Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [mechanical-assembly]

62 questions
44
votes
5 answers

Why did Axial Capacitors Fall Out of Use in the Industry?

When inspecting the boards from electronics made in 1980s and earlier, one distinct feature is the extensive use of axial, electrolytic capacitors as power supply filter. Axial ceramic decoupling capacitors were used as well, to a lesser extent.…
比尔盖子
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What kind of tape is used to hold together electronics during shipping?

Not so fast! This isn't that kind of tape (Kapton). By holding electronics together, I mean to hold mechanical parts together for shipping such as flaps and other parts that can flop such as printers and scanners. It's a very thick material that…
Zhro
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4 answers

Why use kapton tape?

I have noticed a lot of electronics use kapton tape in places where a heat resistant tape isn't necessary. Why is that so? Is it just because it's a good adhesive?
Artichoke
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22
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3 answers

Is 0603 vs 0402 assembly mass production cost optimization still relevant?

Historically, choosing a design avoiding 0402 and finer pitch components was advantageous for mass production cost savings. The yields were improved and accuracy requirements for pick and place machines were reduced. This allowed vendors to choose…
lm317
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21
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3 answers

How to secure cables to a PCB

What is a good way to secure cables to a PCB? There are some good advice in the following post, but the application is slightly different: Securing electrical cables to holes in enclosures? In this case, the strain-relief/securing of the cables will…
K0ICHI
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20
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3 answers

Removing rosin flux residue from PCB

I have a nice looking purple PCB from Laen's batch service, which I have assembled using rosin flux. I have cleaned the board as best I can with isopropyl alcohol, which gets rid of the tackiness of the rosin, and also improves the dielectric…
Zuofu
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14
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2 answers

How is this design for a basic PCB pick and place?

I have zero experience with any serious mechanical design, but out of necessity and curiosity, I'm attempting to build a pick and place machine (for my hobby projects as well as low-volume PCB production) -- but a very basic version of it,…
Thomas E
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Is there an insulation compound for exposed leads on a PCB?

The top of the enclosure I am building is going to be the PCB. The PCB has a 7-segment LCD and the leads are somewhat exposed. Is there an insulation material I can brush on or squeeze on that will stick and cover the leads and prevent accidental…
Bill
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8
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4 answers

Colliding fasteners in electronics retrofit project

I have a mechanical problem with securing a Mini PCIe card into an adapter which then goes into a legacy product's connector. Look carefully at the orange PCB in the picture below and you'll notice that the screw passes through a cranked out "wing"…
user98663
6
votes
2 answers

OK to connect ring terminals directly to a PCB?

I am designing a PCB board and was wondering if there is a reason not to use ring terminals directly to a PCB. The PCB could have a pad surrounding a hole like I often see as ground connections. A small bolt could go through the PCB with two nuts,…
Zach Dwiel
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1 answer

What is the usable area (for connectors) of a PCI Express card bracket?

I have a number of awkwardly shaped connectors that I need to cram into a single PCI Express slot metal bracket without any of them colliding with the host PC case's metalwork. The connectors are a mixture of proprietary and standard. My…
user98663
5
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1 answer

Which side should I place a TO-220 transistor on a heat sink?

On TO-220 heat sinks, there are usually two sides, on which the transistor fits easily. One side is more narrow, surrounding the transistor. The other side is more open. Which of these sides is thermodynamically best option to put transistor on?
hkBattousai
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How are air-core inductors typically constructed?

I'm considering learning to build air-core inductors for power applications. For example, I presently want a .5-1 mH choke capable of handling 50 amps for two seconds. Winding my own air-core seems like it might be a cost-effective solution, but…
Stephen Collings
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3 answers

Are there strong but insulative screws?

Common through-hole power semiconductor devices, like TO-220 and TO-247, can be mounted to a heatsink by running a screw through the hole in the device. However, on TO-220 the hole is often electrically connected to one pins of the device. TO-247…
Stephen Collings
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4
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Is there any difference between Silicone and RTV

I've used silicone RTV that's intended for use on PCBs and have also used 100% silicone purchased from the hardware store to use on PCBs. I was not able to tell a difference between the two. Everything looked and smelled exactly the same. I know…
bunker89320
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