COF depends on the nature of the materials and surface roughness. It is usually symbolized by the Greek letter mu (μ). It is also important to consider the coefficient of thermal expansion of the plastic, particularly if it is to be used in contact with a mating metal part. 1.1 This test method covers determination of the coefficients of starting and sliding friction of plastic film and sheeting when sliding over itself or other substances at specified test conditions. UHMW (Polyethylene) Redco™ Ultra High Molecular Weight Polyethylene (UHMWPE) has extremely low moisture absorption, a very low coefficient of friction, is self lubricating and is highly resistant to abrasion (10 times more resistant to abrasion than carbon steel). Coefficient of friction, ratio of the frictional force resisting the motion of two surfaces in contact to the normal force pressing the two surfaces together. What kind of plastic? Summary The Friction Table offers a convenient and effective way to measure friction. Example applications include slide bearings, bushings and wear liners. For example, static friction can prevent an object from sliding down a sloped surface. The coefficient of friction between two materials in relative sliding may depend on contact pressure, surface roughness of the relative harder contact surface, temperature, sliding velocity and the type of lubricant whether the level of contamination. Much has been It is important to evaluate the coefficient of friction, wear rate, and pressure velocity limitations of the material. Plastic, Molding and Extrusion Material, Polyethylene and Copolymers (Low to High Density) ISO Duravar UHMW utilizing Premium UHMW Polymer Resins is in compliance with ISO#11542-1/2 for molding and extrusion materials. Polystone® M UHMW is a tough, wear resistant plastic that combines an incredibly low coefficient of friction with outstanding impact strength. Static and Kinetic coefficient of friction . Plastic Pipes - Friction Head Loss - Friction head loss (ft/100 ft) in plastic pipes - PVC, PP, PE, PEH Tag Search en: hazen-williams coefficients factors pipe tube For steel and other materials, μ can decrease only when the material in a very high speed (100 m/s or above), but high speed has great effect on polymer materials. The friction force, F, is proportional to the normal force, N, and the coefficient of friction, μ: where μs is the coefficient of static friction and μk is the coefficient of kinetic friction. %PDF-1.5 We have collected some of those tables here. ... Coefficient of Friction - Static (Polished Steel) ASTM D-1894 --- .15 - .20 coefficients. Coefficients of friction between materials are best determined through testing. Due to its low coefficient of friction, PTFE (polytetrafluoroethylene) is often used for sliding applications. Mathematically, μ = F/N, where F is the frictional force and N is the normal force. The interface friction coefficients for soil sliding on 12-inch (305-mm) square, 2-inch (51-mm) thick coupons of PE4710 high density polyethylene (HDPE) were measured in the laboratory by a direct shear <> Coefficient of friction (COF) is a dimensionless number that is defined as the ratio between friction force and normal force (Eqn (2.1)).Materials with COF smaller than 0.1 are considered lubricous materials. Friction force develops between contacting surfaces of two bodies and acts to resist relative motion between the bodies. Redco™ UHMW has the highest impact strength of any thermoplastic presently made and is highly resistant to corrosive chemicals, with an … Coefficient of Friction Steel PVC HDPE Non-Lubed Polywater® J 0 0.2 0.4 0.6 Coefficient of Friction Non-Lubed Lube 1 Lube 2 Lube 3 Lube 4 Lube 5. (a) Oleic acid; (b) Atlantic spindle oil (light mineral); (c) castor oil; (d) lard oil; (e) Atlantic spindle oil plus 2 percent oleic acid; (f) medium mineral oil; (g) medium mineral oil plus ½ percent oleic acid; (h) stearic acid; (i) grease (zinc oxide base); (j) graphite; (k) turbine oil plus 1 percent graphite; (l) turbine oil plus 1 percent stearic acid; (m) turbine oil (medium mineral); (n) olive oil; (p) palmitic acid; (q) ricinoleic acid; (r) dry soap; (s) lard; (t) water; (u) rape oil; (v) 3-in-1 oil; (w) octyl alcohol; (x) triolein; (y) 1 percent lauric acid in paraffin oil. The correlation coefficient between these two variables is a very respectable +0.84. Coefficient of Friction, Plastics to Steel Static 0.30 0.30 Dynamic 0.28 0.28 Coefficient of Friction, Plastics to Plastic Static 0.76 0.76 Dynamic 0.44 0.44 Thermal Properties DSC Melting Point Homopolymer 320 - 329 °F 160 - 165 °C Copolymer 275 – 318 °F 135 – 159 °C Specific Heat (@ 23°C) 70 … Figure 1: Static vs dynamic friction Friction coefficients of thermoplastics against steel. x��][s�r~w��ü�j��9�gR.ֱ)_;r���y�i��/:�:���bи��.3@2S�X�����读�p���v���j�|������ջ�_�����q���ק//o6�������Y�����ן~r�5i�v��뷟~B�N��4B��Q��m^�釾y����O?�����O?�X5�4��������5_�pޜF�|���>�͡9 ���Rn �d�$U��"��?��k�0�s�p�d�v� k�@���.o����C���IZ���W-�_��տo���Z*���&����\��˛5_]Ǿ�uC�[���bEb�~$����ه��X�]��FT���=�h+�8���23r't��75����]i�9�_���L�Wf���ѿ�v�#�zt���k�w�In��1�\�GZã �-��׊�Q�����#��^�O��kBW6�����k�*(������ �Y�^���'lu��ѿ��� ���Pԗ� � Please use one of the following formats to cite this article in your essay, paper or report: APA. Friction coefficients between different wheel/tire materials and concrete . Static friction is friction between two or more solid objects that are not moving relative to each other. Below are provided a small number of values showing approximate values of friction coefficients to be used for steel screw fastened connections. Coefficient of Friction 0.29 0.29 Thermal Properties DSC Melting Point Homopolymer 275 °F 135 °C Copolymer 230 – 273 °F 110 – 134 °C Specific Heat (@ 23°C) 2.25 kJ/kg °K Heat of Fusion Homopolymer 245 kJ/kg Copolymer 140 – 232 kJ/kg Thermal conductivity Homopolymer 0.49 W / m °K Example - Friction Force The friction force of a 100 lb wooden crate pushed across a concrete floor with friction coefficient of 0.62 can be calculated as: Ff = 0.62 (100 lb) = 62 (lb) 1 lb = 0.4536 kg Example - Car Stopping Distance A car with mass 2000 kg drives with speed 100 km/h on a wet road with friction coefficient 0.2. The coefficient of static friction, typically denoted as μ s, is usually higher than the coefficient of kinetic friction. Corrosion resistant steel or nickel base alloys/silver plated materials. On the other hand, high polyurethane coefficient of friction is desirable for applications that want minimal slippage between surfaces. Check out these structural calculators:  • Beam Analysis   • Bolted Joints   • Lug Analysis  • Column Buckling. stream Low coefficient of friction Near-zero moisture absorption. Rubber in contact with other surfaces can yield friction coefficients from 1 to 2. Friction coefficient table of solid lubricants, metals, plastics and anti-friction materials. This self-lubricating polymer has excellent chemical resistance and a broad temperature range. Image Source: Wiki %���� The procedure permits the use of a stationary sled with a moving plane, or a moving sled with a stationary plane. <> endobj The coefficient of friction testing is done to determine the easiness with which two facades when placed in contact with each other are able to slide on one another. @. 1 0 obj 3 0 obj Is this in atmosphere, water, vacuum, some other environment? It is also self-lubricating with extremely low moisture absorption, and it has the highest impact strength of any thermoplastic polymer presently on the market. Plastic film has very low friction due to which there are ample chances of slippage. The coefficient of friction testing helps to determine two values, i.e. Friction coefficient table for various material pairs in atmosphere and vacuum (see the definition of friction coefficient) is shown below.The data was collected from various sources [1,2,3]. DESIGN COEFFICIENT TABLES Hazen-Williams Friction Factor (C) Pipe Material Values for C Range High/Low Average Value Typical Design Value Plastic, PVC, Polyethylene pipe or tubing 160/150 150-155 150 Cement or mastic lined iron or steel pipe 160/130 148 140 Copper, brass, lead, tin or glass pipe or tubing 150/120 140 130 Most commonly referred to as UHMW. A value of zero would mean no friction at all, an elusive property. 4 0 obj At what temperature? Most dry materials in combination have friction coefficient values between 0.3 and 0.6. The three most commonly used … PTFE's coefficient of friction is 0.05 to 0.10, which is the third-lowest of any known solid material (BAM being the first, with a coefficient of friction of 0.02; diamond-like carbon being second-lowest at 0.05). In addition to PTFE, the classic bearing and wear materials made of polyimide, PEEK, PPS, Nylon, Acetal and Polyester are also known for their good sliding friction properties. What kind of rubber? <>/ExtGState<>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> However, it is possible to find tables in the literature for friction coefficients between various materials. Fig.11.5 shows that the friction coefficient of rubber, plastics depend on the sliding speed. {��ǵX=|X����n������� �`��� The versatility of polyethylene has made it a popular plastic for countless industrial applications that require durability, low friction, and chemical resistance. "�? Nevertheless, for the two data points furthest from the regression line (PP and PVC), if we were to use COF to predict surface energy, we’d be off by more than 10 and 8 dynes/cm, respectively. <>>> UHMW (ultra high molecular weight polyethylene) is an extremely tough plastic with high abrasion and wear resistance. endobj Here is an excellent discussion on friction coefficients, plus a comprehensive table of friction coefficients.. Ultra High Molecular Weight Polyethylene is another thermoplastic that exhibits a very low coefficient of friction, along with 10 times the resistance to abrasion than carbon steel. The friction coefficient of rubber will increase with sliding speed increasing, and then remain unchanged or decline. Values outside this range are rarer, but teflon, for example, can have a coefficient as low as 0.04. F = μ k N. sliding (slip between surfaces) where μ s is the … The friction force is the force exerted by a surface when an object moves across it - or … It is famous for its abrasive resistance, toughness, and low cost. At what ambient pressure? Dotmar EPP Pty Ltd. (2019, April 29). F = μ s N. static, impending slip. Low polyurethane coefficient of friction is desirable for applications that want sliding to occur. endobj The static and kinetic friction coefficient values reference table shown in this article will be helpful for finding the COF values of commonly used materials. Is the rubber subject to other forces? The table below is from Barrett, "Fastener Design Manual," NASA Reference Publication 1228, 1990: The table below is from MIL-HDBK-60, "Threaded Fasteners - Tightening to Proper Tension," 1990: Affordable PDH credits for your PE license, Barrett, "Fastener Design Manual," NASA Reference Publication 1228, 1990, MIL-HDBK-60, "Threaded Fasteners - Tightening to Proper Tension," 1990. �; Plastic Co-efficient of Friction - Co-efficient of Friction of Engineering Thermoplastics. O;�,o�������ܼRh^\�C�?m�@Yf60^>��_��[P�;;P���6���"=J��A.Qў�HK�n���/��'���$� The coefficient of friction of plastics is usually measured against polished steel. Fig.1: Showing the Concept of Coefficient of Friction . You can find good background information on friction here.. The coefficient of friction is required in calculating tightening torques and resulting bolt tensile forces and stress and in calculating the resulting friction between the connected surfaces. 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