Gerber file generation in PCB Design - Cell-by-Cell Formula Trace

Concept Flow

Start -> Filter Layer Data -> Convert Features to Gerber Commands -> Combine Commands -> Output Gerber File

The process begins by selecting PCB layer data, converting each feature (pad, track, opening, text) into Gerber commands, then combining all commands into the final Gerber file.

Formula

GenerateGerber(Layer, Feature, Coordinates)

This function takes PCB layer data and converts each feature into corresponding Gerber file commands step-by-step.

Step-by-Step Trace

Step	Expression	Evaluates To	Explanation
1	Select all rows with Layer = 'Top Copper'	Rows 2 and 3	Filtering data for Top Copper layer features: pad and track.
2	Convert Pad at (10,10) to Gerber pad format	D-code for pad at (10,10)	Pad feature translated into Gerber D-code command.
3	Convert Track (10,10)-(20,10) to Gerber draw command	D-code for track from (10,10) to (20,10)	Track converted into Gerber draw command.
4	Select all rows with Layer = 'Solder Mask'	Row 4	Filtering data for solder mask layer opening.
5	Convert Opening (10,10)-(20,10) to Gerber aperture definition	Aperture command for solder mask opening	Opening defined as aperture in Gerber file.
6	Select all rows with Layer = 'Silkscreen'	Row 5	Filtering data for silkscreen text.
7	Convert Text 'R1 at (15,15)' to Gerber text command	Gerber command to print 'R1' at (15,15)	Text converted into Gerber print command.
8	Combine all Gerber commands into final Gerber file	Complete Gerber file with all layers and features	All commands combined to form final Gerber file.

The final Gerber file contains all layer features converted into manufacturing commands.

Variable Tracker

Variable	Value	Description
Layer	'Top Copper', 'Solder Mask', 'Silkscreen'	PCB layers being processed
Feature	'Pad', 'Track', 'Opening', 'Text'	Types of features on each layer
Coordinates	Coordinates like (10,10), (10,10)-(20,10), 'R1 at (15,15)'	Positions and shapes of features
Gerber Commands	D-codes, aperture definitions, text commands	Output commands generated for manufacturing

Key Moments

Why do we filter data by layer first?

What does converting a pad to a Gerber command involve?

How is text handled differently from pads and tracks?

Sheet Trace Quiz - 3 Questions

Which layer's features are converted first in the Gerber generation?

A Top Copper

B Solder Mask

C Silkscreen

D Bottom Copper

Key Result

Gerber file generation transforms PCB design data layer by layer into machine-readable commands that define pads, tracks, openings, and text for manufacturing.

Transcript

We start by filtering the PCB data by layer, beginning with the Top Copper layer. Each feature like pads and tracks is converted into specific Gerber commands. Next, the solder mask layer's openings are translated into aperture definitions. Then, silkscreen text is converted into print commands. Finally, all commands are combined to create the complete Gerber file used for PCB fabrication.