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How to Make PCB Circuit Traces with a MOPA Fiber Laser
Introduction:
Making custom printed circuit boards (PCBs) at your workbench often comes down to a trade-off between chemical etching mess and long factory turnaround times. Can a MOPA fiber laser step in as the ultimate rapid prototyping solution? In this comprehensive guide, we unpack the exact engineering setup for laser PCB copper ablation. Discover how to configure 30W vs 60W MOPA laser parameters, select the optimal lens field size, achieve precise double-sided registration, and eliminate substrate damage—backed by real-world test data and step-by-step processing parameters.
Figure 1. PCB board shown on Instagram
1. Can a laser engraver really make a PCB？
Yes —— but the process is slightly different from what many people imagine.
It doesn't work by "drawing" the trace with a laser. Instead, the PCB circuit layout is designed first, and the laser then selectively removes the unwanted copper. What remains is the conductive trace.
In simple terms, the workflow looks like this:
Figure 2. Diagram of the laser PCB-making workflow
So the actual routing of the circuit is determined by the PCB design file, not by the laser engraver itself. The laser's critical job is removing the copper that isn't needed.
For typical small-scale work, Altium Designer can handle the basic PCB layout and routing. Note that the raw file produced in AD can't be used directly — it needs to be converted into an SVG/DXF or PLT format supported by your laser software. If you're interested in the details of that conversion step, leave a comment below, and depending on interest we may publish a follow-up technical guide covering it.
2. Why Does PCB Copper Removal Require Relatively High Laser Power?
In theory, a lower-power fiber laser can still interact with copper — but the real issue with PCB copper removal isn't simply "can the laser mark the copper?"
The real question is: can it consistently and continuously remove the copper layer in a reasonable amount of time?
2.1 Copper Properties That Make Processing Difficult
High reflectivity — copper reflects a significant portion of energy at certain laser wavelengths, so it doesn't absorb laser energy easily.
High thermal conductivity — even when laser energy does enter the material, copper rapidly conducts that heat away.
Figure 3. Laser copper-removal principle
This means PCB copper removal requires sufficient energy density and a well-designed scanning strategy to remove copper consistently. Compared to a 60W machine, a 30W laser typically needs:
● More scanning passes
● Longer processing time
● Higher risk of heat buildup
● Lower overall processing efficiency
In some cases, it may not be able to remove the copper effectively at all. For this reason, we recommend a 60W MOPA fiber laser for actual PCB fabrication.
Table 1. 30W vs. 60W MOPA processing comparison
|
Comparison |
30W MOPA |
60W MOPA — Recommended |
|
Copper removal capability |
Possible under limited conditions, but consistency may vary |
Better suited for continuous copper ablation |
|
Measured processing time |
Approx. 2.8 hours |
Approx. 38 minutes |
|
Processing speed |
Baseline |
Approx. 4.4× faster |
|
Required scan passes |
More passes required |
Fewer passes required |
|
Thermal accumulation |
Higher risk due to repeated, prolonged scanning |
Shorter exposure time, but thermal control is still required |
|
Parameter window |
Narrower and more sensitive to settings |
Wider and more flexible |
|
Recommended use |
Testing and small experimental projects |
Practical PCB prototyping and repeated production |
3. Why Is MOPA Better Suited for PCB Processing Than a Standard Fiber Laser?
For PCB processing, the real challenge isn't "can the copper be removed" — it's: removing only the unwanted copper while preserving the designed trace width, spacing, and edge integrity, and minimizing thermal impact on the substrate.
That means PCB copper processing has to account for all of the following at once：
● Trace width
● Trace spacing
● Trace edge quality
● Whether copper in non-trace areas is fully removed
● Whether the retained traces are eroded
● Whether the FR-4 substrate is damaged
● Whether the heat-affected zone is controlled
● Consistency across multiple passes
One thing worth clarifying up front: standard Q-switched fiber lasers are not completely incapable of processing copper. Power, frequency, scan speed, hatch spacing, and number of passes are not parameters exclusive to MOPA lasers — standard Q-switched fiber lasers can typically adjust these basic settings too.
