A slightly engraved contrasting mark was created
using an FH marking head and 25 watts of power.

Polybutylene Terephthalate (PBT) is one of the most significant thermoplastic polyesters engineered in the past 35 years. PBT exhibits a great surface finish, is dimensional stable, and has excellent electrical insulation characteristics. When reinforcement is required, materials such as fiberglass, mica, stainless steel or carbon fibers, or other non-orienting fillers are added to the formulation. Today, PBT-based products are used in virtually every type of industrial, medical, and consumer application imaginable.

This electrical connector is manufactured from PBT with 30% glass fiber reinforcement. In addition to the engraved mark (typical of CO₂ lasers), the glass fiber adds an easily readable dark contrast to the mark due to the reaction of the glass fiber to the beam. It is interesting to note that when reinforcing filler materials are added to plastic formulations, CO₂ lasers can often create contrasting marks in a less expensive and much safer manner than shorter wavelength YAG lasers.

To achieve the cycle time required for this application, we selected an FH Series marking head with a 125 mm focusing lens (180 micron spot with a 3 mm depth of focus) to steer the beam from our sealed CO₂ laser. We setup the eight-character string in WinMark Pro using one of WinMark’s twelve built-in fast marking Stroke fonts. At a power of 25 watts and a marking velocity of 25 inches per second, we created the mark in a cycle time of only 0.14 seconds per connector.