Apparatus and method

Apparatus according to any preceding claim, wherein said apparatus has a relatively high stiffness loop.

Apparatus according to any preceding claim, wherein said tool is a grinding machine tool.

Apparatus according to any preceding claim, and further comprising two movement sub-systems by way of which said tool is moved in said two substantially linear axes.

Apparatus according to any preceding claim wherein said tool is a high-performance machine tool further comprising a measuring arrangement mounted so as to extend substantially across a surface of said material and serving to measure the distance between said tool and a referencing region of said measuring arrangement.

Apparatus according to any preceding claim, wherein said apparatus is substantially symmetrical in two substantially vertical planes substantially perpendicular to and intersecting each other.

Apparatus according to any preceding claim, wherein said tool is a numerically controlled machine tool having a tool surface of a pre-determined shape, and a data processing system for generating geometric information in relation to said tool surface.

Apparatus according to any preceding claim, wherein said material is a free-form optic.

Apparatus according to any preceding claim, and further comprising a thermal stabilising system for controlling the temperature of said apparatus.

A method of forming an asphercial surface on a material, comprising rotating said material about an axis of rotation, moving a tool with respect to said surface, and restricting the movement of said tool to movement in two substantially linear axes transverse to each other.

A high-performance machine comprising a tool for working at a surface of a material, a support which supports said material, and a measuring arrangement mounted so as to extend substantially across said surface and serving to measure the distance between said tool and a referencing region of said measuring arrangement.

Apparatus comprising a tool for working at a surface of a material, a symmetrical metrology device, and a support upon which said metrology device is mounted, said metrology device being structurally unloaded and including a single referencing device for providing positional information of said tool with respect to said surface.

Apparatus comprising a tool for working at material, said apparatus being substantially symmetrical in two substantially vertical planes substantially perpendicular to and intersecting each other.

A numerically controlled machine comprising a tool and having two substantially linear axes and a rotational axis, a tool surface having a predetermined shape, and a data processing system for generating geometric information in relation to said tool surface.

A method comprising providing a pre-determined shape to a surface of a tool, operating the tool surface against a material surface, and generating using a data processing system geometric information in relation to the tool surface.

Apparatus comprising a tool having a material-contacting surface, said tool being substantially linearly movable across said apparatus, a forming device located in the substantially linear path of said tool for forming a desired cross-sectional profile on said material-contacting surface, a conditioning device having a conditioning surface for conditioning the formed material-contacting surface, and an inspecting device for determining a cross-sectional profile of said conditioning surface.

A method comprising forming with a forming device a desired cross-sectional profile of a material-contacting surface of a tool arranged to move in a substantially linear path, said forming occurring in said substantially linear path, conditioning said material-contacting surface by a conditioning surface of a conditioning device, and determining with an inspection device the cross-sectional profile of said conditioning surface.