Research Of Variable Pitch Spiral Toolpath Based On The Constraints Of Maximum Scallop Height

Optical Freeform Surface refers to the non rotational symmetry,irregular,wasn't a unified equation to describe the complexity of the Optical Surface.Being limited by the design principle,the traditional optical system is not only complicated structure,large volume,more difficult to meet the high standards of optical performance and image quality requirements.Optical free curved surface is proposed,which can provide optical designers design degrees of freedom.Using less freedom curved mirror instead of the traditional optical system of multiple spherical or surface mirror,not only simplified the structure of the optical system,lose weight,can improve the optical performance,reduce the cost.In modern optical introduction of free-form surface,formed the free-form surface optics.Free-form surface optics is based on modern photoelectric information system for the sending and receiving information,conversion,transmission and storage capability of special needs,break through the traditional concept of optical imaging,using new random structure its optical surface idea,to design the optical system.Are derived from spherical surface to the aspheric optical elements,to the free surface increases the optical imaging system design degrees of freedom,and thus simplifies the system of steel structure,reduce the number of lenses and significantly decrease the size of the lens;To further improve the imaging quality.Make it possible to asymmetric imaging system;Make some system of pure reflection to realize.In the imaging system,not only with the free surface constitute a variety of exotic optical element show special optical performance,financial resources of the people to the traditional optical new province.As the key information transmission components,in computer,optical communication,mobile phones,digital cameras,and listen to all the latest electronic products and manufacturiTool path planning is an important research freeform surface machining.Tool path planning algorithm can affect the quality of the surface quality and processing efficiency and the resulting free-form surface.It is a good tool path algorithm first calculates fast speed,higher efficiency,and secondly take the knife to have a reasonable step size distribution can not be confused and finally its processing efficiency to meet the requirements and the resulting high surface quality.This thesis summarizesthe mainly used freeform optics with their mathematical expression,and then analysis principle curvature of the surface.A new method is proposed to calculate the radial curvature of a single point on surface.By using the method of discrete surface approximate the minimum stepover point on surface.Then studies constant stepover of spiral toolpath algorithm by the minimum stepover value.Papers on toolpath projection algorithm and opposite the scallop height affects the processing precision of outline,research based on the maximum balance constraint algorithm for variable-pitch helical trajectory.With constant stepover toolpath algorithm based on the lowest pitch value,variable stepover interpolation optimization passes,which meet the machining accuracy,efficiency requirementsand the toolpath smoothing.We implement the constant scallop height algorithm based on the cutter contact calculation of cutter location point,the constant stepover algorithm based on the maximum scallop height and the algorithm based on maximum scallop height for variable stepover and toolpath results are compared.Proposes a simulation algorithm of scallop height on surface by discrete surface,respectively,according to the three methods of toolpath planning to simulate the surface scallop height analysis and comparison.In the process of mechanical processing,surface morphology is due to the relative motion between cutter and workpiece and cutting tool cutting edge profile residues in the traces on the surface of the workpiece.And affecting the formation of optical 3 d free-form surface topography factors are many,such as the shape of cutting tool,cutting tool and workpiece material,processing way,in the process of cutting condition and processing factors such as the relative vibration between the tool and the workpiece.Visible,the formation of surface topography is under the influence of above factors,the cutting tool on the workpiece surface formed by a lot of traces,and so on the surface of the surface topography is complex micro geometry.Ultra precision machining aims to get high quality ultra smooth surface,which get good three-dimensional morphology characteristics of the workpiece surface.Three-dimensional topography of machined surface characteristics mainly includes three categories,namely,geometry precision,roughness and waviness,the formation of the ultra precision machining surface is formed by superposition of above three kinds of characteristics of the surface.Processing the surface roughness of the workpiece is an important factor of measuring surface topography,and surface roughness is mainly formed on the surface of the workpiece residual area is the height of the decision,so by solving the residual surface height,can forecast the machining surface morphology,the size of the processing surface residual height also directly determine the surface morphology of good or bad.Evaluate the efficacy of the curved surface machining processing is the most direct and most effective index after the size of the difference between surface and surface theory,namely residual height.From curved surface quality of the method can ensure the surface processing and uniform consistency,machining efficiency is highest at the same time,this article in view of the ultra-precision turning three axis processing technology,through the residual height constraint satisfy the requirement of the ultra-precision turning precision and machining efficiency,site location directly by the knife,calculated by projection algorithm of tool path,face shape is volatile area also can have a stable flat spiral trajectory.