PCBN Inserts for Machining the Un-Machinable
HyperCBN manufactures polycrystalline cubic boron nitride (PCBN) inserts that hold their edge on hardened steel, cast iron, superalloys and other materials carbide simply cannot cut — enabling faster cycle times, longer tool life and grinding-free finishing on standard CNC lathes.
Trusted by manufacturers machining hardened components for
A Sintered Super-Hard Layer, Built for the Cutting Edge
PCBN stands for polycrystalline cubic boron nitride — a man-made super-hard material created by sintering fine CBN crystals together, under extreme heat and pressure, with either a ceramic or metallic binder. That sintered CBN layer is then bonded onto a tough tungsten-carbide substrate, giving PCBN inserts the rare combination of extreme hardness at the tip and shock resistance underneath.
Unlike solid CBN tooling, PCBN inserts use only a thin, precisely engineered CBN layer at the cutting edge, where hardness actually matters, while the carbide body absorbs vibration and cutting forces. This construction by HyperCBN is what makes PCBN inserts practical and cost-effective for everyday production machining, rather than a specialty tool reserved for a handful of parts.
PCBN's hardness — second only to diamond — combined with excellent thermal conductivity and chemical stability at high temperature, lets it hold a sharp cutting edge on hardened ferrous materials that would blunt or weld to a carbide insert within seconds. That is why PCBN inserts have become the standard tooling choice for hard turning, high-speed finishing and interrupted cuts on hardened components across automotive, aerospace, energy and die/mold manufacturing.
Where PCBN Sits on the Hardness Scale
PCBN's edge hardness is what lets it cut materials that stop carbide and ceramic tooling in their tracks.
PCBN Insert Grades We Manufacture
PCBN grades are engineered around CBN content and binder chemistry — the two levers that trade off edge sharpness against toughness for your exact cut.
High CBN Content (>80%)
Metallic binder, superior toughness and thermal conductivity — built for interrupted cuts, roughing and machining cast iron or powder-metal parts.
Low CBN Content (<60%)
Ceramic binder, finer grain structure — delivers a sharper edge and superior surface finish for continuous finishing cuts on hardened steel.
Tipped / Full-Face Inserts
PCBN tips brazed onto a carbide body, or full-face inserts for maximum edge count — matched to batch size and edge economics.
Industries Running on PCBN Inserts
Wherever a hardened or abrasive component needs a repeatable, high-precision finish, PCBN inserts are the qualified tooling choice.
Automotive
Camshafts, gear hubs, brake discs & drums.
Aerospace
Landing gear components, turbine shafts.
Energy
Bearing races, hardened valve parts.
Die & Mold
Hardened tool-steel mold components.
Mining
Wear-resistant parts, slurry pump components.
PCBN Inserts vs. Carbide & Ceramic Tooling
On hardened and abrasive materials, PCBN changes the economics of every cutting operation it replaces.
| Factor | PCBN Inserts | Carbide / Ceramic |
|---|---|---|
| Workable hardness range | Up to 68 HRC | Typically below 45 HRC |
| Tool life on hardened steel | 5–10x longer | Wears rapidly, edge chipping |
| Cutting speed capability | 100–400 m/min | Lower on hardened material |
| Heat resistance | Stable up to ~1200°C | Softens at high cutting temp |
| Insert cost per edge | Higher upfront cost | Lower upfront cost |
| Best suited for | Hardened steel, cast iron, superalloys | Soft-to-medium hardness steel, aluminium |
Selecting the Right PCBN Insert
Our applications team walks every customer through the same three checks before recommending a PCBN grade.
Identify the Material
Confirm hardness (HRC), abrasiveness and thermal conductivity of the workpiece to shortlist CBN content and binder type.
Match Cut Type to Grade
Choose a tough, high-CBN grade for interrupted or roughing cuts, or a fine, low-CBN grade for continuous finishing passes.
Validate With a Test Run
Run a monitored trial, measure tool wear and finish, and fine-tune cutting speed and feed before scaling to production.
Frequently Asked Questions About PCBN Inserts
Answers to what manufacturers ask us most before switching to PCBN.
What does PCBN stand for?
PCBN stands for polycrystalline cubic boron nitride — CBN crystals sintered together and bonded onto a carbide substrate, giving the insert extreme edge hardness with the toughness of the carbide body underneath.
What is the difference between PCBN and solid CBN?
Solid CBN tooling is made almost entirely of CBN material, making it costly and brittle. PCBN inserts use a thin, precisely controlled CBN layer only at the cutting edge, bonded to a carbide body — delivering the same cutting performance at a fraction of the cost and with far better shock resistance.
What materials can PCBN inserts machine?
PCBN inserts are used to machine hardened steel, cast iron, powder-metal components and certain superalloys — typically materials in the 45–68 HRC hardness range that would rapidly wear out carbide or ceramic tooling.
How do I choose between high-CBN and low-CBN grades?
High-CBN-content grades with a metallic binder offer better toughness and are suited to interrupted cuts and roughing. Low-CBN-content grades with a ceramic binder give a finer, sharper edge for continuous finishing cuts and superior surface finish.
What cutting speed should I run PCBN inserts at?
PCBN inserts are generally suited to cutting speeds between 100 m/min and 400 m/min, depending on the workpiece material and grade. Our applications team calculates exact speed and feed recommendations from your part drawing and material spec.
Are PCBN inserts worth the higher upfront cost?
Yes, for hardened or abrasive materials. PCBN inserts typically last 5–10 times longer than carbide on hardened steel, reduce tool-change downtime, and often eliminate a separate grinding operation entirely — lowering total cost per part despite the higher edge price.
Do you offer custom PCBN insert geometries?
Yes. Alongside standard shapes and CBN-content grades, HyperCBN engineers custom nose radii, chip breakers and edge preparations for parts with non-standard profiles or tight production tolerances.
Ready to Machine What Carbide Can't?
Send us your part drawing and hardness spec — our applications team will recommend the exact PCBN grade and geometry for your job.