Questions tagged [dfm]

Design For Manufacturing - Principles and techniques that are used to ensure that a product is more easily manufactured, has higher yield during manufacture and/or exhibits lower cost of manufacturing. May be accomplished through choice of components, extra circuits for testing through to mundane issues like space for fixturing and labeling amongst many other techniques.

further reading

Design for assembly (DfA) for throughole components and surface mount components. The section on surface mount is somewhat outdated, though.

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How to go from newbie to manufactured?

I'm a software guy who wants to get into the hardware side of things so I can enjoy the same creativity from software design in the physical world. I've found plenty of posts here regarding how to get "up and running" in the electronics world, but I…
DJ_R
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Does the PCB have to be thinner than through-hole pin length?

If I have a part that has pins that are 1.2mm long. Can I use a PCB that is 1.2mm thick or does it need to be even thinner than that?
the five states
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Are acid traps real? (2014)

Some people online say that acute angles in trace routing will cause these problems: "Acid Trap" - PCB etchant gets stuck in the corner, and eats away too much, causing open circuit "Peelable" - Narrow strip of photoresist falls off the board before…
AlcubierreDrive
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BGA, big through hole components, and heavy coper planes: manufacturability issues?

Short version: Is it a manufacturing issue to combine BGA components, big through hole components (think full brick DC/DC converters, big relays, ...) and many copper planes (1-2 oz) on the same PCB? I'm thinking about small production batches (2-30…
Sandro
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How close is too close for traces on a PCB?

Are these traces too close for conventional PCB manufacture? DRC check advises against it, but I haven't filled out all the settings for it. For scale, the resistors are all 0603.
Thomas O
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How to make a device in miniSD or microSD form factor?

I would like to design and get produced a device in miniSD or microSD card form factor. This is not actually a memory card, it just uses that connector. There are other devices like that, for example Electric Imp. I'm wondering what type of circuit…
Alex I
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Do vias have to be in the center of test points for in circuit tests?

I am trying to add test points for in circuit tests (ICT.) To keep all test points on top layer, the easiest way is to add pads to the vias. My questions are: Can the vias be located off-center to the pads as shown? I need to fix some clearance…
Peter
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What is the purpose of these unusual IC footprint features?

I am working on creating a footprint for the MAX25254 buck regulator and am puzzled by several inconsistencies which are proving annoying: Inconsistent pad sizes Seemingly unnecessarily complicated shapes Rounded corners but with inconsistent radii…
JYelton
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Balancing copper on inner layers of PCB

A similar question was asked - What is Copper Thieving and why use it? And my question originates from the comments of the answer in the linked question. I have read and understand that to help the etching process, you balance the copper so that it…
efox29
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PCB pads different diameter on top and bottom

When I had a DFM review on a board I have designed, the feedback was that the pads on layer 1 (top) needed to be reduced in size, to: "avoid the issue of copper temperature taking during wave soldering and for reasons of rise of alloy in the plated…
droseman
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Why are reversed geometry (0306, 0204) capacitors not used more often?

It seems that reversed geometry or low inductance ceramic chip capacitors (MLCCs) are simply better in every spec than regular geometry, and may allow using just one value to bypass instead of two (eg a reversed 1uF instead of a 1uF and 0.1uF).…
Alex I
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Via to Pad Clearance

Is it possible to put a via right next to the component pad it is connected to? In other words, if a via and a component pad are on the same net, can they touch as in the image below (red=top layer, yellow= mid layer, gray=via's pad, brown=hole,…
aghoras
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Is there a rule of thumb or an IPC standard for reducing (windowing) solder paste deposition on exposed pads?

I am creating a footprint for a 24-pin QFN package with exposed thermal pad. Sometimes manufacturers will provide solder paste mask guidelines in addition to metallization for the landing pattern, but not always. I believe I need to reduce solder…
JYelton
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Best practice for ICT test point locations

While I have found a few resources ( here here here ) describing the coverage (strive for 100 %!), distribution (avoid clustering, at least 100 mil apart, away from tall components), and size (40 mil if you can) of test points designed for bed of…
calcium3000
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How close can BGA packages be placed to each other?

I'm wondering if there is some rule of thumb about how close different BGA packages can be placed to each other. What limits that besides pick and place accuracy? I'll ask a few board assembly places for their recommendation but I was wondering what…
Alex I
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