Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [manufacturing-process]

54 questions
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Why do some diodes have a glass package?

Put simply, why do some diodes such as most Zeners and Schottky diodes have a glass package as opposed to the more traditional plastic package? Is it ease of manufacturing, thermal properties, or some other electrical phenomenon?
Hugoagogo
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29
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Why are resistors tolerances relative instead of absolute?

Every resistor has a tolerance, this provides the user with an idea of the accuracy of the product. This tolerance is represented by a percentage. This means: a big value resistor will be less accurate than a small resistor with the same…
M.Ferru
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Environmentally sustainable electronics

I am part of my company's work to become more environmentally friendly and sustainable. On a high level for the company that means pursuing ISO certifications (such as ISO 14001) and working according to other standards. But I'm trying to figure out…
Lars Petersson
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16
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Why can my bare PCB be magnetized?

I am working on a magnetic sensors design and noticed that my measured magnetic field bias shifts over time. I have studied the bare PCB and measured that it can be magnetized with a strong magnet. I tested two blank (unpopulated PCBS). The first…
Nullified
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What exactly makes small quantity PCB production costly compared to large quantity PCB production?

The per-PCB cost of manufacturing a small number of PCB is 10 times or more compared to the per-PCB cost of manufacturing a large number of PCBs. So what is it exactly that adds to the cost? People say there is setup cost or initial cost, what is it…
Vidit Katlana
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Solution to detect bad vias in production process

I face the problem of damaged (cracked) vias in a rigid/flex assembly. It is very difficult to detect those defects before mounting the assembly. Products with cracked vias may fail during lifetime while early detection seems difficult. The…
Ariser
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How do components not get knocked off or fall off during reflow?

I am looking at reflow ovens. A lot of them have a metal conveyor belt the boards sit on. On a double sided board, when you put the board on the metal belt, won't the metal belt knock components off as they are only held on by paste? In the case…
SA_A30
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Anyone know the premise of this PCB assembly note?

The assembly note states: Bake bare PCBs in a clean and well ventilated oven prior to assembly at 125*C for 24 hours. Why is this necessary?
klamb
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Microcontrollers Manufacturing Process

I'm interested into know what semiconductor manufacturing process use the most common PIC and AVR microcontrollers, in particular 8 bit microcontrollers. Obviously they are not at the same level of modern CPUs and GPUs (~20 nm), what is the gap…
Oceanic815
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Why are the challenges in using SRAM over DRAM for main memory?

Historically, when compared to DRAM (dynamic ram), SRAM (static ram) is more expensive with a lower density, but it's much faster and more efficient. As a result, SRAM is reserved for devices, such as processor caches and microcontrollers, where…
user148298
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Question on "Parts should be used within 5 days after opening." statement on component shipping package

I've been given the task of verifying a batch of ICs from a chinese broker, to see that the chips the company has bought are what the broker claims they are. The package we've received looks like this, and has this statement (amongst others) on…
Lars Petersson
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Why do some exposed pads have small tabs, and does my PCB footprint need them?

I've noticed a few component packages now that have small "tabs" on the sides of their exposed pad (thermal pad). One example is the Analog Devices ADM7154 LDO: Note the 0.356 x 0.457 mm tabs on the left and right sides of the exposed pad. Why…
TypeIA
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How do custom security certificates find their way onto mass manufactured products?

Amazon and Microsoft both have IoT services that manage message and state brokering. These sort of services generally require machines to have unique security certificates embedded into the firmware so that they can securely authenticate with the…
Inc1982
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What's going wrong with my solder paste / mask?

A short question this - I've got a board with a QFN-32 0.4mm pitch footprint, I ordered this stencil, and a tube of this solder paste, and the result is in the picture below. Now, I'm new to this, but I've done some homework about process and indeed…
John U
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Placing through hole and SMT on the same side

I have a design with huge push buttons (with 6 TH holes.) There's a few of them so they do take up quite a bit of space mechanically from the top. I was thinking of placing the majority of the SMT part on the other side (same side where the TH would…
Hasman404
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