PR Hoffman
The PR Hoffman 93T is a carrier for double-sided planetary lapping and polishing machines. The 93T designation indicates 93 teeth, and the carrier is offered in gear tooth and sprocket variants for the PR Hoffman 4800 machine.[1]
Double-sided planetary lapping carriers are thin, toothed disks that hold workpieces in holes (workholes) while the machine's upper and lower lap plates rotate.
The teeth of the carrier engage with a sun gear and an internal ring gear, causing the carrier to rotate and orbit, moving the workpieces along a planetary path between the lap plates.
In semiconductor and precision optics manufacturing, planetary lapping carriers are used in the lapping and polishing steps that follow wafer slicing and precede final cleaning and inspection.
The PR Hoffman models 93T and 93ST are carriers for double-sided lapping and polishing equipment, including PR Hoffman machine tools.[2][1]
| Designation | Generation | Vintage | Changes | Source |
|---|---|---|---|---|
| 93T - Gear Tooth 4800 - 93T PR Hoffman | — | — | Gear-tooth carrier type listed as 93T. | web.archive.org[2] |
| 93T - Sprocket 4800 - 93ST PR Hoffman | — | — | Sprocket carrier type listed alongside the 93T entry. | web.archive.org[1] |
| 93T Gear Tooth | — | — | Gear tooth configuration for PR Hoffman 4800 machine | web.archive.org[2] |
| 93ST Sprocket | — | — | Sprocket configuration for PR Hoffman 4800 machine | web.archive.org[2] |
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Insert carriers can be made from spring steel (heat treated and tempered), stainless steel, hard rolled spring steel, or cold rolled steel. Lapping carriers can be made from spring steel, stainless steel, hard rolled spring steel, cold rolled steel, Lamitex fiberglass-epoxy sheet, PVC, polycarbonate, vinyl, or phenolic.[2][1]
Available workhole diameters for insert carriers include 76mm (3 inch), 100mm (4 inch), 125mm (5 inch), 150mm (6 inch), 200mm (8 inch), 300mm (12 inch), and 450mm (18 inch).[2]
PR Hoffman can manufacture lapping carriers up to 48 inches in diameter.[1]
The following facts about the 93T are absent from this record as of this revision. First-hand knowledge or a citation closes a gap; every submission is reviewed before publication.
No publicly documented production dates or lifecycle milestones (introduction, end of production, EOL) for the 93T are on record.
Answerable by: OEM historical records or a trade-press announcement
The control-system platform and OS era of the 93T are not on record.
Answerable by: an engineer who operated it or OEM installation records
No publicly documented failure modes or field errata for the 93T are on record.
Answerable by: a field service engineer, process engineer, or maintenance technician
The process node or technology generation of the 93T is not on record.
Answerable by: an OEM datasheet or a fab qualification report
No publicly documented compatible parts, consumables, or accessories for the 93T are on record.
Answerable by: an OEM parts catalog or a service engineer
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Last updated Aug 14, 2026.
PR Hoffman model 32T appears in PR Hoffman's carrier selection lists for double-sided planetary lapping and polishing machines.