Astm d2240 durometers allows for a measurement of the initial hardness, or the indentation hardness after a given period of time. Both methods measure the resistance of plastics toward indentation and provide an empirical hardness value that doesnt correlate well to other properties or fundamental characteristics. The most common scales are the a and d scales, with the shore a scale being used for elastomers and the shore d scale is used to measure rigid plastics. The lowest hardness value of the pencil that mars the material is the materialas relative hardness. The shore micro hardness tester was modeled after the familiar astm d2240 type a durometer, however it employs a much lighter mainspring and a considerably smaller indentor. The hardness value is determined by the penetration of the durometer indenter foot into the sample. Type shore a durometer shore a durometer is appropriate for measuring the hardness of specimens that are flat, parallel, and of a certain minimum thickness. Astm b294921997 standard test method for hardness testing of cemented carbides january 15, 1992 astm international 1.
Lower numbers indicate less resistance and softer materials. An astm designation number identifies a unique version of an astm standard. The test measures the penetration of a specified indentor into the material under specified conditions of force and time. You may purchase the astm standard from the american. The stand features a load weight for the proper testing pressure as noted in astm d2240, a quicklock column for easy adjustment plus a dampening feature.
This article refers to the 2 most commonly used in the roller industry. Astm d2240allows for a measurement of the initial hardness, or the indentation hardness, after a given period of time. D scale consists of 3 test blocks ranging from 20 to 80 durometer. In our range you will find both mechanical and digital durometer gauges e. The material is generally termed rubber or rubberlike. Featuring an 18mm footer that offers high stability and conforms to all international standards, the ad100 is the ideal durometer for a wide range of shore hardness measuring applications. In astm d2240, specific steps and requirements are listed to ensure that laboratory determined hardness measurements are consistent and reproducible. If a timed hardness is desired, force is applied for the required time prior to taking the measurement. Semirigid plastics can also be measured on the high end of the shore. Used to measure the hardness of rubber and plastics according astm d2240, din 53505, iso 868 and iso 7619. Hardness is defined as a materials resistance to indentation when a static load is applied.
If a timed hardness is desired, force is applied for the required time and then read. The test measures the penetration of a specified indentor into the material under specified conditions of. Newage testing instruments recommends that you obtain a copy of the appropriate standard for your application and that you read and understand the standard prior to testing. Shore d scale durometers test the hardness of pipeline coating, hard rubber, acrylic, delrin, kevlar, pvc, nylon, lexan, and epoxies. These scales were invented so that people can discuss these materials and have a common point of reference. Astm d2240 test material testing micom laboratories. Another installment still havent subscribed to star thermoplastics on youtube. Hardness numbers have no units and are commonly given in the r, l, m, e and k scales. The shore durometer is a device for measuring the hardness of a material, typically of polymers, elastomers, and rubbers higher numbers on the scale indicate a greater resistance to indentation and thus harder materials. Specifically, we investigate type a and type m durometer scales as these are commonly used to measure the hardness of elastomer materials used for seals. Shore durometer hardness testing of plastics the hardness testing of plastics is most commonly measured by the shore durometer test or rockwell hardness test. Shore durometer 3 relation between astm d2240 hardness and elastic modulus a semiempirical relation between the astm d2240 hardness and the youngs modulus for elastomers has been derived by gent.
Apr 19, 20 shore a vs shore d hardness 165 wambold road, harleysville, pa 19438 18005236688 2157236051 fax 2157992518 shore hardness astm d 2240 shore hardness is a relative measure of exactly what the term implies hardness. The term is also used to describe a materials rating on the. The surface of the test material will be flat and positioned over an area with plenty of space to allow the pressure of the durometers foot to easily come into contact with it. The shore duromter a and d scales of hardness are commonly used for rubber and soft polymers such as polyolefins, polyurethanes, vinyl, and fluoropolymers. The basic test requires applying the force in a consistent manner, without shock, and measuring the hardness depth of the indentation. Astm d2240 allows for a measurement of the initial hardness, or the indentation hardness, after a given period of time. There are different shore hardness scales for measuring the hardness of different materials.
