Definition
DIN abrasion testing machine is a standard testing equipment used to determine the wear resistance of materials. Its name comes from the test method developed by the German Institute for Standardized Chemistry. This device quantifies and evaluates a material's ability to resist surface loss by simulating the process of material contact with friction media under controlled conditions and undergoing wear. It is mainly suitable for the evaluation of wear resistance of non-metallic materials such as rubber, plastic, leather, textiles, and coatings.
Principle
The core principle of DIN abrasion testing machines is based on the wear phenomenon that occurs when a material moves relative to a standard friction medium under constant load. During testing, specimens of a specific shape are fixed on a rotating drum or flat surface with standard sandpaper or abrasive material attached to the surface. The specimen applies fixed vertical pressure through a lever or spring mechanism, causing it to come into close contact with the abrasive surface. The rotation of the drum drives the movement of the friction medium, and the surface of the specimen is gradually ground to remove the material due to friction. The amount of wear is calculated by measuring the mass loss or volume loss of the specimen after a set stroke or time. The smaller the amount of wear per unit stroke, the stronger the wear resistance of the material.
Measurement method and key parameters
Sample preparation
Specimens are usually cylindrical sheets or strips of a specific size. Its surface should be flat and smooth, free of bubbles, cracks, or impurities. Conditioning is required prior to testing under standard environmental conditions to eliminate the effects of temperature and humidity on material properties.
Testing process
The weighed specimen is fixed in the clamp and the loading device is adjusted to stabilize the specified pressure exerted by the specimen on the abrasive. Start the drum rotation to drive the abrasive movement. The specimen wears out at a set total sliding distance or number of revolutions. After the test, clean the surface of the specimen and weigh it again. Wear mass loss is calculated according to the standard formula.
The result is calculated
The amount of wear is usually expressed as the ratio of mass loss to stroke. The basic formula is:
Δm = (m1 - m2) / L
Among them, m1 is the initial mass of the specimen, m2 is the post-test mass, and L is the total sliding distance. Units are often expressed in milligrams per meter. For materials with known density, it can be further converted to volumetric wear to eliminate the comparison bias caused by density differences.
Influencing factors
The accuracy of test results is influenced by multiple factors. The surface roughness and internal structural uniformity of the specimen directly lead to the discreteness of wear data. The type and particle size grade of abrasives are the core variables affecting the friction coefficient and grinding efficiency, and the abrasive particle distribution of different batches of sandpaper may cause systematic differences. The amount of applied load directly affects the contact stress, too high a load may cause overheating and deformation of the material, and too low a load can make it difficult to distinguish the difference in wear resistance of different materials. The rotation speed of the drum determines the dynamic response of the friction process, and too fast speed may cause heat accumulation and change the tribological properties of the material. Ambient temperature and relative humidity cannot be ignored, high temperature will soften some polymer materials and increase the wear rate; The high humidity environment may lubricate the friction interface and reduce the amount of wear. In addition, the contact angle between the specimen and the abrasive, the rigidity of the fixture, and the frequency of aging treatment on the abrasive surface all need to be strictly standardized.
Applications:
DIN abrasion testing machines have a wide range of uses in non-medical industrial scenarios. The rubber products industry is used to evaluate the wear life of tire tread compounds, belt overlays, seals, and shock-absorbing elements. The plastics field is used to compare the application performance of different formulations of engineering plastics under sliding friction conditions. The leather and textile industry uses this method to screen the abrasion resistance of sole materials, sofa fabrics and industrial filter fabrics. In the field of coatings and coatings, it is used to evaluate the scratch resistance of floor paints and surface paints of vehicles. The wear resistance testing of floor tiles, stone, and other building materials also relies on this equipment to ensure its durability over time.
Key points of selection
When choosing a DIN abrasion tester, you need to pay attention to the following aspects. The load range and accuracy should meet the typical testing requirements of the material to be tested, and the load adjustment mechanism should have good repeatability. Whether the drum diameter and rotation speed match the target standard, different standards have specific regulations on the circumferential speed of the drum and the trajectory of the specimen. Whether the abrasive mounting system is easy to replace and whether it supports a variety of standard sandpaper specifications. The specimen grip should be designed to be compatible with a wide range of shapes and sizes, and rigid enough to dampen vibration generated during testing. The equipment should have the function of automatic shutdown of stroke or number of revolutions to reduce human error. Data acquisition systems should support real-time mass or volume loss recording to improve efficiency. For long-term use, it is necessary to confirm that the machine structure material is wear-resistant and corrosion-resistant, has high maintenance convenience, and has a stable supply of parts.