Grinding abrasive wheels will wear down with use, so leading to poor part quality and irregular surface finishes. To dress it is the best way to restore the grinding process at the expected rates, maximizing the grinding performance and the longevity of the tool.
Dressing is used to remove grains, clogs and excess bonding material from the abrasive wheel in order to return to its original surface finish, sharpness and shape, revealing the fresh grain underneath. On the other side, a sharp and open wheel face will allow maximum possible material removal rates and reduced thermal stress on the workpiece.
The dressing quality (both the truing one – performed at the time of grinding wheel installation – and the standard one – completed at varying intervals during the grinding process on an as-needed basis) clearly impacts on precision of bearing rings and rollers that can be got by grinding process. Any error on the profile of a diamond roll, in fact, will be replicated on the abrasive wheels, so leading to not correct shape of the processed part. Furthermore, any mistake in the choice of diamond types and/or of its characteristics shall have negative influence on the efficiency of the operation. Grinding technicians sometimes attribute wrongly the bearing rings poor quality or the low efficiency of the operation to the grinding wheel, forgetting the importance of their diamond dressing roll in the process.
Indeed, such impact described above is important not only for rotary dresser like diamond rolls and disks but also for stationary dressers like single and multi-point diamonds. However, the difficulty in manufacturing complex profiles on diamond rotary dressers (to be transferred to the grinding wheel with precisions in the order of bigness of 1 micron), together with the relative high cost of this type of rotary tools, makes the case of rotary dresser the most severe one in that respect.
In general, the rotary dressers have the advantage of a faster dressing operation, that makes them as a great option for use with Plunge/centerless, ID and OD grinders.
The frequency of standard dressing depends on many factors such as the amount of material being removed, the surface finish requirements and the accuracy of forms required on the grinding wheel. To choose the proper coupling between dressing wheel characteristics and grinding abrasive specification can positively impact also on the frequency of standard dressing, i.e. the number of grinding cycles between two consecutives dressings (with clear positive influence on the grinding operation efficiency).
Osvaldo Aghemo, co-founder of ICT srl (the Italian consulting company specialized in assisting the bearings, ball screws and bearing components industry worldwide under technical, organizational and commercial points of view), is responsible of the company products line for abrasive grinding and diamond dressing technologies. Interviewed by Bearingnews on the importance of diamond rolls for the precision of rings and rollers in bearings industry, Osvaldo highlighted how “proper dressing of the grinding wheel will ensure an accurate and consistent grinding process. Together with our partners, ICT has developed a set of high precision dressing rolls specific for bearings manufacturing application, all made with the highest quality CVD, natural diamond, synthetic diamond and a combination of them. Thanks to our deep knowledge of grinding processes (ICT distributes Cumi grinding wheels, editor’s note), we are able to customize each tool to the specific requirements of the customer and of the grinding application, in order to deliver it within max 10-12 weeks from our final drawing confirmation by the customer. These are disruptive reaction times to the market, considering that our competitors in most of cases will take more than the triple of time to serve their clients.”
For more info about the strict relationship between diamond dressing and grinding quality and about ICT diamond dressing wheels and other products for bearings industry, please get in touch with the ICT team writing to [email protected] or calling at +39 (0)121 376811.