--- title: "How to Laser Engrave an AR-15 Lower: Setup, Fixtures, and Settings" description: "How to laser engrave an AR-15 lower: fixtures, focus, ATF depth rules, and our Edge 50W presets for anodized marks and deep serial engraving." --- # San Antonio Laser Open main menu Close main menu # How to Laser Engrave an AR-15 Lower: Setup, Fixtures, and Settings [Shane Mohr](https://go.salasers.com/blog/author/shane-mohr) [Share this blog post on Twitter](https://twitter.com/intent/tweet?text=I+found+this+interesting+blog+post&url=https://go.salasers.com/blog/how-to-laser-engrave-an-ar-15-lower-setup-fixtures-and-settings) [Share this blog post on Facebook](http://www.facebook.com/share.php?u=https://go.salasers.com/blog/how-to-laser-engrave-an-ar-15-lower-setup-fixtures-and-settings) [Share this blog post on LinkedIn](http://www.linkedin.com/shareArticle?mini=true&url=https://go.salasers.com/blog/how-to-laser-engrave-an-ar-15-lower-setup-fixtures-and-settings) **Short answer:** To laser engrave an AR-15 lower, lock the receiver in a repeatable fixture, set focus on the flat of the magwell, and run two kinds of jobs: a fast one-pass mark for logos and cosmetic text, and a slower, repeated deep-engrave recipe for anything that must meet ATF's .003" depth rule. A fiber laser is the right tool, because it removes the anodized layer cleanly and can cut into the aluminum underneath. On our Edge 50W with the 220mm lens, the anodized mark preset runs at 60% power and 3,048 mm/s (120 in/s), while the deep "Cut" layer slows to 356 mm/s (14 in/s) at the same power. In our shop, the Edge 50W reaches ATF .003" depth on anodized aluminum in 15 passes. Measure depth on a test spot before you mark a customer's receiver. ## What you are actually doing when you engrave an anodized lower Most forged and billet AR-15 lowers are hard-anodized aluminum. The anodized layer is a thin, hard oxide skin, usually dyed black. A fiber laser does two different things to that part depending on how you run it: - **Surface mark:** A fast pass removes the dyed oxide and exposes the bright aluminum underneath. You get a crisp white-to-silver mark with almost no depth. This is what you want for logos, custom artwork, and cosmetic text. - **Deep engrave:** Slower passes, repeated many times, remove the aluminum itself. This is what you need when the marking is a legal identification mark that has to hit a minimum depth. Mixing those two up is a common mistake. A beautiful surface mark is not a compliant serial number, and a deep engrave run at cut speeds over a large logo wastes time and can leave a rough floor. Decide which job you are doing before you load the file. ## The markings that have to meet a depth rule Under 27 CFR 478.92, licensed manufacturers must mark the frame or receiver with a serial number plus the licensee's name and city and state (or the abbreviated FFL number as a serial prefix), along with model and caliber where required. Engraved markings must be at least .003" deep, measured from the flat surface of the metal, and serial numbers must be at least 1/16" tall. On an AR-15, the lower is the part that carries these marks. Individuals building an NFA firearm on an approved ATF Form 1, such as a short-barreled rifle, have a parallel rule in 27 CFR 479.102: serial number, maker's name, and the city and state where the firearm was made, at the same .003" minimum depth. For the full background, read our [ATF compliance guide for firearm laser engraving](https://go.salasers.com/blog/fiber-laser-engraving-for-firearms-atf-compliance-guide). *This is general information, not legal advice. Confirm your marking obligations with ATF or a firearms attorney.* ## Fixtures: the part that makes it repeatable An AR lower is an awkward shape to hold flat. The side of the magwell is the usual marking area because it is flat and visible, but the receiver wants to rock on its pivot and takedown lugs and on the trigger guard. A good fixture solves three problems: - **It holds the marking face level.** If the magwell flat is tilted, one end of a serial number sits out of focus and engraves shallower than the other. On deep work, that can mean one end of the number passes the depth rule and the other end does not. - **It puts every lower in the same spot.** Use a locating jig or a magwell block that registers off fixed features of the receiver. Then save your job with the artwork positioned to that jig, and you only align once. - **It does not move.** Repeated deep passes take time. Clamp the fixture to the bed so a bump does not shift the part mid-job. A simple jig made from aluminum or acrylic that matches your most common lower, plus a spacer or two for oddball billet receivers, covers most work. Whatever you use, mark a fixture reference line or corner so the next operator loads the part the same way. ## Focus and lens choice Set focus on the surface you are engraving, not on the fixture. Take your focus measurement against the magwell flat itself. For deep engraving, the floor of the engraving moves away from the focal point as material comes out. In our testing, Q-switched sources showed a longer focal range than MOPA sources, which helps keep the beam effective as the engraving gets deeper. If you are deciding between source types, our [MOPA vs Q-switched comparison](https://go.salasers.com/blog/mopa-vs-q-switched-fiber-lasers-for-gun-engraving-which-do-you-need) covers what we found. The presets below were dialed in on the 220mm lens, which gives a good balance of working area and spot size for receiver work. Every Edge ships with multiple lenses (112mm, 220mm, and 300mm field profiles). If you switch lenses, expect to adjust power and speed. ## Our Edge 50W presets for AR-15 lowers These come from the LightBurn settings bundle that ships with every Edge laser. Each preset is a single pass. For depth work, you set the number of repeats per job, and the hatch angle rotates 23.7 degrees on each repeated pass so the fill lines don't stack in the same direction and leave ridges. | Job | Power | Speed | Frequency | Line interval | | --- | --- | --- | --- | --- | | Anodized aluminum mark (flat and rotary) | 60% | 3,048 mm/s (120 in/s) | 25 kHz | 0.051 mm | | Deep engrave "Cut" layer | 60% | 356 mm/s (14 in/s) | Not specified in preset | 0.051 mm | | "Cut / Clean" recipe, clean layer (after Cut layer) | 55% | 2,032 mm/s (80 in/s) | 50 kHz | Not specified in preset | | "Cut / Cut / Clean" recipe, second cut layer | 50% | 711 mm/s (28 in/s) | 28 kHz | Not specified in preset | | Metal "Clean Up" layer | 55% | 3,048 mm/s (120 in/s) | 45 kHz | 0.051 mm | | NFA minimum letter height | 100% | 127 mm/s (5 in/s) | Not specified in preset | 0.051 mm | *Edge 50W, 220mm lens. Starting points; confirm on a test spot.