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| Heads of department of purchases and agents, designers of an arrangement engineers/boards, and others, connected with printed circuit boards, will to see often a phrase "files Gerber", not knowing precisely, what they. This article describes files Gerber as they are made, that they contain, and as they are used. |
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What Files Gerber for Printed circuit Boards, and Who Their Requirements?
Jim Usery
When the engineer of the project of electronics has finished their project krugooborota for the statement, the following step to end of the project of a product should enter, schematic details in the computer based the schematic program of capture. The schematic program of capture which usually is a part of Electronic Automation of the Project (EDA) or the Computer the Automated Project (BOOR PCB) a package of the project of the software, will create the pure list from finished schematic that details each connection to the electric system between each electronic component.
This pure list is used by board of the printed circuit or designer PCB in the course of designing of board of the printed circuit with EDA or the software of BOOR PCB. The finished board of the printed circuit will provide physical meeting and a platform of interrelation for the various electronic components demanded schematic.
The printed circuit board is made of one or more conductor layers of the copper planning, which is engraved to generate making keyboards and traces of interrelation and one or more layers izoljatsionnogo a material, such as filled epoksidnoj pitch fiber glass to separate spending copper layers and to give mechanical force to board.
The unique board of a layer would have components on the main party
Board and incorporating traces on the party of the basis of board. The double board of a layer could have components on the main party only or have components both at top and on the parties of the basis of board along with connection of traces with both parties of board. At multilayered board would be both top and the parties of the basis with components and traces along with many inside layers used for interrelations and for pressure and layers of the plane of the basis.
EDA or the program of BOOR PCB provide the detailed information about
The finished project of board among card files of data for each conductor layer (top, the basis, and any inside layers). The format of File Gerber named in honour of the Scientific Company of Tools Gerber, the pioneer in manufacture of the photoconspirator, is a standard format for these card files of data.
Original format Gerber to which adapt to the standard of RTS-274D EIA and, consisted of a file of a command for each conductor layer and a file of the description of the tool. The command file consisted of a number of the short commands, everyone accompanied nearby X and co-ordinates Y,
Which would give to the photoconspirator the information to create graphic representation. These files of a command became known as files Gerber. The file of the description of the tool, or an aperture file, has defined a trace line widths and dimensional data for all keyboards and geometrical forms on a layer.
These card files of data of the made information of the computer for the project of board of the printed circuit then send to the company of manufacturing of board of the printed circuit to make physical boards. Files Gerber contain all information necessary for cars of the computer, which operate, in printed circuit board (PCB) manufacturing buildings to engrave copper layers, to create making keyboards and communication traces, to drill all necessary apertures, and to reduce board to the necessary size.
As PCB can have from one to many conductor layers, seniors Gerber format RTS-274D EIA, always accepted a number of files of a command (one for each layer PCB) and one "file" of the description of the tool, or an aperture file. The standard for "aperture files" was never established so, everyone EDA or a product of the software of BOOR PCB had an own version of a format of a file of the aperture. If the house of manufacturing of board of the printed circuit could not read a format of a file of the aperture as is sent, the aperture information should be repeatedly entered manually.
Newer format Gerber corresponds to RTS-274X EIA, and this format includes the aperture information in file headings as the enclosed information for each command or file Gerber. This newer format often name X-Gerber. With all information of the aperture included within heading fo a file, each file X-Gerber gives all information requested to make the connected part of layer PCB.
Names of a file for files Gerber should be descriptive enough for pcb the manufacturer to understand, what board and a board layer which each file concerns, such as membdtop.gbr as a file name. Standard process should include with each set of files for the board project a special text file of type readme.txt which defines each name of a file and its statement for the board project. The seller of board will use this readme.txt a text file as a starting point for board production.
Expansions of file Gerber часто.GBR.GBX, или.ART. Sometimes
Expansions, such как.TOP и.BOT или.SMT и.SMB are used instead of expansions типа.GB_. Often expansion of a file for file type (top, the basis, silkscreen, paste, an inside layer) operate EDA or the software package of BOOR PCB or is chosen within a package. This change in expansions does inclusion readme.txt a file as the requirement in a full package of a file for the seller of board.
The list of files for the board project will include silkscreen for top and
Sometimes the bottom layers if components are established from both parties,
Making placings for top and sometimes the bottom layers, solder files of paste of the screen for superficial statements of fastening, drawings of training, files of a mask of solder, group drawings, tops of the owner of the keyboard and the basis of the owner of the keyboard, etc.
For example, for bilaterial (2 layers) pcb, files Gerber will consist of two positive layers Gerber (top and the basis), an aperture file (if not in RTS-274X format), NC Excellon drill a file, a file of the List of the Tool of Training, file Silkscreen for each party with components, soldermask files for top and the basis, and top and files of paste of the screen of the basis for superficial boards of fastening where is applicable. Four boards of a layer would have all these files plus two internal files of a layer, and six boards of a layer will have all these files plus four internal files of a layer.
In Innovative Circuits, Inc we connect to buildings of manufacturing PCB for our own projects of board just as the projects of board given by our clients for which we render services of installation of a payment. Thus we are very familiar with files Gerber both their purposes and functions. But we also understand, that uncountable other people in other organisations which are involved in the order of crude boards or services of installation of a payment, will see or hear term files Gerber, not having knowledge of term, and this article if for them.
Jim Usery
The sales manager and to marketing
Innovative Circuits, Inc.
311A S Parkway With -
Corinth, Mississipi 38834
Office 662-287-2007
Duty-free 866-887-7381
Fax 662-665-9275
jusery@icimfg.com E-mail
Visit our website in www.icimfg.com behind the additional information about Innovative
Circuits, Inc both services and examination which we give to our clients, or for additional technical articles. You can sign also for our free Ezine, Information PCB, at the Homepage basis in www.icimfg.com. |
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| About the Author |
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Jim has begun the professional career in Telecommunications ITT in Milan, Tennessee as the technical student of co-operative society from UNIFORM TIME Martin in falling 1970. It worked in various segments of the industry of telecommunication during the following of 35 years, with positions in working out, management of a product, sales, and client service. Jim diplomaed in 1991 from University of Alabama Huntsville with Owners in Management and now lives in Memfissky area.
Article source: http://www. ArticlesTake.com/author-jim-usery-1698.html |
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