Surface roughness is caused by the machining of various materials during sawing, cutting, punching and other mechanical processes. When you saw a piece of wood to burn it in the fire later, the roughness of the cut surface is essentially irrelevant. The function and energy efficiency of the piece of wood \u2013 which is simply intended to burn and provide heat \u2013 are not affected by this. The situation is quite different for components such as gears, gearboxes or roller bearings, where machine parts are constantly in motion and in continuous surface contact. If the individual parts are not as smooth and friction-free as possible, they will \u2018grind\u2019, or you will, so to speak, have \u2018sand in the gears\u2019. Ultimately, this could result in a total failure and, consequently, an extensive repair or the need to replace the part.<\/p>\n\n\n\n
Roughness is a term used in the field of surface physics. In tribology (the study of friction), roughness means that the rougher the surfaces of two objects moving relative to one another, the greater the friction losses they cause. This phenomenon is particularly significant in moving machine parts such as gearboxes and roller bearings. Roughness leads to high operating temperatures, accelerated wear of the individual components and, in the worst case \u2013 where incorrect lubricants are used or maintenance is inadequate \u2013 to total failure.<\/p>\n\n\n\n
Depending on the material used, modern manufacturing technology now employs various processes to minimise surface roughness. These include, amongst others, polishing and electropolishing, grinding and pickling, etching, sandblasting and honing. However, a certain degree of roughness always remains, albeit perhaps only at the nanoscale, which is not detectable to the naked eye or by touch. In such cases, appropriate lubricants and regular inspection or maintenance help to mitigate the effects of surface roughness.<\/p>\n\n\n\n
The DIN 4760 standard classifies surface finish deviations into six classes, although the values for the first four classes may well overlap:
Grade 1: Deviations from the standard form
Year 2: Waviness
Grade 3: Roughness caused by grooves
Year 4: Roughness caused by grooves
Year 5: Roughness in the microstructure
Year 6: Lattice structure of the respective material
Surface roughness in grades 1 to 4 can normally be detected visually and by touch. For the higher grades, 5 and 6, a microscope or electron microscope is required to examine the surface texture or detect defects.<\/p>\n\n\n\n
There is a wide range of measuring instruments available for determining the roughness of surfaces, bores and grooves. They are generally quite straightforward to use. The instruments measure the average roughness depth (unit: Rz) and the average roughness value (unit: Ra) in micrometres (\u00b5m) and are capable of transferring the values directly to a PC or laptop for more detailed analysis. Depending on the workpiece, the measuring instruments should comply with the DIN 4762, 4768, 4771 or 4775 standards to ensure that the results obtained after testing are accurate.
Commercially available measuring instruments generally operate using three methods. Manual methods include, for example, the Rugotest, in which the comparison is carried out visually or haptically by touching the surface against a reference sample. In profile-based methods such as the indentation method, a diamond is moved across the surface at a constant speed to measure the roughness. Thirdly, there are area-based methods, in which the measurement is carried out using optical techniques, for example via confocal microscopy or conoscopic holography.<\/p>\n\n\n\n
To a limited extent, the roughness of a surface can be seen with the naked eye or felt with the fingers. Whether this check is sufficient depends on the material used and the intended purpose of the machine parts in question. However, only measuring instruments capable of detecting even the finest irregularities can provide true certainty as to whether a surface is suitable for the intended operation.<\/p>","protected":false},"excerpt":{"rendered":"
Begleiterscheinungen tribologischer Reibkr\u00e4fte Die Rauigkeit von Oberfl\u00e4chen entsteht durch die Bearbeitung unterschiedlicher Materialien beim S\u00e4gen, Schneiden, Stanzen und anderen mechanischen Vorg\u00e4ngen. Wenn Sie ein St\u00fcck Holz s\u00e4gen, um es sp\u00e4ter im Kamin zu verbrennen, spielt die Rauigkeit der Schnittstelle im Grunde keine Rolle. Die Funktion und Energieeffizienz des Holzst\u00fccks \u2013 es soll einfach nur verbrennen […]<\/p>","protected":false},"author":1,"featured_media":522,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_robots_primary_cat":"none","_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","inline_featured_image":false,"footnotes":""},"categories":[18],"tags":[],"class_list":["post-519","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-know-how"],"acf":[],"_links":{"self":[{"href":"https:\/\/rewitec.ideehost.com\/en\/wp-json\/wp\/v2\/posts\/519","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rewitec.ideehost.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rewitec.ideehost.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rewitec.ideehost.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/rewitec.ideehost.com\/en\/wp-json\/wp\/v2\/comments?post=519"}],"version-history":[{"count":1,"href":"https:\/\/rewitec.ideehost.com\/en\/wp-json\/wp\/v2\/posts\/519\/revisions"}],"predecessor-version":[{"id":523,"href":"https:\/\/rewitec.ideehost.com\/en\/wp-json\/wp\/v2\/posts\/519\/revisions\/523"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/rewitec.ideehost.com\/en\/wp-json\/wp\/v2\/media\/522"}],"wp:attachment":[{"href":"https:\/\/rewitec.ideehost.com\/en\/wp-json\/wp\/v2\/media?parent=519"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rewitec.ideehost.com\/en\/wp-json\/wp\/v2\/categories?post=519"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rewitec.ideehost.com\/en\/wp-json\/wp\/v2\/tags?post=519"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}