| New Design Tips:
Our Pre-Engineering staff have created a whole new set of design
tips to help you build better boards. These creatively-named tips will
help to get your files approved much quicker.
From the desk of Pre-Engineering...
We are making some modifications to the design tips to improve the value to customers. Instead of design tips every month, we plan to (on occasion) have file/capability tips to help ensure that orders move quicker through Pre-Engineering. This cuts down on potential problems that could effect your lead times.
After reviewing the orders received last month, the items responsible for most delays were:
pads and clearances
Below is our recommendation to review before placing your next PCBpro order:
1) Make sure hole sizes have pads that are 0.017" plus any required amount at junction.
2) When holes pass through ground and power layers, the area of isolation needs to be 0.013" radius, or rounded to hole size plus 0.025" minimum for diameter. |
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IDENTIFYING NON-PLATED HOLES!
We recommend that you include a drill drawing to identify the non-plated holes in your design.
Because design packages often calculate the amount of clearance around a non-plated hole differently than a plated hole, the non-plated holes can end up with less allowance for passing through solid copper ground and power planes.
While this is not a problem when the non-plated information is supplied in a drill drawing, it only becomes one if the non-plated information is omitted. The result being mounting holes that short the power and ground planes together. OUCH!!
Remember to always identify your non-plated holes. |
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DON'T LEAVE WITHOUT INSTRUCTIONS!
After the end of the project, make sure you send in the files with your order before taking your vacation (add a note saying "use my default parameters.." if documented information conflicts with the files or our capabilities). Guess how many one week turn jobs were not on the dock when the Engineer expected them after leaving town? This can happen due to missing files, or items requested in an old read me that conflicted with our product capabilities. Make sure this holiday season to provide plenty of instructions and backups if you are not going to be in the office. |
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AVOID BUYER BEWARE
If you are having a purchaser order for you, please make sure they have all of the information to place the order. A lot of buyers and purchasing agents do not have all of the correct information to quote/order correctly, resulting in hold-ups and delays of your order. PCBpro has a unique feature in the MyPro Members section that allows you to add CC: (courtesy-copy) e-mails to others for your saved quotes, orders, etc. This would allow your buyer and yourself to have copies of all activity on PCBpro.
Update your account by clicking on the links on the left side of the MyPro Members page the next time you log in. It will make you and your buyer happy, which makes us happy because your order will be correct without delays! Update your account now, click here. |
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CHECK YOUR SOFTWARE'S DEFAULT SETTINGS
You spent hours getting your design just right and when the boards arrive you noticed that all of the references from the Silkscreen layer did not show up. The "Default" settings on some software packages for silkscreen use .001, .003, .004 and .005 mil lines for the letters in the text. PCBexpress & PCBpro are capable of producing down to .007 reliably.
This could have been averted if:
1) 'Review Your Files' had been added when you placed your order. If so, then our Photo department would have seen the error. We will not review your files unless you select the 'Review Your Files' option.
2) Make sure and check the outputs in the design package for any settings that will cause a manufacturing problem. We have a list of our minimum requirements on the PCBpro Web site under " File requirements" or click here. |
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WEEBLES WOBBLE, BUT THEY DON’T….
In the printed circuit board production process there is: drill machine X & Y true position capability, drill bit deflection, image film stability, Multi-layer layer to layer shifting, routee tolerances, and plating allowances. These will be different depending on what board production facility you have chosen (and thanks for choosing us at PCBpro.com).
We have added up our entire machine and process tolerances and ask that circuit board designs allow for these processes (to list just a few):
- Outer layer pads should be 0.017” more than the drill holes (if you have to go a mil or two less try using teardrop shaped pads to limit the amount of breakout that could occur at the pad / trace junction).
- Inner layer clearances should be 0.025” more that the drill holes.
- Copper features should be 0.010" away from the routee line for outer layers, and .025" for inner layers.
For more visit our pcb capabilities page. |
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PLEASE LOOK BEFORE YOU LEAP!
Use the parameters on our pcb capabilities page to learn about our manufacturing capabilities prior to layout of your design, and prevent processing failures. By setting the pad sizes, clearances, minimum traces and spaces, your design will make it through the manufacturing process and will prevent board failures.
