Material Conversion, Curve Generation, CNC Grinding and Polishing
Firstly raw material is converted into the approximate shape of the lens, this minimizes time spent removing material later in the process.
The first of several grinding steps for curved optics is curve generation, a rough grinding process that produces the general spherical curvature of the lens. This step is to mechanically remove material and form the best-fit spherical radius on both sides of the lens, the radius of curvature is checked and controlled using a spherometer during the process.
To prepare for computer numerically controlled or CNC grinding, the spherical part must be attached to a metal holder in a process known as blocking. A sub-aperture asphere grinding tool containing small pieces of diamond is used to remove the material and forms the aspheric surface. Each grinding step utilizes progressively finer diamond pieces.
The next step after several rounds of grinding is CNC polishing, a cerium oxide polishing compound is used during this step in order to removing the sub-surface damage and convert the ground surface to a polished one which would be examined under a microscope to ensure the lens to meet the specified surface quality.
In-process metrology is used to monitor the center thickness, aspheric surface profile & other parameters and to make self-correction between the grinding and polishing steps.
CNC Grinding and Polishing vs Conventional Grinding and Polishing
Paralight Optics uses several models of computer numerically controlled or CNC grinders and polishers, each is optimized for a different range of lens sizes, together we are capable of producing lens diameters from 2mm to 350mm.
The CNC machines allow for a stable and cost-efficient production, however the conventional grinders and polishers can be operated by highly skilled & professional technicians with rich experience and manufacture highly precise lenses.
CNC Grinders and Polishers
Conventional Grinders and Polishers
Centering Machine
Paralight Optics utilizes both Manual Centering Machine and Auto Centering Machine by grinding its outer diameter, we are capable of achieving a centration down to 30 arcseconds, easily to the 3 arcminutes specification for most of our optics. The centration is tested after being centering to ensure the optical and mechanical axes are aligned.
Manual Centering Machine
