Applications Newsletter

October 2002

Issue 49

Laser Marking Labels

Laser-markable label material developed by 3M for Nd:YAG laser applications is easily marked, kiss cut, and perforated using a Synrad 10W CO2 laser and an FH Series marking head.

   3M™  Laser Markable Film Label Material 7874 is an adhesive-backed white label with a black surface coating that is easily ablated by the CO2 laser to provide attractive and easily readable finished labels. The perforations, kiss cuts, and marking were all made using 10W of laser power. Adjusting the scan speed of the marking head determines the process: marking of the label occurs at a scan speed of 25”/second; kiss cutting of the label without damaging the backing material occurs at a scan speed of 9”/sec; and perforation of the label and backing occurs at a speed of 6”/sec.

   With a 200mm focusing lens, six labels within the 3.8” x 4.7” mark field are processed at one time. Because the label stock is on a roll, the label stock is simply indexed forward so that another series of labels can be processed. In this particular example, the entire process (text, 1D, and 2D barcode marking; backing perforation; and label kiss cutting) was performed on six labels in a cycle time of 27 seconds.

Cutting Mild Steel

Edge view of 0.025” mild steel cut using a Firestar f100 laser at a speed of 130ipm with 40psi O2 assist gas.

Top view of 1” disk cut from 0.025” mild steel showing polarization effects. The laser is polarized right to left.

   A Firestar f100 laser with a linearly polarized beam was used to cut these 0.025” mild steel samples.  The cuts were optimized in the direction of polarization at 130ipm using 100W and 40psi O2 assist gas (upper picture).  A positive meniscus focusing lens generating a 0.004” spot was used for beam delivery.  These cutting conditions were then applied to make the circular cut in the bottom picture.  Cuts in the direction of polarization (horizontally) provided clean burr free cuts, cuts away from the polarization direction (vertically) provided cuts with a burr.  Heat affected zones, on right and left sides of the circle, corresponds to the amount of burr adhesion on the back of the cut edge.  Using a quarter-wave plate or phase retardation reflector, the linearly polarized beam can be changed to a circularly polarized beam.  This beam delivery setup allows for even cutting characteristics in all directions.