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Because the format that use via pcb production machine is gerber format so pls send us gerber or send DXP Protel camtastic to us we will provide you gerber file pls do not save as your files just gerber would be correct save of your pcb files

Gerber format

The Gerber format is a file format used by printed circuit board (PCB) industry software to describe the images of a printed circuit board (copper layers, solder mask, legend, drill holes, etc.). The Gerber format is the de-facto industry standard for printed circuit board image transfer.[1][2][3]

The Gerber format specification can be freely downloaded.[4]

There are two versions. RS-274X ("extended Gerber") is the most commonly used today. The previous version was a subset of EIA RS-274-D ("standard Gerber"); it is deprecated and is largely superseded by RS-274X.

The Gerber format was developed by Gerber Systems Corp., a company founded by Heinz Joseph "Joe" Gerber.[5] The format is now controlled and owned by Ucamco through its acquisition of Barco ETS, a company that previously acquired Gerber Systems Corp.[6][7]

Contents

Introduction

Inside many electronic devices is a PCB onto which components are connected. These PCBs may be designed using a computer aided design (CAD) system.[8] One way to physically realize a design is to transfer the computerized design information to a photolithographic computer aided manufacturing (CAM) system.[9] Gerber is a widely used file format for performing this transfer.[10] Once the bare board is fabricated the Gerber file plays no role in the final assembly of components onto the board.

RS-274X extended Gerber

The RS-274X Gerber format, also known as extended Gerber or X-Gerber, is a 2D bi-level vector image description format.[4] It is a superset of RS-274-D standard Gerber, which is itself a subset of the EIA RS-274-D format for numerically controlled machines.

It is a human readable ASCII format.[11] It consists of a sequence of commands and coordinates. Its imaging primitives are line draw, flash (display) predefined shapes at a given location and outline fill. Positive and negative graphics objects can be combined.

An example of a RS-274X file:

G04 Film Name:   paste_top*

G04 Origin Date: Thu Sep 20 15:54:22 2007*

G04 Layer: PIN/PASTEMASK_TOP*

%FSLAX55Y55*MOIN*%

%IR0*IPPOS*OFA0.00000B0.00000*MIA0B0*SFA1.00000B1.00000*%

%ADD28R,.11X.043*%

%ADD39O,.07X.022*%

...

%AMMACRO19*

21,1,.0512,.0512,0.0,0.0,45.*%

%ADD19MACRO19*%

%LPD*%

G75*

G54D10*

X176250Y117500D03*

Y130000D03*

Y163750D03*

...

G54D39*

X496250Y142500D03*

Y137500D03*

Y132500D03*

Y127500D03*

M02*

An RS-274X file contains the complete description of a PCB layer image without requiring any external files. It has all the imaging operators needed for a PCB image. Any aperture shape can be defined. Positive and negative objects can be combined. Planes can be specified without the need to "paint" or "vector-fill" as in RS-274-D.

RS-274X is a complete, powerful and unambiguous standard to describe a PCB layer. It can be input and processed fully automatically. This makes it well suited for fast and secure data transfer and for reliable and automated workflows.

The format specification is published.[4] A tutorial is available.[12]

Usage

Gerber files are typically produced by PCB designers using specialized Electronic Design Automation (EDA) or PCB CAD software. These files are sent to PCB fabricators where they are loaded into a CAM system to prepare data for each step of the PCB production process. In this workflow they transfer the layer information from CAD to CAM. They are also used to specify drilled hole information, which can be viewed as image layers; however, the Excellon Format is used more often to transfer drilling information.[13] Gerber files are also used to drive quality control machines, such as automated optical inspection.

A quality RS-274X file is very convenient to work with.[14] Sometimes the numerical precision is too low, causing significant rounding errors on tight-tolerance PCBs. The Gerber output resolution (grid) should always be at least a factor of 10 better than the resolution (grid) of the CAD system.[citation needed] Some systems still use "painting" to define copper areas instead of using outline fill, or use painted SMD pads instead of the flexible aperture definitions. Painting does not make a file invalid, but it makes it very difficult, time-consuming and error-prone for manufacturers to process. Painting should not be used.[15] Note that these issues are not due to the RS-274X format itself but due to poor implementations. Many outstanding implementations exist, producing top quality RS-274X files.

The RS-274X format does not specify which PCB layer the file represents. Extensions have been proposed to specify this.[14] In any case, it is sufficient to specify the function in the file name and to specify the format in the extension - e.g. ".GER" for Gerber. Some designers, however, use cryptic file names and document them in a free-format text file. This means that the manufacturer has to browse all the files in the dataset to find the necessary production information. In other cases the function is indicated by misusing the file extension - e.g. .BOT for Bottom Layer.[14] In this case the manufacturer has to open the file to find out the format. Contrast this with the rest of the world; nobody has to open a PDF file to know it is a PDF file.

