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V-Groove Keep Out Area

#29040

V-Groove Keep Out Area | 10 June, 2004

I have been given a v-groove score keep out area dimension of 1mm from the edge of the groove to the component body; except the dimension becomes 5mm for ceramic components. 5mm seems like a very large value. Does anybody have experience with this? Is it really necessary to keep ceramic components that far from a v-groove score?

Thanks.

Bob

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RDR

#29042

V-Groove Keep Out Area | 10 June, 2004

It really depends on how you depanel these, If you are using a machine you can probably get away with the 1mm, If not, the 5mm is there to help reduce the cahnce of fracturing the component. Some interesting notes about having a defined keepout is it is really dependent upon board rigidity. For example if you had a board that was 2" thick you probably won't bend it that much when you break it apart so really no need to woory about fracturing the parts from stress. Now take a board at .015" the entire board will bend so all parts are going to see stress. I know that these examples are exaggerated but I have actually broke ceramics that were even farther from the edge than the 5mm you state. It also depends upon the orientation of these parts (end cap facing scored edge = bad) With the right process/equipment/and or operators you can deviate from this to some degree.

Russ

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Rob

#29061

V-Groove Keep Out Area | 11 June, 2004

I can't imagine a board to be 2" thick. Am I misunderstanding here? The thickest board I work with is 0.09" thick. That translates to 2.28mm. Did someone say that there is a standard to follow with regards to components near board edges or V-grooves?

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#29066

V-Groove Keep Out Area | 11 June, 2004

Bob: This links to a good discussion on scoring by George Verboven. [It discusses "keepout", but doesn't address your question, because George's "keepout" is not the same as yours]: http://www.tkb-4u.com/articles/other/vscore/vscore.php

The information on that page was initially developed by AccuSystems Corp. Maybe they [ http://www.accusystemscorp.com ] can answer your question.

Further, PWBADV-SG02 "PWB Advanced Designer Certification Study Guide" discusses scoring [Page 285, Section 5.2], but pretty sure that it does not address the DFM-type of keepout that you ask about.

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RDR

#29067

V-Groove Keep Out Area | 11 June, 2004

No Rob you didn't misunderstand, I forgot the decimal point! Lets try this .2" thick (I have built this and yes it was V-Scored) We didn't break any caps on that baby just fingers, that was the wildest VScore job I have ever seen I don't know how they did it because the score lines were not very wide and they left about .04" of material! Any way I was more or less trying to make a point of how I beleieve that Vscore should be handled on a case by case basis in some or even most instances. For example, if you have one of those Vscore depanelers all you should have to meet is that machines clearance requirements which will vary from mfg to mfg and model to model. If you are breaking by hand then ??

P.S. It would be fun to try to depanel a 2" thick board with V-Score wouldn't it! (no router/hacksaw/waterjet/lasers allowed) Russ

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