The real difference comes primarily from the laser source's pulse control capability. Traditional Q-switched fiber lasers generally have a fairly limited pulse-width range, while MOPA fiber lasers can adjust pulse width across a much wider range, and can combine pulse width and frequency more flexibly depending on the specific laser source. Published data from JPT and Raycus also show that MOPA products typically offer a wider pulse-width adjustment range, while standard Q-switched products tend to have a more concentrated range — the exact range still depends on the specific laser source model.
Parameters used in PCB processing fall into two categories:
● Pulse Width
● Frequency
● Average Power
● Scan Speed
● Hatch Spacing
● Number of Passes
● Focus / Defocus
MOPA's core advantage is adding pulse width as an important additional adjustment dimension, giving engineers many more parameter combinations to work with. This allows finer control over:
● How long a single pulse acts on the copper layer
● The interval and overlap between pulses
● Cumulative energy received per unit area
● The rate of copper removal
● The heat impact on trace edges
● Consistency across multiple passes
It's worth noting that a shorter pulse width isn't necessarily better, and a longer pulse width doesn't necessarily mean more efficient copper removal. Pulse width, frequency, power, speed, hatch spacing, and number of passes all work together to determine the final result. Research on nanosecond lasers applied to copper also shows that pulse width, repetition rate, energy density, and scanning method all affect the copper surface's removal quality, oxidation level, and microstructure.
Figure 4. Q-switched vs. MOPA process control for PCB ablation
MOPA's edge in PCB processing isn't that it offers features standard fiber lasers completely lack, but rather that it provides a significantly wider processing window.
A processing window refers to the range of parameters that can simultaneously satisfy:
● Copper in non-trace areas is consistently removed
● Copper traces that need to be retained aren't noticeably eroded
● Trace edges remain intact
● Adequate insulation forms between traces
● The FR-4 substrate isn't noticeably damaged
● Results are repeatable across continuous processing
If too little energy is applied to the copper, you may see:
● Residual copper
● Incomplete isolation between traces
● The need for more passes
● Inconsistent removal in localized areas
If too much energy is applied, you may see:
● Eroded trace edges
● Traces becoming narrower than designed
● An expanded heat-affected zone
● Damage to adjacent copper that should be retained
● Damage to the FR-4 substrate surface
● Continued heat buildup across multiple passes
Research on laser PCB processing similarly shows that laser power, repetition rate, scan speed, and multi-pass strategy all affect the heat-affected zone, carbonization, and edge quality.
So the goal of parameter tuning isn't simply to increase power — it's to balance three things:
● Copper removal efficiency
● Trace processing precision
● Thermal protection of the substrate and neighboring traces
Figure 5. Finding the right energy balance for PCB copper removal
In practical testing, we recommend using a small parameter matrix and adjusting incrementally, rather than jumping straight to high power. You can fix the trace file and test area, then adjust in sequence:
● Pulse Width
● Frequency
● Power
● Scan Speed
● Hatch Spacing
● Number of Passes
After each pass, check for:
● Remaining copper in non-trace areas
● Erosion at trace edges
● Whether trace width matches the design
● Whether fine spacing forms adequate isolation
● Discoloration, carbonization, or pitting on the FR-4 surface
● Whether a multimeter continuity test passes
The final result is also influenced by:
● Copper thickness
● PCB surface condition
● Laser spot size
● Lens field specification
● Focus accuracy
● Hatch fill direction
● Scan path
● Scan interval
● Fume and debris extraction conditions
So the reason PCB work suits MOPA better shouldn't be reduced to "MOPA is more powerful" or "standard fiber lasers can't remove copper."
A more accurate way to put it:
MOPA provides a wider and more flexible processing window, making it easier to balance copper removal efficiency, trace precision, and thermal impact.
