4PCB
Advanced Circuits, Inc. (ACI)

CAM Procedures - Free PCB File Check

CAM Based Quoting: Design for Manufacturability Check

It is important for Advanced Circuits to provide the proper tools for you to check your printed circuit board design and confirm that it is ready for manufacturing. For customers that do not have the printed circuit board specifications available, we will extract the pertinent information from CAD data supplied with a request for quote. While we may find some design issues that might cause your PCB order to be put on CAM hold during this review, because we do not perform our complete CAM procedure at this time there may be some issues that are not identified until after your order is placed. Please review the quote carefully for notes regarding the files submitted and to insure that the boards' specifications are correct.

The Best Way to Get Your PCB Quotes - FreeDFM™

Advanced Circuits offers  FREE Online QUOTES, ORDERS, and STATUS of your  PCBs.  As the leader in the quick turn printed circuit board industry, we value your time and want get your quotes as fast as we can and that your printed circuit board order perfectly fits your requirements.  The fastest and most accurate way to receive a PCB quote is through our Design for Manufacturability (DFM) check web site FreeDFM.com. This FREE web based PCB File Check provides you with a full file review to insure that we have all of the files needed as well as an analysis of the design with feedback on 22 of the most common manufacturability issues. This service provides you with the following at no charge. 

Our DFM check tool is easy to use and can help prevent delays in the manufacture of your printed circuit boards. Go to www.FreeDFM.com to upload your files now.

  1. Free PCB design file check for manufacturability. We check to make sure we have the files and data necessary to build your job
  2. Results e-mailed to you in minutes
  3. A graphical report, delivered in minutes, showing any potential issues with detail as to their nature and location
  4. Reduced possibility of CAM Hold issues after the PCB is placed
  5. Enables 48% faster total thru-put from order placement to shipment
  6. Also provides a price quote with your choice of turn times

After Your Order is Placed - CAM Normalization Process:

During the normalization procedure the CAD files submitted with each order are standardized so that they can be processed through our automated panelization step as well as through our PCB manufacturing processes.

The Basic Steps of the Normalization Process are:

  1. Re-naming the files to our standard naming convention
  2. Checking to insure that all necessary files are present.
  3. Importing Gerber and NC drill files into our CAD system.
  4. Reviewing that the boards' specifications in the order match the data supplied (based on information in Gerber files, non-Gerber prints and other document files).
  5. Preparation of files for Custom Spec orders, there are basic modifications that are made to most every set of files received by Advanced Circuits. These modifications are required for our Custom Spec process and are not intended to alter the functionality of your design in any way. The following is a listing of some of the changes made.

Outer Layers:

  1. Pads are removed for non-plated holes. (Unless pads are greater than .050 larger than the hole size. If these holes are placed directly into a copper plane a clearance is created in the plane to avoid exposed copper)
  2. Text outside of outline is removed.
  3. The board outline is removed from artwork if present.
  4. Pads are added for all holes that do not have pads for Standard Spec orders as all holes are plated under this program.
  5. Copper extensions for gold fingers will be added to connect to gold bus bar.

Inner Layers:

  1. We will add a .020" clearance border around negative inner layers for the outer edge of the board.  Clearances will be increased to .020" (.010” per side) over the hole size when possible around a drill  hole and around the edge of a cutout.  If all of these cannot be done without impacting the connectivity of the planes the order will be placed on hold. This is done to accommodate the inner layer clearance requirement at least 0.010" from the edge of a hole to any adjacent copper on the inner layers, and to prevent exposed copper.
  2. Clearances that are smaller than the hole size are assumed to be intended as direct connections to the plane and will be removed.
  3. On boards with edge fingers that will be beveled a .150" clearance will be added along the edge that will be beveled. This is required to avoid exposed copper along the beveled edge.
  4. Text outside of outline is removed.
  5. Non-functional pads on positive layers removed.
  6. The board outline is removed from positive artwork if present.

