There are a number of good reasons for not silkscreening a PCB. Silkscreen is a source for errors that can delay fabrication. It is an extra process step usually manual that adds cost to a PCB. Incorrectly applied it can be a contaminant in solder joints (silkscreen on pads). Any or all of these maybe a good reason for leaving it off. If I were creating a PCB with no silkscreen I would make an effort to identify polarization of components. The convention has been square pad for pin 1 on through-hole discreet and dip parts. We use an extended pin for SMT ICs and a hash mark for SMT discreets. In addition to parking polarization We supply a component placement map that identifies the placement of all components with copper features shown for orientation. I know this doesn't make life easier for the assembler but sometimes you gotta' do what you gotta' do. Jeffrey A. McGlaughlin Sr. PCB Designer Battelle Memorial Institute Columbus Ohio [log in to unmask] -----Original Message----- From: Rick Thompson [SMTP:[log in to unmask]] Sent: Monday, 14 February, 2000 12:36 To: [log in to unmask] Subject: Re: [TN] Silkscreen, Pin-1 markings, etc.... Steve, FWIW, we actually get quite a few boards without silkscreen or with minimal silkscreen, not including all components. When we get it, its usually done because of lack of usable space for marking, even away from the components. Ideally in those cases, we get both X/Y data information for programming and a marked up assembly drawing showing the locations for inspection. It's not what we'd want if given the choice, but it's usually workable. As for the square pad on pin 1, while it's pretty common, I don't think it's any kind of standard. Again, we see a variety of uses for square pads, not always indicating pin 1. Enough so that we discourage our operators from making that assumption unless there's some other corroboration with other markings or the customer verifies that is the case. Rick -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Stephen R. Gregory Sent: Monday, February 14, 2000 4:13 PM To: [log in to unmask] Subject: [TN] Silkscreen, Pin-1 markings, etc.... Hi ya'll! Is there anything that says a board should have silkscreened reference designators on them, or pin-1 markings or indicators (like a square pad for PTH locations) incorporated into the design? I know there sometimes isn't room to put a reference designator right next to a location, but in those cases I've seen the designer find room someplace else on the board and then arrange the reference designators in the order that the parts are in, then have a line going to the beginning of that row of components. What I'm talking about usually I see when passive components are so tightly spaced there's no other way. I've hardly ever run across boards that didn't have some sort of way you could tell what goes where...I've seen maybe 2 or 3 boards in all the time I've been working, and that's including the board I have now. So is there some sort of requirement, or is it just good sense to make things easier to build? Thanks! -Steve Gregory- ############################################################## 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. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ############################################################## ############################################################## 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. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ############################################################## ############################################################## 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. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################