hmmm... I would suggest that your mechanical design should take into account the inacurracy associated with the v-grooving, again it is application specific, but getting too tight with PCB's is fraught with danger, not sure what the CTE of FRx is, but can't be too good.
It sounds like a tough call for a scientific approach to specifying the v-groove depth, as the load distributions on the board is likely more important than the board weight as a whole. Danny > -----Original Message----- > From: Dennis Saputelli [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, 5 June 2002 9:45 AM > To: Protel EDA Forum > Subject: Re: [PEDA] Issues related to Excellon Format and Scoring > > > right, but keep in mind that the location of the V groove is not as > accurate as routing so that may be an issue in some boxes > > (in fact i had a few large bds once with the V groove going diagonally > across the whole thing! must have slipped) > > anybody know any scientific method of specifying V groove > depth for the > given board weight and size? > sometimes the fabricator will ask me this question and i > usually answer > to do what you usually do > > Dennis Saputelli > > > Danny Bishop wrote: > > > > HI all > > > > with regards to below: > > > > scoring (or v-grooving) is a cheaper way to manufacture > boards as the > > scoring tool has to remove less material, so it can move a > lot faster. The > > boards will be a lot cheaper with this method. The tradeoff > is that you need > > more clearance from copper and components to the edge of > the board, which > > may or may not be a problem depending on the design. > > > > Routing can be used with a panelized manufacturing process, > you just need to > > leave some areas for break off tabs - this is a small area > that is not > > routed, but several small drill holes are made to enable > you to snap them > > out of the panel after the boards are populated. > > > > cheers > > > > > > > > > Secondly, some FABSs specify different distances between > > > Pad/Trace to Board > > > > Edge for 1) Routing Method 2) For V-Cutting (scoring). So > > > whats the point in > > > > specifying different distances and What does the Terms > > > "Routing Method" and > > > > "Scoring" refer to ? > > > > > > You probably need to work out with YOUR board fabricator what > > > they need in > > > this regard, and then see how it works out in your board > > > design. You probably > > > don't > > > want the router to trim the board right across a component > > > hole, but maybe your > > > > > > design really needs this. As long as you say this is really > > > what you want, > > > most > > > board houses can make it that way, but they will call back > > > and say they think > > > you > > > have an error in the routing outline. I put a trace on a > > > mechanical layer and > > > have > > > it added to all layers, and tell the board maker to route the > > > board outline to > > > that > > > trace. That seems to satisfy most makers. > > > > > > Scoring is how you have the router cut part way through the > > > board, so you can > > > put large panels into your pick and place machine, and then > > > break them apart > > > into single small boards after stuffing, soldering and > > > testing. Most makers > > > charge > > > extra for this. If you are making them by hand, don't bother > > > with scoring. > > > > > -- > ______________________________________________________________ > _____________ > www.integratedcontrolsinc.com Integrated Controls, Inc. > tel: 415-647-0480 2851 21st Street > fax: 415-647-3003 San Francisco, CA 94110 > * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
