Best Practices in PCB Design: Exporting Gerber Files

Best Practices in PCB Design: Exporting Gerber Files

Overview

This document provides Ultiboard users with practical tips and recommendations on what to do when exporting a PCB design to fabrication.

This document will discuss how to best work with the Ultiboard design environment to generate Gerber files and NC drill files to send to a fabrication house such as Sunstone Circuits.

This is the second in a series of articles that:

1. Help you finalize for fabrication in Ultiboard
2. Discuss exporting Gerber files for prototype fabrication
3. Provide a step-by-step check-list before prototype fabrication

Table of Contents

1. Creating the Gerber files for PCB Manufacturer
2. Drill Tables
3. Next Step

1. Creating the Gerber files for PCB Manufacturer

After verifying all components and completing the final PCB checks, the Gerber files will need to be generated and  uploaded to the board manufacturer’s web page.

For more information on the Gerber Export dialog process, please view this article which provides more context to the dialog box, and what the various settings mean.

Exporting Gerber Files from NI Ultiboard

Gerber Properties

To begin generating the PCB files, the settings for each of the various file types will need to be established.  The first files needed are the Gerber files which allow the manufacturer to create the basic artwork for each of the layers.  From the menu:

1. Launch the Export setup window from the menu by selecting File > Export….
2. Ultiboard has default settings for different export schemes such as Fabrication or Fabrication and Assembly
3. To export Gerbers and Drill files select Fabrication from the drop down menu and the units system used by your board manufacturer

Figure 1 - Export Dialog Box

The RS-274X standard is preferred as it is the most current and widely used Gerber format and automatically assigns the D-code aperture setting whereas the RS-274D requires the manual setup of aperture settings. Aperture D-codes set the basic drawing tool sizes and styles used by the manufacturer to physically create the various layers of the PCB.

In the Gerber properties window, the following Available Layers will be automatically selected, you can add more layers to the export if needed.

1. Board Outline
2. All copper layers (Copper Top, Copper Inner 1, Copper Inner 2, Copper Bottom, etc…)
3. Drill (may be optional for quick turn PCB services using standard drill sizes)
4. Drill Symbols (may be optional for quick turn PCB services using standard drill sizes)
5. Silkscreen Top and Silkscreen Bottom (for single sided boards only the top silkscreen layer may be required)
6. Solder Mask Bottom and Solder Mask Top (may be optional for quick turn PCB services)

It is important to complete the following steps to finalize export: 

• In the Units section select Imperial (Mil)
• In the Digits section, select integer 2 and decimal place 4
• Oversize the Soldermask based on PCB manufacturer’s recommendations (some quick-turn PCB manufactures suggest over sizing the PCB mask to allow for adequate spacing around pads for the solder mask tolerances).

 Now, go the the Output Configuration tab and this where you can define where all the Gerber and Drill files will be saved on your computer. By default it will be set to the same directory where your design file is saved.

Figure 2 - Export Dialog Box Output Configuration

2. Drill Tables

In any PCB, there are typically many holes that need to be drilled for things such as through-hole parts, vias and mounting holes.   There are multiple files relating to the drilling of the holes in the PCB.  The one essential in the creation of the PCB is the NC Drill file (NC = Numerically Controlled).  The NC Drill export selection will create two files, a ‘.drl’ and ‘.rep’. 

The rep is a report file listing a summary of the drill sizes and quantities.  The drill sizes are associated with an individual drill bit (i.e. “tool”) so the tool numbers (“T#”) are shown as each individual sized hole.   If the number of drill sizes can be kept to a minimum, the cost of the PCB will be reduced since it will take less time to switch between sizes when the PCB is being made.

The drl file shows the exact locations of each hole.  It is sorted by the tool number tool number so the PCB manufacturer knows the size and location of all the holes for a specific drill bit size.

In addition, there are two Gerber files that are related to PCB drilling.  The Drill and Drill Symbols are created when the Gerber RS-274Xis selected and subsequently these files are used in documentation such as the assembly drawing to verify all hole sizes and drill locations are correct.

The Drill Gerber file shows round images at each hole with the radius of the image the same as the hole radius.  When viewing this layer, the user can observe the hole sizes, locations and relations to other locations on the PCB.

The Drill Symbols Gerber file has symbols shown for each tool.  For example, if there are 5 different hole sizes needed for drilling into the PCB, there will be 5 different symbols on this Gerber layer.

3. Next Step

Now that you have finalized your design it is time to review the files for fabrications. 