Supplementary data

An RS-274X file specifies a single conductor or mask layer image. The drill data is usually specified in Excellon format. The netlist, if present, is usually specified in IPC-D-356.[16] Layer names, material stack up are typically provided in informal text files or drawings.[citation needed] However, Ucamco itself recommends[14] the use of a subset of IPC-2581 for these. Typically, all these files are "zipped" into a single archive.

RS-274-D standard Gerber

Standard Gerber, is largely superseded by extended Gerber. It was created from a subset of the Electronic Industries Association RS-274-D specification,[17] a format to drive mechanical NC machines in a wide range of industries. Be aware that the term RS-274-D is often used incorrectly (with the qualifying "Gerber" postfix omitted) to refer to the standard Gerber subset, rather than the original RS-274-D superset itself. Standard Gerber is used to drive vector photoplotters, which indeed were 2D NC machines. It is a simple ASCII format consisting of commands and X, Y coordinates.[18] An example of a Gerber RS-274-D file:

D11*

X1785250Y2173980D02*

X1796650Y2177730D01*

X1785250Y2181480D01*

X1796650Y2184580D02*

D12*

X3421095Y1407208D02*

X3422388Y1406150D01*

M02*

RS-274-D was designed in the 1960s and 1970s to drive numerical controlled machines such as vector photoplotters, machines now all replaced by raster-photoplotters. An RS-274-D file on its own is not an image description because it does not contain all information: the coordinate unit and the definitions of the apertures are not defined in the RS-274-D file. (Apertures are the basic shapes, similar to fonts in a PDF file.) The coordinate units and apertures were supposed to be set manually by the plotter operator. They were typically described in a free-format text file, called an aperture file or a wheel file (because the apertures were mounted on a wheel and rotated into the light beam), intended for human reading. There are no standards for wheel files in RS-274-D, so the designer and the plotter operator had to agree on these on a case-by-case basis.[18]

It only supports a few simple imaging operators. To work around this limitation constructions such as "stroking," also known as "painting" or "vector-fill" are needed. Standard Gerber was well-suited to drive vector plotters and was constrained by the technology then available. It was designed for a manual workflow. It is not suitable for fully automated data transfer between PCB designers and manufacturers. PCB manufacturers have to enter coordinate units and aperture definitions manually.

RS-274-D has been deprecated by Ucamco.[14]

Timeline

  • On 27-Aug-1980 the first edition of the Gerber Format: a subset of EIA RS-274-D; plot data format reference book[19] was published by Gerber Systems Corporation as a specification to drive their range of photoplotters.
  • In 1986 the Gerber format was extended to support apertures with variable sizes to produce rectangles of arbitrary sizes within a given range and tapered lines. This functionality is not in practical use any more.
  • In the 1980s the Gerber format was adopted by several other photoplotter vendors and also computer-aided manufacturing systems for PCB manufacturing. It became the de-facto standard.
  • On 26-Apr-1991 with the availability of raster scan capability the Gerber format was extended for polygon areas and Extended Mass Parameters, allowing the user to dynamically define apertures of different shapes and sizes as well as planes and polygons without the need for "painting". The Extended Mass Parameters where originally designed in the early 1990's by Gerber Systems Corp. under impulse of AT&T.[20]
  • On 16-Aug-1994 the last edition of the Gerber Format Guide: a subset of EIA RS-274-D; plot data format reference book was published by Gerber Systems Corporation.
  • In April 1998 Gerber Systems Corporation was taken over by and integrated in Barco, Belgium. Barco's PCB division is now called Ucamco (former Barco ETS).
  • On 21-Sep-1998 the RS-274X Format User's Guide was published by Barco - Gerber Systems Corporation.
  • In January 2012 the RS-274X Format User's Guide was updated to revision H.

Related formats

Over the years there have been several attempts to replace Gerber by formats containing more information than just the layer image, e.g. netlist or component information.[7] None of these attempts have been widely accepted within the electronics manufacturing industry, probably because the formats are complex.[14] Gerber remains the most widely used data transfer format.[1][2][3]

