![\"Caster](\"https:\/\/www.bulldogcastors.co.uk\/blog\/wp-content\/uploads\/LOGO-180316-3-1.png\"){kind=logo}
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As discussed in our previous Blog about Natural Rubber<\/a><\/strong>, it can extremely difficult to tell the difference between high grade\u00a0rubber casters<\/strong> and a medium or low grade rubber casters<\/strong>.\u00a0 After all, most rubber looks pretty much the same, however in the case of Rubber Caster Wheels<\/strong>, whilst the appearance may be the same there could be many significant differences that affect the performance and life of the Casters wheel<\/strong>, for example Abrasion & Wear Resistance, Compression Set, Creep, Resilience, Hysteresis (Heat Build Up)<\/strong> to name a few.\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0<\/strong><\/p>\n Considering the above fact, it is important that when specifying a Rubber Caster Wheels Mechanical Properties <\/strong>and grade that a complete specification is defined, allowing the products mechanical properties to be controlled.<\/p>\n The ASTM D2000 standard<\/strong> can be used to specify almost any mechanical property, including the specifying Rubber Caster Wheels Mechanical Properties<\/strong>. \u00a0The specification is given as a \u201ccode\u201d, called a \u201cLine Call Out\u201d which details the required mechanical properties. This code can be provided to manufacturers and noted on drawings and specification documents.\u00a0 All Rubber Based Caster Wheels<\/strong> can be defined by \u201cLine Call Out\u201d specification.<\/p>\n The ASTM D2000 Line Call Out is also extremely useful for Quality Testing<\/strong> and Inspection<\/strong> purposes, as all parts of the defined specification can be tested and measured to ensure they conform. This may be an abrasion test of the Casters Rubber Wheels<\/strong>, or the resistance to a certain fluid or chemical.<\/p>\n A typical Line Call Out is specified below, where each part of the \u201ccode\u201d defines a specific requirement.\u00a0 This would be a typical Line Call Out for a Black Rubber Caster Wheels Mechanical Properties<\/strong>, in which we will explain below in detail:<\/p>\n ASTM D2000 <\/u><\/strong>\u00a0M<\/u> 4<\/u> AA<\/u> 7<\/u> 14<\/u> A13 B13 C12 G21 Z1<\/u><\/strong><\/span><\/p>\n As discussed above, the Line Call Out specifies the\u00a0Caster Wheels Mechanical Properties<\/strong>, its Test Method<\/strong> and corresponding property requirements<\/strong>.\u00a0 Below we will break down the above example Line Call Out into its separate parts, and describe their meaning:<\/p>\n The \u201cASTM D2000\u201d part of the code specifies which ASTM standard is being used.\u00a0 In this case it is the ASTM D2000 \u2013 Specifying Mechanical Properties for Rubber Products<\/p>\n The ‘M’ indicates Metric units (for example MPa).\u00a0 If the \u201cM\u201d is not present it indicates imperial measurements (for example PSI).<\/p>\n The Grade Number, in this case \u201c4\u201d indicates the allowable deviation of mechanical properties after a test (for example, a maximum change of the rubber hardness of the wheels tires<\/strong> after a fuel immersion test).<\/p>\n The first letter of the 2 digit reference, in this case an \u201cA\u201d, specifies the required Heat Resistance of the Rubber Caster Wheels tire<\/strong>, according to ASTM D573<\/strong>.\u00a0 This specification relates to a constant temperature that the rubber wheel<\/strong> must withstand, in this case 70\u00b0C and must not be confused for a materials resistance to short term temperatures. In the case of Castor Wheels, the majority of applications will require no more than \u201cA\u201d or \u201c70\u00b0C\u201d, however our Polymer based Casters can accommodate above 350\u00b0C.<\/p>\n The letters below show the related temperature requirements:<\/p>\n A<\/span><\/strong> =\u00a0\u00a0 70\u00b0C The second letter of the 2 digit reference, in this case also an \u201cA\u201d, specifies the required Resistance to Oil (IRM 903 Oil) according to ASTM D471, where the rubber casters wheel is submersed in the oil<\/strong> for a set period of time (70 hours) and at a controlled temperature, after which the amount of swell is measured.\u00a0 This can be important where the equipment is used in an area where contaminants are present, such as a Tool Trolley on Casters in an Automotive Workshop<\/strong>.