This final article in this series is a prototyping check-list for any engineer looking to use a quick-turn PCB fabrication house, such as PCBWay (www.pcbway.com/e)

website: www.pcbway.com/e

For PCB prototype, please feel easy contact Erin KOU (erin.kou@pcbway.com)

PCB share: Tutorial 2 for Eagle: Printed Circuit Board Layout

Tutorial 2 for Eagle: Printed Circuit Board Layout

author:Jeremy Blum Shared by Erin KOU

website: www.pcbway.com/e

For PCB prototype, please feel easy contact Erin KOU (erin.kou@pcbway.com)

PCB share: Tutorial 3 for Eagle: CAM Output and DFM

Tutorial 3 for Eagle: CAM Output and DFM

author:Jeremy Blum Shared by Erin KOU

website: www.pcbway.com/e

For PCB prototype, please feel easy contact Erin KOU (erin.kou@pcbway.com)

PCB Recycling: The Core of Your Electronics Is More Valuable Than You Think

By Anne Staley,  Shared by Erin KOU  from PCBWay

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The screen you are looking at this very moment will someday be recycled. Electronic recycling is fast becoming just as important as plastic and steel recycling. This is because your household electronic devices – old VCRs, stereo systems, television sets and desktop computers – contain valuable metals and components that can be broken down, recycled and reused. Those dusty shelves in your garage might hold more monetary value than you’re aware of!

What are PCBs?

PCBs (or Printed Circuit Boards) are copper-coated plastic layers that connect electrical components using conducting tracks, metals and glass. To the untrained eye, it simply looks like an electronic maze on a green metal plate, but its components are quite special. Electronic waste is made up of PCBs and various cables that require careful demanufacturing by approved recycles so they can be used again.

Source: Wisegeek.org

Why is e-waste valuable?

Computers, microwaves, video cameras – anything that runs on electricity and contains memory chips also contains metals and elements like gold, lead, mercury, iron and cadmium. They also have plastic (the outer casing), glass and fiberglass (the monitor). A major percentage of electronic waste contains plastic, glass and metals, which can (and should) be easily extracted. All of these individual parts can be separated from the unusable elements and refined to manufacture other products.

They are valuable because obtaining these metals means that new metals don’t have to be procured by using raw materials. This e-waste fact sheet suggests that recycling 1 million laptops can save enough energy to power 3,657 U.S. homes for a year.

E-recycling is definitely something that must be practiced by one and all, since it eases the strain put on the earth’s natural resources. Recycling facilities safely remove and dispose of parts that would otherwise rot in landfills and pollute groundwater.

How are electronics recycled?

There are two ways in which electronic waste can be recycled–shredding and dismantling. Shredding involves the use of large machine equipment that enables the recovery of recyclable metals from the electronic devices. Dismantling yields more of the smaller components that can easily be put to use again. Taking the electronics apart in this way requires careful manual handling and the use of tools (to remove the smaller ‘bits and pieces’ that make up the electronics we use every day).

Some of the PCB components that can be recovered by dismantling are:

• Capacitors
• Switches
• Audio sockets
• TV plugs
• Resistors
• Motor
• Screws
• CRTs
• LEDs
• Transistors

What can you do?

E-waste/electronic recycling is valuable to the environment, yes, but it can also be valuable to you! Yes, you can sell electronic scrap to waste recycling facilities. Most recycles, like Sims Metal Management, will pay you for your electronic trash. Your EOL (end-of-life) electronics – electronics that have become unusable – can be collected and sold for a good sum to a number of facilities.

Source: Pacebutler.com

Some common items that contain PCBs and other recyclable parts are:

• Laptop and desktop computers
• Game consoles (Xbox, PlayStation, etc.)
• Photocopiers
• Cell phones
• Video and digital cameras
• Tablets
• Speaker systems
• DVD players
• GPS devices

The recycling of old electronics is massively helpful to the earth’s resources and the environment. What’s more, it also puts a tidy sum into your pocket. So when the computer you are using right now has reached its EOL, remember that its circuit board, monitor and casing are all valuable and can be traded in at an electronics recycling center.

website: www.pcbway.com/e

For PCB prototype, please feel easy contact Erin KOU (erin.kou@pcbway.com)

Sequential LED Circuit

website: www.pcbway.com/e

For PCB prototype, please feel easy contact Erin KOU (erin.kou@pcbway.com)

PCB share: Export Gerber files from Altium

Export Gerber files from Altium

Sourced by Erin KOU [www.pcbway.com/e]

Softwares needed

You need winzip or winrar, you probably already have it installed. If not: winzip or winrar

Export Gerber files from Altium

Design rule check

Make sure you run design rule check (Tools->Design Rule Check...) before you generate Gerber files. DRC usually makes sure that your board doesn’t exceed the manufacturer’s production abilities.

