Copper Waterjet Cutting: C101, C110, and Tellurium Copper

Copper is highly reflective to near-infrared laser wavelengths and conducts heat away extremely fast, which makes it one of the hardest metals to laser cut. It demands high laser power, risks damaging back-reflection into the laser source, and many shops decline to laser thick copper at all. Abrasive waterjet cuts copper by erosion, so reflectivity and thermal conductivity are completely irrelevant. The cut is cold, square, burr-light, and free of oxide scale or heat tint, and it does not anneal or soften the edge the way a thermal cut would. For bus bars, electrodes, and electrical contacts, that means clean profiles with no thermal distortion and preserved temper. Waterjet also handles thick copper plate that lasers cannot reach. The tradeoff is speed on thin sheet, but for copper the reflectivity issue usually settles the question in waterjet's favor.

No. Abrasive waterjet is a cold cutting process, so the copper never reaches annealing temperature and the temper stays intact right up to the kerf wall. This matters for hard-temper bus bars and spring contacts where strength and conductivity both depend on the cold-worked condition. A thermal cut would locally anneal the edge, softening it and changing its properties. The waterjet edge also has no oxide scale or heat tint, which is important for electrical joints because surface condition affects contact resistance. The cut surface is clean bare copper ready for deburring and then plating or joining. If your part is a hard-drawn conductor or a precision contact where edge properties matter, the cold waterjet cut preserves exactly what you specified, which thermal and even some mechanical processes would compromise.

A 90,000 psi abrasive waterjet cuts 0.25 inch C110 copper at roughly 8-14 inches per minute at a Q3 finish, 0.5 inch at about 4-7 ipm, and 1 inch at 2-3 ipm. Copper cuts at rates broadly similar to mild steel because, although soft, it is dense; the softness does not speed the erosive cut much. Practical good-quality maximum is around 3-4 inches, with thicker possible at slower speeds and more taper. Because copper defeats lasers and deforms under mechanical shearing, waterjet is often the practical choice across the whole thickness range, not just for heavy plate. For thin copper sheet in high volume where a stamping die can be justified, a die may be cheaper per part, but for prototypes, bus bars, and custom profiles the tooling-free waterjet wins.

It is minor and easily removed. Copper is soft and ductile, so the waterjet leaves a small, soft burr on the bottom edge of the cut, slightly more noticeable than on harder metals but still minor. It knocks down quickly with a flap disc, deburring wheel, or hand tool, and many bus bar and contact applications tolerate it as-is after a light deburr. The top edge is square and clean. Because the cut is cold, the burr is not a hardened or oxidized feature, just displaced soft metal. For parts that will be plated or joined into a low-resistance electrical connection, deburring the mating area is worthwhile, and where a precise surface is needed a light machining pass cleans the Q3 striations on the lower edge. Overall the burr is a cosmetic and prep consideration, not a quality limitation.