<\/p>\n The letters below show the related maximum oil swell percentage:<\/p>\n A<\/strong><\/span> – No Requirement The Temperature & Oil Resistance as specified in points 4 & 5 above will dictate the available polymer type that is used for the wheel.\u00a0 Whilst the standard does not always specify the exact polymer, the requirements of Temperature & Oil Resistance narrow down the choice of materials. Therefore whilst a Line Call Out may not specify the exact material, it generally narrows the options as follows:<\/p>\n AA<\/strong> – Natural rubber, Reclaimed Rubber, SBR, Butyl, EP Polybutadiene, Polyisoprene In the case of Black Rubber Casters<\/strong>, these are generally specified with the \u201cAA\u201d designation, using a Blend of Natural Rubber & SBR (Similar to an Automotive Car Tire).\u00a0 Where Other requirements are required, such as Oil Resistance then the Caster Wheel manufacturer<\/strong> may use a \u201cBC\u201d, Chloroprene rubber wheel.<\/p>\n The next digit, in this case a \u201c7\u201d specifies the hardness of the Rubber.\u00a0 Rubber hardness<\/strong> is measured using the Shore A Scale, as specified by ASTM D2240<\/strong>.\u00a0 In order to obtain the required Shore A Hardness, the digit (for example \u201c7\u201d) is multiplied by 10, giving the Shore A Hardness.\u00a0 In this instance 70 Shore A.\u00a0 The Tolerance is typically +\/- 5 shore unless otherwise specified.\u00a0 The Shore Hardness is important for Caster Wheels, as it determines the \u201croll resistance\u201d<\/strong>, \u201cShock\/Impact Resistance\u201d<\/strong> and \u201cWear resistance\u201d<\/strong><\/p>\n The next two digits specify the Minimum\u00a0 Tensile Strength of the rubber.\u00a0 As the Line Call Out is specified in Metric Units (represented by the \u201cM\u201d as explained above) the Tensile Strength is specified in MPa, so in this case 14 MPa.\u00a0 The Tensile Strength of a Caster Wheel has a direct correlation with the impact resistance<\/strong> of the wheel.<\/p>\n The remainder of the code is where the specific mechanical properties<\/strong> of the material are defined.\u00a0 Depending on the application where the Caster Wheels are being used, there may be various properties of the rubber tire that are required.\u00a0 The Letters (as underlined above) indicate the mechanical property to be defined (i.e. \u201cA\u201d = Heat Resistance) and relates to a specific testing method (\u201cA\u201d = ASTM D573 Test Method).\u00a0 For example, Compression Set<\/strong>, as defined by \u201cB\u201d is extremely important for Rubber Caster Wheels<\/a>.\u00a0 High Compression set would result in the wheel taking permanent deformation<\/strong> if the wheel is left in the same position for a few days.<\/p>\n Each letter relates to a different type of mechanical property and corresponding test method, as follows:<\/p>\n A<\/strong><\/span> = Heat Resistance (ASTM D573) Note: The above ASTM test methods are examples only, and dependent on the grade of material and suffix numbers (as below) specify the exact Test method (for example ASTM D573, & ASTM D865 are both Heat Resistance test methods that may be applicable).<\/em><\/p>\n The Suffix Numbers determine the Test Method and required results of the test.\u00a0 This is an extremely detailed part of the specification, which it outside of the scope of this Blog post.\u00a0 In order to review all test methods users should firstly purchase ASTM D2000 standard<\/strong>, and any relevant standards that they need to specify.\u00a0 Key Standards for Caster Wheels<\/strong> would be Compression Set<\/strong>, Resistance to Fluids<\/strong> and Temperature resistance<\/strong>.\u00a0 To give an example of one specification \u201cA13\u201d, which relates to Heat Resistance, ASM D573 which tests the material for 70 hours at 70 deg C, with Change in hardness (Max +10 shore), Change in Tensile Strength (Max -25%) and Change in Elongation (Max -25%)<\/p>\n Bulldog Castors<\/a> Ltd<\/strong> \u2013 Unlike most of our competitors we employ Polymer Engineers<\/a> to provide the best expertise in the design & manufacture of Caster Wheels<\/strong>.\u00a0 Bulldog also have in house testing to measure mechanical properties \u2013 Can your Caster Wheels Supplier<\/strong> offer the same?<\/p>\n![\"Caster](\"https:\/\/www.bulldogcastors.co.uk\/blog\/wp-content\/uploads\/Natural-Rubber-UK-150x150.png\")
