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PR Series

The PR Series of double-sided planetary lapping and polishing machines have a time-proven design. With thousands of machines built, the dependability, versatility, ease of operation, and low cost of ownership of the PR-Series machines is tough to beat. The PR machines are well-suited to laboratory, research and development, as well as production environments.

The base PR Series machine design employs a non-rotating top and bottom plate, variable-speed outer ring gear and center sun gear drive, and down force generated by the freely floating top plate. The planetary action simultaneously removes equal amounts of material from both sides of the parts being processed.

The PR Series machine configurations provide capability for a broad spectrum of precision processing requirements on parts that are thin and fragile, parts that have a high aspect ratio, and parts that have a low surface area. The rugged machine construction withstands harsh environments and provides a stable platform for producing flat and parallel parts. Additionally, we offer a range of optional features as well as design customization to satisfy the individual needs of our customers.


In 1990, PR Hoffman introduced the Servo-RS Model 1500, the first machine in its new Servo RS™ series. The design of this machine series drew from over 50 years of experience with developing and building double-side planetary lapping and polishing machines. In the following years, we have expanded and refined the family of Servo RS Machines to include the model 1900, 3100, 5400, 6600, and 7600 double-side machines, which feature nine carrier work holder sizes that range from 2.5” (64mm) to 27.7”(703.6mm) in diameter.  In addition we have our SSP-619 single-side polisher for work pieces up to 18”(450mm).

The base machine designs in the Servo RS™ series all employ a fixed bottom plate, independently programmable rotating top plate, center gear, and ring gear, and precise, servo-controlled down force control. We also offer a counter-rotating 4-way machine design option on the 1900 and 3100 models. All machine motions incorporate advanced drive technologies for precise control and high efficiency.

All Servo-RS machines utilize a common motion controller and Windows PC-based software with touchscreen interface. They offer a range of optional features as well as design customization in order to address individual needs of customers.