  • IPC-D-350 C Printed Board Description in Digital Format, 1989. This specification was standardized as IEC 61182-1 in 1992 and withdrawn in 2001. Rarely, if ever, used.
  • DXF Sometimes used. These are typically constructed as drawings, PCB objects (tracks and pads) are lost, which makes them very difficult to use in CAM.
  • PDF Rarely used. Very impractical to work with because PCB objects (tracks and pads) are lost.
  • DPF Format, now at v7, a CAM from Ucamco. Sometimes used.
  • The Electronic Design Interchange Format, EDIF. Rarely, if ever, used.
  • ODB++, a CAM format from Mentor Graphics. Sometimes used, the prevalent non-Gerber format.[21]
  • GenCAM: IPC-2511A Generic Requirements for Implementation of Product Manufacturing Description Data and Transfer Methodology, 2000. Rarely, if ever, used.
  • GenCAM: IPC-2511B Generic Requirements for Implementation of Product Manufacturing Description Data and Transfer XML Schema Methodology, 2002. Rarely, if ever, used.
  • Offspring: IPC-2581 Generic Requirements for Printed Board Assembly Products Manufacturing Description Data and Transfer Methodology, 2004. Rarely, if ever, used, but receiving more attention recently.[22]
  • STEP AP210: ISO 10303-210, Electronic assembly interconnect and packaging design, first edition 2001, second edition 2008 (to be published)
  • Fujiko: JPCA-EB02[23], based on work by Prof. Tomokage of Fukuoka University. Rarely, if ever used, but emerging as a new standard in Japan.[citation needed]

What is a Gerber File?

Introduction to Gerber Files

Gerber is a standard electronics industry file format used to communicate design information to manufacturing for many types of printed circuit boards. In many ways, Gerber is the electronics world's equivalent of PDF.  This odd little format, a hybrid machine control language and image, is a core component of the electronics manufacturing supply chain. If you're involved in building electronics for fun or profit you have (or soon will) come across it. You may even come to depend on it.

I've written this article to provide a general explanation of:

  1. The Contents of a Gerber file
  2. The use of Gerber Files in PCB Manufacturing
  3. Gerber Files and PCB Design Considerations

I hope you find this article useful, and generally accurate. In any case, I am happy to receive your comments, suggestions and corrections – just drop an email us

Contents of a Gerber File

The content of a Gerber file is ASCII text (i.e. English letters, digits and a few special characters) and looks like a human could almost read and understand. Here's an example:

G75*
G70*
%OFA0B0*%
%FSLAX24Y24*%
%IPPOS*%
%LPD*%
%AMOC8*5,1,8,0,0,1.08239X$1,22.5*%
%ADD10C,0.0080*%
D10*
X000281Y000835D02*
X002472Y006196D01*
M02*

When the format was first created, these commands called out instructions for a special kind of machine called a photoplotter which used them to create a picture on photographic film by precisely controlling a light source. Today, however, photoplotters aren't always a part of the process and Gerbers are treated more like image files. So why doesn't the industry just use image files like postcript? It's a bit of a catch-22: The machines use Gerbers because CAD/EDA/CAM software creates Gerbers; And, the software creates Gerbers because the machines use Gerbers.  Alternative formats like ODB++ exist, and are probably superior to Gerber for the most part (except for mandating the use of more expensive hardware and software, all controlled by one company).  Nonetheless, Gerber is here for the long-haul so we're well served by a little understanding of it.

About RS-274D and RS-274X

There are two "standards" for Gerber files out there:  the "old" and the "new".  The old standard (D) spreads information for a single layer accross at least two files.  The new standard (X) allows all the information for a layer to be contained in a single file.  The biggest benefit of this comes down to data management (or in plain English, the fact that it's much easier to keep track of one file than two files).

The types of instructions Gerber file instructions are (roughly):

  1. Configuration Parameters ("%...*%" blocks)
  2. Macro and Aperture Definitions (AM and AD parameters)
  3. Drawing Commands
  4. X/Y Coordinate information for the locations of features

Instruction types #3 and #4 are shared between the X and D variants of Gerbers.  That is, the old and new formats share the same commands and capabilities when it comes to basic drawing of lines and simple shapes.  However, the new "X" version also allows the definition of some important options as well as reusable blocks of data called apertures and macros.  In a version "D" file set (rememeber, always at least two files) the apertures are defined in an external file that can be one of many different formats. This is why an "X" file (ahem) can be viewed and rendered by CircuitPeople standalone -- all the pad shape and line widths are built into the one file -- and why "D" files are considered less desirable by PCB fabricators.

Configuration Parameters

Gerber files containing blocks of text starting and ending with percentage symbols ("%...*%") are probably the RS-274X variety.  Sometimes we see files with parameters but with external aperture definitions, which is an error but our software will accomodate it. 

Macro and Aperture Definitions

Apertures define the thickness of traces, size and shape of pads.  Macros (AM parameters) define shapes for registration marks, logo, and other special geometry that appears in a design.  Macros are a "less often" used feature of Gerber.  Macros support complex composition rules, and even some equation-driven parametrics.  It's a shame they aren't use more often in CAM output.

 one reason manufacturers shy away from the "D" variant gerbers  is that customers often forget to include them with their order. Don't do that.  If you do, the best thing that can happen is that your order will be delayed.

