Hi!
I’m just about done with a design and going to order a pcb. I can’t get in touch with any vendor pcb shop due to the week end, so I figure I drop a post here instead.
I have a design with several small boards that are separated by perforated spacers. Is this something that can by an issue when the board is manufactured?
Without seeing what it looks like, we can’t tell for sure.
Breakaway tabs are certainly very manufacturable, yet not all manufacturers will do it. Some of the very affordable Chinese ones don’t like it, or will at least charge extra. Unless the board becomes very unstable mechanically, I think it’s not a problem of manufacturability as such, but just not wanting to do it. A lot of ‘unnecessary’ drill hits for perforated lines reduce tool life and rise costs.
Best to ask explicitly.
The board house will tell you if they have issues.
If the perforation drill holes (center/center) aren’t closer than 2 diameters, they shouldn’t have any problem.
Also, sub-boards might incur an extra fee per board, depending on the board house for the extra milling I guess?
Don’t reduce the space between sub-boards to less than what the board house is able to mill… 1mm router bits are the small end of the scale, bigger is better here (I’ve done 1mm for last 4 boards and no problem).
The tab width and distance between tabs influences mechanical stability… I’m still impressed by the stiffness that 3mm wide tabs with 3x 0.5mm drill holes at a spacing of ~50mm create between sub-boards.
Also:
If you want breakaway tabs, dirtyPCBs.com is the last cheap PCB fab I know that does them for you without charging extra. (Itead, Seeed and PCBWay all started charging or refusing to do it.)
Thanks for all input. It really helps! 
Elecrow did mine for free as well in 10x10 cm as soon as I ordered ENIG and a stencil (they did charge extra when I used HASL and no stencil in the past). With ENIG and stencil they’re even cheaper than DirtyPCBs for me.
Thanks for the info. I wouldn’t say it’s a matter of price, but still ever $$ counts right? 
I would have used DirtyPCB, but had some troubles at the start (they were always very helpful, though, so service is very good!). Anyhow, I’m in the Tropics, so better to have some long term corrosion protection on the boards, as the HASL will be a PITA to solder some years down the road…
I’ll check with the manufactures. Maybe I should start with dirtypcb if they don’t charge extra for this stuff.
How do you folks do 270deg corners? I.e. a ‘normal’ corner is 90deg and a cut away corner is 270deg, ah well I guess everyone gets it. My idea was to have a semicircle, about 1-2 mm diameter, on the least critical wall. Advice would be appreciated. 
I use Seeed Studio Fusion for PCB prototyping, they have a stric checking before production, there will be a professional engineer contact you if your board couldn’t be made.