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The shock pulse measurements were carried out on test bearings to ensure that the bearing fault due to contaminated lubrication condition existed. Surface roughness measurements of a turned workpiece was carried out as an offline monitoring method. Talysurf-6 (Taylor Hobson) was used for this purpose.To minimise the effect of cutting tool wear and breakage on acoustic emission and surface roughness, care was taken to ensure cutting tool sharpness. For each set of experiments a fresh cutting tool insert was used; i.e., the tool was not allowed to wear more than a standard specification.
4 Conclusion
In this study, critical subsystems and components have bee identified for lathes using failure data.The application of condition monitoring techniques like vibration, acoustic emission (AE) and surface roughness monitoring have been successfully implemented for diagnosing faulty bearings in a lathe. We have reached the following conclusions:
·Headstock subsystem is critical because it faces a longer downtime and frequent failures of components like spindle bearings and gears.
·For defective bearing conditions, overall vibration levels at headstock spindle beatings are higher than those in defect free lathes. This increase in vibration level is much greater at higher feed and depth of cut values.
·For defective beating conditions, significant peaks at the beating fault frequencies are observed.
·Larger sized contamination particles increases surface waviness considerably. As a result, the vibration level increased considerably at larger particle sizes.
·AE levels show an increasing trend with an increase in feed rate and depth of cut.
·For defective bearing conditions, AE levels are higher than those measured under healthy conditions. The increase in AE levels is much greater for higher values of feed and depth of cut.
·For defective bearing condition, surface roughness value increases sharply.
·It is observed from the FAAS study that smaller contaminant particles ease the wear out of the bearing elements.
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摘要：磨削复杂几何零件的技术取得了显著的进展。如今，一些工厂正在考虑增加一个磨削主轴到一个车床，以节省购买一个额外的昂贵的新磨床的费用。磨削主轴可以用一个车削镗杆来替换，它需要两种类型的软件。由一个程序和子程序磨削工件的轮廓来对机床运动进行控制。