Use the free viewer: http://www.Pentalogix.com/Download/download.html to confirm your files will be interpreted correctly prior to sending. If you can load them using "Viewmate", then we can too.
The amount of time you spend setting up your software outputs, and confirming they load correctly, will insure a working board that will be shipped when you need it. |
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Mirror, Mirror on the wall. Can you tell me? It’s your call.
All you need is a one sided job. Therefore, you output a drill layer "abc.txt" and a copper layer "abc.top". You think to yourself, “This should be an easy job". Upon reading it into Viewmate (a free download from the people at www.Pentalogix.com) you see that a drill file and copper layer shows up. Job done! You zip it up and send the file in.
On the receiving end, our job is to produce the films and decide how this board will be built. Quick multiple choice…would we:
a) Place the copper layer on the top side of the laminate
b) Place the copper layer on the bottom side of the laminate
c) Mirror the image (Y axis) and place the copper layer on the top side of the laminate
d) Flip the image in the X-axis and place the copper on the bottom side of the laminate.
e) Build the job 4 different ways and hope that one of them is what the Customer had in mind.
To avoid your job being put on hold, please use text to label your board. That way if your software packet mirrors upon output, or you view your work from the solder, top, component, bottom, layer 1, layer 2 or whatever, we will build it right.
Here is an example:
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GARBAGE IN, GARBAGE OUT
Well, we would not call any ones design garbage, but if you designed your board with the software’s defaults without changing to what the board shop can produce, Garbage is what can happen. One example is Silkscreen output. It is possible to produce silkscreen using .007” lines. Some Software uses .001, .003, .004, etc. for there Silkscreen outputs. You may not see your Silkscreen! |
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USE THE FORCE
After you get a copy of our Mfg requirements sheet, configure your design software to the recommended out puts, and have downloaded a free copy of “Viewmate” from www.Pentalogix.com to review the files before you send them in. |
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THAT SIR IS ILLOGICAL!
As Logic dictates - power before ground unless after signal when ground is first and that signal needs to be…. Please let the board shop know your layer stack up. A number in the layer name, or layer designator will do. |
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WHAT’S UP DOC
A readme file listing what you are ordering, a list of files, their order (stack up) if a multi layer board and any special needs will help. While you are at it, if this is a first time order for you say “use your default parameters for this product line, disregard any of my notes that say otherwise “, will be greatly appreciated (and keep the order moving along). |
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DON’T CRY OVER SPILLED MILK….
Try using teardrop shaped pads. They allow for that drill wander and Image shift and will help keep a healthy (over .002) annular ring. |
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WHERE’S THE BEEF?
When outputting your Silkscreen layer, be sure that the lines used are at least .007” or you may not see them on the board. This is due to our ability to print through the silk screen. |
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LIONS AND TIGERS AND BEARS – OH MY!
Well Circuit Board Design isn't Kansas. Go to our pcb capabilities chart. The shaded areas in the column are numbers that will keep you out of trouble. |
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WEEBLES WOBBLE, BUT THEY DON’T….
Well, in our production process we have drill wander, image shift, and routee tolerances. So we ask for the outer layer pads to be .017" more than the drill holes, Inner layer backsets .035" more than the drill holes, and copper features backset .025" from board edges. |
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THE FILES
Extra files add confusion and missing files add delays. When ordering a 4-layer board with Solder mask and One side Silkscreen, send in 7 layers and a drill file. A missing file layer will mean a delay. Extra files will delay if they contain information in conflict with the order form i.e. print, readme, old tool file which was not changed etc. The shotgun approach of sending in every thing that the program will output will just tick John Wayne off, so Make my day and use the 44. (This tip not been sponsored by the American movie classic assoc, nor the NRA). |
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Danger, Danger Will Roberson!
If you are a user of revision numbers (a great idea), check your drawing, file text and order number for the correct one. When revision numbers are different, it forces us to confirm which is the correct one. Most of the missed changes occur in the document header, or a generic print that was not updated. |
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WHAT? I DID NOT SAY THAT!
