PCBWay’s ordering flow includes an engineering review: after you upload a Gerber set, their team checks the files and may come back with questions before production. That review is a real safety net — and a slow way to discover a problem you could have seen yourself in five minutes, days earlier, for free. Every question their engineers raise about your files is a question the files themselves already answer, if you open them in a viewer and look. Gerbv is built for exactly that look: a free, open-source viewer for Gerber RS-274X files, Excellon drill files and CSV pick-and-place data, running entirely offline on your own machine. This guide sets out the pre-check workflow to run before a PCBWay upload, so the engineering review becomes a formality instead of a debugging session. If the viewer is new to you, begin with how to open and view Gerber files; Gerbv is on the download page.
Why an offline check beats relying on the review
Three reasons. Timing: a problem found in your viewer costs a re-export; the same problem found in review costs the exchange of messages across time zones and a production slot that moves while you answer. Knowledge: the reviewer sees files, not intent — they can flag that an outline looks unusual or a drill file seems inconsistent, but only you know the board must measure a specific size, that a cutout is deliberate, or that the silkscreen shows last revision’s labels. Checking with intent in hand is a different, stronger check. Evidence: when your set has been opened, stacked, measured and verified by you, a review query becomes a lookup — you can answer from your own inspection instead of starting one. None of this replaces the board house’s checks; it means you stop outsourcing the ones you can do better and earlier.
The pre-check workflow, step by step
Extract the exact ZIP you intend to upload and open the folder in Gerbv. Count and identify: one file per layer your board needs — copper layers, mask, silkscreen, paste where relevant, outline, drill file — each identifiable by content, per loading and aligning Gerber layers. Outline alone: a single closed shape of the designed size under measurement, with any cutouts and slots present and deliberate. Engineering queries about board shape almost always start here, so make the answer boring. Drill overlay: stack the Excellon file over both copper sides as in viewing drill files — hits centred in pads, tool list matching the design, mounting holes where the enclosure expects them. Layer pairs: mask openings centred on the pads they expose; silkscreen legible, complete and clear of exposed pads; paste openings matching their surface-mount pads. Scale and units: two known dimensions, far apart on the board, both measuring as designed — the standing defence against the exported set being read at the wrong scale.
The details reviewers ask about
A few file details attract a disproportionate share of engineering questions, and all are checkable in advance. Board outline definition: if the edge is drawn on a layer the house does not expect, or shares a file with unrelated mechanical marks, clarify it in the export so the outline layer contains the outline. Slots and cutouts: confirm they appear in the data as you intend — a routed feature that exists only in a drawing note will generate a question, or worse, silence and no slot. Drill sizes at the extremes: the very smallest and largest tools in the drill report are the ones worth a second look against the components and hardware that use them. Text and polarity on the bottom side: view the bottom layers as manufactured, and confirm nothing reads mirrored that should not. File naming: clear layer names reduce mapping questions to zero; if a filename could mean two layers, rename it at export time. Each of these is a two-minute confirmation in Gerbv and a potential day in an email thread.
Upload the checked set, keep the record
When the workflow passes, upload that exact archive — and if a single file changes afterwards, re-export the complete set and re-check it, because a set is only verified as a set. Keep the checked ZIP with the project files as your release record: if questions do arrive, you are answering about files you have personally inspected, measurement by measurement. The full twelve-point gate behind this workflow is the PCB pre-order checklist, which applies unchanged whatever board house you choose; for the companion walkthrough aimed at a different destination’s upload flow, see checking your files before uploading to JLCPCB. Gerbv’s own place in the toolchain is summarised on our Gerber viewer page.
Frequently asked questions
Doesn’t PCBWay check my files anyway?
Yes — their engineering review is a genuine safety net. The point of checking first is timing and knowledge: you find file problems when they cost a re-export rather than a message thread, and you check them against your design intent, which no reviewer can see.
What do engineering reviews most often query?
At the file level, the recurring themes are outline definition, slots and cutouts, drill data consistency, and anything ambiguous about layer identity. Every one of those is visible in Gerbv before upload — the guide above walks through each.
Should I re-check if I change one file after checking?
Yes, as a set: re-export the complete set from the EDA tool, re-extract the new archive, and run the workflow again. A set is only verified as a whole; swapping one file invalidates the registration and completeness checks that were run on the old combination.