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FAQ
Get Started with BetterDFM
Download BetterDFM brochure
Sample of a Web PCB quote
Demo of BetterDFM process
Internet Explorer users click here
Examples of Reports
DFM report
Netlist Compare report
Gerber Layers shown in PDF format

Better DFM: Frequently Asked Questions

  

Q1. What is Better DFM?  

Better DFM is an online tool to check the Design For Manufacturability. It is run on your PCB design files (Gerber file format) and it gives you detailed information about where it finds design rule issues in your files. For example, if you think your PCB design has minimum trace of 6 mils, and you run Better DFM, it will highlight any areas where the traces are 5 mils.

Q2. How does Better DFM help me?  

  • Save time and money-- Catch your PCB design errors ahead of time and prevent On-holds and Re-spins
  • Peace of mind-- Ensure you have complete set of files for manufacturing. Ensure your Gerber files electrically match your CAD design.
  • Convenience-- Get (optional) instant price quote, place order online.
  • Q3. How do I use Better DFM?  

    Running Better DFM on your design is an EASY 3-Step process:
    (You can also see a flash demo here)
    STEP 1. Log on to our website, put in your design specs and upload your Gerber files.
    STEP 2. Our software will unzip your files and present those to you, where you will:
    a) Identify layer assignment. For each file indicate what layer it is. E.g., sm1.gbr = Soldermask top layer, rotator1.gbr = Layer 1 etc.
    b) Verify Drill Info-- and tell us which holes are plated or non-plated
    STEP 3. Get a FREE DFM reports in your email. (including reports for Netlist compare etc.)

    Q4. What is the 40-point Checklist that Better DFM performs on my PCB design files?   

    Better DFM does a comprehensive Design For Manufacturability analysis on your files.
    Our 40-Point Checklist includes the following DFM checks:

    Signal Checks
    • Conductor Width
    • Spacing
    • Annular Ring
    • Drill to Copper
    • Hole Registration
    • Text Features
    • Missing Copper
    • Features Connection
    • Missing Holes
    • Unconnected Lines
    • Rout to Copper
    Plane Checks
    • Drill to Copper
    • Annular Ring
    • Spacing
    • Conductor Width
    • Thermal Air gap / Spoke Width
    • Missing Copper
    • Rout to Copper
    • Drill Registration
    • Clearance smaller than hole
    Solder Mask Checks
    • Solder Mask Clearance
    • Coverage
    • Rout to Mask
    • Spacing
    • Missing Solder Mask Clearance
    • Exposed Lines
    • Partial Clearances
    Silk Screen Checks
    • Silk Screen to Mask Spacing
    • Silk Screen to Copper Spacing
    • Silk Screen to Hole Spacing
    • Silk Screen to Rout Spacing
    • Line Width
    • Text Height
    • Silk Screen Over Copper Text
    Drill Checks
    • Hole Size
    • Duplicate Holes
    • Hole Spacing
    • Touching Holes
    • Plane Shorts
    • Holes to Rout
    • Missing Holes

    Q5. Why is Better DFM better?  

  • Our Better DFM uses YOUR design rules to check against. Not against an arbitrarily fixed set of rules. You tell us what rules you are designing to and we'll check against that!
  • We provide a full Netlist compare. If you load your IPC 356 format Netlist with your files, we will create a Netlist from your gerber files and compare it with your IPC netlist. If there are any Shorts and Opens we will show you which Nets they are on.
  • We provide a precise analysis in our DFM, with exact location and real graphics.
  • We can accept multiple drill files, and you can indicate which holes are plated or non-plated, and which layers they go through.
  • For each layer in your Gerber files, Better DFM gives you PDF file showing that layer matched up against the Drill holes, so you can spot any alignment issues.
  • Our Better DFM is hooked up to our popular Web PCB online service. So (if you choose) you can ask for an INSTANT price quote, and get some of the best value PCB pricing out there.
  • If you choose to order PCBs, it is a cinch. Just pull up your quote and place an order online. It takes less than a minute!
  • Q6. What do the Better DFM reports look like?  

    Better DFM provides the following reports
    REPORT 1. DFM Report (provided if we detect any issues in your gerbers)
    REPORT 2. Netlist Report (provided only if we find opens and shorts in your files)
    REPORT 3. PDF images of each layer of your gerber files.
    See examples of reports:
  • DFM report
  • Netlist Compare report
  • Gerber Layers shown in PDF format
  • Q7. What are the most common issues I should watch out for before submitting my file for
    Better DFM?
      

    If you are having trouble running Better DFM, please check for the following most common pitfalls!
    1. If any file in your gerber packages is corrupt or missing.
    2. If some gerber file has not been assigned correctly; for example, on Layer Assignment screen, if you assign your bottom copper layer as top layer.
    3. If a complete board outline has not been provided. (We need full outline, not just crop marks.) The board outline must be on one of the layers, preferably on the soldermask layer.
    4. If the layers are not properly aligned in your design.
    5. If your drill file is corrupt or incomplete.
    6. If any of your drill holes lie outside or on the board outline OR if your board has NO drill holes!
    7. If the Gerber data is not in 274x format or if the Gerber files are not 1:1 (true size).
    8. If the Copper pour areas in your design are filled with trace width of less than 10 mils and less than 1 mil overlap.
    9. If the actual dimensions of your board are not what you entered. (We want you to be very accurate: e.g., 4.353" X 3.221")
    10. If your Netlist file is not in IPC-356 format. (Note that uploading a Netlist file is optional)

    Q8. Please explain more to me regarding board outlines and filled areas.  

