A laser marking service is the cheapest traceability you will ever buy, but its position in the finishing sequence decides whether the code survives the product. Mark before anodizing and the mark is sealed under the oxide — maximum abrasion resistance, slightly softened edges, and contrast that depends on how the dye takes up. Mark after anodizing and the laser removes or bleaches the dye layer, giving the sharpest, highest-contrast code at the cost of a surface interruption in the oxide. Serial numbers, QR codes and UDI marks almost always want the second; decorative logos on a wear surface usually want the first.
激光打标是你能买到的最便宜的追溯手段，但它在完成工序中的位置，决定了这个码最终能不能活到产品寿命终点。先打标再阳极氧化，标识被封在氧化膜之下——耐磨性最好，边缘略有扩散，对比度取决于染料吸附情况；先阳极氧化再打标，激光会去除或漂白染料层，得到最锐利、对比度最高的标识，代价是氧化膜表面留下一处间断。序列号、二维码与 UDI 标识几乎都选后者；磨损面上的装饰 LOGO 通常选前者。
The same logic extends to plating and coating. On plated parts, mark after plating wherever the code has to read consistently, because plate thickness varies enough across a rack to change the result of a shallow ablation; where the plate itself has to stay unbroken for corrosion reasons, specify a mask and validate against the salt-spray hours your finish requires. For marking steel parts headed for powder coat there are only two practical routes: mark into the finished coating at low fluence, or mask a pad and mark bare metal. Either way, put the requirement on the drawing rather than leaving it to the shop floor.
电镀与喷涂同理。电镀件上，凡是要求标识码读取稳定的场景都应在电镀之后打标，因为挂具上不同位置的镀层厚度差异足以改变一次浅气化去除的效果；如果出于防腐原因不允许破坏镀层本身，就指定遮蔽，并按你要求的盐雾小时数做验证。需要粉末喷涂的钢件打标，实际只有两条路：低能量密度打进涂层里，或者遮蔽标识区留出裸金属再打标。无论选哪条，都请把要求写进图纸，而不是留给车间自行判断。
What we need to quote it is short and specific: the artwork or the variable-data rule, the mark location shown on the drawing, whether the code is 1D, 2D or human-readable text, and whether it has to verify to a grade. Two-dimensional codes are graded to ISO/IEC 15415 and linear barcodes to ISO/IEC 15416, and the grade you ask for changes both the process and the inspection time — verified grade C or better on every part costs more than simply readable, and both are legitimate choices. Full parameter detail, including how steel, stainless, cast iron and aluminium each behave under the beam, is set out in our laser marking service guide.
报价所需的资料不多但必须具体：图纹或可变数据规则、图纸上标明的标识位置、是一维码、二维码还是人眼可读文字，以及是否需要按等级验证。二维码按 ISO/IEC 15415 评级，一维条码按 ISO/IEC 15416 评级；你要求的等级会同时改变工艺方式与检验工时——每件都验证到 C 级以上，比只要求「可读」要贵，两者都是合理选择。钢材、不锈钢、铸铁与铝在光束下的分材料表现，以及完整参数细节，请看我们的激光打标服务指南。
