Cutting, Rough Grinding, Beveling and Fine Grinding
Once an optic has been designed by our engineers, the raw material is ordered into our warehouse. Substrates can be in the form of a flat plate or a crystal boule, the first step is to cut or drill the substrates into the appropriate shape of the finished optics that are called blanks by our dicing or coring machines. This step minimizes time spent removing material later in the process.
After the substrate is machined into roughly the shape of blanks, the re-blocked optics are ground in one of our surface grinding machines to ensure that the planes are parallel or lie at the desired angle. Prior to grinding, the optics must be blocked. The pieces of blanks are transferred to a large circular block in preparation for grinding, each piece is pressed firmly onto the surface of the block to remove any air pockets, as these can tilt the blanks during grinding and result in uneven thickness across the optics. The blocked optics are ground in one of our grinding machines to adjust the thickness and to ensure two surfaces are parallel.
After the rough grinding, the next step will be cleaning the optics in our ultrasonic machine and beveling the edges of the optics to prevent chipping during processing.
The clean and beveled blanks will be re-blocked and go through several more rounds of fine grinding. Rough grinding wheel has diamond grit metal bonded to the surface and rotates at a high speed of thousands of revolutions per minute to quickly remove excess material of the surfaces. In contract, fine grinding uses progressively finer grits or loose abrasives to further adjust the thickness & parallelism of the substrate.
Plano Rough Grinding
Optical Contacting
Polishing
Optics can be blocked for polishing using pitch, wax cement or a method called “optical contacting”, this method is used for optics that have stringent thickness and parallelism specifications. The polishing process is using cerium oxide polishing compound and ensure to achieve the specified surface quality.
For large volume fabrication, Paralight Optics also have different models of machines which grind or polish both sides of an optic simultaneously, optics are sandwiched between two polyurethane polishing pads.
Additionally our skilled technicians can adopt the technology of using pitch to polish highly precise flat
and spherical surfaces from silicon, germanium, optical glass and fused silica. This technology delivers supreme surface form and surface quality.
High Precision Polishing Machine
Low-Speed Polishing for Small Sizes
Double-Sided Polishing Machine
Quality Control
Once the fabrication process is complete, the optics will be removed from the blocks, cleaned, and brought to in-process quality control for inspection. Surface quality tolerances vary from product to product, and can be made tighter or looser for custom parts upon customer request. When optics meet the needed specifications, they will be sent to our coating department, or be packaged & sold as finished products.
