How to Generate NC Drill Files in EasyEDA: Complete Guide for PCB Engineers

EasyEDA handles drill file generation differently than most traditional PCB design tools. Instead of requiring a separate export step, EasyEDA automatically generates NC drill files as part of its unified Fabrication Output process. This approach simplifies the workflow considerably, but it also means the drill export options are less obvious to users who learned PCB design on other platforms.

After using EasyEDA for numerous projects ranging from simple breakout boards to more complex multilayer designs, I have found that understanding how drill files work within this ecosystem prevents the confusion that sends many users to the forums looking for answers. This guide covers everything you need to know about generating NC drill files in EasyEDA that manufacturers will accept without revision requests.

Understanding NC Drill Files in EasyEDA

EasyEDA exports drill data in standard Excellon format, the industry-standard format accepted by virtually all PCB manufacturers worldwide. The software automatically generates properly formatted files with embedded tool definitions, eliminating the common problem of missing tool tables.

When you generate fabrication output in EasyEDA, the system creates separate drill files for plated and non-plated holes. This automatic separation helps manufacturers process your board correctly since plated holes require electroplating while non-plated holes skip this step.

What EasyEDA Drill Files Contain

Element	Description	Example
Header	Format declarations and metadata	M48, METRIC or INCH
Tool Table	Drill bit size definitions	T1C0.300 (0.3mm drill)
Coordinates	X and Y hole positions	X015000Y010000
Tool Changes	Commands to switch drill bits	T01, T02
End Command	Program termination	M30

EasyEDA generates clean, well-formatted Excellon files that include all necessary information in the header section. Most manufacturer CAM systems parse these files correctly without requiring manual intervention.

EasyEDA Standard vs EasyEDA Pro Drill Capabilities

Feature	EasyEDA Standard	EasyEDA Pro
Through-hole vias	Supported	Supported
Blind/buried vias	Not supported	Supported
Separate PTH/NPTH files	Automatic	Automatic
Drill table placement	Not available	Available
Custom coordinate format	Limited	Full control
Slot holes	Via solid region	Multiple methods

EasyEDA Standard focuses on simpler two-layer and four-layer designs where through-hole vias handle all layer transitions. For complex multilayer boards requiring blind or buried vias, EasyEDA Pro provides the additional capabilities needed.

Generating NC Drill Files in EasyEDA Standard

The drill file generation process in EasyEDA Standard is straightforward because it bundles drill export with the overall Gerber generation workflow.

Step-by-Step Fabrication Output Process

Open your completed PCB design in the EasyEDA PCB Editor. Before generating output, run Design Rules Check (DRC) to verify your design has no errors that could cause manufacturing problems.

Navigate to the top menu and click Fabrication → Fabrication Output or use the Fabrication Output button in the toolbar. EasyEDA opens a dialog showing preview options and export settings.

The Fabrication Output dialog displays a visual preview of your board along with layer selection options. EasyEDA automatically selects all necessary layers for manufacturing, including the drill layers.

Click Generate Gerber to create the complete fabrication package. EasyEDA generates a ZIP archive containing all Gerber files plus the drill files.

Files Generated by EasyEDA

Filename	Purpose	Layer Type
Gerber_TopLayer.GTL	Top copper	Gerber
Gerber_BottomLayer.GBL	Bottom copper	Gerber
Gerber_TopSolderMaskLayer.GTS	Top solder mask	Gerber
Gerber_BottomSolderMaskLayer.GBS	Bottom solder mask	Gerber
Gerber_TopSilkscreenLayer.GTO	Top silkscreen	Gerber
Gerber_BottomSilkscreenLayer.GBO	Bottom silkscreen	Gerber
Gerber_BoardOutlineLayer.GKO	Board outline	Gerber
Drill_PTH_Through.DRL	Plated through holes	Excellon
Drill_NPTH_Through.DRL	Non-plated through holes	Excellon

The drill files appear in the ZIP archive alongside the Gerber layers. EasyEDA automatically names them clearly so manufacturers can identify which file contains which hole types.

Understanding the Automatic PTH and NPTH Separation

EasyEDA automatically separates holes into two categories during export:

Hole Type	Output File	Typical Uses
Plated Through Hole (PTH)	Drill_PTH_Through.DRL	Component pads, vias
Non-Plated Through Hole (NPTH)	Drill_NPTH_Through.DRL	Mounting holes, slots

This separation happens based on the Plated attribute you set for each pad or hole in your design. Pads with Plated set to “Yes” appear in the PTH file. Pads with Plated set to “No” appear in the NPTH file.

