Precision on the Mold: High-Contrast Marking on Armoloy XADC Coated Copper
In injection molding and precision tooling, copper molds are highly valued for their exceptional thermal conductivity. To protect these molds from wear and improve part release, engineers often coat them with Armoloy XADC—an ultra-hard, thin-chrome formulation.
However, when it comes to adding permanent traceability marks or logos to these molds, manufacturers face a classic dual dilemma. Copper is highly reflective, while the Armoloy XADC coating is incredibly thin and precise. Standard laser setups are too aggressive; they risk burning completely through the protective coating, exposing the copper substrate to corrosion and ruining the mold's tight tolerances. Conversely, too little energy results in faint, unreadable markings.
At Laser Flow Labs, we recently completed a job requiring high-contrast marking on these exact coated copper molds. Here is how our engineering team tested, refined, and dialed in the process to achieve a perfect mark without compromising the coating.
The Physics of the Challenge
To mark this mixed-material substrate successfully, we had to balance two distinct properties:
Reflective Substrate: Raw copper reflects standard fiber laser wavelengths (1064 nm), meaning the heat can dissipate rapidly through the mold instead of marking.
Delicate Coating: The Armoloy XADC coating must remain fully intact to preserve its wear-resistant properties. Traditional "etching" or engraving that removes material is a non-starter.
Standard Q-switched lasers with fixed pulse durations deliver heat too broadly, causing thermal stress that can delaminate the thin coating from the copper. To solve this, we bypassed general settings and utilized our 50W HO-MOPA fiber laser.
Step-by-Step: Finding the "Sweet Spot"
Our testing and refinement process focused on minimizing the Heat Affected Zone (HAZ) to protect the coating's bond with the copper:
Step 1: Shorter Pulse Durations: We shifted away from standard long pulses and utilized MOPA’s adjustable pulse widths, dialing them down to the 4–10 nanosecond range. Shorter, high-frequency bursts deliver high peak power to the surface instantly, preventing heat from sinking deeply into the highly conductive copper.
Step 2: Micro-Annealing: We tuned the frequency to induce a "cold" surface color change. Instead of vaporizing the Armoloy, the highly controlled energy grew a dense, dark oxide layer directly on the coating's surface.
Step 3: Verification: We verified under magnification that the mark achieved sharp, high-contrast edges without any cracking, micro-pitting, or delamination of the Armoloy XADC.
The Result: Zero-Damage Traceability
The final marks are crisp, dark, and perfectly flush with the surface, ensuring they will not trap material during molding runs or degrade the performance of the tool. By preserving the integrity of the Armoloy coating, the mold remains fully protected against wear and corrosion.
This project highlights why we treat laser marking as an engineering discipline. When a generalist shop says a coated part is "unmarkable" or risks damage, we use advanced pulse tuning to find a precise, repeatable flow.
Do you have a coated tool, insert, or mold that needs permanent marking? Contact our engineering team at info@laserflowlabs.com or call (612) 446-5488 to set up a free feasibility study.
