Janice, I believe part of the problem is due to a vaguely worded surface copper thickness requirement. For the drawing note as worded now, I would interpret the one ounce copper foil to be a STARTING foil thickness requirement of 0.0014" with one ounce of copper plated being equal to 0.0014". This DOES NOT mean inspect for a minimum of 0.0028" surface copper (not even a nominal of 0.0028"), because of the variation in the copper foil thickness as received by your board manufacturer and manufacturing processing as you noted. For the current drawing note, I would inspect for a total surface copper thickness of 0.0024" (0.0010" minimum foil thickness after processing + 0.0014" copper plating on the surface). FYI, the 0.0010" final copper foil thickness you discussed matches that in IPC-RB-276 for 1 ounce starting copper weight (internal layers). Recommendations: 1. Be sure of what you need for your conductor thickness. If you used Figure 3-4 of IPC-D-275 to arrive at a surface conductor thickness of 2 ounces, then be aware that these charts "include a nominal 10 percent derating (on a current basis) for normal variations" including conductor thickness, conductor width, etc. For this situation, lets assume you want a nominal design value of 2 ounces of copper. 2. Clearly state your conductor thickness on the drawing. Generally, people use ounces of copper to refer to a starting copper foil weight (thickness). Your drawing does not clearly state a finished minimum copper thickness (unless elsewhere on the drawing you reference IPC-RB-276. You should translate the "ounces of copper" to be plated to a thickness in inches (or millimeters for the rest of the world). I suggest replacing your note that says "* one ounce copper foil and another ounce plated on the surface foil." with one that says: "minimum starting copper foil weight of 1 oz/ft2 plated to a total copper thickness of 0.0024" minimum". Change the last number to 0.0025" if you want to more closely follow the intent of the 10% derating mentioned above. This note clearly states a finished copper thickness requirement for inspection and allows the fabricator maximum flexibility for his processes. 3. Depending on the design and your supplier's processes, there may be a cost premium to plate a thicker copper plating to meet your thickness requirement. In comparison, the standard surface total conductor thickness (foil + plated copper) for a one ounce copper foil is 0.0018" in IPC-RB-276, para. 3.9.2.3. You are asking for at least 0.0006" additional copper plating than the "standard". Regards, David Estes PCB Commodity Manager Texas Instruments (214) 997-2942 ------------------------------------------------------------------------------ On May 9, Janice Lund wrote: Main question: ON HIGH VOLUME DOUBLE SIDED POWER BOARDS. WHAT PERCENTAGE DIFFERENCE WOULD THE PRICE INCREASE BE, OF A STANDARD MANUFACTURABLE BOARD PRICE SHOULD I SEE (of .001" minin the hole), IF ANY, TO A TOTAL FINISHED THICKNESS OF 2 OUNCE COPPER ? (please read below to find out what my vendor says they can do without increasng the price) History: My boards are power boards requiring a total of 2 ounce copper on the surface and a minimum of .001" in the holes. These are submitted to UL for approval of our product with the accurate requirements, because at least my prototype house reads my print and gives me what I require. My prints states: * .001" minimum (not average minimum) copper in the holes * one ounce copper foil and another ounce plated on the surface foil. I am aware that the copper plating process plates a ratio of 1:0 in the hole to 1:2 on the surface. Therefore, .001" minimum plate in the hole should result in .0012" plated on top of the surface foil. I would assume that no vendor would risk plating the absolute minimum and therefore would attempt to plate .0012" in the hole, resulting in .0014" plate on top of the surface foil. I am aware that 1 ounce foil has a tolerance of +/- .0002" on the foil thickness. I am also aware that deburring , scrub and micro-etch may remove another .0002" from the surface of the foil. Based on this, the absolute minimum should be -> .0010" foil + .0012" plate = a total copper thickness of .0022" . Whereas, my copper hole requirement is .001" minimum with the maximum controlled by the hole size and tolerance. I expected to receive boards with 2 ounce finish minimum copper thickness and copper thickness in the hole in excess of .001" to reach the surface thickness requirement. WAS I WRONG?? ( please to not reference IPC-A-600 as my print takes precedence over that spec.) My Production Fabrication Vendor states the best they can give us .0020" - .0025" on the surface for our specified 2 ounce copper .0028" requirement. Needless to say they were not giving us close to that before. (so I will believe an improvement it when I see it). The fact is, if we accept their minimum of .0020", aren't we now still under the .001" minimum in the hole?? My Vendor also stated that there would be a price increase if a total of 2 ounce total was required. Seems to me, if they took the job, they should of been able to do the work requirements! Lets just say I have a tolerance on the 2 ounce of .0004" minus and .001 plus (just to have a plus) which is about 15% of .0028". Aren't I really only asking them to produce boards that will have .0002" more that what they should be giving me already. Should that cost me?? Thanks in advance!