Laser marking plastics,
qualified grade by grade.

A polymer marks only if something in it absorbs the laser wavelength. At 1064 nm that is sometimes the resin and more often the pigment, the filler, or an additive. Where energy is absorbed, one of two things happens. On light-colored resins the polymer carbonizes and the mark reads dark gray to black. On dark resins, typically those colored with carbon black, the surface foams: gas bubbles form in a thin melted layer and scatter light, and the mark reads light gray to tan and sits slightly proud of the surface.

Pulse control decides which result appears and how clean its edges are. The JPT M7 MOPA source adjusts pulse width from 2 to 500 ns, which keeps heat input low enough to avoid melted edges on small text and Data Matrix modules. The mark is a change in the material, not a layer on top of it, so there is nothing to rub off or dissolve in cleaning agents. Capabilities lists the equipment.

We run a fiber source only, with no CO2 or UV laser, so materials that need those wavelengths are outside our range. That includes water-clear and transparent grades, which transmit 1064 nm, and natural polyolefins and fluoropolymers without an additive.

A laser-marking additive is a masterbatch or pre-compounded ingredient that absorbs 1064 nm energy and converts it into a local color change. It goes in at the molder, at a low loading, and it is how polypropylene, polyethylene, natural acetal, and TPU parts are made markable. Resin suppliers also offer laser-markable versions of many standard grades.

If you control the resin specification and the part must carry a permanent mark, selecting a laser-markable grade at the design stage is the most reliable route. If the resin is fixed and does not respond, the fallback is a laser-marked acrylate label bonded to the part: see asset tags and, for IUID content under MIL-STD-130, UID labels.

Contrast on plastics runs from strong, as on natural PEEK and white ABS, to marginal. Two parts in the same resin from different molders can mark differently because the colorant package differs. Data Matrix readability is therefore rated per grade, not per polymer family, which is how the material marking guide lists it.

Send a molded coupon or a few scrap parts in the production resin and color. They come back marked, with the recommended process and a read-back result, before you release the drawing. Production codes are then read back 100% and graded per ISO/IEC 15415, or AIM DPM-1-2006 for direct part marks; see quality. On low-contrast grades a larger module size buys reading margin. The mark size calculator and Data Matrix generator help size and mock up the symbol.

Treat the mark as qualified for a specific resin, colorant, and filler. A change of color or resin supplier is a reason to re-check the mark, like any other process change. For device housings and components, medical device marking covers UDI content. Biocompatibility and sterilization validation of the marked part remain with the device manufacturer; we supply marked samples for that work.