Choosing TBM Disc Cutters by Ground Type: 17, 19 and 20-Inch Ring Options

Disc cutter selection starts with the rock, not the catalogue. Seventeen-inch cutters remain the practical baseline for mixed faces and smaller diameters, while 19 and 20-inch discs deliver deeper penetration and longer ring life on large-diameter shields. Ring grade matters just as much: standard steel rings suit soft and fractured ground, heavy-duty steel covers medium-hard rock, and carbide-insert rings are the choice where intact rock strength reaches 300 MPa and above. The assembly behind the ring decides how that metallurgy performs. A cutter is a system of ring, body, bearing, seal and pin; a premium ring on an undersized bearing simply moves the failure point. Expect roughly 10-30 m of advance per ring in hard rock and 50-100 m in soft ground, and track wear against those bands. Seal condition and bearing play should be checked at every ring change, not only when a cutter seizes. For buyers, interchangeability is the quiet cost saver. OUSUN cutters are dimensioned to interchange with major international brands, so rings, hubs and bearings slot into existing cutterheads without adapter work. Supplied factory-direct from Deyang, Sichuan — China's largest TBM industrial cluster — disc cutters and related spares typically ship in 2-4 weeks, a lead time worth planning around for long mountain drives in CIS countries where cold-climate hard rock and winter logistics compress the maintenance window.