As a rule of thumb the prepreg pressed thickness should be no less than double the thickness of the copper to be encapsulated. so one piece of 7628 will barely encapsulate 1 3-ounce layer. your top and bottom panel note indicates that you may be heating too fast. If ANY boards are heating at more than 10 degrees C / minute try slowing things down a bit further. what do you call high resin content ? Top spec is not high - we would call high 50% plus. E-Mail me if I can help further. Regards, Dave Heywood. [log in to unmask] ---------- From: [log in to unmask] To: [log in to unmask]; Dave Heywood Subject: [TN] air voids in multi Date: 23 January 1998 04:51 <<File Attachment: ENVELOPE.TXT>> Can anyone shed some light on a problem i am having in my lam dept. We are getting pockets of air (bubbles) trapped in low pressure areas towards the middle of the panel Seen only on the top or bottom panel of each book This only happens on cores with 2-3 oz cu. So far we have tried heat rise 12 -16 F /min b-stage with more resin- we are using 7628 only vacume assist press and hydrolic low pressure vs high no kiss cycle flatness of plates not able to modify the pettern thank you for any suggestions ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ############################################################## ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ##############################################################