ACD is a Printed Circuit Board design service bureau specializing in quick turn, complex, printed circuit boards. We can meet your design needs for rigid boards, rigid flex, flex circuits, and MCM-L using such advanced CAD tools as PADS PowerPCB, Mentor Graphics Expedition, and Cadence Allegro. Whether it is a complex design that you need "yesterday" or a simple design with no set schedule, we will make the extra effort to ensure that we deliver a quality product exactly when you need it...or sooner!

How We Quote
 

Using the data you provide, ACD bases all quotes on a combination of factors:

	Equivalent integrated circuit (EIC) count. (EIC = Total Number Of Pins/14).
	Board density (total usable board area divided by the equivalent integrated circuit (EIC) count.
	Type of circuitry
	Overall board complexity
	Component type
	Layout guidelines
	Turn time requirements (standard vs. quick turn)

All of these factors help ACD determine the labor required to perform layout services.  The quoted  price is a fixed cost for all known parameters at the time of quoting. The only issues that typically change our quotes are incomplete/incorrect input data, engineering changes, and/or a change in schedule.

Design Process

I. Design Review

A discussion with the customer is held to review mechanical information, component specs, design parameters and number of layers, fixed and/or suggested component placement, and critical signals which require special routing. At this time the lead designer will inform you of the many methods of communicating to us any additional information that you may have. This will include modem, e-mail, FTP, FAX, and shipping instructions.

II. Data Prep and Mechanical Setup

A parts list is prepared and specs are checked for any missing information. The customer is contacted with any questions that arise about the mechanical or component information. The board mechanical information is then compiled and new library parts are created.

III. Component Placement

Components are placed following the customer's input on any fixed locations and suggested placement guidelines. The first goal is to optimize the critical signals and secondly to provide the best overall routing flow. The customer will be given a set of plots showing the board dimensions, components with fixed placement, component pin outs, and hole sizes. This information should be checked carefully.  This information is also supplied to ACD's internal checking group. Plots showing a complete placement will typically come later and the placement will be reviewed and modified as needed to meet all spacing, height, and routing requirements. The customer is asked to approve the placement before routing begins as any changes to the net list or placement after this time could be very difficult to incorporate and may cause adjustments to the turn time and price that was quoted on the design.

IV. Routing

Routing may be done in several phases depending upon the design. If highly critical signals such as ECL or high speed clocks exist they may be routed by hand and reviewed for customer approval. Once approved, these signals will be locked down so that they are not moved by the autorouter. Other groups of signals may exist that are less critical but still need to be kept short or require ECL type routing. These signals are added to a control file in which source, termination, maximum trace, stub lengths, and routing priorities are assigned. The auto-router then routes these signals first using the parameters given in the control file. After the auto-router has completed routing and finished its clean up passes, any signals that failed to route are routed by hand. At this point some additional manual clean up is done.  If mitering is required, it is done at this stage. Check plots are generated for the customer's review both during the critical routing phases as needed, and also once the routing is completed. Reports on line lengths and parallelism are also available to aid the customer in verifying the design.

V. Post Processing

Some work is required to clean up silk-screen markings and re-number components when required, and also to add board numbers and other markings. If re-numbering is required, a was/is list is supplied to the customer to use in back annotating the schematic. Design rule checks are run to verify connections and spacing and any errors are corrected. At this time gerber files are created for all routing layers, silk-screens, masks, paste, and fabrication drawings, as well as drill and bit files. A basic fabrication drawing is included in the standard package. If detailed fabrication and assembly drawings are needed they can be created and may be pen plotted in the customer's format or output to Autocad drawing files.

VI. CAM and Deliverables

The gerber and drill data are loaded into the CAM Station for another round of design rule checks. These include spacing checks, pad stack checks for minimum annular ring, potential plane shorts, and checks for un-terminated traces. Additional requirements such as coupons, board panelizing, and tooling for board fabrication are done here. Data and check plots are then generated and passed through a final visual check. In addition to visual checks, the CAM station also produces an IPC-D-356 netlist which is then compared with an IPC-D-356 netlist from the Cad package. At this point the deliverables are sent to the customer. This concludes the design / layout process.

VII. ECNs

Minimal design changes are typically required during the layout of a new design, and these will be implemented without additional charges. Significant ECNs requiring re-work of part of a layout which has already been completed, will result in additional charges and may change the delivery schedule. These charges will be calculated at an hourly rate based upon the time required to implement the ECNs.

The goal in this page is to describe our steps in the quoting and designing of your printed circuit board. This is by no means the only process we use, but it is the most common. We are very willing to create a specialized process to meet your requirements more efficiently.  If you have any questions, please feel free to call a member of our sales team anytime at (972) 664-0900.