The shore a hardness scale measures the hardness of flexible mold rubbers that range in hardness from very soft and flexible, to medium and somewhat flexible, to hard with almost no flexibility at all. The model 307l type d durometer is designed to measure astm american society for testing and materials d2240 type d hardness. In rubber lining the a scale is most commonly used but in hard rubber products the d scale may be referenced. Astm d2240 is a test method designed to test the depth of an indentation in the material being tested. Detailed descriptions of the various configurations are available on the individual durometer pages, which may be visited directly from the shore durometer selection guide using the text link in the part number column. A durometer calibrator or calibration device must conform to national and international standards such as din iso 7619, iso 868, iso 7619 and astm d2240. The test method designation is astm d2240 while related methods include the like of.
The indentation is created by a given force on a standardized indentation head. Shore d hardness test durometer scale hardness of plastic. The test method designation is astm d2240 while related methods include the like of iso 7619. Flatten the tip of the pencil lead with the included 400 grit sandpaper, then insert the pencil into the tester. A number in parentheses indicates the year of last. Asker durometers offer optional peak indicators to more closely monitor the difference between the peak reading. There are several different types of durometer scales used to properly measure the hardness properties of materials, but the two most common scales are the astm d2240 type a and d scales. The hardness astm d2240 of a material is determined using one of twelve different durometer scales. Astm d2240 05 standard test method for rubber property. The astm d2240 standard recognizes twelve different durometer scales using combinations of specific spring forces and indentor configurations. These durometers can be used either with a test stand or handheld. For greater repeatability and the processing of the measurement data, you can add a test stand and data acquisition software for our digital durometers. This particular portable analogue durometer meets and surpasses the d2240 specification listed by the american society for testing and materials astm.
A durometer test instrument is used to measure shore hardness. Specifically, astm d2240 durometer hardness testing is restricted to thermoplastic elastomers, vulcanized thermoset rubber, elastomeric materials, cellular materials, and some plastics as defined by the astm committee on terminology in astm d1566. Astm d2240 15e1 standard test method for rubber property. Scale a is designed to measure the hardness of softer plastic materials, like out urethane rollers which have a durometer hardness of 55 and 70, while scale d. The shore durometer is a device for measuring the hardness of a material, typically of polymers, elastomers, and rubbers. The ad100 displays hardness readings on an easytoread analog scale calibrated in 0 to 100 shore units.
The three scales commonly seen in the roller industry are oo, shore a, and shore d. Shore durometer hardness testing of plastics is described, and conversion charts correlating various scales are presented. Listed below are common american society for testing and materials astm standards that reference hardness testing. Jan 14, 2019 a standardised test used industrywide, the shore d hardness technique measures the depth of penetration of an indenter, generally using astm d2240 and iso 868 test methods. Oo scale durometers ptcs shore oo durometer gauge measure the hardness of polyethylene foam roll, sponge rubber, very soft rubber. Oct 14, 2011 for the love of physics walter lewin may 16, 2011 duration. Different shore hardness scales are used to measure the hardness of different materials. American roller adheres to the astm international standard test method astm d2240, and classifies compounds according to the three common durometer scales. Any specification may be referred to as either a shore or type for example, shore a 70 durometer or type a 70 durometer.
Durometers are described in the american society for testing and material specification astm d2240, which is the recognized specification for the instrument and test procedures. Hardness and durometer are used interchangeably in the roller. Official specifications list the different durometer scales as types. The rockwell hardness test is a hardness measurement based on the net increase in depth of impression as a load is applied. Astm d2240 durometers allow for a measurement of the initial hardness, or the indentation hardness after a given period of time. Each scale results in a value between 0 and 100, with higher values indicating a harder material. A number in parentheses indicates the year of last reapproval. These scales establish a common point of reference for comparing materials. D224015e1 standard test method for rubber propertydurometer hardness indentation hardness rubber.
