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PCB Documentation Mistakes That Cost Time, Yield, and Money

Poor PCB documentation causes delays, misbuilds, and yield loss. Learn the most common documentation mistakes manufacturers see every week and how to avoid them.
January 20, 2026 by
PCB Documentation Mistakes That Cost Time, Yield, and Money
Kari Rantakoski

In PCB manufacturing, documentation is not paperwork—it is the contract between design and production. When that contract is unclear, incomplete, or contradictory, problems are inevitable.

At Comtec Labs, we see the same documentation-related issues every week.
The electrical design may be excellent, simulations perfect, and prototypes functional,
yet production still struggles.

Why?
Because documentation forces manufacturers to guess. And guessing is where yield, schedule, and quality are lost.

Why Documentation Becomes Critical in Production

During prototyping, documentation problems are often hidden. Engineers clarify intent verbally, small deviations are tolerated, and issues are fixed manually. 

In series production, this flexibility disappears.

Production requires:

  • Clear, unambiguous instructions

  • Consistent data across all files

  • Defined acceptance criteria

Without these, every build becomes a risk.

Ambiguous Fabrication Notes

One of the most common mistakes is vague fabrication notes. Phrases like “standard tolerances apply” or “as required” leave too much room for interpretation.

Clear fabrication notes must explicitly define:

  • Materials and stackup

  • Surface finish

  • Controlled tolerances

  • Special processes

If something matters, it must be written down.

Conflicting Drill Tables, Stackups, and Gerbers

Another frequent issue is inconsistency between files. Drill tables that do not match Gerbers, stackup drawings that conflict with fabrication notes, or outdated files mixed with new ones.

These conflicts:

  • Delay CAM processing

  • Increase error risk

  • Force manual intervention

Consistency is one of the strongest yield drivers.

Revision Control Failures

Poor revision control creates chaos. When BOMs, drawings, and manufacturing files
reference different revisions, manufacturers cannot know which version is correct. 

Strong revision discipline is essential, especially during ramp-up and change management.

Documentation as a DFM Tool

Good documentation is not bureaucracy. It is a DFM tool.

Clear documentation:

  • Reduces questions

  • Shortens lead times

  • Improves first-pass yield

  • Enables predictable scaling

It is one of the simplest ways to reduce manufacturing risk.

Ready to Reduce PCB Surprises?

If you’re navigating complex requirements, tight schedules, or production risk, Comtec Labs offers a full suite of services to streamline your workflow:

PCB design service
PCB prototyping service
PCB component sourcing
PCB component assembly
PCB testing service
PCB repair and modifications
Printed circuit board production
PCB mass production

Test Points: Small Detail, Big Impact