Marking 2D Codes on Powder-Coated Steel

We have successfully marked powder-coated steel in the past (see Issue 142); however for this customer, the application request involves marking powder-coated steel using two different methods so they can better evaluate cycle times, equipment cost, and permanency of the resulting marks. The application, marking 2D Data Matrix codes on automotive parts for traceability, compared readability and cycle times of low-power (25 W) marks versus higher-power (60 W) marks.

Our marking setup consisted of a Firestar t-Series laser, an FH Flyer marking head equipped with a 125 mm high-power lens, and our WinMark Pro laser marking software. In WinMark Pro, we first created a 13-character 2D ECC200 code consisting of a matrix of 16 x 16 cells with an overall size of 6.35 mm (0.25”) square and then we created a 13-character human-readable stroke text object that measures 2.54 mm (0.10”) high.

For the first trial using 25 watts of power, we set the 2D Barcode Bitmap property to Yes, which creates a filled raster-style mark, entered a Power (duty cycle percentage) equivalent to 25 watts, set a marking Velocity of 889 millimeters per second (35 inches/sec or IPS) for the 2D code, and set a Velocity of 127 mm/sec (5 IPS) for the human-readable text object. This mark, shown in the upper photo, was created in a cycle time of 0.82 seconds. The powder coating was cleanly ablated from the steel part and the mark received an overall grade of “A” using the AIM (Association for Automatic Identification and Mobility) specification. In extreme cases where the powder-coating in or around the mark area is later scratched or abraded, the 2D Data Matrix format contains an error correction algorithm that allows the code to be scanned and properly decoded even if some of the cells are damaged or missing.

This mark was produced using 25 watts of power
in a cycle time of 0.82 seconds. The raster-style
2D code was marked at a speed of 35 inches per second (IPS) while the human-readable text was marked at 5 IPS.







This mark was created by removing the powder coating with 60 watts of power at 25 IPS. Next,
we marked a 2D code on the bare steel surface
using 60 watts at a velocity of 0.25 IPS and
finally we marked the text string with 60 W
at a speed of 2 IPS. Overall cycle time per
piece is 15.8 seconds.

This sheet of 0.5 mm (0.020”) thick alumina
ceramic contains 16 individual parts. The thru
holes and rectangular center in each part are
cut out by pulsing a 100 watt laser for 2 ms at
a frequency of 143 Hertz while moving the beam
at a rate of 6 inches per minute.

Cutting Reinforced Aluminized Paper

Reinforced aluminized paper—a kraft paper product reinforced with glass fiber and bonded to aluminized film—is commonly used as a protective covering for blanket, batt, or rigid insulation in installations requiring a vapor and/or radiant heat barrier.

To cut this material, we set up our XY beam delivery system with a 63.5 mm (2.5”) optic that provides a 100-micron (0.004”) focused spot with a 1.8 mm (0.07”) depth of focus. An air assist consisting of CDA–clean, dry air at 1.4 bar (20 PSI) was delivered coaxially with the beam. At a power level of 60 watts, we achieved cut speeds of 3.05 meters per minute (120 inches/minute). The cut edge is clean and there are no signs of charring or discoloration on the aluminized film or the kraft paper edges.

This sample of aluminized paper, having an overall thickness ranging from 0.088 mm (0.0035") to 0.165 mm (0.0065”) was cut using 60 watts at a speed of 120 inches per minute. Both the kraft paper and aluminized film layers are cleanly cut with no edge charring or discoloration.