Understanding the diamond carving process

Rich Smylie, GMN
By Richard Smylie | Aug 30, 2018
Diamond-carved nameplate manufactured at GMN

Diamond carving, also known as diamond drag engraving, is a common metal decoration technique that enhances metal components by adding a unique texture. Performed at the back-end of the manufacturing process, this technique creates extremely fine, sharp, and crisp lines on an embossed aluminum surface, which cannot be achieved through any other decoration process. These deeply carved lines on the metal surface also provide a tactile feel, further augmenting the appearance of the component.

Our latest video features the diamond carving operation from our Monroe, NC Division. Illustrating the process of diamond drag engraving in detail, the video also dives deeper into the various textures, patterns, and looks that you can achieve with this technique.

Decorative enhancements if any, such as screen printing or brush finishing, are always applied on the metal before the carving process. Once the aluminum sheet is decorated, the area to be diamond carved is embossed or raised to a height ranging between 0.015” to 0.018”. The embossed sheet is then cut into strips and held in-position on a flatbed table by vacuum. The strips are lubricated with oil to enable smooth and uniform engraving of the metal without galling. The strips are fed into a machine that consists of a large 12” rotating wheel, also referred to as the platinum. A small industrial-grade diamond chip, approximately 0.125” in diameter, is mounted to the platinum. As the wheel spins, the diamond chip abrades the aluminum surface with every rotation, thereby creating parallel lines at a depth of 0.003”. Diamond, being the hardest mineral, works flawlessly to create the desired pattern. In addition, the height of the wheel from the flatbed table can be adjusted vertically to compensate for metals with varying thicknesses and/or embossing heights.    

The spacing between the lines is determined by the speed of the wheel. The slower the speed, the broader the gap between each line, and the faster the speed, the lesser the gap. The number of lines per inch and the angularity of the lines is often customized according to the design intent. The texture or pattern can vary from extremely fine textures that create a subtle shimmer to coarse lines that add a more jagged look.

While diamond carving has been a popular technique for several decades, GM Nameplate (GMN) brings a creative twist to the process. GMN’s expertise and capabilities allow you to apply a layer of transparent ink of any color to the diamond-carved surface. It not only adds a unique look, but also retains the beauty and texture of diamond carving. The ink is always transparent to enable one to see the scribed lines below. Once the ink is screen printed, the ink is cured by baking the component in strip form.

Seen largely on electronics and handheld appliances, GMN has developed diamond-carved nameplates for numerous companies including Mitsubishi, Philips, Bose, and Lincoln. To see the process of diamond carving, watch our video below.