Industry Photos: Parker
Industry Photos: Parker Hannifin® Industry 10 12 Many different types of plastics and elastomers (e.g. seals) are used in modern machine tools. MOTOREX had the compatibility of its ORTHO cutting oils tested and, together with machine tool manufacturers, defined the requirements for all plastics used. Perfect harmony: MOTOREX ORTHO cutting oils The cutting oil must not, under any circumstances, soften the plastics and elastomers or create an excessive increase in volume. In the Parker® test an HNBR test bar was stored in the cutting oil before the bar was subjected to a precisely defined test. Although the cutting oil is only actually needed at the point of action where tool and workpiece meet, a low oil-mist machining fluid spreads into other parts of the machining center over time even despite complete encapsulation. On the one hand, this protects all metallic surfaces and parts, but it also means direct contact with plastics, paints and electrical components. The members of MOTOREX’s “Seals and Plastics” synergy project were particularly interested in the compatibility of the company’s ORTHO cutting oils with plastics and elastomers. Independent laboratory test at Parker Hannifin® Parker Hannifin GmbH & Co. KG, a leading seal manufacturer, operates an independent test laboratory in Bietigheim- Bissingen, Germany, that is accredited to DIN EN ISO/IEC 17025. Two types of ORTHO cutting oil were tested there for their compatibility with SRE elastomers NBR-1 and HNBR-1 (see box for definition on page 13) to the strict ISO standard 6072. The compatibility of non-metallic materials with the cutting oil used is of major importance, because it is no use to the operator if he achieves outstanding cutting performance, tool life and surface qualities but uses a machining fluid that causes problems of compatibility with parts made from plastic and elastomer. What is meant by optimum compatibility? The two central parameters of the Parker ® test as regards compatibility with elastomers are also in keeping with real-world requirements, as they relate to the hardness, measured in Shore, and the volume of the elastomer. Hence a seal covering a cable connection on an electric motor must not stretch excessively or become brittle under the influence of oil mist. The test is comprehensive and checks specific weight, tensile stress, tensile strength at break, and percentage elongation at break etc. It also determines the limiting values within a narrow tolerance band. The Parker ® test uses the measured values of a naturally “mild” HLP hydraulic oil as a reference basis. It would go well beyond the scope of this article to reproduce the test results in whole or even in part. A test result without the “ifs and buts” The two tested high-performance cutting oils, MOTOREX ORTHO NF-X 15 and NF-X 46 Hydro, fully meet the requirements of DIN 51524-2. From this it can be concluded that all materials that are suitable for HLP hydraulic oils are also suitable for use with the cutting oils from the MOTOREX ORTHO family. The knowledge obtained from the test also applies to MOTOREX’s novel additives package, which is used in the ORTHO cutting oils. It is highly efficient in conjunction with the selected basic oils, especially at elevated operating temperatures, but still very “mild”. Elastomer seals may only expand or shrink by a clearly defined percentage rate. Similarly, polyurethane pipes must not become brittle or fragile under the influence of the machining fluid. As a result, flawless surface finishes are obtained and all components that come into contact with the machining fluid are protected. Synergies used and specifically communicated Only by openly communicating the test results and the knowledge gained can the user also finally derive real benefit. This is why MOTOREX has disclosed all the information from this synergy project to the machine and seal manufacturer. As a result it has been possible to specifically develop problem components and employ optimized sealing materials. Would you like to find out more about cutting oil compatibility with plastics and elastomers? If so, please contact us. The Parker® test The chemical laboratory of the Parker Packing Division® is accredited as a test laboratory for a large number of test procedures, including procedures for the manufacture, testing, analysis and damage analysis of parts made from high-polymer materials, in particular elastomers, to EN ISO/IEC 17025. In a standard test procedure, two different SRE elastomers were tested for 7 days at a temperature of 100° C. The test specimens were made from the following materials: NBR-1 (Acrylonitrile Butadiene Rubber) = Acrylonitrile Butadiene Rubber (standardized to ISO 1629) HNBR-1 (Hydrogenated Acrylonitrile-Butadiene = HNBR mixture from which sheets -Rubber) are produced for test purposes.This is also known as a standard reference elastomer (standardized to ISO 6072) MOTOREX ORTHO’s balanced additives package prevents expensive damage such as softened plastics. All electrical connections in a modern machine tool are scrupulously sealed and protected. 13