After outputting your design files, use Pentalogix’s “Viewmate” software to verify because “What you see is what you will get”…. Some communication guru came up with a technique to verify that communication takes place. A Message, Sender, Receiver, and Interference are on the diagram. Having the Senders message restated by the Receiver verifies that the Interference did not corrupt the message, and that the Receiver understood it. You are the Sender. Your design is the Message. The Board Shop’s software is the Receiver. The software’s output, zip utility, e-mail, missed keystrokes, and software’s input can be Interference. By using “Pentalogix’s viewer, you can see how our Software interprets your designs, and what the board will look like. |
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BUT WHAT IF IT’S WRONG?
We have added option for this doubt. It is our 'Review Your Files' Option. While we are not design engineers, we do know what we do well, and use a set of design rules that will insure that your design will make it through our production process. We have let the designer know what will work at our pcb files page. In addition, we will contact you if the design may pose any production problems. |
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THE CUSTOMER IS ALWAYS RIGHT!
Your design is right, and you will get it just as is looks if you pre-viewed it with “Viewmate” software by Pentalogix. If the Customer’s design happens to be wrong, we refer to the 5 bold words that begin this paragraph. We call it a logic loop of wonderful bliss, because we can do no wrong when the Customer is always right! |
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WHERE ARE YOU?
After the end of the project, make sure you send in the files with your order before taking your vacation (and a note saying Use your default parameters if information is conflict with them). Guess how may one week turn jobs were not on the dock when the Engineer expected them after leaving town due to missing files, or items requested in an old read me conflicted with our product capabilities. |
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You say “Tomayto” and I say “Tomauto”.
Top, component side, Top copper, Layer 1, “*” .top, “*” .lyr1, all mean the same thing. Different design packages output names differently (as well as file orientation), as well as people do. Seeing a layer reference designator as text somewhere on the board helps us get the layers in the correct order and orientation. It’s as simple as adding “1”, “2”, etc just outside the cut line. |
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WELCOME TO THE SHERWOOD FOREST
Think of the PCB Drilling operation as Robin’s Archery target having a bull’s-eye and 3 rings. The bull’s-eye is the drill size.
The first rings thickness is the Drill machine tolerance (within .005 of true position for our drill machine). The second ring is the plating allowance (We give this ring .0035 approx). This is why we ask for a pad .017” larger than the hole to prevent break out. We do not want Robin to miss the target.
The last ring is what you need at the minimum at your trace to pad junctions (add this to the .017”).
Add a fourth ring and you can cover inner layer clearances. (This will account for Layer to Layer shifting -up to .005”), which is why we ask for an inner layer clearance of .035 more than the hole size. |
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From the Musical “DRATS” (to be read while humming the song “Memories”)
UP late at night, all alone in the middle of the night,
Wondering if all is all right, if the design is going to work in the light,
When the ship truck, Comes to our dock in the morn,
Then I will know, All is well…..
Take the guess work and needless worry out of your project, use our Design check option, or go to our pcb capabilities chart to get a list of our to set your software’s parameters with. |
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Additional Design Tips...
Our goal is to provide design tips to help you build better boards. We want to help eliminate potential problems so your board can run through our shop (or any circuit board manufacturing shop) without hassles or delays. We hope you will find these tips helpful and beneficial to your PCB needs. |
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View your Gerber and Excellon files with a separate viewer--not just your
design package. We recommended you try Pentalogix's freeware Viewmate program:
http://www.Pentalogix.com
This step may identify any of your software's output abnormalities. |
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Check to make sure the board shops capability and capacity is in line with
what you will need. Find out their tolerances and change the outputs of
your design package to reflect those. That way your design's requirements
for traces, spaces, thickness, tool sizes, or a particular standard, are
accounted for. |
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Audit your outgoing files to be sure the purchase order information matches your drawings and readme notes. All duplicated information (part numbers, quantity, part size, readme text, file labels, etc.) should match up. Don't forget to include your name, phone number, email & available times for a contact to help save time. |
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*** Design Tips of your own? ***
If you have tips of your own or potential problems others might be able
to avoid, please send them for others to use. Send them to here.
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: PCB Library : PCB Design Tips
