What is Pitch Polishing?
Pitch polishing is a similar concept to the lapping process except it is using a pitch plate and much finer polishing media.
Lapmaster Wolters is a manufacturer of single-sided pitch polishing machines for a wide range of optical components, e.g. optical surfaces, filters, prisms and for the reconditioning of our customers' optical components.
Typically, components range in size from 20mm diameter to 600mm diameter. Other sizes are achievable depending on both machine and component size and type.
Significant skill is required for pitch polishing, achieving tighter tolerances for surface flatness, roughness, parallelism, and cosmetics than you would achieve using the conventional lapping process with coarser abrasives.
The pitch polishing process also produces a significantly improved surface quality with a typical Ra of less than 5 Å.
Pitch plates are a semi-fluid surface with a consistency similar to bitumen (asphalt) and are manufactured at our UK site. Concentric, spiral, radial and cross-hatched grooving is either hand cut or machine cut to allow the polishing slurry to flow beneath components, resulting in exceptional surface roughness and surface flatness.
Typical Optical Polishing Manufacturing Specifications on our Lapmaster 48 Air Bearing Machine:
| Specifications | Measurements |
| Diameter | ≤ 300mm Optical Reference Flat |
| Flatness | ʎ/20 |
| Surface Roughness | ≥ 5 Å rms |
| Cosmetics (scratch/dig) | 60-40 to 10-5 |
What are Lapmaster Wolters pitch polishing consumables?
Cerium Oxide
Cerium Oxide (CeO2) offers an enhanced polishing performance for optical flats, as well as other applications like filters and prisms. Cerium oxide has long lasting polishing efficiency providing excellent surface quality. Cerium oxide can retain its effectiveness over longer periods, even when used under demanding polishing conditions. This abrasive is used strictly for polishing glass like materials on soft polishing pads or pitch polishing plates. The average particle size utilized is typically somewhere in the range of one to three microns. Some brands of cerium oxide have a slightly high pH level. These abrasives cause an oxidation of the surface being polished. The oxidized material is mechanically removed by the rotating action of the pitch plate or polishing pad.
Why use Lapmaster Pitch Polishing Machines / Systems?
With its brand Lapmaster, Lapmaster Wolters offers a complete line of pitch polishing machines for all pitch polishing requirements. Both fully in integrated machines for high-volume pitch polishing in industrial production applications as well as small volume machines are available. Lapmaster Wolters also offers used pitch polishing (rebuilt and refurbished) and upgrade services for existing polishing machines. We provide you with sophisticated, customer-specific solutions in the field of pitch polishing. As a solution provider, we also offer a complete range of accessories and consumables as well as comprehensive training and repair services.