Learn how to deep engrave brass coins with a MOPA fiber laser. This beginner guide covers depth maps, LightBurn settings, 3D relief engraving, and post processing. 

A brass coin with a raised, sculpted design looks like it came out of a mold. It is actually laser work: a fiber laser cuts different depths into the surface, and once you polish and darken it, the height difference reads as a relief.

This guide uses official settings for the em-smart Dual 2, a 30W MOPA fiber laser paired with a 20W diode. Before we get into the steps, here is a video from TechNapa, a creator who has made several brass pieces on the Dual 2, so you know what you are aiming for:

What Is Brass Relief and Deep Engraving?

Relief engraving works from a grayscale image rather than a fixed shape. Treat the depth map like a height map: black is the deepest point, white is the highest, and the gray tones in between are the transition.

Figure 1: A grayscale depth map rendered as a 3D preview, the same principle used for the brass coin relief in this guide. 

The laser is not physically pushing anything up. It just removes less material from the light areas, so those areas end up standing taller than the parts it cut deeper into. Polish the coin and that height difference is what your eye picks up as a sculpted relief.

Deep engraving pushes the same idea further, aiming for a stronger depth difference instead of a shallow gradient. How far you can actually push it comes down to power, the brass itself, your scan strategy, and pass count together, no single dial controls it. In practice, even a modest depth reads as convincing 3D once the surface is cleaned and the recesses are darkened.

The mechanism behind all of this is LightBurn's 3D Sliced mode, which cuts your grayscale depth map into slices before engraving. The Dual 2 goes up to 256 slices, one for each shade in a standard grayscale image. More slices means smoother transitions in the final relief; fewer means a rougher, more stepped look. Passes are a separate lever: they control how much material actually comes off at each of those depth levels.

MOPA is worth knowing early, if only because it comes up constantly in fiber laser conversations. It is not a requirement for deep or relief engraving, a standard fiber laser can do this too. What MOPA adds is independent control over pulse width, power, and frequency, which gives you more room to fine tune deep engraving, fine marking, and color marking.

What You Need

• A fiber laser, standard or MOPA (this guide uses official settings for the em-smart Dual 2, a MOPA machine, but a standard fiber laser such as the Dual SE can get you relief and deep engraving results too, with its own settings)

• A solid brass blank or coin

• A grayscale depth map

• LightBurn software

• Calipers, to measure your coin accurately

• Isopropyl alcohol, a wire brush or rotary tool, a brass darkening solution, and steel wool for cleanup and finishing

The Workflow at a Glance

1. Choose a solid brass blank

2. Create or download a grayscale depth map

3. Prepare the coin artwork in LightBurn

4. Set up the 3D Sliced image parameters

5. Run a small test before committing to the full job

6. Run the deep engraving pass

7. Run an optional cleanup pass if needed

8. Clean and polish the coin

9. Darken the recessed areas for contrast

Step 1: Choose the Right Brass

Get this part wrong and no amount of tweaking parameters later will save it. Some cheap coin blanks are not solid brass at all, just a base metal with a thin brass colored coating, and that coating engraves and darkens very differently from the real thing. Cheaper batches also tend to vary more from piece to piece in thickness and surface quality.

Since deep engraving eats into a lot of material, buy stock a bit thicker than you think you need so it does not warp or burn through. Dedicated metal suppliers, local metal or hardware shops, and bulk manufacturing platforms are all reasonable places to source solid brass blanks.

Step 2: Create or Download a Depth Map

A normal photo will not work here, you need a grayscale image where brightness controls depth. As a beginner, two options get you there quickly. Laserpix has a brass coin category with ready made depth maps, some free and some paid. Or convert your own image using a site like imagemap, which generates a depth map automatically and gives you a limited number of free credits to start.

What separates a good depth map from a bad one: clear separation between subject and background, smooth grayscale transitions rather than harsh blocky edges, and enough contrast to actually show depth. Skip the detailed portrait for your first attempt. Most of what goes wrong on a first try traces back to the depth map, not the laser settings.