    Board Outlines
    You need to provide the correct board outline on one of the gerber files (we prefer it be on soldermask layer). The outline needs to be constructed by single line (not multiple line segments) that connect to each other (10 mil line width preferred), and the dimensions are calculated using the center of the line. See examples below:
    An example of a good Outline
    (Notice how the measurement is taken from center of the line)
    The board outline needs to be constructed by single line (not multiple line segments) that connect to each other (10 mil line width preferred), and the dimensions are calculated using the center of the line
    Some examples of bad outlines:
    Crop marks instead of line
    Example of Bad PCB Board outline. Crop marks instead of line Example of Bad PCB Board outline. Not Clean at the corner
    Not Clean at the corner

    Here the outline is made using multiple lines and overlapping lines, instead of a single line. This is not allowed
    Here the outline is made using multiple lines and overlapping lines, instead of a single line. This is not allowed.


    Filled Areas
    Filled areas must be filled using 10 mil outlines with 1 mil overlap. Use 0 and/or 90 degree lines to do the fill. We have found that some CAD systems will leave gaps on the fill areas when using 45 degree line. Crosshatch is not allowed. See examples below.
    Here we have one mil (0.001") overlap
    Filled areas must be filled using 10 mil outlines with 1 mil overlap


    This is an example of a plane area using a Cross Hatch pattern. Cross Hatch patterns are not allowed.
    Plane area using a Cross Hatch pattern

    Q9. Please explain in more detail what you mean by Positive and Negative polarities.  

    Here are examples that will show you what we mean by positive or negative polarities for different kinds of layers. (Please note: red represents data and black represents absence of data)
    Silkscreen:
    Positive Negative
    Positive polarity for Silkscreen

    Negative Polarity for Silkscreen

    Solder Mask:
    Positive Negative
    Positive polarity for Soldermask

    Negative polarity for Soldermask

    IMPORTANT NOTE ABOUT Soldermask Polarity: It is important that you understand that the polarity of Soldermask is almost always POSITIVE from a manufacturing perspective. There is some confusion in the industry about this because during design stage and in many design software these may be referred to as negative, but from a PCB manufacturing perspective, these are called positive.

    Here is how you can understand how PCB manufacturers interpret polarity in a soldermask:

    If your soldermask data represents the "absence of soldermask" then the data is in POSITIVE polarity.

    In other words: if your data shows the places which you WANT TO SOLDER, then your soldermask layer is in POSITIVE format.

    So when you are in the layer assignment screen on our website, it is most likely that soldermask should be assigned as positive polarity.

    Plane Layer:
    Positive Negative




    Signal Layer:
    Positive Negative




    Q10. Please explain the different options that Better DFM provides for minimum Annular Ring Width checks?  

    The Annular Ring Width refers to the width of the pad surrounding the hole.
    Let's clarify by using an example.
    If pad is 20 mils diameter and hole is 8 mils diameter, then Annular Ring Width is (20 - 8)/2 = 6 mils.
    See more details about Annular Rings here
    When you run Better DFM, you can go under "Advanced Options" and choose should be checked about your annular rings.
    You have 4 options to choose from:
  • If you are okay with accepting Tangency on pads in the manufactured board, then our DFM will look for a minimum of 5 mils (0.005") annular ring width in your design.
  • (Tangency is the default option, and the DFM will check for 5 mils minimum annular ring width)
  • If you wish to have minimum 1 mils annular ring on pads in the manufactured board, then our DFM will look for a minimum of 6 mils (0.006") annular ring width in your design.
  • If you wish to have minimum 2 mils annular ring on pads in the manufactured board, then our DFM will look for a minimum of 7 mils (0.007") annular ring width in your design.
  • If you are okay with accepting Breakouts on pads in the manufactured board, then our DFM will look NOT LOOK for any minimum annular ring width in your design.
  • ( NOTE: accepting Breakouts is typically NOT recommended!)

    Q11.When I assign the “plating type” to holes during BetterDFM process, what do the different options mean?  

    When you are on the second screen of Better DFM we show you all the different drill hole sizes you have in your gerbers and ask you to assign a “plating type” to each hole size.
    Please use this guide to assign.

  • PLT = Plated through Hole
  • Via = Via hole (which is also plated)
  • NPT = Non-Plated through hole
  • Laser = Laser hole (which is also plated)
  • Q12. Can you give me more technical details about format of gerber files to upload, Data polarities, format of drill files, etc?  

    Click here for Technical Details, Hints, and Do's and Don'ts about Better DFM.

    Q13. Who do I contact for support?  

    If you have any issues or questions about Better DFM
    • Send us an email at BetterDFM@protoexpress.com
    • Or contact us by phone at 800-763-7503 and ask for "Better DFM Support team"
    • Or submit an online service request here
    Need Help Getting Started With Better DFM?
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