The Hole tool in EasyEDA creates non-plated holes by default, which is correct for mounting holes and mechanical features. Vias and component pads are plated by default.

Drill File Format Settings in EasyEDA

EasyEDA uses sensible default format settings that work with most manufacturers. Understanding these settings helps when troubleshooting compatibility issues.

Default Coordinate Format

Unit System	Format	Resolution	Example
Metric (mm)	3:3	0.001mm	X015000Y010000
Imperial (inch)	2:4	0.0001 inch	X1500Y1000
Large boards	4:2	0.01mm	X01500Y01000

EasyEDA automatically selects the appropriate format based on your design units and board size. For most designs under 100mm, the default 3:3 metric format works correctly.

When your PCB size exceeds the range that 3:3 format can represent, EasyEDA automatically switches to 4:2 format. This prevents coordinate overflow issues that could cause holes to appear in wrong locations.

EasyEDA Pro Format Customization

EasyEDA Pro provides additional control over drill file format settings:

Setting	Options	Recommendation
Unit	mm or inch	Match your design units
Integer digits	3, 4, or 5	Default usually works
Decimal digits	3, 4, 5, or 6	Higher = more precision
Zero suppression	Leading or Trailing	Leading is most compatible

In EasyEDA Pro, access these settings through the custom configuration option when exporting Gerber files. You can create multiple configurations for different manufacturers.

Working with Different Hole Types

EasyEDA provides several methods for creating holes in your PCB design. Each method affects how the hole appears in the drill file.

Creating Plated Through Holes

Plated through holes connect copper on multiple layers and include electroplated barrel walls. In EasyEDA, these come from:

Source	Default Plating	Drill File
Via tool	Plated	PTH.DRL
Pad (multi-layer)	Plated	PTH.DRL
Pad (Plated: Yes)	Plated	PTH.DRL

Vias placed using the Via tool are always plated and always appear in the PTH drill file. Component pads set to Multi-Layer are also plated by default.

Creating Non-Plated Through Holes

Non-plated holes have bare substrate walls without copper plating. Use these for mounting hardware and mechanical features:

Method	Result	Drill File
Hole tool	NPTH round hole	NPTH.DRL
Solid Region (Type: NPTH)	NPTH cutout/slot	NPTH.DRL or GKO
Pad (Plated: No)	NPTH hole	NPTH.DRL

The Hole tool on the PCB toolbar creates simple non-plated round holes. For mounting holes, this is the quickest approach.

Creating Slot Holes

Slot holes require special handling in EasyEDA since the standard Hole tool only creates round holes:

Method	Steps	Output Location
Solid Region	Draw region, set Type to NPTH	Board outline (GKO) if >6.5mm
Convert Track	Draw track, right-click “Convert to NPTH”	NPTH.DRL
Slot Pad	Create pad with Hole Shape: Slot	PTH.DRL or NPTH.DRL

For circular slots with diameter 6.5mm or less, EasyEDA includes them in the NPTH drill file. Larger slots and non-circular shapes appear in the board outline file (GKO) instead, and manufacturers route these with a milling operation.

Verifying Drill Files Before Manufacturing

Never submit drill files without verification. EasyEDA provides built-in tools for checking your files, and several external viewers offer additional verification capabilities.

Using the EasyEDA Gerber Viewer

EasyEDA includes an online Gerber viewer that performs basic DFM (Design for Manufacturability) checks:

1. Go to gerber-viewer.easyeda.com
2. Upload your Gerber ZIP file
3. Review the rendered board image
4. Check that drill holes align with pads

The viewer shows top and bottom photo-realistic previews and highlights potential issues like missing layers or alignment problems.

Recommended External Gerber Viewers

Viewer	Platform	Key Features
Gerbv	Windows, Linux, macOS	Free, open source, reliable
FlatCAM	Windows, Linux, macOS	CNC output, measurement tools
CAM350	Windows	Industry standard, DFM checks
ViewMate	Windows	Professional features, free version
GerberLogix	Windows	Quick preview, basic DFM

Load both your Gerber files and drill files together in a viewer. Enable layer transparency and zoom into pad locations to verify drill hits center correctly on copper features.

