Anan: There are quite a few things that could cause this effect. Here are a few of the most common. 1. High Chloride: Analyze bath for chloride PPM concentration. If you do not have that capability look at all your anodes, if they have a gray color then that's an indicator of excessive chloride and/or polarization. All anodes should have a uniform black film. 2. Low Additive(brightener,leveler,carrier): Check the additive levels. If you don't have the more sophisticated analytical equipment to do this, it can be done using a Hull Cell. 3. Torn Anode Bags: Pull the bags inspect for tears or holes. This can be done visually or you can fill them with water and check for leaks. 4. Sulfuric Acid(high) and Copper Sulfate(low) out of balance: Analyze for concentration and ratio. 5. Metallic Contamination: Analyze for trace metal impurities. Such things as lead can cause roughness. Dummy plate bath at low current density with corrugated dummy panels. 6.Incorrect Anodes: Make sure you are using phosphorized copper (0.03-0.08%)anodes. 7. Old or Contaminated Sulfuric Predip:Make up a new predip. 8. Bad Rectifier: The rectifier could be working incorrectly putting out excessive ripple or amperage variation at times. Check rectifier for correct output. Question: Does it appear in high or low current density areas? Does it appear to be in one area of the plating tank? Regards Michael Barmuta Staff Engineer Fluke Corp. Everett WA 425-446-6076 -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Anan Zreik Sent: Thursday, September 01, 2005 6:19 AM To: [log in to unmask] Subject: [TN] chocolate plating ' Hi every body : every so often for a long period of time we get a "chocolate copper" residue on the surface of our boards on our electrolytic copper plating line . This "chocolate plating" can be removed by hand , and it is not connected to the copper below . does anybody know this phenomena , and its cause?? --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------