Polycrystalline-diamond-compact (PDC) cutters were originally developed for oil-well drilling, but in the last decade they have migrated to a very different arena: the micro-trenching machines that cut 25–50 mm-deep slots for fiber-optic ducts in urban streets. In these units a PDC tooth only 8 mm wide must penetrate asphalt, steel-reinforced concrete and occasionally granite curb, while maintaining a kerf width tolerance of ±1 mm and a tool life long enough to avoid daily bit changes.
Cutting envelope and failure mode
A micro-trencher wheel rotates, comparable to a metal-cutting operation, but the work-piece is a highly heterogeneous composite of aggregate, bitumen, and occasionally rebar.
The dominant wear mechanisms are micro-chipping of the diamond table at quartz interfaces and gross fracture when a PDC impact-loads rebar.
PDC cutter Selection
PDC blanks range from 8 to 19 mm in diameter; for micro-trenching the 13-mm round blank is the sweet spot because it delivers 1.8 kW of usable cutting power without overloading the 25 kW hydraulic side-arms.
Key specification of PDC cutters used for micro-trenching
1308 (Ø13 × 8 mm) → most widely used; balances cost, heat-path and impact strength for 30–50 mm trenches.
1613 (Ø16 × 13 mm) → chosen when > 35 MPa concrete or occasional re-bar is expected; taller carbide substrate absorbs bending.
0808 (Ø8 × 8 mm) → light-duty asphalt or curb work; lowers wheel weight and power draw on mini-skid-steers.
1004-DA dome-top → patented dome places diamond in compression during steel impacts; preferred by Ditch Witch for mixed urban pavement.
Custom 0603 → specialty narrow kerf; cut from 19 mm round blanks to give 6 mm cutting width while retaining 3 mm diamond table for wear.
Table thickness: 2.0–2.3 mm; below 1.5 mm the diamond overheats, above 2.5 mm residual stress promotes spalling
Chamfer: 0.15 mm × 20° double-chamfer on the leading edge reduces edge-initiated fracture by 35 % in drop-test rigs
In summary, the successful transfer of PDC technology from petroleum to urban pavement is not simply a matter of substituting one cutter for another; it requires a holistic re-design of the tooth body, the cutter specification and the cooling strategy so that the extraordinary wear resistance of diamond can be exploited without sacrificing the impact resistance demanded by mixed urban geology.
ZZbetter can produce the PDC cuter and also the complete blades for micro trenching. We can also produce it according to your drawing.
