What's the space needed on PCB for v-cut?

I'm using 0.8mm board thickness boards.So I plan to do single panel with v-cut provision.Let me know how much space provide board to board and then how much depth indicate to fab house for V-CUT .

with Advance Thanks

Re: v-score depth on pcb

I always requested a minimum web of 0.5mm on 1.6mm boards, and a groove angle of not more than 45 degrees. Ref IPC-2222A page 16. For a 0.8mm board I would suggest some experimentation, to small a web and the panel becomes unstable to handle, to much web and the cutter can wander during de-panelisation.
That said there are some points to consider with v-scoring:
It is one of the most stressful ways to de-panelise PCB's, be careful of MLCC caps near score lines and other components sensitive to bending and stress, even if you are using a cutter. The automatic in line cutters are better than manual ones.
With V-scoring you have to plan your panel out carefully, as it is very easy to make a panel that will sag during the thermal cycles, hense I never had a web less than 0.5mm. You need to know what heat cycles your board is going through: Reflow, 2 side SMD, Wave, Selective Solder. At 0.8mm I presume there are no heavy components, as weight distribution on the panel is important.
I'm not a big fab of v-scoring, but have used it quite extensively in a high volume production.

Thank you Marce.

Dear Marco;
- please if you can give us the standard to know how i can calculate the the size of V-cut
- second when i send gerber to fabricator i create layer named Vcut and i drow lines where i need V-cut; i assume the line width is the line width as shown in image is it correct or what?
Or this line width discribe the web size and how i can spacift the angle of the Vcut


Best regardes;
Eslam sakr
PCB Desgine engineer

This should help. When I do lins on a V-cut layer for a manufacturer I just use a very thin line 0.1mm or so, as it is just a guide line for there machining, I specify how much web to be left and the maximum andgle of the V-cut blade.
http://www.vscore.biz/vsguide.html

Marc