Drawing Commands

Gerber has three drawing primitives: flashes, lines and arcs .  It can be a challenge to represent complex geometry using only these shapes.  Luckly, RS-274X also adds "Step and Repeat" which allows us to create patterns of features. CAM systems are clever in the way they create Gerber files.  For example, the system may "pour" a large area of black then draw over it with a "scratch" layer of wide geometry.  Only three commands are issued, but the result seems more complex:

image003

Gerber files in PCB Manufacturing

The purpose of the PCB is to mechanically support components as well as move the proper number of electrons to where they are need. That is, the PCB is made with channels (traces) of conductive material along which electricity flows (if you will) from component to component.

A "bare" PCB is one that has yet to have components attached, and is generally constructed of conductive material and non-conductive  material. Copper is the most commonly used conductor with various forms of fiberglass, FR-4 being the most common, as the insulator.  However, due to requirements for high thermal conductivity many other materials are used as well.  There are a lot of ways to make a PCB, but in this paper I'm only going to talk about one common method. PCB manufacturing process is one that starts with sheets of composite material with a uniform layer of copper plated of the entirty of one or both sides. Channels (traces) are formed by selectively removing portions of the copper conductor. In this process, Gerber files provide the "picture" of where copper should remain:

image005

I literally mean a picture of where the copper should exist on each layer . But there is more to a PCB than just copper, which when exposed to air oxidizes making it difficult to adhere to with solder. Over the copper will be a layer of solder mask (commonly green) and probably some white letter referred to as silkscreen, legend or nomenclature.  Gerber files provide pictures of where the solder mask paint, silkscreen paint, or cut-outs in a stencil will go.

 For a "simple" two layer PCB, they can receive up to nine files:

  1. An image of the copper conductor for the top side of the circuit board.
  2. An image of the copper conductor for the bottom side of the circuit board.
  3. An image of where solder mask is to be applied on the top layer.
  4. An image of where solder mask is to be applied on the bottom layer.
  5. An image of where silkscreen is to be applied on the top layer.
  6. An image of where silkscreen is to be applied on the bottom layer.
  7. The locations of the drilled holes, and descriptions of the properties of the holes. Often, PTH and NPTH (see below) are separated into different files.
  8. The outline of the board, including internal cutouts and other machining operations (scoring, slots, etc.)
  9. A README file with the name and intended use of each of the above files.

In addition to these files, a manufacturer will need other information that generally isn't included (and shouldn't be included, IMHO) in the Gerber data:

  1. Are the bottom layers (copper, mask and silk) shown as viewed from the top or as viewed from the bottom?
  2. How thick does the copper need to be on the outer layers, inner layers and in the barrels of holes and vias?
  3. If the holes are supplied as a "drill drawing" in a gerber or DXF file, the table of sizes has to be manually translated to NC (Excellon) file(s).
  4. What colors should be used for the solder mask and silkscreen?
  5. What material should be used for the core?
  6. How thick does the finished PCB need to be?

While the construction of a PCB is conceptually simple, correctly manufacturing the circuit board can be complex. A general outline of the traditional PCB manufacturing process for a simple two layer board (meaning a board with two conducting layers) may look like the following:

  1. Drill all the holes in the panel that will be plated with copper. This step includes preparation of an NC drill program for the automatic drill machines most shops use. Excellon is a very common format for these NC programs, because Excellon drills are very commonly found in shops around the world.
  2. Carefully clean the copper surfaces and carefully remove any "burrs" on the edges of the holes caused by drilling.
  3. Coat the entire surface of the copper with photo resist. Resist is a material that is soluble unless "cured" with heat or a strong light source, and that is chemically inert during the following process.
  4. Attach the appropriate films to each copper side, and expose the "clear" sections to light to cure them.
  5. Remove the uncured resist, leaving the cured resist to protect the copper from being plated with tin in the next step.
  6. Put the panel in a chemical bath (various formulations are used) to add a very thin layer of tin to the surfaces no longer protected by resist. This coating will protect the copper from being removed in the etching step, below.
  7. Remove the cured etch resist using a different solvent, or mechanical means.
  8. Put the panel in a chemical bath (various formulations are used) to remove the unprotected copper from the panel.
  9. Put the panel in another chemical solution that will deposit a thin (or thick, depending on the design specifications) layer of copper on all remaining copper and hole barrels. This layer of copper increases the thickness of the traces, and provides the copper inside the holes to carry electrons between layers.
  10. At this point the entire panel is coated with solder mask paint. Like the resist, the solder mask can be cured with strong light.
  11. Remove the unexposed solder mask


Readme text file:

Please include a "Read.Me" text file that contains the following information:

  • List of every file name with a brief description as to what it is.
  • List all non-Gerber specs for this job
  • Your contact information

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