That would be due to aspect ratio, dia. vs depth of barrel. The process of plating into the holes gets more difficult the 'longer and skinnier' the hole is. The other cost driver is the accuracy requirements and annular ring restrictions place on the board.
Most shops can handle 14 mil holes with 24 mil pads.... in a .062 thick or thinner board. Bill Brooks PCB Design Engineer , C.I.D., C.I.I. Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 http://pcbwizards.com -----Original Message----- From: Back, Norb [mailto:[EMAIL PROTECTED] Sent: Thursday, May 13, 2004 1:00 PM To: Protel EDA Forum Subject: Re: [PEDA] VIA Importance: High I guess it all deepens on the shop One shop we use for the simpler boards said 20mil or smaller for finished hole would have an increase cost per board And the other shop we use said 14.5mil was no extra cost at 4 layers, 6 layers or more was a different story though Thanks Norbert -----Original Message----- From: Tom Robinson [mailto:[EMAIL PROTECTED] Sent: Thursday, May 13, 2004 2:50 PM To: Protel EDA Forum Subject: Re: [PEDA] VIA Thanks guys for the info. tr :) -----Original Message----- From: Brooks,Bill [mailto:[EMAIL PROTECTED] Sent: Thursday, May 13, 2004 1:27 PM To: 'Protel EDA Forum' Subject: Re: [PEDA] VIA I have used 14/24 successfully without any manufacturing price/yield issues. When you go below that threshold the price starts to climb. Bill Brooks PCB Design Engineer , C.I.D., C.I.I. Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 http://pcbwizards.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/[EMAIL PROTECTED] * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
