The invention is directed to a reusable mold for making a contact lens and the reusable mold has at least one of the mold halves is made from an oxide glass having a Knoop Hardness less than HK 350. The invention is also directed to a method for making an optical part by single point diamond turning an oxide glass having a Knoop Hardness HK less than 350.

A vibration cutting process diagnostic device diagnoses the propriety of a vibration cutting process to machine the sectional shape of a working object into a non-complete round shape by reciprocating a movable shaft. This device includes a frequency analyzer to calculate a frequency component contained in a position command signal for the movable shaft on the basis of shape data, which is machining shape data on a workpiece treated as the working object, and a machining speed set value; and a process diagnosis executor to diagnose the propriety of machining the shape data under the machining speed set value on the basis of the frequency component and a movable shaft parameter of the movable shaft.

A method for producing a freeform Fresnel surface having a number of Fresnel facets with a respective Fresnel segment surface and a trailing edge includes the production of the freeform Fresnel surface via machining processing of a starting body based on the construction data for the freeform Fresnel surface. With the aid of the circular cylinder casing surfaces and/or cone casing surfaces, the projection of the edges of the Fresnel facets on the x-y-plane represent circular paths for the creation of the construction data.

A method for producing a freeform Fresnel surface having a number of Fresnel facets with a respective Fresnel segment surface and a trailing edge includes the production of the freeform Fresnel surface via machining processing of a starting body based on the construction data for the freeform Fresnel surface. With the aid of the circular cylinder casing surfaces and/or cone casing surfaces, the projection of the edges of the Fresnel facets on the x-y-plane represent circular paths for the creation of the construction data.

A production method for a ring-shaped part is provided with: an inner cutting step for reciprocating a first cutting blade in the radial direction D4 from a state of contact with the center of the thickness of one end 91a of a rotating cylindrical blank 91 and moving toward the other end 91b in the axial direction D1 to form a semicircular track while cutting the inner circumferential R1-side of the cylindrical blank 91; an outer cutting step before, after or simultaneously with the inner cutting step for reciprocating a second cutting blade in the radial direction D4 from a state of contact with the center of the thickness of the one end 91a of the rotating cylindrical blank 91 and moving toward the other end 91b in the axial direction D1 to form a semicircular track while cutting the outer circumferential R2-side of the cylindrical blank 91; and a separation step after the inner cutting step and the outer cutting step for cutting the portion 92 of the cylindrical blank 91, the inner circumferential R1-side and the outer circumferential R2-side of which have been cut, from the remainder 93 of the cylindrical blank 91 to obtain a ring-shaped part 94 with a roughly circular cross-section.

A temporary part is mounted onto the chuck of the diamond turning machine. A diamond turning tip of the diamond turning machine is used to form a reference surface on the temporary part, registering a baseline for a motion control system of the diamond turning machine. While the temporary part remains mounted to the diamond turning machine, a workpiece is mounted onto the temporary part, and the diamond tip is controlled relative to the reference surface to diamond turn a surface profile on the workpiece. Because the baseline established by the reference surface compensates for positional variations from mounting parts directly onto the chuck of the diamond turning machine, the length of the workpiece can be shaped to a designated length with a high degree of accuracy.

A temporary part is mounted onto the chuck of the diamond turning machine. A diamond turning tip of the diamond turning machine is used to form a reference surface on the temporary part, registering a baseline for a motion control system of the diamond turning machine. While the temporary part remains mounted to the diamond turning machine, a workpiece is mounted onto the temporary part, and the diamond tip is controlled relative to the reference surface to diamond turn a surface profile on the workpiece. Because the baseline established by the reference surface compensates for positional variations from mounting parts directly onto the chuck of the diamond turning machine, the length of the workpiece can be shaped to a designated length with a high degree of accuracy.

The invention is directed to a reusable mold for making a contact lens and the reusable mold has at least one of the mold halves is made from an oxide glass having a Knoop Hardness less than HK 350. The invention is also directed to a method for making an optical part by single point diamond turning an oxide glass having a Knoop Hardness HK less than 350.

The invention is directed to a reusable mold for making a contact lens and the reusable mold has at least one of the mold halves is made from an oxide glass having a Knoop Hardness less than HK 350. The invention is also directed to a method for making an optical part by single point diamond turning an oxide glass having a Knoop Hardness HK less than 350.

An automatic lathe includes a main spindle that rotates a workpiece about a shaft center, a cutting tool that processes the workpiece, a feeder that moves the cutting tool, an input receiver that receives inputs regarding an eccentric distance and a radius, and a controller that controls the movement by the feeder such as to set a virtual circle having a radius of the distance, to set an offset virtual circle having a center at a position where a center of the virtual circle is offset from the shaft center of the workpiece in the radial direction of the workpiece by the radius, and to move the cutting tool along an circumference of the offset virtual circle in relation to a rotation of the workpiece by the main spindle. A hole is processed, which has the radius at a position away from the shaft center by the distance.