Alumina ceramic is a compound formed from metallic (aluminum metal) and non-metallic (oxygen) elements and is the most common of the structural ceramics. Alumina is hard enough to serve as a grinding medium or a bearing; its corrosion-resistance makes alumina ceramic a perfect lining for refractory vessels or for implantation into the human body; and its material characteristics make it a great thermal or electrical insulator.

Machining fired alumina is a difficult, but necessary procedure when manufacturing high-tolerance parts because parts made from green (unfired) alumina can exhibit subtle dimensional variations due to inconsistent shrinkage during the firing process. CO2 lasers provide a distinct advantage when processing fired ceramics because the laser’s localized heating effect limits thermal stressing to a small region surrounding the cut path. In this particular application, we are actually scoring, not cutting, the ceramic. Scoring speeds are faster than cutting speeds, which further reduces heat input into the material, resulting in a fracture-free edge when the finished material is snapped along the score lines.

Generally, alumina is laser-machined on specialized cutting systems that tightly control assist gas pressure and laser pulsing parameters; although in specific cases, a laser/marking head combination can perform almost as well. In this particular application, the process called for a highly flexible system that could perform many tasks, including scoring 96% pure aluminum oxide to specific lengths.

PETG, or glycol-modified polyethylene terephthalate, is a form of polyester (PET) used to create blister packaging, display units, and bottles for soaps and detergents. Many food and pharmaceutical products are packaged in PETG because of its purity.

PETG offers many of the same advantages as polycarbonate, but at a much lower cost. Products manufactured from PETG provide excellent clarity and impact resistance. In addition, PETG products can be die-cut and thermoformed without affecting structural integrity, they print easily when graphics are required, and resist stress whitening when bent.

When considering material specifications for products that will require CO2 laser processing during manufacturing such as cutting, drilling, or degating, PETG provides another distinct advantage over polycarbonate—a cleanly cut edge with no yellowing or discoloration.