Introduction to Laser Marking of Plastics and Resins

# Introduction to Laser Marking of Plastics and Resins

Plastics and resins are ubiquitous in industrial applications — from electronic housings to automotive interiors, from medical devices to everyday packaging. Laser marking has become the preferred solution for plastic identification due to its permanence, non-contact nature, and high speed.

**Marking Characteristics of Common Plastics:**

**ABS (Acrylonitrile Butadiene Styrene)**
Carbonizes and turns black under laser irradiation, offering high contrast and clear marking. Both UV laser and fiber laser can achieve good results.

**PC (Polycarbonate)**
Has good laser absorption and can produce either white or black markings depending on laser parameter settings. UV laser delivers the best results.

**PP (Polypropylene) and PE (Polyethylene)**
These two materials have poor absorption of infrared laser, resulting in unsatisfactory marking effects. UV laser or CO2 laser is more suitable.

**PET (Polyethylene Terephthalate)**
Has extremely high absorption of CO2 laser, producing clear markings. Commonly used for beverage bottles and food packaging.

**Laser Type Selection Recommendations:**
– UV Laser (355nm): Suitable for almost all resins, good color rendering, minimal thermal damage
– CO2 Laser (10.6μm/9.3μm): Suitable for PET, paper, wood, etc., good absorption for some resins
– Fiber Laser (1064nm): Suitable for carbon-containing resins (e.g., ABS, PBT), poor results on transparent resins

**Types of Marking Effects:**
– Black marking: Laser carbonizes or colors the resin
– White marking: Laser creates micro-bubbles on the resin surface, forming white contrast
– Coating removal: Removes surface coating to expose the base material color

**Summary:** There is no “one-size-fits-all” solution for plastic marking. The appropriate laser wavelength must be selected based on the material type. UV laser has the strongest versatility and is the top choice for plastic marking.