Drill Files:

  1. Non-plated holes are identified and labeled
  2. Drill files are saved in a standard format.
  3. Double drill hits (duplicate drills), and any drill hits with smaller drill hits inside them will be removed.
  4. Drill chart tolerances that are all blank, or +/- 0.0 will be ignored and the order type tolerances will be used instead.

Rout Files:

  1. We are unable to use CNC rout files for extracting data
  2. Board outlines on .GKO (Gerber Keep out) layers will need to be verified as the actual outline.
  3. The largest diameter routing bit is 0.093" (used to produce 0.100" spacing), using this bit reduces routing costs by allowing multiple panels to be simultaneously routed.
  4. The cutting path that the machine takes is called the NC route path; normally you need not to worry about it. You want to relay to manufacturing any specific cutting requirements you might have.
  5. With regard to the board and slot outlines. We would prefer to have these included in the Gerber files (solder mask and drill/fab files) with a line width .005" or 0.010". This line width will not affect the board price as the board outlines are disregarded when the minimum trace width is determined.

Solder mask:

  1. Clearances are increased to meet a minimum of .004” swell for manufacturing. This is .002” per a side. If Clearances will expose traces or ground plane an FYI will be sent and we will continue to process the order as is. If soldermask clearances are missing then the order will be placed on hold for verification.
  2. Text outside of outline is removed.
  3. The board outline will be added to this layer if not already present. This will be used for reference during production

The Following are the Options that Advanced Circuits has available regarding via holes:

"Exposed Vias"

  1. These will be processed with a clearance in the solder mask image that is equal to or greater than the via pad size plus .005" solder mask swell.
  2. If you have a requirement other than this we can accommodate clearances as small as the finished hole size plus .005" Please include any specific requirement in the fabrication notes and/or order documentation.
  3. These can be quoted and ordered with our standard parameters.
  4. Unless prior arrangements have been made the boards will be built based on the solder mask image files submitted.
  5. Most design software packages have accommodations for including or excluding the vias from the solder mask images.

"Tented Vias"

  1. These will be processed with no clearance in the solder mask image for the the vias.
  2. This will result in the pads being covered with solder mask and the holes may be open, partially plugged or completely plugged.
  3. As we do not have dry film solder mask available we cannot offer vias tented in such a way as to guarantee that all of the holes will be completely covered.
  4. These can be quoted and ordered with our standard parameters. Unless prior arrangements have been made the board will be built based on the solder mask image files submitted.
  5. Most design software packages have accommodations for including or excluding the vias from the solder mask images.

"Plugged Vias"

  1. These will be processed with an additional process that will fill the vias with a solid material that will prevent solder and air flow thought the vias.
  2. The entire via cavity may not be completely filled.
  3. These orders will require a custom quote.

"Filled Vias"

  1. These will be processed with an additional process that will fill the vias with a solid material that will prevent solder and air flow thought the vias.
  2. The entire via cavity will be filled.
  3. These orders will require a custom quote.

Silkscreen:

  1. We increase any text widths below 0.005" to a minimum of .005".
  2. A silkscreen clip layer (Corresponding solder mask layer) is created to eliminate ink on pads. We do not add via clearances if the via holes are tented.
  3. The board outline is removed from artwork if present.
  4. Text outside of outline is removed.

Solderpaste:

  1. We delete outside text and panelize if design is ordered as an array.

Additional Markings:

  1. Our UL logo and date code (WKYR) will be added in either copper or silkscreen on all Custom Spec Orders unless otherwise specified. An internal reference number (Ex. P94301) will be added to Standard Spec orders in copper.
  2. Additional customer required markings will be added as requested.

Panelization arrays: Tab-Route/Score:

What is scoring?

Scoring is a "v" groove cut into the top and bottom surfaces of an array configuration of multiple PCB's or a PCB with removable rails or frame. The cut depth is set such that the material left is the lesser of .018" or 1/3 of the finished thickness. When this process is used the printed circuit boards are typically set up side by side and end to end with no gap between the edges. This results in the v-grove cutting into the area of the boards, so a .015" clearance between the edge of the boards and any conductors is required.