* ## A step-by-step workflow ### 1. Prep the receiver Clean the marking area with a degreaser so oil and fingerprints don't affect the mark. Strip any parts that would keep the receiver from seating in the fixture. ### 2. Lay out the artwork Build legal markings as separate layers from decorative art. Size the serial number at or above 1/16" tall from the start, measured at the base of the characters, and keep enough spacing between characters that deep engraving won't merge them. ### 3. Run the cosmetic mark For logos and custom text on anodized aluminum, use the anodized mark preset. One pass is usually the whole job, since you are only removing the dyed layer. ### 4. Run the deep engrave For serial numbers and required markings, use the "Cut / Clean" recipe, or "Cut / Cut / Clean" when you want a smoother floor. Set the repeat count for the job, let the hatch angle rotate between passes, and finish with the clean layer to clear residue from the engraving. ### 5. Measure, then document Check depth from the flat surface of the metal with a depth gauge or indicator. Don't guess. Once a job passes on your fixture and lens, save it as a template with the repeat count so the next lower runs the same way. For reference, in our shop the Edge 50W reaches ATF .003" depth on anodized aluminum in 15 passes, and our Edge 30W reaches it on a 1/16"-tall serial number in steel in 20 passes, about 2 minutes. Your count can change with lens, focus, and the part, so confirm it on your own setup. Our [guide to fiber laser engraving depth](https://go.salasers.com/blog/how-deep-can-a-fiber-laser-engrave-atf-.003-depth-tested-on-30w-50w-100w) covers the settings that control depth. ## What about Cerakoted and polymer lowers? A Cerakoted aluminum lower is a coating over metal, so a fiber laser will remove the coating and then reach the aluminum. Plan the job around which layer you are marking. Polymer lowers are a different material entirely and need their own settings. Our post on [engraving polymer with a fiber laser](https://go.salasers.com/blog/can-a-fiber-laser-engrave-polymer-pmags-glock-frames-and-grips) includes our Cerakote-removal and polymer presets. ## Frequently Asked Questions ### Can a fiber laser engrave a serial number on an AR-15 lower? Yes. A fiber laser can engrave aluminum deep enough to meet ATF's .003" minimum when you run repeated deep-engrave passes and verify depth. In our shop, the Edge 50W reaches .003" on anodized aluminum in 15 passes. Use a dedicated cut recipe, not a surface mark. ### Why does my anodized mark look white but not deep? Because a fast pass only removes the dyed oxide layer. That is correct for cosmetic work. Our Edge 50W anodized preset runs at 3,048 mm/s (120 in/s) for exactly that reason; depth requires slower, repeated passes. ### What settings should I use for an AR-15 lower on a 50W fiber laser? On our Edge 50W with the 220mm lens, start with 60% power at 3,048 mm/s for cosmetic marks and the 60% / 356 mm/s Cut layer for deep markings. Treat them as starting points and confirm on a test spot. ### Do I need a rotary attachment for AR-15 lowers? Not usually. The magwell side is flat, so a fixture on the bed works. A rotary is for round parts like barrels and suppressor tubes. ### Who is allowed to engrave the required markings on a lower? Marking obligations fall on licensed manufacturers and importers, and on individuals making NFA firearms on an approved Form 1. If you are unsure which rules apply to your shop, check with ATF or a firearms attorney. ## Talk to a Laser Specialist SA Laser is a veteran-owned company in San Antonio, Texas, in business since 2012, working with gun shops, gunsmiths, and FFL dealers. Every Edge Series fiber laser (30W, 50W, or 100W) ships with LightBurn, a LightBurn settings bundle of presets like the ones above, multiple lenses, a full supply kit, and a 2-year warranty. If you want your team confident on receiver work quickly, our 5-day, in-person [Spark training](https://salasers.com/spark/) is hands-on time on the machine. [Request a quote or a call](https://salasers.com/forms/), or call us at [(888) 964-3568](tel:+18889643568). ### Leave a Comment #### About - Menu Item One - Menu Item Two - Menu Item Three #### Services - Menu Item One - Menu Item Two - Menu Item Three #### News - Menu Item One - Menu Item Two - Menu Item Three Follow us on Facebook Follow us on LinkedIn Follow us on Twitter Follow us on Instagram ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "Shane Mohr", "url" : "https://go.salasers.com/blog/author/shane-mohr" }, "dateModified" : "2026-10-08T11:59:50.384Z", "datePublished" : "2026-10-08T11:59:50.000Z", "headline" : "How to Laser Engrave an AR-15 Lower: Setup, Fixtures, and Settings", "mainEntityOfPage" : { "@id" : "https://go.salasers.com/blog/how-to-laser-engrave-an-ar-15-lower-setup-fixtures-and-settings", "@type" : "WebPage" }, "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://go.salasers.com/hubfs/White%20logo.jpg" }, "name" : "SA Laser" } } ```