Analysis Of The Cause Of Surface Quality Defects Of MK8440A CNC Roll Grinder

The quality of roll surface has been an important indicator to measure the quality of roll. Any slight error of the key functional module of roll grinder in design and manufacture will have a certain impact on the processing quality of roll. Analyses and researches on the quality defects of roll surface and their incentives have great significance on the development of high-precision roll grinder. The textual research object is a CNC roll grinder called MK8440 A, which is produced by a domestic machine tool company. The quality defects of roll surface and related issues existed on the roll grinder been studied. The research achievements have certain guiding significance for the design and improvement of the roll grinder.At first, the quality defects of roll surface and their incentives which frequently present in the grinding process of roll were generalized. The incentives were classified into two categories: the design and manufacture of machine related and the processing conditions related. Then the research methods of the two types of incentives were analyzed, but the primary analyses focused on the theory of vibration differential equations and transfer matrix method that were related to the study in this paper.After the scrupulously checking of roll surface ground by MK8440 A, these types of quality defects of surface roll were judged, including chatter marks, diagonal lines and so on. Then the main causes of these quality defects were found, that is the insufficient stiffness of support system resulted by the unreasonable design of center, the misalignment of bearing installation resulted by the low assembly precision of driving system o headstock and the poor processing conditions respectively.Based on the theory of vibration differential equations, a double time delay model of grinding system with insufficient stiffness of the support system were proposed. The basic idea of transfer matrix method is be referenced to establishing a new transfer matrix that describe the vibration characteristics of headstock driveline with the misalignment of bearing installationMATLAB, the numerical simulation and analysis software, was used to analyze the influence of a number of factors on the vibration and the quality of roll surface, such as the feed rate, some angle of the structures of MK8440 A and the misalignment of bearing installation. The analyses have been checked by the vibration signal detection and analysis platform based on LabVIEW, which was set up by the research group. The results show that the mathematical model and analysis method are effective and feasible.