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Electronics Forum | Wed Jan 29 14:22:56 EST 2003 | russ
Most bowing I see is caused by an asymetrical layer stackup of the PCB. (different copper thicknesses throughout the stackup) e.g. for a 4 layer board - 2 oz. copper on layer 1, 1 oz. copper on layer 4, etc... I would doubt that is the V-score since
Electronics Forum | Mon Mar 03 05:35:21 EST 2003 | Kelly
We just had this issue a couple months ago with a single sided FR-4 board which was scored. We found that the design was a factor but also the depth of the v-score. Since then we have re-designed the part further away from the score line. At the same
Electronics Forum | Thu Feb 06 14:47:50 EST 2003 | MA/NY DDave
Hi "some customers/designers want to have via holes to be present in the PCB pad, due to some belief that it helps in heat dissipation. " As I think about this I don't know exactly why they would be concerned. I can imagine in some exotic products
Electronics Forum | Fri Feb 28 12:02:15 EST 2003 | MA/NY DDave
Hi You are right. I guess some of us missed this point in the way this on line dialog works. I like to put the specification that the PCB supplier must adhere to, on the Physical Print. The Physical print is often used by outgoing and incoming insp
Electronics Forum | Mon Mar 03 13:22:20 EST 2003 | MA/NY DDave
Hi I see David F already gave a good answer. The basic advantage, if you can afford it, is a more stable PCB during the soldering process. Higher Tg enables this. Also some materials serve to match CTEs (coefficient of thermal expansion) a bit bett
Electronics Forum | Thu Feb 27 14:41:48 EST 2003 | jax
Cad rotation should not change with relation to how the part is presented to the machine. It should only depend on how the part is orientated on the PCB when the PCB is at 0 rotation. There is a seperate field to input part rotation inside a feeder.
Electronics Forum | Sun Mar 30 21:17:17 EST 2003 | MA/NY DDave
Hi I don't know your PCB, circuit, or product application, and probably should steer you to at least the ESD Association http://www.esda.org/ for one place in case you find anything that you really love. I do know some of these people first hand and
Electronics Forum | Mon Apr 21 16:39:50 EDT 2003 | k_h
You might try reducing your solder paste volume. To much solder paste gives the part a pool to float in, nullifying the positive effect of surface tension. I use an aperture on stencil for the heat sink which is 5mils reduced on each side and a 25mil
Electronics Forum | Sat Apr 19 12:00:07 EDT 2003 | modeltech
I am completely new to SMT design and for my next project I plan to use SMT for the first time. Since production volumes of the PCB's will be low, hand soldering is definitely an option, and will be necessary for my prototype PCB assembly. My proble
Electronics Forum | Thu Apr 24 23:04:45 EDT 2003 | yukim
I've been struggling with this problem for a while. We have two products: A, which is Ok and B, with tombstone defect (0603 & 0805 capacitor chips). A & B have the same design: pad sizes, separation between pads, components orientation. Both have s
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