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drylin E7 Plastic Bearings vs PTFE-lined Plain Bearings

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Learn more at www.igus.com/drylin The bearing liner is also molded with a lengthwise slit, enabling an easy, tool-free, "slip fit" installation into the housing bore. drylin ® liners are molded with features on the outer diameter to allow for anti-rotation and to maintain axial security. The housing, or adaptor, is an aluminum sleeve, giving a bearing the same installation dimensions as standard recirculating ball bearings. PTFE-Lined Bearings Polytetrafluoroethylene (PTFE)-lined metal bearings are another option for linear bearing applications. A typical bearing of this type is made up of a thin, self-lubricating layer, sometimes gold in color, embedded with PTFE, which is permanently bonded to an aluminum housing. It should be noted that the liner is not replaceable. Just like drylin ® , their outer shells are designed for dimensional interchangeability with linear ball bearings. The Latest Self-Lubricating Liner Material: igus ® E7 A new dry-tech material has been added to igus ® linear technology, the E7 material. E7 was engineered for optimized service life and low friction on ferrous shafting; in particular, case-hardened steel or hardened stainless steel, which are common materials in the industrial marketplace. The E7 material is also effective on softer stainless alloys, such as 303/304/316, which offer superior corrosion resistance. Laboratory Test Comparing E7 to PTFE-Lined Bearings Testing was conducted to compare the friction and wear properties between the E7 material and PTFE-lined bearing technologies at the igus ® test lab, located in Cologne, Germany. Testing Information Bearing A: igus ® E7 dry-tech plastic linear plain bearing – injection molded tribo- polymer bearing liner, clipped into an aluminum adaptor (shell). The outer diameter of this bearing liner is designed with structural features to keep it secured both radially and axially in the bearing adaptor. The inner diameter of the E7 liner has grooves, reducing thermal expansion and acting as channels for dirt or other debris. Bearing B: Polytetrafluoroethylene (PTFE) impregnated bearing. This is comprised of a gold colored bearing liner incorporating PTFE as its primary tribological feature, which is permanently bonded into an aluminum housing. r b1 z d2 Y Y 2:1 d1 t igus E7 General Properties Density Color Moisture absorption (23ºC; 50% r.h.) Moisture absorption submerged in water Mechanical Properties Flexural modulus Flexural strength Max. permissible surface pressure (20ºC) Shore D hardness Thermal Properties Max. long-term service temperature Max. short-term service temperature Max. short-term ambient temperature Min. service temperature Electrical Properties Specific volume resistivity Surface resistivity 1.05 g/cm 3 dark grey <0.1% of bearing wt. <0.1% of bearing wt. 1,477 MPa (214,220 psi) 22 MPa (3,150 psi) 18 MPa (2,610 psi) 61 70º C (158º F) 90º C (194º F) 120º C (248º F) -50º C (-58º F) >10 9 cm >10 9 Bearing A Bearing B Testing in progress at the igus ® in-house laboratory, Cologne, Germany Images show the anti-rotation and axial fixation features

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