How do I indicate score lines?

When placing an order that requires scoring please indicate this requirement by checking the score option on the order form. If the CAD files supplied with the order already have the boards step and repeated, indicate the locations of the score line in the fabrication or panel print. If you are supplying the CAD data as a 1-up image please supply a drawing with the array configuration that you would like including tooling holes, fiducials and step and repeat requirements.

Our standard score angle is 30 degree (blade angle total), but we can also do a 60 degree angle at a premium price.

We can set up your scored array for you (Standard and Custom orders), If we have:
  1. Your single board files (1-up files)
  2. The total number of board in the array and if the number of board in the X direction and the Y direction. (boards will be placed edge to edge (0 mils between)
  3. The width of the Top, bottom, left, and right rails (standard is 0.5"), if required.
  4. Select scored array on your order.

What is tab routing?

A tab route is used to create arrays, often called "route and retain". The customer can place more than one board (same or different design) up in a given area in an array or panelized configuration. This is typically for the convenience of the customer or for assembly requirements that utilize pick and place machines to load components. The PCB's are then separated by breaking or cutting the tabs. Tabs are usually 0.100" in width and are placed with at least 1 on each side of the boards. The tabs are usually .050" is width.

How do I tab rout my board?

We can set up your array for you (Standard and Custom orders), If we have:

  1. Your single board files (1-up files)
  2. The total number of board in the array and if the number of board in the X direction and the Y direction. (Please allow 0.100" between your individual boards for tab rout spacing)
  3. The width of the Top, bottom, left, and right rails (standard is 0.5"), if required.
  4. Select tab route array on the order.

When placing an order that requires tab routing please indicate this requirement by checking the tab rout option on the order form. If the CAD files supplied with the order already have the boards step and repeated, indicate the locations of the tabs in the fabrication or panel print. If you are supplying the CAD data as a 1-up image please supply a drawing with the array configuration that you would like including tooling holes, fiducials and step and repeat requirements.

Click Here to view a default array drawing

Tab Rout Spacing:

Please allow 0.100" spacing between your individual pcb boards for tab rout spacing.

  • Artwork, drills and rout will be panelized as required when an array is ordered. Additional tooling holes and fiducials will be added upon request.

Unless an array setup is specifically requested the following standards will apply:

  • For tab-rout orders .100" spacing will be added between boards.
  • No spacing between score boards will be added unless there are routing requirement that would necessitate additional spacing.
  • .500" rails will be added around entire array.
  • Score lines will extend to the end of the array.
  • Jump scoring will require a minimum of .250" spacing before the start of the score line and .250" past the score line.
  • Tooling holes or fiducials will be added per customer specification, in the absence of any specification these will be added based on our standard configuration.

Click Here to view sample default array drawing

If perforated tabs (mouse bites) are requested we will use a .060 tab with two .018 holes in each tab. The edge of the perforations (mouse bite) holes will be on the edge of the outline.

The files are then saved and stored on our network.

CAM Panelization Process:

During the panelization process the files prepared during the normalization process are copied to fill our 18" x 24" production panels.

The basic steps of this process are:

  1. Importing Gerber and NC drill files into our CAD system
  2. Step and repeating the images into the usable area (16" x 22") of our production panels.
  3. Adding the panel identification and tooling features to the border of the panels.
  4. Saving the Gerber images of the panel artwork (conductor layers, solder mask images and legend images) and sending them to the photo department for laser photo plotting.
  5. Saving the NC drill files and placing them on our network so that they will be available for the CNC controllers to retrieve
  6. Creating the NC rout programs that are used to add slots, large holes and cut the individual boards from the production panels. These are then placed on our network so that they will be available for the CNC controller to retrieve.
  7. Preparing the data files used for our Quality Assurance steps. The reference data that is used for Automation Optical Inspection (APQI) and Electrical Test (ET) are prepared and placed on our network so that they will be available when needed during production.