Bare Board Fabrication · Process · Files · Quality
PCB Fabrication Guide: From Gerber Files to Finished Bare Boards
PCB fabrication turns your design files into a tested, unpopulated circuit board — laminate preparation, drilling, copper patterning and plating, solder mask, surface finish and electrical verification. This guide explains each step, what your fabricator needs from you, and how boards are checked before they ship.
- Complete Process Reference Six fabrication stages explained with engineering notes
- ISO 9001 · IATF 16949 · UL Certified quality system for bare board manufacturing
- Prototype to Production Quick-turn samples through repeat volume builds
Quick Answer · Scope · Capability Reference
What PCB Fabrication Covers — and Where It Stops
Fabrication and assembly are two different contracts. This page covers the bare board only: the verified, unpopulated PCB that components will later be soldered onto.
PCB fabrication is the process of manufacturing a bare printed circuit board from design files — preparing and cutting laminate, drilling holes, forming and plating copper circuits, applying solder mask and surface finish, then verifying the board with electrical and visual inspection. No components are mounted during fabrication.
Included in Fabrication
- Engineering review of Gerber and drill files (CAM / DFM check)
- Laminate preparation, imaging, etching and copper plating
- Mechanical and laser drilling, including PTH and via formation
- Solder mask, silkscreen legend and surface finish
- Routing, scoring and depanelization of the bare board
- Electrical testing, AOI and final quality inspection
Not Part of Fabrication
- Component sourcing and procurement
- SMT stencil printing and component placement
- Reflow, wave or selective soldering
- Post-assembly inspection (AOI / X-ray of solder joints)
- Box build, programming and functional test
Need the board assembled as well? Turnkey PCB assembly is handled by our assembly partner JHYPCB. You receive fabricated bare boards from PCBELEC, and assembly is coordinated as a separate scope.
Fabrication Capability Quick Reference
| Item | Reference Range | Notes |
|---|---|---|
| Layer count | 1–64 layers | Higher counts and HDI builds reviewed per design |
| Base materials | FR-4 (standard & high-Tg), metal-core, polyimide flex, high-frequency laminates | Rogers, aluminum and copper-base options by construction |
| Board thickness | 0.1–8.0 mm | Construction-dependent; see our thickness reference |
| Copper weight | 0.5–10 oz | Heavy copper builds quoted per stackup |
| Min trace / space | 2.5 / 2.5 mil | Standard builds; tighter geometries on review |
| Min mechanical hole | 0.15 mm | Laser microvias available for HDI stackups |
| Surface finishes | HASL, lead-free HASL, ENIG, OSP, immersion tin, immersion silver, hard gold | Selected by assembly process and shelf-life requirements |
| Verification | 100% electrical test + AOI | IPC-A-600 Class 2 / Class 3 acceptance on request |
Values above are reference ranges, not a commitment for every construction. Your quotation confirms the achievable limits for your specific stackup, material and quantity.
The Process · Six Stages
How a Bare Board Is Fabricated, Step by Step
Every board follows the same six-stage path, whether it is a 2-layer prototype or a 16-layer production build. Each stage below links to a detailed process article from our engineering blog.
Stage 01 · CAM
Engineering Review & Material Preparation
Your Gerber and drill files are checked for manufacturability, the panel layout is planned, and laminate is cut to size. Most fabrication delays start here — with incomplete or contradictory files.
MI, Cutting & Drilling PreparationStage 02 · Drilling
Mechanical & Laser Drilling
Through-holes, vias and tooling holes are drilled to the sizes defined in your drill files. Hole quality sets the ceiling for plating reliability and annular-ring integrity.
The PCB Drilling Process ExplainedStage 03 · Plating
Copper Plating & Through-Hole Metallization
Hole walls are metallized and copper is electroplated to build conductor thickness. This stage decides whether your vias survive thermal cycling in assembly and in the field.
Copper Plating & RoutingStage 04 · Imaging
Pattern Transfer, Etching & AOI
The circuit pattern is imaged, unwanted copper is etched away, and automated optical inspection compares every trace against your design data before the layers are laminated.
Pattern Plating & AOIStage 05 · Finishing
Solder Mask, Silkscreen & Surface Finish
Solder mask protects the circuits and defines solderable areas, the legend is printed, and the surface finish — HASL, ENIG, OSP and more — is applied to exposed copper.
Solder Mask, Silkscreen & FinishStage 06 · Verification
Routing, Electrical Test & Final QC
Boards are routed or scored from the panel, then every net is electrically tested for opens and shorts before final visual inspection, packaging and shipping.
Testing, QC & ShippingWant the complete walkthrough?
Follow a 4-layer board through the entire line, from inner-layer imaging to final testing: 4-Layer PCB Manufacturing Process — Step-by-Step Guide.
Before You Send Files · DFM Checklist
Is Your Design Ready for Fabrication?