The real difficulty in laser PCB processing isn't removing all the copper — it's removing only the unneeded copper while protecting the traces and substrate that need to remain.
4. Is a Bigger Working Area Always Better?
Not necessarily. This is a common misconception among first-time galvo fiber laser users.
For the em-smart Basic MOPA series, we currently offer lens fields in several working areas, such as:
110 × 110 mm
150 × 150 mm
175 × 175 mm
Many customers instinctively choose the largest, 175 × 175 mm. But if PCB work is the main use case, there's a trade-off between working area and processing fineness. All else being equal, a larger scan range generally means a larger effective spot size. A larger spot reduces edge control for very fine PCB traces.
So: a larger working area doesn't automatically mean it's better suited for PCB work.
For PCB use, prioritize how large your PCB actually is and how fine your traces need to be. If your PCB is small but requires very fine traces and spacing, a smaller lens field usually has the advantage. If your PCB is larger, you'll need to balance working range against fineness.
Recommended configuration:
Table 2. Field Lens Selection for PCB Work
|
Field lens |
Work area |
Best suited for |
|---|---|---|
|
110 × 110 mm |
Smaller |
Small, high-precision PCBs |
|
150 × 150 mm |
Medium |
Balanced work area and precision |
|
175 × 175 mm |
Larger |
Larger PCB layouts where area is the priority |
5. How Long Does One PCB Take with the em-smart Basic MOPA 60W?
Based on our test data, processing the copper layer of a single-sided PCB with the em-smart Basic MOPA 60W takes roughly 0.5-2 hours.
Note that processing time is affected by many factors, including:
● PCB size
● Copper thickness
● Trace complexity
● Area of copper to be removed
● Laser scan speed
● Hatch spacing
● Number of passes
● Single-sided vs. double-sided
● Whether local areas need reprocessing
In particular: PCB surface area doesn't directly equal processing time. For example, take two identical 100 × 100 mm PCBs: if the first one requires removing most of the copper, the scan volume will be very large; if the second one only needs a small area removed, processing time can be significantly shorter. So compared to the PCB's outer dimensions, the copper removal area is usually a more direct indicator of the actual workload.
5.1 Controlled Real-World Test
Continuing from Section 2, we ran a simple controlled-variable experiment, using different machine models to process two boards, A and B, with identical materials and the same trace layout.
Controlled variables:
● Same trace layout
● Single-sided copper-clad board
● Lens field: 150 × 150
● PCB substrate: FR-4
● Board size: 100 × 100 mm
● Laser software: LightBurn
● Same ambient temperature and humidity
Figure 6. Trace layout preview
Going from a blank board to a usable PCB requires three main steps: engraving/copper removal, drilling, and cutting the board. We tested two em-smart MOPA models: the 30W MOPA took a total of 2.8 hours to complete the same job, while the 60W MOPA took about 38 minutes — roughly 4.4× the throughput (about a 342% increase) and a 77% reduction in processing time.
Detailed engraving parameters below:
5.1.1 MOPA 30W
The 30W MOPA completed the full sequence in about 2.8 hours.
Table 3. 30W MOPA Test Parameters
|
Process |
Time |
Speed |
Frequency |
Power |
Pulse width |
Mode |
|---|---|---|---|---|---|---|
|
Copper stripping |
1.5 h |
500 mm/s |
20 kHz |
100% |
200 ns |
Fill |
|
Drilling |
18 min |
300 mm/s |
48 kHz |
100% |
100 ns |
Fill |
|
PCB cutting |
1 h |
500 mm/s |
20 kHz |
100% |
200 ns |
Fill |
|
Cleanup |
Included in total |
2000 mm/s |
20 kHz |
60% |
200 ns |
Fill |
Figure 7. Copper stripping parameters - 30W MOPA
Figure 8. Drilling parameters - 30W MOPA
Figure 9. PCB cutting parameters - 30W MOPA
Figure 10. Cleanup parameters - 30W MOPA
5.1.2 MOPA 60W
The 60W MOPA completed the same sequence in about 38 minutes. That is approximately 4.4 times the throughput and a 77% reduction in processing time compared with 2.8 hours.