Our PCB manufacturing capabilities are outlined at the home page of http://www.pcbway.com/e, please using Design Rule Wizard to modify the rules accordingly.

Make sure there are no errors. If there are errors, you need to fix them before you can continue to generate Gerber files.

Generate Gerber File

In PCB view, select File -> Fabrication Output -> Gerber files. Then in the popup dialog, select General tab, set Unit to inch and format to 2:5:

In Layers tab, select "Used On" for the Plot Layers drop down, select "All OFF" for Mirror layers. Check "include unconnected mid-layer pads", and uncheck "Mechanical layers to Add to All plot":

In the Drill Drawing tab, deselect all check boxes, and select Graphic Symbols:

In Apertures tab, make sure RS274X is selected:

In Advanced tab, select "Separate file per layer" for Batch Mode option. Also select "Suppress leading zeros" for Leading/Trailing Zeros, select "Reference to relative origin" for Position on Film and select "Unsorted" for Plotter Type, then click OK:

After a few seconds, Gerber files are generated. You don't need to save the generate CAM file, just close it.

Generate NC Drill File

Then in the PCB view, select File -> Fabrication Outputs -> NC Drill Files, in the NC Drill Setup dialog, select "Inches" for Units, "2:5" for Format, "Suppress leading zeros" for Leading/Trailing Zeros and "Reference to relative origin" for Coordinate Positions, then click OK:

Click "OK":

Click "OK"

Package Gerber File

Altium saves all generated Gerber and NC Drill files in the "Project output folder", usually it is in the same folder as your PCB project folder. Rename the project output folder to something meaningful so you know what it is.

Then zip all files in the output folder and send to us for PCB fabrication.

The following summarizes the Altium Gerber file extensions:

GTL---Top layer
GBL---Bottom layer
GTO---Top overlay
GBO---Bottom overlay
GTP---Top paste
GBP---Bottom paste
GTS---Top solder
GBS---Bottom solder
G1 ---Midlayer 1
G2 ---Midlayer 2
...
GP1---Internal plane 1
GP2---Internal plane 2
...
GM1---Mechanical 1
GM2---Mechanical 2
...
GKO---Keepout layer
GG1---Drill guide
GD1---Drill drawing
GPT---Top pad master
GPB---Bottom pad master

website: www.pcbway.com/e























For PCB prototype, please feel easy contact Erin KOU (erin.kou@pcbway.com)

PCB Share: Created your own PCB layout with eagle PCB

Created your own PCB layout with eagle PCB

Sorced by Erin KOU (www.pcbway.com/e)

If you have created your own PCB layout with eagle PCB, the next step is to produce prototype PCBs from the layout.

PCB manufactures  do not usually support all the PCB layout files from these software, however, they do support the standard gerber file format. It doesn't matter how you create the PCB layout, as long as you can export gerber files from your layout, the board can be produced by any manufacture, including PCBWay(www.pcbway.com/e)

In this tutorial, we are going to show you how to export gerber files from your eagle brd file, so that you can send it to PCBWay for manufacture.

Softwares needed

You only need one software: eagle PCB. Download from here: download eagle PCB free version

You also need winzip or winrar, you probably already have it installed. If not: winzip or winrar

Export Gerber files from eagle

Generate Drill Rack file

Select Run from File menu:

In the pop up dialog, select drillcfg.ulp from the list and click Open:

Then select Inch and click OK:

Don't change anything and click OK:

Click Save:

Now you have the drill configuration file created.

Generate Excellon drill files

Select File -> Cam Processor... from the menu:

Click File -> Open -> Job...:

Select Excellon.ulp, and click open:

Click process Job:

The file will be created instantly. Close the window by clicking the 'x' icon on the right too corner:

Generate gerber files

Select File -> Cam Processor... from the menu:

Click File -> Open -> Job...:

Select Gerb274x.ulp, and click open:

Now this is important, make sure "Mirror" is unchecked on all tabs, then click "Process Job...":

It may take a couple seconds to generate all files, once it is done, close the dialog:

Zip up generated files and send to PCBWay (erin.kou@pcbway.com)

Now open windows explorer, zip up the generated gerber files as rar or zip format, then send to PCBWay for manufacturing. Before you send it, you may want to upload the zip file to online gerber viewer website and they will check if they are correct.

These are the files:

• *.drl Drill rack data
• *.drd Excellon drill description
• *.dri Excellon drill tool description
• *.cmp Component side data
• *.sol Solder side data
• *.plc Component side silk screen data
• *.stc Component side solder stop mask data
• *.sts Solder side solder stop mask data
• *.gpi Gerber photoplotter information data

website: www.pcbway.com/e

For PCB prototype, please feel easy contact Erin KOU (erin.kou@pcbway.com)