Three years ago a survey was conducted by the SMART Group of 250 printed board suppliers on their current and preferred solderable finish for surface mount boards. The results are included here for your reference. The survey is now being repeated to also cover the cost associated with different solderable finishes. A survey also conduct three years ago considered the cost of printed board manufacture based on a standard model, the results are also included here. Next week a new survey will be posted on the Internet examining the trends in different solder finishes and the cost associated with them. If you are a PCB manufacturer and found the information here of value then please take a couple of minuets to complete the next questionnaire and return next weeks Email. The final results will be circulated to all contributors. The more contributors the more accurate incite will be obtaining on the current trends on alternative solderable finishes. Remember that 500 SMART Group member companies in Europe's largest Trade Association are interested in solderable finishes and improving their assembly yields. Bob Willis SMART Group SMART Group Survey Results To provide further information on the European market for alternative finishes a brief survey was circulated to the 215 UK printed board manufacturers listed by Technical Reference Publications. The survey was also circulated to eight companies in mainland Europe. From the 223 forms circulated a total of 41 were returned after completion. Most of the responses were from UK companies with only three returned from Europe. The manufacturers were first asked which solderable finishes do they currently offer their customers for surface mount products. The most widely offered finish was solder levelled 24% with traditional tin/lead reflow 22%. Gold over nickel was offered by 17% of the companies. Other finishes which were offered for surface mount boards were immersion tin, roller tin, nickel, horizontal levelling, bare copper with no protective coating and solder paste and reflow. Only one or two companies offered any of these alternatives. Two of the suppliers offering these alternatives were involved in flexible circuit manufacturer. The printed board manufacturers who responded indicated that in terms of volume of boards or square inches solder levelling was the most often specified finish 69% followed by traditional tin/lead finish 26% and organic coatings 5%. The solder levelling process was indicated by 52% of the companies as offering the best compromise between the requirements of the assembler and the ease of fabrication. There was very little difference between the three other finishes tin/lead reflow, gold over nickel or organic coatings. In terms of popularity with customers the following finishes are being most often requested for surface mount products. The finishes are listed in order of popularity. 1. Solder Levelling 2. Tin/Lead Reflow 3. Gold over Nickel 4. Brushed Tin/Lead 5. Organic Coating (Entek, Glicoat T) 6. Flux Lacquer Coating (Different Manufacturers) The difference in solder finish costs below are based on the following model. The model printed board for cost calculation is a double sided board produced from FR4 laminate incorporating surface mount pads down to 0.025" pitch on both sides. The board size is 6.28" x 8.95" with photoimagable solder resist on both sides and silk screen legend on one side. There are 2368 holes, four different sizes the smallest being 0.018". Track size is 0.006" with 0.008" spaces. An estimate of 20% should be used for open copper areas requiring the solderable finish. The price should be shown for a single batch of 500 and a 1000 boards with the tooling costs. Copper protective finish 500 PCB's L8.84 each 1000 PCB's L8.28 each Hot air levelled 500 PCB's L9.44 each 1000 PCB's L8.85 each Nickel/gold 500 PCB's L9.51 each 1000 PCB's L8.95 each One off: Tooling cost L426 Electrical test fixturing L550 Remember that next week we will be circulating the new survey so please contribute to the leading Surface Mount Association and be SMART. Bob Willis Tel: (44) 01245 351502 Fax: (44) 01245 496123 Home Page: http://ourworld.compuserve.com/homepages/bwillis Email: [log in to unmask]