Table 4. 60W MOPA Test Parameters
|
Process |
Time |
Speed |
Frequency |
Power |
Pulse width |
Mode |
|---|---|---|---|---|---|---|
|
Copper stripping |
13 min |
1500 mm/s |
48 kHz |
100% |
200 ns |
Fill |
|
Drilling |
15 min |
500 mm/s |
48 kHz |
100% |
200 ns |
Fill |
|
PCB cutting |
10 min |
1000 mm/s |
48 kHz |
100% |
200 ns |
Fill |
|
Cleanup |
Included in total |
2000 mm/s |
20 kHz |
50% |
200 ns |
Fill |
Figure 11. Copper stripping parameters - 60W MOPA
Figure 12. Drilling parameters - 60W MOPA
Figure 13. PCB cutting parameters - 60W MOPA
Figure 14. Cleanup parameters - 60W MOPA
6. Can Both Single-Sided and Double-Sided PCBs Be Made This Way?
Yes. In our testing, we used the em-smart Basic MOPA 60W to process both types of boards and confirmed: the laser itself can process both sides, but double-sided PCBs introduce one important additional challenge — alignment / registration.
Single-sided PCB: Fix in place → Focus → Process
Double-sided PCB: Process front → Flip the PCB → Reposition → Process back
Figure 15. Single-sided vs. double-sided PCB laser processing
A single-sided PCB only needs one positioning step. A double-sided PCB needs to be flipped and repositioned for the back side. Locating pins, tooling holes, mechanical stops, and fiducial marks all help improve repeat-positioning accuracy.
So the real difficulty with double-sided PCBs isn't "can the laser process the second side" — it's whether accurate positional correspondence can be maintained after flipping.
If the alignment error between the two sides is too large, it can affect:
● Vias
● Through-holes
● Pads
● For double-sided PCBs, we recommend using:
● Positioning fixtures
● Tooling holes
● Mechanical stops
● Fiducial marks
● A consistent flipping method to improve repeat-positioning accuracy.
Figure 16. Double-sided PCB registration: aligned vs. misaligned
Correct alignment keeps traces, pads, vias, and through-holes concentric on both sides. Excessive X-Y offset after flipping can break front-to-back alignment and affect electrical connections.
7. Is This Method Suitable for Making PCBs Every Day?
From an equipment standpoint, the em-smart Basic MOPA 60W fiber laser can support day-to-day PCB processing needs. But it's important to distinguish between PCB prototyping / small-batch production and mass PCB manufacturing — these are two very different production scenarios.
Laser PCB processing is better suited for:
● Electronics Prototyping
● Hardware R&D
● Maker Workshop
● University Lab
● Engineering Studio
● Small-Batch Electronics
● Custom Electronics
● Same-Day PCB Iteration
For example, a hardware engineer might revise a PCB design in the morning and want a physical unit to test that afternoon. The traditional route might look like:
Design → Upload to PCB factory → Wait for production → Shipping → Receive and test
With in-house laser PCB capability, it becomes:
Design → Laser process → Solder → Test the same day
Figure 17. Traditional outsourcing vs. in-house laser workflow
For R&D, small batches, and fast iteration, this speed advantage can matter more than minimizing the per-unit cost of a single PCB.
● Chemical Etching
● CNC
● Imaging
● Plating
● Automated Production Line
But if the goal is producing hundreds or thousands of standard PCBs per day, a professional PCB factory's chemical etching, CNC, imaging, plating, and automated production line remains the more mature solution for mass production.
8. What Should You Watch for When Processing PCBs Continuously?
If the machine is used for PCB processing on a daily basis, there are a few things to keep an eye on beyond just the laser parameters.
