Today, Xiaobo was asked by the receptionist again: What is the difference between TXT in GERBER files and TXT in documents? After a lot of effort, Xiaobo finally explained it to her.
Everyone knows that Gerber files are one of the indispensable materials for the production and manufacturing of flexible circuit boards, and are also commonly used in circuit board manufacturing files.
Below is a detailed explanation of GERBER for everyone to read slowly:
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Format of Gerber file:

RS-274-X (commonly used)

RS-274-D (commonly used)

RS-274

Fire 9000

Mda 9000

Barco DPF

The standard gerber file format can be divided into two types: RS-274 and RS-274X, which differ in that:

The Gerber file in RS-274 format is a separate file from Aperture.

The RS-274X format aperture is integrated into the gerber file, so there is no need for an aperture file (i.e., containing D-code).

Data format: integer to decimal places

Commonly used: 3:3 (metric, integer to 3 digits, decimal to 3 digits)

2: 4 (Imperial, 2 integers, 4 decimals)

2: 3 (Imperial, 2 decimal places, 3 decimal places)

3: 3 (British system, integer to 3 digits, decimal to 3 digits)

Leading zero, trailing zero, and non leading zero:

Example: 025690 becomes 25690 (Leading) after leading zero

025690 becomes 02569 (Trailing) after zero crossing

025690 becomes: 025690 (None) after being non-conductive to zero

Company:

METRIC（mm）

ENGLISH（inch or mil）

Unit conversion:

1 inch = 1000 mil = 2.54 cm = 25.4 mm

1 mm = 0.03937 inch = 39.37 mil

positive

The GERBER description refers to the circuit layer of a flexible circuit board, and the graphic description mainly includes copper parts. Or GERBER describes it as a solder mask layer, and the graphic description mainly refers to the solder mask part (i.e. the ink covered part).

 

Negative film

The GERBER description refers to the circuit layer of a flexible circuit board, and the graphic depicted is mainly the copper free part. Or GERBER describes it as a solder mask layer, and the graphic description mainly refers to the part without solder mask (i.e. the part without ink cover).

 

Composite sheet

The hierarchy described by GERBER is composed of layers of different polarities. Usually, it is a combination of excavation layer and positive polarity layer. The polarity of the excavation layer is c, mainly used for flexible circuit board circuit protection or additional process data.

Common meanings of GERBER file suffixes

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Top Layer. GTL top-level wiring * GTL

Bottom Layer. GBL bottom layer routing * GBL

Top Overlay. GTO Top Screen Printing * GTO

Bottom Overlay. GBO Bottom Screen Printing * GB0

Top Paste. GTP solder paste layer, solder aid layer, (used for making steel mesh) * GTP

Bottom Paste. GBP Bottom Surface Paste (for making steel mesh) * GBP

Top Solder. GTS Top Solder Mask (also known as Anti Tin Layer, Negative Film) * GTS

Bottom Solder. GBS Bottom Solder Mask (also known as Anti Tin Layer, Negative Film) * GBS

Top Pad Master. GPT Top Main Pad * GPT

Bottom Pad Master. GPB Bottom Main Pad * GPB

MidLayer1. G1 internal routing layer 1

MidLayer2. G2 internal routing layer 2

MidLayer3. G3 internal routing layer 3

MidLayer4. G4 internal routing layer 4

Internal Plane1. GP1 internal plane 1 (negative film)

Internal Plane2. GP2 internal plane 2 (negative film)

Mechanical1. GM1 mechanical layer 1

Mechanical2. GM2 Mechanical Layer 2

Mechanical3. GM3 Mechanical Layer 3

Mechanical4. GM4 Mechanical Layer 4

Keep Out Layer. GKO prohibits wiring layer (can be used for board shape) * GK0

Aperture Data.APR aperture file

Drill Data. DRL Drilling Data

Drill Position.TXT drilling position

Drill Tool Size.DRR Drill Hole Size

Drill Report. LDP Drilling Report

 

More detailed explanations of some layers:

solder maskSolder mask green oil layer refers to the part of the board that needs to be coated with green oil; Because it is a negative output, the actual effect of the part with a solder mask is not green oil, but tin plating, which appears silver white

Paste mask: a layer of solder paste and auxiliary solder layer, which is used during machine mounting and corresponds to the solder pads of all mounting components. It is the same size as the top layer/bottom layer layer and is used for opening the steel mesh and leaking solder.

 

1. The meaning of solder mask layer is to open windows on the green oil of the entire solder mask to allow welding!

2. By default, areas without solder mask must be coated with green oil!

3. Paste mask layer is used for surface mount packaging! SMT packaging uses: top layer layer, top solder layer, top paste layer, and the top layer is the same size as the top paste, while the top solder is one circle larger than them. The DIP package only used the top and multi-layer layers (after some decomposition, I found that the multi-layer layer is actually the top layer, bottom layer, top and bottom layers with overlapping sizes), and the top/bottom layer is one circle larger than the top/bottom layer.

 

The phrase 'The copper layer corresponding to the solder layer needs to have copper before tin plating or gold plating' was said by a person working in a PCB production factory. His meaning is that in order to make the effect of tin plating on the part painted on the solder layer, the corresponding solder layer part must have copper skin (i.e., the area corresponding to the solder layer must have a top layer or bottom layer part)! The solder layer represents the area that does not cover green oil!

The difference between solder mask and paste mask:

Paste mask is commonly known as "steel mesh" or "steel plate" in the industry. This layer does not exist on the printed circuit board, but is a separate steel mesh with hollowed out SMD solder pads on top. The shape of the hollow out is generally the same as that of SMD pads, with slightly smaller dimensions. This steel mesh is used in the SMD automatic assembly welding process to apply solder paste on SMD solder pads.

That is to say, PASTE MASK is only used for SMT machines and does not perform additional processing on PCBs

Firstly, place the ". edge" character in the Drill Drawing layer (with a recommended height and width of 30/5mil). After outputting the Gerber file, you will see detailed information about the properties and quantity of the drill holes.

GDD Drill Drawing, a drilling layer used to display the location information of drilling holes.

GDG Drill Guide, a drilling guide layer used to display drilling settings information.