If you already have a 3D model, some CAD or 3D software can render it and export the result as a grayscale image, which works the same way as any other depth map. In the example above, a Jesus head STL model is rendered and exported as a PNG depth map ready to bring into LightBurn. 

Figure 2: A 3D model (STL) rendered and exported as a grayscale depth map (PNG), an alternative to generating one from a flat photo. 

Once your depth map is ready, the next stop is LightBurn's Cut Settings Editor, where Image Mode gets set to 3D Sliced. This is the setting that tells the software to read your grayscale image as depth information rather than a flat picture.

Figure 3: Selecting 3D Sliced under Image Mode in LightBurn's Cut Settings Editor. 

Step 3: Prepare the Coin in LightBurn

1. Import your depth map into LightBurn and move it onto the second layer. Keeping the coin outline on its own layer means you can use it for positioning without accidentally engraving the outline itself.

Figure 4: Import the depth map into LightBurn

2. Measure your coin with calipers to get an accurate diameter, commonly 40 mm, and set your imported image to match in width and height.

3. Draw a new circle at the same diameter as your coin. This is a positioning and masking tool, it will not be engraved. Hold shift while drawing to keep it round, and give it a different color from the image so you can tell them apart.

Figure 5: Draw a new circle at the same diameter as your coin

4. Select the image and the circle outline together, right click, and choose Apply Mask to Image. This crops the square depth map into a clean circle. Confirm the crop preview once it looks right.

Figure 6: Apply Mask to Image

5. Turn off the layer the circle outline sits on, so only the newly cropped circular image remains visible.

Figure 7: Turn off the layer the circle outline sits on

6. Double click the image on the right hand layer panel to open its settings, then apply the parameters from the table below.

Figure 8: Double-clicking the image layer in LightBurn to open its Cut Settings and apply the parameters from the table below. 

7. Before engraving, hide the image layer and turn the outline layer back on, click Preview, and check your physical coin's position under the laser. Once it lines up, flip it back, image layer on, outline layer off, and you are ready to start.

Figure 9: Frame to Preview

One note on cleanup: em-smart's official guidance for relief work generally leaves the cleanup pass off, since the 3D Sliced parameters below are already tuned for a clean result on their own. If your material still shows residue afterward, set up a separate cleanup layer with a lighter, faster pass and test it on scrap first.

Step 4: Set Up the Deep Engraving Parameters

These are the official Dual 2 settings for this process, not universal settings for every fiber laser or brass blank. If you are on a standard fiber laser such as the Dual SE, these exact values will not transfer since MOPA pulse width is not adjustable on that machine, though the same logic (3D Sliced mode, bidirectional scanning, scan angle rotation) still applies with settings suited to your machine.

 

Step 5: Run a Test Before the Full Engraving

Do not jump straight to 1000 passes. That run takes hours, and if your depth map or focus is off, you will not find out until it is done. Run a smaller test first, on scrap if you have it, using a reduced pass count just to check depth, focus, and how the material responds. This is our suggested workflow rather than an official parameter, but it saves real time. Compare what comes out against "What Should Your First Test Look Like?" below before committing to the full job.

Step 6: Run the Deep Engraving Pass

Once your test looks right, run the full engraving with the parameters above. Depending on design size and pass count, this can take a couple of hours or more. Let it run.

Figure 10: The finished, polished, and darkened relief. 

Step 7: Run an Optional Cleanup Pass if Needed

Check the surface once the main engraving finishes. The official settings above are tuned to leave a clean result without an extra pass, so treat this as optional. If residue is still visible on your material, switch off the image layer, turn on a cleanup layer with a lighter, faster pass, and run it without moving the coin.

Step 8: Polish and Darken the Brass

This is the step that actually makes a relief look finished rather than just engraved.

