PCB Fabrication Files
PCB Manufacturing Files List
Designing a PCB is excellent, but the final step in the design process is to prepare the design for manufacturing and assembly.
For JHYPCB or any PCB manufacturing company to accurately quote your board with minimal delay, it is crucial to provide a complete set of PCB data files using industry-standard file types. Before getting a quote, find out what information you need to provide to ensure a smooth PCB manufacturing process.
- What information are needed for PCB manufacturing?
- What do you need to prepare for PCB manufacturing order in advance?
Preparing for PCB Fabrication
Even after the layout is completed and is ready for fabrication, there are some final cleanup steps that are needed to get the board ready for production.
PCB Fabrication Files
Your PCB fabrication files are needed to fabricate the bare board. PCB design software will include some utilities that can take your design files and automatically generate your fabrication files. As a professional PCB manufacturer, we will need three sets of files in order to begin fabrication.
In PCB design, the term “artwork” refers to the generation of a stencil that uniquely defines the pattern to be placed on the board. Each layer in the PCB needs to be rendered as artwork that shows the locations of copper, holes, silkscreen, solder mask openings, solder paste mask locations, the board outline, and drill hit locations.
There are three fabrication file formats used in PCB fabrication:
- Gerber files: These files are the most popular among fabricators, and they have been around the longest. Gerber files come in two possible formats: RS-274-X and X2 formats.
- ODB++: This set of files includes the standard set of data listed in Gerber files plus some additional data. The additional data can include materials in the stack-up, the bill of materials, component placement, and board dimensions.
- IPC-2581: This is the newest artwork standard in the PCB industry. It consolidates all aspects of a design, including layer descriptions and test/assembly details, into a single file in XML format.
What is Gerber files?
Gerber files instruct PCB manufacturers where to print copper, solder mask, and silkscreen. As an example, a double-layer PCB, with copper layers, soldermask and silkscreen layers on each side, has a total of six Gerber files.
The example below shows the view we will see when examining your fabrication files. This picture is from a copper layer in a PCB, and we can clearly see some traces and copper pour in this layer.
When our engineers review manufacturing files, multiple layers are often stacked together to check for missing or incorrect information in each layer. Computer-aided manufacturing (CAM) software can be used to overlay multiple layers so that they can be inspected prior to fabrication. The software will also check your manufacturing files to ensure the design meets manufacturing capabilities. If the design fails these checks, we will send you a request to make changes before starting manufacturing.
We will need one of these three file formats when you are ready to send your board for manufacturing. These formats are called “vendor neutral” because any PCB design program can generate them. In addition to your artwork files, we also need (at least) NC drill files and some other information to make the PCB.
NC Drill Files
These files are basically text files, and they are human readable. These files are used to program CNC drilling machines that will place drill hits around the PCB during fabrication. The data in these files tells the CNC machine where to move the drill bit during operation, so the data is basically a large set of coordinate data for each drill hole, as well as the hole diameter. If you wanted, you could open NC drill files in a text editor and view the data yourself.
A fabrication drawing is created to show how the different layers in a PCB stackup and used to build the bare board. In addition, it should show where drill hits are placed as well as the drill sizes used in the PCB. It should also show a dimensioned drawing of the board and a dimensioned stackup so that we can see all the information on the materials and processing steps needed to convert your fabrication data into a bare PCB.
The example above shows a basic fabrication drawing for a 4-layer PCB. In this drawing, we have a few important pieces of information:
- Dimensioned drawing of the fabricated board; the symbols show drill locations with different drill sizes
- Stackup drawing that shows the layer thicknesses, required dielectric constant, and the fabrication file names corresponding to each layer
- A drill table that lists each drill size and drilling tolerances
- Requested fabrication tolerances
- Other fabrication requirements (plating, testing requirements, etc.) specified in the fabrication notes
The point of creating a fabrication drawing is to compile all of these pieces of information into a single location. If you ever want to get a quote for your board, you can send your drawing along with your fabrication files to help us prepare an accurate quote.
Although fabrication drawings are very useful for compiling all of your design and production data into one location, it is not always required by every manufacturer. If you submit your design to a manufacturer, they might generate a fabrication drawing in their own format from your design data. In cases where you have specialized fabrication and testing requirements, it’s best to work with your manufacturer to ensure they can meet your requirements, and then you can specify these in your fabrication drawing.
All in all, you need provide information as follow for PCB manufacturing:
|Gerber Files||Gerber X2 is the latest Gerber file format.|
|Also known as Extended Gerber, or X-Gerber format. It is a widely accepted Gerber file format and is commonly used.|
|We also accept ODB++ file in lieu of Gerber files.|
|NC Drill Files||For best results, it is always recommended that NC Drill files are created using a similar format as that of Gerber files.|
|The file formats of NC Drill Files are generally NCD, DRL, TXT.|
|Fabrication Drawing||Non-essential, please provide us if you have.|
|Specification of bare board||Finished copper thickness of both internal and external layers|
|Finished PCB thickness with tolerances|
|Solder mask requirements|
|special requirement such as impedance control, specific dielectric thicknesses, via plugging|
|Materials: FR-4, Metal, High Tg, Rogers, PTFE (Teflon), and special materials are avaliable|
|Panelization Files or Requirement|
|Here is the normal specification, Base material, FR 4; board thickness,1.6mm; copper thickness,1oz copper; Finished surface, HASL lead free; green solder mask, white silkscreen.|
What will we do?
1. DFM Evaluation and Analysis
After you’ve created your order with us and you’ve sent in your fabrication files, we will perform a DFM evaluation to ensure the board can reliably pass through our process.
We use specialized software to quickly scan Gerbers for any features that could produce a fabrication defect leading to a scrapped board.
Here are some of the most common problems:
- Tight clearances, as shown in the example above
- Missing teardrops in high-reliability designs
- Annular rings that are too small
- Through-holes that are too small or too large
- Stackup thickness or layer thickness that is non-standard
- Antipads that are too small due to clearance settings
- Disconnected planes/polygons and vias
- Thin solder mask slivers between SMD pads
2. DFA Inspection
DFA inspection is needed to ensure there will be no soldering defects. If you also entrust us with the task of PCB assembly, we can also perform this inspection.
3. Engineering Questions
Our engineers will review your provided Gerber files and production requirements and raise engineering questions based on our company’s process capabilities. Once all engineering questions are resolved, production documentation is generated, and production begins.
For more information, you can also email us at email@example.com