Shore hardness testers analog and digital tried, tested and up to the minute these shore electronic hardness testers are used for determining the hardness of plastics and rubber to iso 76191, astm d2240, iso 868, nft 51109 and bs 903 part a26. Shore d hardness is a standardized test consisting in measuring the depth of penetration of a specific indenter. Hardness is an essential characteristic of rubber, elastomers and plastic products. Determine the relative hardness of resins, film, lacquer, and paint by testing their resistance to scratches by graphite pencils. Rubber bands are approximately 40 a durometer, while standard oring seals are 70 a durometer.
Shore microhardness durometer tester for astm d2240 type m. Test methods used to measure shore d hardness are astm d2240 and iso 868. Shore a scale is applicable for rubber and soft plastics whereas shore d is for hard. A scale consists of 7 colorcoded rubber test blocks of various type a durometer hardness values ranging from 30 durometer to 90 durometer, and are housed in a convenient, rigid, customfit protective box. This makes the shore micro hardness tester quite suitable for its intended purpose, yet too delicate to be used as a hand held instrument. There are two standard astm d2240 hardness durometer scales for rubber, shore a flat cone indentor and shore d pointed cone indentor. They are easytouse, portable and very accurate with a high degree of repeatability. The test requires applying the force in a consistent manner, without shock, and measuring the hardness. Feb 15, 2012 used to measure the hardness of rubber and plastics according astm d2240, din 53505, iso 868 and iso 7619. The pencils are calibrated to specific lead grades for hardness. Shore durometer hardness testing of rubber and plastics. Higher numbers on the scale indicate a greater resistance to indentation and thus harder materials. To perform correct measurements, a durometer must be calibrated regularly. Durometer hardness can be an instantaneous reading or set to be taken up to 15 seconds after load is applied.
Active standard astm d2240 developed by subcommittee. A measurement is taken on each test block and compared to the hardness value displayed on the durometer. What is a durometer the durometer is the international standard for the hardness measurement of rubber, plastic and other nonmetallic materials. The set shown figure 3 represents hardness values of 25, 46 and 75 on the d scale. Shore durometer wikimili, the best wikipedia reader.
Durometer hardness testing is performed according to the procedure described in astm d2240. However, the astm d224000 testing standard calls for a total of 12 scales, depending on the intended use. Flatten the tip of the pencil lead with the included 400 grit sandpaper, then insert the. Ptc instruments shore d scale classic style durometer. Thetest requires applying the force in a consistent manner, without shock, and measuring the hardness. Shore a scale is the most widely used scale for the roller industry. With readings taken between 0 and 100, shore hardness measures are dimensionless. Select the optimum durometer type based upon material hardness. The dampener lowers the durometer at the same rate for each test, resulting in superior repeatability for all durometer tests. Maximumreading indicator, tolerancesetting highlow buttons, usb and rs232 connectivity. The test methods employed vary greatly from a field applied test to a very controlled laboratory test.
There have been a few attempts to relate astm d2240 and elastic modulus. Standard test method for rubber propertydurometer hardness1. These scales are properly referred to as durometer types. Durometer hardness is used to determine the relative hardness of soft materials, usually plastic or rubber. Whenever possible, a durometer measurement should be taken at least 12 mm approx. There are a few different methods to measure hardness. There are 12 scales and there is no mathematical relation between the various scales as they are arbitrary scales. Nextgen material testings model 307l astm type d durometer is ideal for gauging and determining the hardness of plastics, hard rubber, soft metals, epoxies, and other like materials. Rubber propertydurometer hardness 1 this standard is issued under the. Choose from our selection of durometer hardness testers in a wide range of styles and sizes. The depth is proportional to the material hardness, its ductility and the shape of the indentation head. Asker hand held durometers measure hardness from sponge to hard rubber and plastics, covering the range of shore d, shore a, asker c and asker f hardness scales. As you can see from the chart below, there is overlap on the different scales.
300 1077 484 125 100 1138 65 1412 645 411 1010 1335 1610 937 1133 1617 1245 305 1590 1151 489 336 182 1227 45 415 1123 306 62 1186 899 690 64 413 492 119