziness, and pilling specified in the inspection agreement.
If the agreement says that the wear test is over when it reaches the specified friction times, then the test result is that after the wear test reaches the specified friction times, the tested sample is compared with the original sample to rate the discoloration, fuzzing, and pilling degree of the tested sample, and the discoloration grade, fuzzing grade, and pilling grade of the tested sample are used to explain the change in appearance quality.
Conclusion
By using the Martindale method, there are three ways to figure out how well a fabric will hold up to wear: the sample damage method, the mass loss method, and the change in appearance quality method. The sample damage test is the most common of the three methods.
With this method, there aren’t many mistakes, the test results are easy to understand, and it’s easy to compare how well different fabrics wear. It is often used to make clothes and fabrics for decorating. The expression forms of the test results of the measurement method of mass loss and the appearance quality change method are fairly complicated, but they can show the wear-resistant status of samples in different friction stages and are very useful for analyzing how fabrics are used in production enterprises or scientific research institutions.