Wayne,
We no longer use the "pizza cutter" style machine to separate scored boards except for a very few cases. We use a Fancort VPD instead. Our testing has shown the "pizza" style cutter to induce too much strain further than the mfr says. "Break-away" tabs are problematic unless you "cut" them somehow. We did a study a while ago with strain gauges, but I don't know if I can locate the data. If so, I'll send it to you.
Steve
Sent from my iPad
> On Aug 15, 2018, at 9:22 AM, Wayne Thayer <[log in to unmask]> wrote:
>
> Hi Steve-
>
> Thanks for the info. That sounds very reasonable, but it would be nice to
> have more analytical data such as
> -Which orientation is more susceptible to damage? (seems obvious with the
> tabs but I'm not certain on the scores)
> -It seems obvious that smaller parts would be less susceptible, so maybe
> they can be closer to the edge?
>
> Wayne Thayer
>
> On Tue, Aug 14, 2018 at 11:49 AM, Vargas, Stephen M <
> [log in to unmask]> wrote:
>
>> Wayne:
>>
>> We recommend keeping larger size ceramic style parts at least .200"
>> from the PCB edge where depanelization is required. For V-Scores, we ask
>> that a route in the breakaway be added to minimizes the stresses. For
>> mouse-bites, we like to see the tabs as far as possible from the edge
>> parts.
>>
>> Regards,
>> Steve Vargas
>>
>> Lockheed Martin RMS-Rotary and Mission Systems
>> Polaris Contract Mfg.
>> 15 Barnabas Rd
>> Marion, MA 02738
>> 774-553-6192
>> [log in to unmask]
>>
>> Please consider the environment before printing this e-mail
>>
>> -----Original Message-----
>> From: TechNet <[log in to unmask]> On Behalf Of Wayne Thayer
>> Sent: Tuesday, August 14, 2018 2:36 PM
>> To: [log in to unmask]
>> Subject: EXTERNAL: Re: [TN] MLCC spacing/orientation to V-score or
>> Perforated Tabs
>>
>> That doesn't give me "warm fuzzies"! I have personally seen pizza wheels
>> result in a broken cap 0.125" away (no visual cue, 10% of parts had the
>> problem). Leaving a potential reliability issue to each pcb assembly house
>> is a real problem for me. And not just me, for all of us who use PCBs. I
>> did find a paper from Kemet which touched on the issue, but not in any
>> clear, useful guideline kind of way.
>>
>> Wayne Thayer
>>
>>> On Tue, Aug 14, 2018 at 11:03 AM, John Maxwell <[log in to unmask]> wrote:
>>>
>>> Depend on vendors recommendations for best results
>>>
>>> Sent from my iPad
>>>
>>>> On Aug 14, 2018, at 1:24 PM, Wayne Thayer <[log in to unmask]>
>>> wrote:
>>>>
>>>> Hi-
>>>>
>>>> Is there an IPC standard for distances from components to board edge
>>>> for the V-score or perforated tab techniques? I've been able to find
>>>> several recommendations from manufacturers, but I couldn't find the
>>>> applicable
>>> IPC
>>>> doc.
>>>>
>>>> Wayne Thayer
>>>
>>
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