1. Clean the coin with isopropyl alcohol to remove residue.

2. Polish lightly with a wire brush or a rotary tool fitted with a soft wheel.

3. Apply a brass darkening solution, often labeled as brass black, with a cotton swab. Let it react for a few seconds, then rinse.

4. Rub the surface down with steel wool once dry.

Darkening is where the depth actually becomes visible. The recesses hold onto more of the dark finish, and polishing lifts it back off the raised areas. That contrast, dark in the low spots and bright on the high ones, is the relief.

Safety note: deep engraving removes a lot of metal, so make sure your ventilation and fume extraction can keep up. Follow your laser manufacturer's safety instructions, wear gloves with the darkening solution, and skip unknown alloys or coated materials.

What Should Your First Test Look Like?

Skip chasing a specific depth number. Instead, check your test piece for:

• Are the darkest areas visibly deeper than the lightest ones?

• Do the grayscale transitions look smooth, without harsh steps?

• Is the edge of the design clean, without stray burn marks?

• Any visible scan lines across the surface?

• Any excessive discoloration or scorching?

• Can you still make out fine details after polishing?

If most of that checks out, go ahead and run the full job.

How to Fix Common Deep Engraving Problems

• Relief looks inverted, raised where it should be recessed. Turn on Negative Image and run again.

• Relief looks flat even with 3D Sliced enabled. The depth map is probably the issue. A narrow grayscale range gives the laser less depth information to work with, so try a map with clearer contrast between high and low areas.

• Visible horizontal or vertical stripes. Check bidirectional scanning is on, scan angle is 45 degrees, and angle increment is enabled.

• Engraving looks too shallow. Add more passes, or slow down your scanning speed.

• Burning, scorching, or heat warping. Reduce pulse width and max power together, then increase speed.

Frequently Asked Questions

How do you make a 3D relief engraving on brass?

Start with a grayscale depth map instead of a normal photo, then engrave it in 3D Sliced mode in software like LightBurn. The laser takes more material off the dark areas and less off the light ones, building a graduated surface as it goes. Polishing and darkening afterward is what actually brings the contrast, and the relief, into view.

What is the best depth map for brass relief engraving?

Clear separation between subject and background, smooth grayscale transitions, and enough contrast to create real depth differences once engraved. For a first project, go simple rather than a highly detailed image.

Can you deep engrave brass with a fiber laser?

Yes. It removes small amounts of material over many passes rather than in one shot. A MOPA fiber laser adds extra control over pulse characteristics, which helps when you are tuning for depth, contrast, or finish.

What laser is best for deep engraving brass?

Standard and MOPA fiber lasers can both do it. MOPA, like the one in the em-smart Dual 2, adds independent pulse width control for more fine tuning room, but it is not a hard requirement for the technique itself.

How deep can a fiber laser engrave brass?

There is no single number, it depends on power, pass count, scan strategy, and the brass itself. Depth builds up gradually over many passes, which is exactly why testing on scrap first matters.

Can a 30W MOPA laser engrave brass?

Yes, 30W is a common power level for brass relief and deep engraving work like the coin in this guide.

What does MOPA mean on a fiber laser?

Master oscillator power amplifier, a design that lets pulse width be tuned separately from power and frequency. For more on what that unlocks, see our guide: What Can a MOPA Laser Do?

MOPA laser vs fiber laser: what is the difference?

Every MOPA laser is technically a fiber laser. A standard fiber laser has a fixed pulse width, no way around it. MOPA gives you control over that pulse width too, which is what makes things like color marking on stainless steel possible. For brass relief specifically, both types get the job done, MOPA just gives you more room to fine tune it.

Try Brass Relief Engraving Yourself

Solid brass, a decent depth map, the settings above, and a few hours of patience, that is really all this takes. No prior fiber laser experience required.

The em-smart Dual 2 pairs a 30W MOPA fiber laser with a 20W diode in one machine, which is what made this whole workflow, and the settings above, possible in the first place. See the em-smart Dual 2 and start planning your first brass coin.