Common Verification Checks

Check	What to Look For	Problem Indicator
Alignment	Drills centered on pads	Offset holes visible
Hole count	Total matches design	Missing or extra holes
Tool sizes	Correct diameters listed	Wrong sizes in tool table
Scale	Proper 1:1 size	Board appears too large/small
Separation	PTH and NPTH correct	Mounting holes in wrong file

A systematic visual check catches most export errors before they reach manufacturing.

Troubleshooting Common EasyEDA Drill Problems

Experience with EasyEDA has revealed several recurring issues that users encounter during drill file generation.

Problem: Drill Layer Misaligned in Viewer

When drill holes appear offset from copper pads in a Gerber viewer, the issue is usually coordinate format mismatch rather than an actual alignment problem.

Cause	Solution
Viewer format setting wrong	Change viewer digits setting from 3 to 4
Large board auto-format	Viewer may need 4:2 format setting
Mixed unit files	Ensure viewer uses correct units

In Gerbv specifically, right-click the DRL layer, select “Edit File Format”, and change the digits setting. This often resolves apparent misalignment that does not actually exist in the data.

Problem: Empty or Missing Drill Files

If your Gerber ZIP contains no drill files or the files appear empty:

Cause	Solution
No holes in design	Verify pads have hole diameters set
All holes filtered	Check pad Plated settings
Export incomplete	Re-run Fabrication Output

Open your PCB design and check that component pads have proper hole diameter values. Pads with zero hole diameter do not generate drill hits.

Problem: Manufacturer Cannot Read Drill File

If your manufacturer reports format issues:

Issue	Solution
Unsupported extension	Rename .DRL to .TXT or .EXC
Format mismatch	Ask manufacturer for required format
Missing tool table	EasyEDA embeds tools; may need extraction

Most manufacturers accept EasyEDA’s default output. Some local manufacturers may require specific file extensions or separate tool table files.

Problem: Slots Not Appearing in Drill File

Slots created using Solid Region may appear in the board outline file instead of the drill file:

Slot Size	Output Location	Manufacturer Handling
≤6.5mm diameter circular	NPTH.DRL	Drilled normally
>6.5mm or non-circular	GKO (outline)	Routed/milled

This behavior is intentional. Larger cutouts require routing rather than drilling, so EasyEDA places them in the board outline. Most manufacturers handle this correctly, including JLCPCB.

File Organization for Manufacturing

Proper file organization prevents confusion when submitting to manufacturers.

Standard EasyEDA Output Package

File Category	Extensions	Count
Copper layers	.GTL, .GBL, .G1, .G2	2-8
Solder mask	.GTS, .GBS	2
Silkscreen	.GTO, .GBO	2
Board outline	.GKO	1
Drill files	.DRL	2
Paste mask	.GTP, .GBP	2

EasyEDA packages everything into a single ZIP file that you can upload directly to most PCB manufacturers.

Manufacturer-Specific Considerations

Manufacturer	Notes
JLCPCB	Direct integration, accepts EasyEDA output natively
PCBWay	Standard Excellon format works
OSH Park	Accepts .DRL extension
Seeed Fusion	Standard format compatible
iTead Studio	May prefer .TXT extension for drill

JLCPCB has deep integration with EasyEDA since they share the same parent company. You can order boards directly from within EasyEDA without downloading files manually.

Advanced Drill Features in EasyEDA Pro

EasyEDA Pro offers additional capabilities for complex designs requiring advanced drill features.

Placing a Drill Table

EasyEDA Pro can generate a drill table showing all hole sizes with identifying symbols:

1. Go to Top Menu → Place → Drill Table
2. Configure table parameters
3. Click to place the table on your PCB

The drill table automatically counts PTH and NPTH holes by size and assigns symbol identifiers. This documentation helps manufacturers verify drill data.

Custom Export Configurations

EasyEDA Pro supports saving multiple export configurations:

Configuration Option	Purpose
File naming	Custom prefixes/suffixes
Layer selection	Include/exclude specific layers
Precision settings	Adjust integer/decimal digits
Unit selection	Force mm or inch output

You can create configurations for different manufacturers and switch between them quickly. Configurations sync to your account for access across devices.

