slicer board about done

I thought you said the problem was it was too much work to communicate the layout requirements? Did that change after you realized how much work layout can be for a design that is not obvious?

Is your J1 ref des under the part?

V-score can stress the components if you are too close. Seems like you are quite close...

Thanks, but we have a cool pizza-cutter machine for separating v-scores and it seems to be OK. We don't bend and snap.

No professional bends and snaps. The initial scores are not deep enough to allow that without damage to SMDs.

Rick C snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

Get a laser and hook up air extraction to it and slice it with light.

Sheesh.

My laser could do it right down to the thousandths.

Can your laser make a clean cut on an 0.062 thick multilayer PCB? How fast would it cut?

We have a Boss laser that we bought for engraving anodized aluminum. It even engraves nice text onto machined bare aluminum. But it's really slow cutting plastic and such. The pizza cutter will zip through a v-score in seconds and doesn't need programming or fixturing.

Why in your area? Nowadays this does not seem to matter much. (Not that I know anyone to suggest, your sub-100 ps thing is something you really want to do yourself anyway). There are some people doing all sorts of mad designs going much below

John Larkin <jlarkin@highland_atwork_technology.com> wrote in news: snipped-for-privacy@4ax.com:

aluminum.

You make a half inch "rail" on both sides of the PCB and cut slots between the PCB and the rail with small 3/16 'tabs' that have 3 0.040 holes drilled into them that allow you to break off the rails after pick and place and solder ops. The laser would be for snipping off those little tabs clean instead of jagged. The rails are excellent straight edges that will never warp and are super straight. Especially with 0.092 material.

A fresh sharp burr on a dremel works too, but fiberglass eats them alive and they are like $12 each.

Carbide dental burrs cost under $1 each and last a long time.

Have you actually cut PCBs with your laser?

We do some boards with slots and tabs. We have a pneumatic gadget to cut them apart.

I think manufacturing prefers the v-score these days. Less board warping or something.

On a sunny day (Thu, 23 Sep 2021 17:39:46 -0700) it happened John Larkin <jlarkin@highland_atwork_technology.com> wrote in snipped-for-privacy@4ax.com:

I do small boards with a hand jigsaw:

We have a miniature bench circular saw with a fine-tooth carbide blade. It makes a very clean 0.05" wide slice in a pcb. I lay out prototype boards with a bunch (10 or more often) of different circuits, and populate then saw them up for people to test.

We assign part numbers to all our prototypes, even hand-dremeled ones, and document the assembly and test results. That turns out to be very useful.

Really fast stuff can't be Spiced... you have to try it.

On a sunny day (Fri, 24 Sep 2021 07:42:49 -0700) it happened snipped-for-privacy@highlandsniptechnology.com wrote in snipped-for-privacy@4ax.com:

Yes

I think with lasers you will need all sorts of safety measures, I'd rather keep away from that,

Which is to say that John hasn't worked out how to include the stray capacitances, track inductances and a mutual inductances, not to mention dispersion in his microstrip tracks. Non-dispersive buried stripline might be predictable enough for Spice to work.

Spice obviously won't know about right-angle bends in stripline and microstrip. If you laid out your fasts tracks with only 45 degree (or less) changes of direction you probably wouldn't need to tell Spice about the extra capacitance at the bends.

You probably wouldn't do well with an FR4 substrate - the fibre-glass weave is coarse enough to put perceptible discontinuities in transmission lines across it, which will show up with really fast edges.

Yes, that looks like it will damage the PCBs

Best way is to use the bump and have them milled away. That's how the professional EMS does it

Cheers

Klaus