<\/strong><\/span><\/p>\n![\"Caster](\"https:\/\/www.bulldogcastors.co.uk\/blog\/wp-content\/uploads\/CASTER-WHEELS-ASTM-LOGO-1-150x150.png\"){kind=logo}
<\/em>The American Society of Testing and Materials (ASTM)<\/strong> have developed an International Standard for specifying the mechanical properties of Vulcanised Rubber Products<\/strong>, such as Caster Wheels<\/strong>, Rubber Mouldings<\/strong> & Industrial Rubber Goods<\/strong>.\u00a0 This standard is called ASTM D 2000: Standard Classification System for rubber products.<\/em><\/span><\/strong><\/p>\n
\nHow to read and ASTM D2000 Line Call Out<\/u><\/strong><\/span><\/p>\n
\nASTM Standard Reference<\/span>
\n<\/u><\/strong>ASTM D 2000<\/u> M 4 AA 7 14 A13 B13 C12 G21 Z1<\/span><\/strong><\/span><\/p>\n
\nUnits of Measurement (Metric\/Imperial)<\/span>
\n<\/span><\/u><\/strong>ASTM D2000 M<\/u><\/span> 4 AA 7 14 A13 B13 C12 G21 Z1<\/span><\/strong><\/p>\n
\n Grade of Requirements<\/span>
\n<\/u>ASTM D2000 M 4<\/u><\/span> AA 7 14 A13 B13 C12 G21 Z1<\/span><\/strong><\/p>\n
\nMaterial – Heat Resistance<\/span>
\n<\/u>ASTM D2000 M 4 A<\/u><\/span>A 7 14 A13 B13 C12 G21 Z1<\/span><\/strong><\/p>\n
\nB<\/span><\/strong> = 100\u00b0C
\nC<\/span><\/strong> = 125\u00b0C
\nD<\/span><\/strong> = 150\u00b0C
\nE<\/span><\/strong> = 175\u00b0C
\nF<\/span><\/strong> = 200\u00b0C
\nG<\/span><\/strong> = 225\u00b0C
\nH<\/span><\/strong> = 250\u00b0C<\/p>\n
\nMaterial – Oil Resistance<\/span>
\n<\/u>ASTM D2000 M 4 AA<\/u><\/span> 7 14 A13 B13 C12 G21 Z1<\/span><\/strong><\/p>\n
\nB<\/strong><\/span> – 140% Swell
\nC<\/strong><\/span> – 120% Swell
\nD<\/strong><\/span> – 100% Swell
\nE<\/strong><\/span> – \u00a080% Swell
\nF<\/strong><\/span> – \u00a060% Swell
\nG<\/strong><\/span> – \u00a040% Swell
\nH<\/strong><\/span> – \u00a030% \u00a0Swell
\nJ<\/strong><\/span> – \u00a0 20% Swell
\nK<\/strong><\/span>\u00a0–\u00a0 10% Swell<\/p>\n
\nMaterial Designation (Type and Class)
\n<\/span><\/u>ASTM D2000 M 4 AA<\/u><\/span> 7 14 A13 B13 C12 G21 Z1<\/span><\/strong><\/p>\n
\nAK<\/strong> – Polysulfides
\nBA<\/strong> – Ethylene propylene, high-temperature SBR and Butyl compounds
\nBC<\/strong> – Chloroprene polymers (Neoprene), cm
\nBE<\/strong> – Chloroprene polymers (Neoprene), cm
\nBF<\/strong> – NBR polymers
\nBG<\/strong> – NBR polymers, Urethanes
\nBK<\/strong> – NBR
\nCA<\/strong> – Ethylene Propylene
\nCE<\/strong> – Chlorosulfonated Polyethylene (Hypalon), cm
\nCH<\/strong> – NBR polymers, Epichlorohydrin polymers
\nDA<\/strong> – Ethylene propylene polymers
\nDE<\/strong> – CM, CSM
\nDF<\/strong> – Polyacrylic (Butyl-Acrylate type)
\nDH<\/strong> – Polyacrylic polymers, HNBR
\nEE<\/strong> – AEM
\nEH<\/strong> – ACM
\nEK<\/strong> – FZ
\nFC<\/strong> – Silicones (High Strength)
\nFE<\/strong> – Silicones
\nFK<\/strong> – Fluorinated silicones
\nGE<\/strong> – Silicones
\nHK<\/strong> – Fluorinated elastomers (Viton, Fluorel, etc.)
\nKK<\/strong> – Perfluoroelastomers<\/p>\n
\nRubber Hardness
\n<\/span>ASTM D2000 M 4 AA 7<\/u><\/span> 14 A13 B13 C12 G21 Z1<\/span><\/strong><\/p>\n
\nRubber Tensile Strength
\n<\/span><\/span>ASTM D2000 M 4 AA 7 14<\/u><\/span> A13 B13 C12 G21 Z1<\/span><\/strong><\/p>\n
\nCaster Wheels Mechanical Properties – Type
\n<\/span>ASTM D2000 M 4 AA 7 14 A<\/u><\/span>13 B<\/u><\/span>13 C<\/u><\/span>12 G<\/u><\/span>21 Z<\/u><\/span>1<\/span><\/strong><\/p>\n
\nB<\/strong><\/span> = Compression Set (ASTM D395)
\nC<\/strong><\/span> = Ozone or Weather Resistance (ASTM D1171)
\nEA<\/strong><\/span> = Fluid Resistance (Aqueous) (ASTM D471)
\nEF<\/strong><\/span> = Fluid Resistance (Fuels) (ASTM D471)
\nEO<\/strong><\/span> = Fluid Resistance (Oils and Lubricants) (ASTM D471)
\nF<\/strong><\/span> = Low Temperature Resistance (ASTM D2173)
\nG<\/strong><\/span> = Tear Resistance (ASTM D624)
\nJ<\/strong><\/span> = Abrasion Resistance (ASTM D5963)
\nM<\/strong><\/span> = Flammability Resistance (defined by manufacturer)
\nP<\/strong><\/span> = Staining Resistance (ASTM D295)
\nZ<\/strong><\/span> = Special Requirements (specified by the manufacturer)<\/p>\n
\n<\/strong>Caster Wheels Mechanical Properties \u2013 Method & Requirements
\n<\/strong><\/span><\/span>ASTM D2000 M 4 AA 7 14 A13<\/u><\/span> B13<\/u><\/span> C12<\/u><\/span> G21<\/u><\/span> Z1<\/u><\/span><\/span><\/strong><\/p>\n