Handling Blind and Buried Vias

EasyEDA Pro supports blind and buried vias that connect specific layer pairs:

Via Type	Layer Connection	Drill File
Through	All layers (1 to N)	Standard PTH.DRL
Blind top	Layer 1 to inner layer	Separate file per pair
Blind bottom	Inner layer to bottom	Separate file per pair
Buried	Inner to inner only	Separate file per pair

Each layer pair generates its own drill file since manufacturing requires drilling at different stages of the fabrication process.

Useful Resources for EasyEDA Users

Official EasyEDA Resources

Resource	URL
EasyEDA Standard Docs	docs.easyeda.com
EasyEDA Pro Docs	prodocs.easyeda.com
EasyEDA Forum	easyeda.com/forum
Gerber Viewer	gerber-viewer.easyeda.com
JLCPCB Help	jlcpcb.com/help

Gerber Viewer Downloads

Tool	Source
Gerbv	gerbv.github.io
FlatCAM	flatcam.org
ViewMate	pentalogix.com

Component and Footprint Libraries

Library	Description
LCSC	Integrated component database with footprints
EasyEDA Libraries	Built-in extensive library
SnapEDA	Third-party footprints (integrated in EasyEDA)

Frequently Asked Questions

Why does EasyEDA generate two separate drill files?

EasyEDA automatically creates separate files for plated (PTH) and non-plated (NPTH) holes because these require different manufacturing processes. Plated through holes need electroplating to create conductive barrel walls, while non-plated holes are simply drilled without additional processing. Separating these into distinct files helps manufacturers route each hole type to the correct production step. The files are named Drill_PTH_Through.DRL and Drill_NPTH_Through.DRL to clearly identify their contents.

How do I export just the drill file without Gerber files?

EasyEDA does not provide a separate drill-only export function. The Fabrication Output process always generates the complete set of manufacturing files together in a single ZIP archive. This design choice ensures you never accidentally send incomplete manufacturing packages to fabricators. If you need only the drill file, simply extract the .DRL files from the downloaded ZIP archive. The drill files are self-contained Excellon format files that work independently of the Gerber layers.

Why do my drill holes appear offset when I view the Gerber files?

Drill offset in Gerber viewers is almost always a coordinate format mismatch between the viewer settings and the actual file format, not a real alignment problem. EasyEDA uses 3:3 format by default for metric units. If your viewer expects a different format, holes appear scaled or offset incorrectly. In Gerbv, right-click the DRL layer, select “Edit File Format”, and adjust the digits setting (try changing from 3 to 4). The underlying data is correct; only the viewer interpretation needs adjustment.

Can I create slot holes in EasyEDA Standard?

Yes, EasyEDA Standard supports slot holes through several methods. For plated slots, create a pad and set Hole Shape to “Slot” in the properties panel. For non-plated slots, use the Solid Region tool with Type set to “NPTH”, or draw a track and right-click to select “Convert to NPTH”. Note that circular slots 6.5mm or smaller appear in the NPTH drill file, while larger or non-circular slots appear in the board outline file (GKO) and are manufactured by routing rather than drilling.

Does EasyEDA support blind and buried vias?

EasyEDA Standard only supports through vias that span all layers of your PCB. For designs requiring blind vias (connecting outer layer to inner layer) or buried vias (connecting inner layers only), you need EasyEDA Pro. The Pro version handles the additional complexity of generating separate drill files for each layer pair, which manufacturers need since blind and buried vias are drilled at different stages of the multilayer lamination process.

Best Practices for Reliable Drill Export

Following consistent practices ensures manufacturers receive usable files every time.

Before Generating Output

Run DRC to verify all holes have proper clearances. Check that component pads have correct hole diameters assigned. Verify mounting holes are set to non-plated if that is your intent.

During Export

Use the Fabrication Output button rather than individual layer exports. Let EasyEDA generate the complete package automatically. Do not manually edit the resulting files unless you have specific manufacturer requirements.

After Export

Load both Gerber and drill files into a viewer to verify alignment. Check that the hole count matches your expectations. Verify slot holes appear either in the drill file or board outline as expected for their size.

Upload the complete ZIP to your manufacturer without extracting files. Most manufacturers prefer the original archive since it preserves file associations and prevents accidental file substitution.

Generating NC drill files in EasyEDA becomes routine once you understand that the process is integrated into the overall fabrication output workflow. The software produces clean, manufacturer-ready Excellon files that work with virtually any PCB fabrication house worldwide.