Daniel, First, I would like to thank you for the opportunity to steal away from my otherwise hectic routine to answer your questions. As a matter of fact, anything that pulls me away from my normal routine is appreciated. Second, I believe that you have probably stumbled across the most well versed people with the highest grade of information possible to answer your technical (as well as political, theoretical, hysterical, and cultural) questions completely and accurately. Working for a company who manufactures finished PCB products (Burn-In boards, to be exact), I think I have a decent knowledge of what processes are needed to manufacture a Circuit Board. I know that my fellow colleagues on the list have more experience then I, and I will bow to their teachings if they find contradictory statements in my explanation. Question 1: Most of your process is correct, except for #3 (Dry Paste) which isn't necessary, and would actually be detrimental, as the moisture in the solder paste is flux (and other things) and would make the solder paste virtually unsolderable. (There was a discussion recently about the life expectancy of screened paste and the impact on the solderability) Also, #6 is unnecessary, as the wave solder process runs the solder over the bottom of the board, and the components are held in place by gravity. Also, there are some other minor steps that I feel need to be mentioned, Touch-up of the boards, Quality Control, and Test. Of course, if your processes are correct, you might be able to get away from the Touch-up (removal of excess solder, adding solder) process all together. We haven't gotten to that point yet, but I can taste it! QC and Test are vital, as you don't want to send your customer a widgit that doesn't work. Question 2: Batch sizes can be as low as 1 pc. (qualification pc.) or as large as you want to think. I know of some companies local whose batch sizes are in the 10,000's. Think about how many widgits are in your local store, how often they are bought, and how many stores worldwide carry your particular widgit. This will give you a base number for how many units are sold worldwide, then you have to calculate your market-share (never an easy thing) and how many other competitors are making widgits just like yours. I would say for the widgit you are basing your report on, a batch size could be 10,000 pcs a month. Question 3: Setup and run times vary on a) size of company, b) equipment being used, and c) how well you know your processes. I would say that a medium sized company with fairly updated equipment and a good knowledge of processes could probably push out 10,000 pcs a month, if it is the only product they are producing, as this reduces the setup time, and it would be able to process the same product around the clock. Each of the processes except for the Quality Control can be an automated step, reducing the down time due to breaks and lunches. Even the QC part can be partially automated due to AOI (Automated Optical Inspection), but there still has to be someone there to verify the machines findings. As I see it, my theoretic company running at full capacity should be able to process 14-15 parts per hour with little downtime running 3 shifts 7 days a week. (What can I say, I am a slave driver!) Question 4: There are many different PCB manufacturers across the world, including cheaper (and I believe this is true in every sense of the word) manufacturers overseas in Asia (another big topic of discussion recently that turned into a pedestal of political opinion). Most of the widgit manufacturers outsource the PCB and parts, as they are not manufacturers of PCB and parts, only the finished product. My company procures several outside sources to manufacture PCBs, purchases parts for suppliers and distributors, and only does the design of the PCB and the manufacture of the finished product, although we have in previous history maintained our own PCB shop and supplied ourselves. It comes down to business basic #48, which is to never get into a business you know nothing about and cannot focus 100% of your resources to learn it. Question 5: There are a multitude of companies that manufacture electronic components, including the horn and possibly the ionization chamber (I am sure my esteemed colleagues would actually be able to find a company that specializes in ionization chambers, and thanks for the tip on the "Short Sniffer", as I am intrigued by it and plan to procure at least one in the next week). Finally, I want to say that the University of Cincinnati is a fine establishment, my sister graduated from there some years ago with a Bachelors in Business Something-or-Other, and I appreciate the opportunity to answer some if not all of your questions. If you need any more information, you can feel free to contact me off-line and I will do my best to answer your questions. Thanks, Rob Eason Dir of Mfg CEIBIS - Cody Electronics, Inc. Burn-In Solutions Santa Clara, CA -----Original Message----- From: Daniel Themann [mailto:[log in to unmask]] Sent: Wednesday, August 14, 2002 3:30 PM To: [log in to unmask] Subject: [TN] Smoke Detector Circuit Board Dear List, I recently contacted the Australian Surface Mount and Circuit Board Association with some technical questions relating to PCB manufacturing, but their instructors are currently traveling and Dianne Hunt recommended that I contact Technet. I am a student at the University of Cincinnati and my teammate and I must write a report describing in detail how a circuit board is manufactured. I recognize that you are certainly not employed to assist college students with technical questions, but if you have a moment and could address the following points without too much trouble, I would very much appreciate your help. Our circuit board comes from a smoke detector and is approximately 1.5" by 3.5". It contains both surface mount (resistors, capacitors, etc.) and through- hole components (ionization chamber, electric horn, battery contacts, etc.). These components are placed on ONE SIDE ONLY. We have tentatively drawn up the following process steps. 1. Screen Print Solder Paste on side one 2. Place surface mount components on side one 3. Dry paste 4. Reflow Solder 5. Insert through hole components on side one 6. Invert Board and apply adhesive on side two 7. Wave solder 8. Final Clean Question 1. Does the process described above seem reasonable? In particular, is step 6 necessary if all components are applied to one side only? Question 2. What type of batch sizes would be reasonable in "low volume" and in "high volume" processes for a board of this type and size? Question 3. What would be approximate setup and run times for each process? We need these times both for our process route sheets and as input into our cost analysis. Question 4. Is it possible to purchase the board itself (without the components attached) from an outside vendor and to simply attach the components in-house? Or does the manufacture of the board and the soldering processes by which the components are attached constitute one continuous process? If the board itself can be purchased outside, how much might it cost given low and high volumes? Question 5. Does you know of any companies that manufacture special through- hole components such as the electric horn and the ionization chamber? Do you know where prices on such components, and more common components such as resistors and capacitors, could be obtained? If you could spare us a few minutes of your time we would be most grateful. If you feel that you can assist with some questions, but not with others we would still appreciate any insights you can offer. If you know of anyone else who might be able to help, please feel free to forward this message on. The project is due in less than two weeks so timely responses would be fantastic. Thank you in advance for your help. Sincerely, Daniel Themann Arthur Jackson ---------------------------------------------------------------------------- ----- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------