摘要:
A regulating wheel dressing system in a centerless grinder, having a dressing tool for dressing a regulating wheel, which dressing tool is adapted to be feed-controlled in a direction parallel to the axis of rotation of the regulating wheel and also in a crossing direction by a feed control means, which in turn is controlled biaxially simultaneously by a control means. Coordinate values of plural points on a rotated hyperboloid of one sheet of revolution to be formed on the regulating wheel are calculated and the dressing tool is feed-controlled for coordinate interpolation between the plural points with those coordinate values as target points. The regulating wheel can be dressed to the rotated hyperboloid of one sheet of revolution in high accuracy independently of changes of its diameter and even where it is stepped for supporting a stepped work.
摘要:
A device for detecting the position of a wheel head of a grinding machine is provided with a housing secured to the wheel head and a support rod secured at its opposite ends to a stationary base in parallel relation with the moving direction of the wheel head. The support rod passes through the housing at a pair of holes formed on opposite end walls of the housing. A linear scale is secured to the housing within the housing, and a scanning unit is fixed on the support rod within said housing for reading scale gratings on the linear scale when the housing is moved bodily with the wheel head relative to the support rod.
摘要:
An apparatus for truing and dressing a grinding wheel made of cubic boron nitride is provided. A support head supporting a truing wheel and another support head supporting a dressing roll are separately and independently arranged on a wheel support of a grinding machine. The truing wheel is rotated in the same direction as is the grinding wheel so as to true the grinding wheel in an up-cut manner, and the dressing roll is rotated in a direction opposite to that of the grinding wheel so as to dress the grinding wheel in a down-cut manner. The dressing roll is fed toward the grinding wheel to be ground thereby and then returned a predetermined amount away from the grinding wheel prior to a truing operation.
摘要:
In a centerless grinding machine, a work blade for rotatably carrying a workpiece is movable by a blade feed device in a direction normal to a first line extending across the axes of grinding and regulating wheels. Present diameters of the wheels, a desired finish diameter of the workpiece and a predetermined value representing the sine of a center height angle are stored in a data memory. The center height angle is represented by the sum of angles which a second line extending across the axes of the grinding wheel and the workpiece and a third line extending across the axes of the regulating wheel and the workpiece respectively make relative to the first line when the workpiece is finished to the desired finish diameter. When each of the wheels is dressed, a data rewriting circuit replaces the diameter of each wheel being stored in the data memory with a new diameter after such dressing. Based upon those data being stored in the data memory, a calculation circuit calculates a center height position at which the axis of the workpiece with the desired finish diameter is to be located for maintaining the center height angle constant independently of the variations in diameters of the wheels. The blade feed device positions the work blade to the calculated center height position so that the center height angle can be maintained constant.
摘要:
A method and apparatus for grinding a cylindrical surface of a workpiece by a traverse movement of a grinding wheel having a relatively narrow grinding surface. To improve the cylindricity of cylindrical surface, the traverse grinding is divided into a rough traverse grinding and a finish traverse grinding. In the rough traverse grinding, a traverse girding is carried out with a large depth of cut which would causes a deterioration of the cylindricity at one end of the cylindrical surface. In the finish traverse grinding, a traverse girding is carried out with a small depth of cut to improve the cylindricity. In another embodiment, one of grinding conditions such as the traverse speed of the grinding wheel, the rotational speed of the workpiece and the peripheral speed of the grinding wheel is changed when the grinding wheel approaches an end of the cylindrical surface at which the traverse grinding ends so as to make the grinding force constant, thereby improving the cylindricity of the cylindrical surface. In other embodiments, the position of the wheel head is compensated based upon the measured diameter of the cylindrical surface so that the entire area of the cylindrical surface has a desired diameter. This compensation also improves the cylindricity of the cylindrical surface.
摘要:
A numerically controlled machine tool for machining a non-circular workpiece according to profile data. The servomotor drive unit of the machine tool includes a frequency voltage converter which outputs a velocity compensation signal proportional to the frequency of position command pulses in the servomotor drive units. A position error signal is modulated by the velocity compensation signal. The numerical controller of the machine tool can measure the position error and phase error, and can compensate for these errors. The numerical controller operates according to ideal profile data and measures the actual position change of a tool slide corresponding to the angle position change of a main spindle. Then, the numerical controller calculates the position error and phase error depending on the actual position change and ideal profile data, and produces execution profile data which are compensated for position error. During machining operation, the numerical controller offsets the rear out position of the execution profile data by the calculated phase error so as to eliminate the phase error.
摘要:
An operator's panel for a numerical controller of a grinding machine comprises a main frame of a generally box shape, which is carried on a front portion of a bed of the grinding machine for pivotal movement about a horizontal axis. A manual pulse generator for supplying the numerical controller with pulse signals is mounted in the main frame, and a manual feed handle is secured to an input shaft of the pulse generator. A mechanism is further provided for locking the main frame at such an angular position as desired by an operator of the grinding machine.
摘要:
A high rigidity fluid bearing adapted to rotatably support a rotary shaft on a stationary base and a method for manufacturing the same. The fluid bearing is provided with a bearing bushing which includes a plurality of fluid pockets spaced apart in the circumferential direction, a land portion surrounding the fluid pockets, throttles connected respectively to the fluid pockets, and a raised land formed in each of the fluid pockets. On the bearing bushing, a deformable portion is formed around the raised land. The bearing bushing is urged and fixed to an arbor inserted therein and having a diameter smaller than that of the bore thereof at one end of each raised land so as to form a wedge-shape clearance between the raised land and the arbor. The outer periphery of the bearing bushing fixed to the arbor is machined to a true or proper circle. After removed from the arbor, the bearing bushing is fitted to the stationary base. Each raised land is then arranged so as to protrude toward the outer periphery of the rotary shaft, inserted to the bearing bushing beyond the surface of the land portion to thereby form the wedge-shape clearance to bring a high rigidity to the fluid bearing.
摘要:
A numerical control grinding machine, in which rough grinding and finish grinding wheels are used to machine a workpiece into a predetermined shape. A sensor detects the finish grinding wheel contacting the workpiece surface when shifting from the rough grinding to finish grinding operations and determines its position. The numerical controller of the grinding machine calculates the difference between actual and theoretical sizes of the workpiece and completion of the rough grinding operation based on the finish grinding wheel position. After that, the controller compensates the rough grinding wheel position in the next machining cycle for the difference calculated by the controller.
摘要:
In a numerical control grinding machine using a grinding wheel made of cubic boron nitride, a computerized numerical controller controls the infeed movement of a wheel head to effect a rough grinding and a first fine grinding on a rotating cylindrical workpiece by the grinding wheel and to halt the first fine grinding in response to a sizing signal from a sizing device which measures the diameter of the workpiece being ground. At the halt of the first fine grinding, the numerical controller advances rest jaws to press the workpiece upon the grinding wheel until another sizing signal is issued from the sizing device. Until the number of the workpieces ground after each truing operation reaches a predetermined number, the numerical controller increase the infeed rate of the grinding wheel in each of the rough and first fine grindings toward a desired infeed rate on a step-by-step basis. Further, the numerical controller diminishes a set size which determines the time point to issue the first-mentioned sizing signal from the sizing device, toward a desired set size on a step-by-step basis with the increases in number of the workpiece ground after each truing.