8.1 Fume and Particulate Handling
PCB copper processing generates:
● Metal particulate
● Fumes
● Particulates or gases from substrate processing
● We recommend pairing the machine with a fume extractor / local exhaust ventilation system to promptly clear fumes from the work area. This affects not just the working environment but also:
● Laser optics
● The lens field assembly
● The machine's internals
● Long-term processing stability
Material Safety Information
8.2 Confirm the PCB Substrate
● Don't process material of unknown origin. Different PCB substrates can produce different:
● Particulates
● Decomposition byproducts
under laser exposure. Before processing, confirm the copper material, the substrate material, and its material safety information.
Note: All boards tested and shown in this article use FR-4 substrate.
● Flat Fixture
● Vacuum Table
● Clamp
● Positioning Jig
8.3 Keep the PCB Flat
PCB processing is very sensitive to focus. If the board warps:
Board height changes → focus shifts → spot size changes → energy density changes → uneven copper removal
We recommend using a flat fixture, vacuum table, clamp, or positioning jig to keep the PCB stable and flat during processing.
8.4 Control Focus
For fine traces, focus is never a "minor issue." A focus shift directly affects:
● Spot size
● Trace fineness
● Copper removal capability
● Edge quality
Make sure to focus precisely before PCB processing, and avoid significant changes in board height.
● Protective Lens
● F-theta Lens
● Extraction System
8.5 Regularly Check the Lens Field and Protective Lens
Continuous copper processing generates a fair amount of particulate. For long-term use, regularly check the protective lens, F-theta lens, and extraction system for contamination. Contaminated optics can lead to:
● Reduced laser energy
● Degraded spot quality
● Abnormal local energy distribution
which in turn affects PCB processing consistency. em-smart's engineering team recommends checking these once a week.
9. Who Is Laser PCB-Making a Good Fit For?
This approach isn't suited for every PCB production scenario. But it's especially valuable for:
● Hardware engineers who need to quickly make and revise PCB prototypes
● Electronics makers running frequent small-quantity PCB projects
● R&D teams looking to shorten the prototype-to-testing cycle
● University labs needing quick validation for teaching, experiments, or electronic designs
● Custom electronics workshops with low volume but frequently changing PCB designs
● Hardware startups in a fast-iteration phase, who don't want to wait on a PCB factory and shipping for every revision
Figure 18. Key user groups and benefits of laser PCB prototyping
One of the biggest advantages of laser PCB-making isn't necessarily the lowest cost per board — it's faster iteration and greater independence.
10. Real Test Data
The following parameters were used for the copper-clad board shown on em-smart's Instagram. Treat them as starting points: results vary with copper thickness, substrate, lens field, focus, material flatness, and extraction conditions.
Table 5. MOPA 60W Laser Parameters for PCB Fabrication
|
Process |
Power (%) |
Speed (mm/s) |
Pulse width (ns) |
Frequency (kHz) |
Line interval (mm) |
Scan angle (°) |
Passes |
|---|---|---|---|---|---|---|---|
|
Copper stripping |
50 |
1500 |
150 |
48 |
0.05 |
45 |
8 |
|
Cutting |
100 |
1000 |
200 |
48 |
0.03 |
45 |
30 |
|
Drilling |
100 |
1000 |
200 |
48 |
0.03 |
0 |
20 |
|
Cleanup |
30 |
1500 |
150 |
48 |
0.05 |
0 |
2 |
For more test results and technical discussion, join the em-smart Discord community. Related-blog links and the 30W vs. 60W comparison-video URL should be added before publication.
References Mentioned in the Source Draft
● JPT CL2 Air-Cooled Fiber Laser / MOPA laser documentation
● Raycus 30W Q-switched pulsed fiber laser documentation
● Raycus 100W MOPA fiber laser documentation
● Research on nanosecond laser processing of copper (Coatings)
● “Processing of Printed Circuit Boards Using a 532 nm Green Laser” (Opto-Electronics Review)
