35 results about "Freeform surface machining" patented technology

The invention discloses a method for curve surface grinding with a cylindrical grinding wheel at a virtual ball cutter radius. The method includes the steps that 1, the attitude angle of the cylindrical grinding wheel is designed, and the inclination angle of the axis of the cylindrical grinding wheel on a curve surface tangency point normal vector is designed through a virtual ball cutter model; 2, a cutter path is planned and determined according to the curved surface tangency point normal vector and the virtual ball cutter model, and the set inclination angle in the step 1 is guaranteed through a rotating shaft of a machine tool; 3, by the adoption of an axial feeding mode, a workpiece is subjected to grinding machining according to the cutter path. The cylindrical or quasi-cylindrical grinding wheel can be used for four-axis machining of a free curved surface, and the method has the advantages that planning of the cutter path is simple and flexible, the precision of a machining shape is high, and surface roughness is low, and is suitable for machining free curve surfaces of optical glass and other hard brittle materials.

The invention relates to a method for controlling a machining track of a numerically-controlled machine tool. The method comprises the following steps of: determining the number N of positions to be smoothly machined; initialing N displacement storage units and storing the planned displacement of current movement in a machining plan into a current displacement storage unit; taking an average value of the N displacement storage units as the actual displacement of the current movement; and circulating the process to finish the machining. By utilizing the method disclosed by the invention, the displacement in single time of movement in the machining plan is realized by being dispersed into N times of movements so that the displacement variables among multiple times of close movements are reduced, the fitting degree of a machined free-form surface is better, and the degree of finish of the machined surface is higher; therefore, with the method disclosed by the invention, under the condition that a machining file does not need to be lengthened, the degree of finish of the machined free-form surface is increased, the increase of data processing amount of the numerically-controlled machine tool is avoided, and the cost of the numerically-controlled machine tool is reduced under the condition that application requirements are same.

The invention relates to an arc length parameter curve processing track generation method of a free curved surface. The method comprises following steps of smooth and continuous characteristic curve processing track extraction, given precision parameter curve processing track generation and processing track arc length parameterization. In the step (1), processing tracks generated by computer aidedmanufacturing software (CAM) are classified according to arc length characteristics; and discrete free curve processing tracks with smooth and continuous characteristics are extracted; in the step (2), fitting is performed on the extracted discrete free curve processing tracks under the given precision, so parameter curve processing tracks meeting a geometric representation precision requirementare obtained; and in the step (3), by use of the method of continuous iteration arc length re-parameterization, arc length re-parameterization is performed on the parameter curves obtained in the step(2), and finally, the arc length parameter curve free curved face processing track is obtained. According to the invention, the difficulty level in real-time interpolation and speed planning in freecurved face processing is reduced; and smoothness and processing precision in the processing process are improved.

The invention discloses a machining error rapid detection and compensation method based on an NURBS curved surface. The method comprises the steps that a designed NURBS curved surface is analyzed, and a series of characteristic points are selected as a sequence P to be measured; according to a machine tool processing curved surface applied to the designed NURBS curved surface, points to be measured in the sequence P to be measured are measured to acquire an actually measured sequence Q'; the deviation between the actually measured sequence Q' and the sequence P to be measured is computed; if the deviation is less than or equal to the machining accuracy, adjusting is not needed; if the deviation is greater than the machining precision, the sequence P to be measured is adjusted according to the deviation to acquire a compensation sequence W; 4) a control point C is adjusted according to the compensation sequence W to acquire a compensation curved surface; and machining is carried out according to the compensation curved surface to acquire a machining curved surface, wherein the error between the machining curved surface and the designed NURBS curved surface is small. According to the method provided by the invention, the efficiency of the detection of an on machine measurement method on the machining accuracy of a free curved surface is improved, and compensation machining can be carried out on the free curved surface.

The invention discloses a generating method of a three-dimensional elliptical vibrating cutting optical freeform surface machining path. The generating method is used on a triaxial diamond ultra-precision machine tool and an elliptical vibration generating device. A machine tool spindle can perform rotary motion, a working table can perform X-direction and Z-direction motions, and simultaneously a diamond cutter performs three-dimensional elliptical motion through the elliptical vibration generating device. The generating method of a cutter path track comprises building a workpiece Cartesian coordinate system, and obtaining an expression of the predesigned free optical curved surface S under the workpiece Cartesian coordinate system and a cylindrical coordinate system; determining coordinate values of xi, j(L) and yi, j(L) of a cutter location point PL (i, j); solving coordinate values of xi, j(L2) and yi and j(L2) of a new cutter location point PL2 (i, j) adding to elliptical y-directional displacement and x-directional displacement; solving the z coordinate value zi, j(L2) of a cutter location point PL2 (i, j) according to the coordinate values of xi, j(L2) and yi, j(L2) of the cutter location point PL2 (i, j); solving z coordinate value zi, j(L3) of a new cutter location point PL3 (i, j) added to elliptical z-directional displacement; and performing processing motion according to the steps, traversing processing points of the freeform surface, and finally generating the processing path.