Run these eight checks before submitting your files. They cover the issues our CAM engineers flag most often — each one is cheaper to fix in design than after tooling.
| Check | Why It Matters | Reference |
|---|---|---|
| Trace width / spacing | Below the process minimum, etch compensation eats your conductor and yield drops. | ≥ 3/3 mil for standard builds; scale up with copper weight |
| Annular ring | Insufficient ring plus drill wander causes breakout and open vias. | ≥ 0.05 mm outer layers after drilling |
| Hole-to-copper clearance | Too-tight clearance risks shorts after plating tolerances are applied. | ≥ 0.20 mm recommended |
| Aspect ratio | Deep, narrow holes plate unevenly and fail in thermal cycling. | ≤ 8:1 for standard PTH |
| Stackup & material callouts | Without layer order, dielectric and copper weights in the fab notes, CAM must guess — and guessing delays your build. | State stackup, thickness and material in fab notes |
| Impedance requirements | Impedance needs target value, tolerance and reference layer to be controlled and verified. | Specify per net class, e.g. 50 Ω ±10% |
| Surface finish selection | Finish drives shelf life, flatness for fine-pitch assembly, and cost. | Match to assembly process, not price alone |
| Panelization & depaneling | V-cut, tab-routing and breakaway rails affect edge clearance and assembly handling. | Define rails, tabs and scoring in drawings |
Reference values reflect standard-build capability. Construction-specific limits are confirmed during engineering review.
Not sure whether a feature is manufacturable? Send the files — our engineers review every design before quoting and flag issues with specific layer and location references.
Request a Free DFM ReviewFabrication Library · From Our Engineering Blog
Go Deeper on Every Fabrication Topic
These articles expand each stage of this guide — process details, materials and design files, finishes and verification. Part of the PCBELEC fabrication knowledge base.
Avoid These · Three Common Mistakes
Where Fabrication Projects Usually Go Wrong
These three issues cause most of the delays and re-spins we see in incoming orders. All three are free to fix before you submit your files.
Mistake 01
Treating “Standard” as Universal
A nominal 1.6 mm thickness or a “standard” 4-layer stackup is a convention, not a capability guarantee. Materials, dielectric thicknesses and achievable tolerances differ between fabricators and between constructions.
Instead: confirm the specific stackup and tolerances against your fabricator’s capability table before freezing the design.
Mistake 02
Sending Gerbers Without Fabrication Notes
Gerber files describe copper geometry — they do not state board thickness, material grade, copper weight, surface finish or acceptance class. Missing notes mean engineering questions, and questions mean days lost before tooling starts.
Instead: attach a fabrication drawing with stackup, thickness, finish, tolerances and any impedance requirements.
Mistake 03
Choosing a Surface Finish on Price Alone
HASL is the lowest-cost finish, but its uneven surface can defeat fine-pitch assembly, and some finishes tolerate longer storage than others. The cheapest finish is expensive if it causes solder defects or expired boards.
Instead: match the finish to the assembly process, component pitch and expected shelf life — see our surface finish selection guide.
FAQ · PCB Fabrication Questions
Frequently Asked Questions About PCB Fabrication
Short answers to the questions buyers and engineers ask before sending files. For anything project-specific, use the inquiry form below.
What is PCB fabrication?
PCB fabrication is the manufacturing of a bare printed circuit board from design files. It covers laminate preparation, drilling, copper patterning and plating, solder mask, silkscreen, surface finish, and electrical testing. The output is a verified board with no components mounted — component assembly is a separate process.
What is the difference between PCB fabrication and PCB assembly?
Fabrication produces the bare board; assembly (PCBA) solders components onto it. PCBELEC fabricates bare boards. If you also need assembly, our partner JHYPCB handles component sourcing and turnkey assembly as a coordinated scope.
What files do I need to submit for fabrication?
Gerber files in RS-274X format for every copper, mask and silkscreen layer, plus NC drill files and a fabrication drawing with stackup, board thickness, copper weight, surface finish and tolerances. See our manufacturing file requirements for the complete checklist.
How long does PCB fabrication take?
Lead time depends on layer count, materials, surface finish and quantity. Standard prototypes are typically measured in days, and production builds in one to several weeks. Quick-turn service is available for urgent schedules — confirm the achievable lead time with your quotation.
What factors affect PCB fabrication cost?
The main cost drivers are layer count, board area and panel utilization, material grade, copper weight, minimum feature sizes, surface finish, quantity and lead time. Tighter tolerances and special processes (controlled impedance, heavy copper, HDI) add engineering and process cost.
How are bare boards tested before shipping?
Boards go through automated optical inspection (AOI) during production and 100% electrical testing for opens and shorts before packing. Acceptance follows IPC-A-600, with Class 2 or Class 3 criteria as specified in your order. See our testing and inspection page for methods and coverage.
Fabrication Inquiry · Free Engineering Review
Discuss Your PCB Fabrication Project
Send your files for a free DFM review and quotation. Every design is checked by our CAM engineers before pricing — issues are flagged with specific layer and location references, not generic warnings.
What to Include With Your Files
- Gerber files (RS-274X) for all copper, solder mask and silkscreen layers
- NC drill files with plated / non-plated holes separated
- Fabrication drawing: stackup, thickness, copper weight, finish, tolerances
- Impedance requirements, if any, with target values and reference layers
- Quantity per build and your target delivery date
Not sure your files are complete? Check the manufacturing file requirements first.
Need Assembly as Well?
PCBELEC fabricates the bare boards. Turnkey assembly — component sourcing, SMT and through-hole — is handled by our partner JHYPCB. Mention it in your inquiry and we will coordinate both scopes.
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