Waterjet "etching" is a method of cutting faster, and usually at lower pressure, to cut only part-way into the work, instead of the usual through-cut. It's great for graphics and text for pendants and small plaques, and is also sometimes used to ease sheet metal bending. Etching works best in hard, ductile materials. Stainless steel and brass offer the most predictable aesthetic results.
Several factors combine to affect the instantaneous depth of a waterjet etch. Etching requires design considerations, adapting designs to best accommodate the intent as well as the medium. Obtaining aesthetically pleasing results, with a consistent depth and smooth transitions, requires a special machine setup and programming. We've spent a lot of time with this, in many materials and applications. This is another specialty of ours that's rarely found in other waterjet shops.
Our most effective use of etching is at a controlled shallow depth penetrating .01" to .03", using both a lower cutting pressure and lower abrasive flow than normal cutting, and with designs using single pass kerf-width cuts that remove material in a "U" cross-section about .03" wide. Most etched parts are done in two setups: low pressure etching, followed by conventional cutting for the through- and perimeter cuts.
Etching is not a substitute for machining 3D profiles.
These 2" diameter pendants were waterjet cut and etched in 16 gauge stainless steel, then brush finished to smooth the edges and create a uniform appearance.
The cursive writing font is Bob's own creation, since sold to OMAX and included in their waterjet software distribution.
This design was a collaboration with the customer, to adapt their graphic to best fit the medium and their budget for 700 finished pieces.
These dragonfly pendents are cut and etched in 10 gauge stainless, then brushed. Here the etching creates a more 3-dimensional appearance, with finer detail than could be realized with through-cuts.
These are a Burner's lagniappes, again an adaptation/collaboration with the customer.
These are waterjet cut in 14 gauge steel, with deep etches along the bend lines, cut most of the way through the material. A deep etch like this can be cut consistently if the geometry is a straight line or smooth arc, and starts and ends off the part.
This going-away present was waterjet cut and etched in 5/32" copper, then polished, and the kerf-width etch filled with ink. Thick copper sure shines up nice.
For this small plaque, the 1/4" high lettering was cut and etched in 16 gauge stainless steel, then brush finished. This uses Bob's cursive writing font for smooth transitions between letters.
The font is a bit peculiar, but it's expedient, ideal for some applications, and cheaper than CNC engraving in stainless steel.