The terms "engraving" and "marking" have always caused problems in the interpretation of their meaning. Marking is the act of identifying an object superficially without other specification. Engraving is marking engraved cells. A laser allows superficial marking (1 to 20 µm) or engraving up to 600 µm, dependent on the type of laser used.
There are currently numerous marking processes, which differ depending on the material to be marked. Their use is often limited to a particular application.
The following processes are most often used for plastics:
In the mold: The molded parts are marked in relief or in engraved cells.
Screen-printing: use of stencil as for electrochemistry. It is spread over a framework and ink is scraped laterally and is left on the part in the exposed areas.
Pad printing: use of a rubber pad which takes an imprint and ink from apparatus machined with the desired marking or text.
Ink jet: computer controlled projection of ink across nozzles.
Heat transfer: application of a heated metal part to the material. The text must be machined on the apparatus.
Laser beam: computer-controlled laser irradiation.
The development of laser engraving has increased because of rapid changes in new constraints and concepts, such as quality and security. The laser can respond to required changes. It can be integrated into a production line and carry out repetitive operations at high-speed. It can also carry out individual operations as a one-off, thanks to its high level of adaptability.
The permanence of laser marking eliminates downtime due to ink spillage, smearing, rubbing off, scratching or the use of solvents.
Clariant Masterbatches has a specially formulated masterbatch series that optimizes color laser marking of plastics, especially PE and PP polymers, which are traditionally difficult to mark due to their non-porous, low-energy surfaces. Clariant's laser mark masterbatches can be created in numerous custom colors, along with a wide range of contrasting shades for light colored products.
Combining Clariant laser mark masterbatches with the energy of a computerized industrial laser creates indelible color markings -- ranging from logos and text to bar codes -- for a host of applications including packaging, small appliances and electrical/electronic equipment, among others.