Papers by Keyword: CNC Grinding

Abstract: Traditional manufacturing and finishing operations of crystal products use intensive specialized labour resulting in high cycle times and production costs. It is intended to investigate the applicability of automated finishing technology, namely grinding in a CNC machining centre, with consideration of material’s characteristics and geometric variability to crystal processing. A case study will be presented, involving cutting tools development, cutting parameters optimization, CAM programming of machining strategies and toolpaths, product clamping systems and finally product machining and quality control that is being implemented at Vista Alegre Atlantis company.

Abstract: Additional power head with common milling machine.Two and a half axis CNC system are used for CNC grinding circular surface curve trajectory. The advantages of this processing method are: We can avoid the influence on processing of lead screw clearance because of changing the parts clamping position,effectively ensure the integrity of the great circle arc curve trajectory. Because of using digital control technology in grinding process is instantaneous automatic compensation of grinding wheel wear, the machining accuracy of parts in outline is improved, the machining error is decreased. it will effectively ensure the consistency of the large circle curve precision.This method has the effect of infer other things from one fact for CNC grinding of large circular arc curve parts. Broaden the scope of application of CNC technology and practical.

Abstract: With high precision special rotary tool is widely used in automotive, mold, aerospace, machinery, electronics and other fields, the demand of manufacturing for such type and quantity of cutting tool is more and more big, lead to the demand for multi-axis CNC tool grinder which provides efficient, high quality production support for it also increasing. In terms of hardware and software multi-axis CNC tool grinder in developed countries are relatively mature, but domestic did not have enough for this research, especially for development of CNC tool grinding machine operation software system, and rarely reference data. In view of the domestic manufacturer in urgent need of independent research and development of CNC tool grinder, this article will research tool grinding automatic programming and simulation technology of CNC tool grinding machine operation software system, through analyzing the four main steps of NC grinding four-blade overall end milling cutter, parametric programming with MATLAB, and grinding trajectory data in the form of mixed programming of MATLAB and VC+ + will be post processed into NC programs, then simulation in VERICUT virtual machine tool, finally the actual grinding out overall end milling cutter.

Abstract: At present, CNC grinding efficiency has been low, the main reason is the grinding tool-grinding wheel. The service life of grinding wheel is an important element for restricting the grinding efficiency, and the main reason for affecting grinding wheel service life is the distribution of the grinding wheel grits. The chaotic distribution of grinding wheel grits reduces grinding efficiency. This paper analyzes the physical and chemical characteristics of the CBN grits, puts forward that through adding the magnetic field method in the process of electroplating wheel, changes the position and posture of CBN grits on the grinding wheel base body, and makes its an orderly distribution. And thus this method greatly improves the grinding efficiency and service life of the electroplating CBN grinding wheel.

Abstract: A novel algorithm for the ball-end mill relief using a five-axis computer numerical control (CNC) grinding machine and the simulation of the ball-end mill based on a CAM system is presented in this paper. In this study, In order to obtain an accurate normal relief angle, which is one of the key factors affecting tool cutting performance, a tool coordinate system based on the required relief angle and the cutting edge was established. Then, by the proposed tool coordinate system, an algorithm to determine the position between the grinding wheel and the tool is proposed, and then the relevant formulations are deduced. The coordinates of grinding point when the step of relief surface is grinded are calculated.Using the input data of a ball-end mill geometry, wheels geometry, wheel setting and machine setting, the NC code for machining will be generated. Then the code will be used as input to simulate the ball-end mill machining in 3 Dimension before real machining. The algorithm of ball-end mill relief can be authenticated by the 3D simulation system.

Abstract: Grinding is a widely used manufacturing method in state of art industry. By realizing needs of manufacturers, grinding parameters must be carefully selected in order to maintain an optimum point for sustainable process. Surface roughness is generally accepted as an important indicator for grinding parameters. In this study, effects of grinding parameters to surface roughness were experimentally and statistically investigated. A complete factorial experimental flow was designed for three level and three variable. 62 HRC AISI 8620 cementation steel was used in grinding process with 95-96% Al2O3 grinding wheel. Surface roughness values (Ra, Rz) were measured at the end of process by using depth of cut, feed rate and workpiece speed as input parameters. Experimental results were used for modeling surface roughness values with linear, quadric and logarithmic regressions by the help of MINITAB 14 and SPSS 16 software. The best results according to comparison of models considering determination coefficient were achieved with quadric regression model (84.6% for Ra and 89% for Rz). As a result, a reliable model was developed in grinding process which is a highly complex machining operation and depth of cut was determined as the most effective parameter on grinding by variance analysis (ANOVA). Obtained theoretical and practical acquisitions can be used in various areas of manufacturing sector in the future.

Abstract: To facilitate the manufacturing of an end mill, this paper presents a manufacturing model of a flat-end mill using a five-axis computer numerical control (CNC) grinding machine. Using input data of end mill geometry, wheels geometry, wheel setting and machine setting, the NC code for machining will be generated directly from a solid modeling then used as input to simulate the end mill machining in 3 Dimension before machining. The 3D simulation system of the end mill grinding is generated by VBA and AutoCAD2008. Machining simulation consists of a sequence of Boolean operations on difference between the tool and the grinding wheels through NC code. Then the major design parameters of a cutter, such as relief angle and inner radius, can be verified by interrogating the section profile of its solid model. The manufacturing model presented in this paper provides a practical and efficient method for developing CAM software for the manufacture of an end mill.

Abstract: Most of the commenly adotped interpolation algorithems are for the curve machining on CNC machine tools with Cartesian coordinates configuration. For a CNC machine tool with non-Cartesian configuration, new trajectory interpolation algorithem must be developed to machine complex part sueface. Based on the analysis of the geometric characteristics and the CNC grinding principle of indexable inserts, this paper proposes two interpolation algorithems to grind the nose surface of indexable inserts with constant or variable back angle. The algorithm precision analysis is also made in this paper.

Abstract: Evaluation and measurement of form errors distributed on 3D ground curved surface are proposed due to the difficulty of processing measured points of 3D ground curve surface in comparison with axisymmetric curved surface. First form curved surface grinding is conducted by arc-shaped diamond grinding wheel, second ground curved surface is measured by contact measurement to obtain 3D measuring data, next transfer mode from CNC grinding to measuring reference frames is established, then effective and applicable 3D compensation arithmetic for probe sphere error is introduced, finally 3D form errors are investigated in connection with reference frame transfer and probe sphere compensation. It is confirmed that form error PV of is improved form 203 m / 8 cm2 is obtained by using reference frame transfer and probe sphere compensation, enhancing measuring accuracy by about 29 %.

Abstract: An arc envelope grinding method for non-axisymmetric aspheric surface was proposed in order to achieve the mould core used for the precision injection molding of optic reflector. In grinding, the arc-shaped diamond grinding wheel trued on CNC grinder was used to envelope workpiece and generate curve surface, and the spacing distance between tool paths is controlled by the equal-envelope height between wheel and workpiece. In this paper, arc envelope grinding principle was investigated in connection with wheel coordinate calculation and tool path number. The theoretical analysis and grinding experiment showed that arc envelope grinding may improve form grinding efficiency especially for large curvature and smoothness of ground surface and a smooth curve surface can be produced when the equal-envelope height is less than a certain value.