Questions tagged [pcb-fabrication]

About the manufacturing of PCBs (Printed Circuit Boards).

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1answer
4k views

Proper storage of ferric cloride PCB etchant

I etch about half a dozen printed circuit boards each year at home, using an aqueous ferric chloride AKA iron(III) chloride etchant solution. As I want to minimize the costs and hassle of buying new ...
3
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1answer
3k views

Eagle - Oval pad

How to make a through hole pad other than circular shape in Eagle? I need an elongated circle / elliptical sort of pad. This is the best I could achieve: This is what I did: 1) Made polygons on Pad ...
0
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1answer
249 views

How to probe traces on a PCB

I have some PCB's that I have ordered from China. The PCB has a BGA component along with traces which go from the BGA component to another BGA IC(USB controller) and finally to USB. Right now I am ...
0
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1answer
102 views

Where can I find some basic information about ICT? [closed]

I'm trying to find some information about the basics of ICT (In Circuit Testing) but having trouble finding anything useful. From the few things I managed to find, I gather that an ICT tester is a ...
0
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2answers
209 views

PCB coating for a high temperature environment

What PCB coating is good for a high temperature environment (my environment is about 30-70 C), and is available in a spray can or so that is easy to implement without need of a device/machine?
3
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1answer
497 views

Apply etch resist on copper

I cannot get my toner etch resist on to my copper board. I'm doing with the iron, but each time I try the ink does not transfer completely. I've tried many things - applying some water on it, ...
4
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1answer
317 views

Galvanic action on gold plated PCB

It has been always said that having gold plating on a PCB has lots of advantages. Not only does it give a good clean low resistance contact, but the perfect flat surface. However based on the galvanic ...
0
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1answer
997 views

V-cut gerber format

I prepared a panel on Eagle Cad. now I am preparing Gerber files for the production. What device output and file extension do I need to save the v-cut layer?
5
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6answers
6k views

DIY PCB Manufacture: Photoresist or Toner Transfer?

So here's what happening: I have my board layout ready to go on eagle, and am looking for a good way to produce this board at home, of a quantity of about 2 or 3, so not large scale at all. All the ...
5
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3answers
982 views

Good way to affordably manufacture low-quantity PCB?

I am thinking about making an open-source development board for a specific field in power conversion. If there is interest from local universities, I will manufacture a few hundreds of these boards. ...
6
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3answers
7k views

Components to avoid using on an ultrasonic cleaner

What components populated on a PCB are not safe to clean in an ultrasonic cleaner? It is not limited, but I specifically wonder below components if they are safe to use or some requires special ...
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3answers
413 views

Four layer PCB, leaks current on edges

I was testing a four-layer PCB and got electric shocks several times when trying to touch the edges of the PCB. The four layers are: top/+15V/ground/bottom layer. It seems that there are several "...
9
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4answers
2k views

Is it always possible to reduce the number of layers on a PCB by making the board larger

I see that a 2 layer PCB is really cheap to prototype. A 4 layer PCB is almost 4x more expensive . I have a design that uses DDR3 RAM where I need to match trace lengths. However I also need to keep ...
1
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0answers
313 views

castellated holes size and spacing [closed]

I'm about to create surface mountable module with at least 65 castellated mounting holes but I am wondering about few things: Is there a minimum size for a castellated hole? Is there a minimum ...
1
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2answers
1k views

How to etch Double sided pcb?

I am trying to etch my circuit on a double sided copper clad at home. After designing my circuit I took a print on tracing paper and used iron to get the trace on copper clad. When I used iron paper ...
1
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1answer
1k views

Is every pad in eagle a via?

Correct me if Im wrong, a via is a hole that join two or more layers in a PCB. I have a PCB design who has the pads to solder but I want solder only one side, do all my pads that are connected to my ...
4
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1answer
636 views

Are we still protecting pcbs with wax?

I've just replaced my smoke detector. It was manufactured in 2006 by BRK. This is an ionization-style detector. I took it apart and the track side of the circuit board is covered with a thick waxy ...
8
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2answers
11k views

How much space should be left between a PCB's edge and traces and holes

I am designing a PCB for use with an Arduino mega and I am wondering if there is a good rule for how much space I should leave between the edge of the PCB and various items like: traces (ground, 5v ...
1
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1answer
232 views

Pastemask. Manufacturing PCBs

after finishing some designs, it is time to manufacture and assemble them. For making these designs I have to create all padstacks, footprints, etc from scratch, so I took PCB Editor examples as ...
4
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1answer
462 views

How to reduce the AVR MCU footprints on PCB? [duplicate]

I want to make my circuit board very small. I have seen many smaller boards with complex circuit. But I am not sure how do they do it? Is it all Custom circuit implemented on VHDL or some micro ...
10
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2answers
1k views

What is the purpose of the brown pads on this PCB?

This PCB has wire connections to external coils that are soldered to pads on the board. Each of the connections has a patch of brown material carefully placed in between the two pads. What is the ...
4
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3answers
2k views

QFN Standoff (Solder Joint) Height

When designing a QFN footprint, I've read from (reputation limited, only 2) sources... http://www.freescale.com/files/analog/doc/app_note/AN1902.pdf http://www.atmel.com/images/doc8583.pdf ...that ...
8
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2answers
3k views

Vias without annular ring on internal layers, non-functional pads in a via

My PCB layout package (Altium) has an option to define the full stack of a via so one may have different sized annular rings on different layers. I was wondering if it is considered "manufacturable" ...
0
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2answers
106 views

How an electrical component behave after being exposed to excessive current/voltage? [closed]

I wan't to know more about how to recognize a damaged component due to excessive impulse or constant current exposure. Particularly resistors, ceramic/electrolyte capacitors, protective diodes, ...
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1answer
1k views

Hydrogen Peroxide for PCB Etching

I found 500 mL of hydrogen peroxide. It says 12% and food grade. Normally, before, what I found was 3% only, and there wasn't any note like food grade at all. Is this suitable while etching PCB? Is ...
8
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3answers
1k views

Panelization (& Depaneling) a Metal Core PCB

What is preferred way to panelise a Metal Core PCB (MCPCB) - V-scoring or Tab-routing? The engineering challenge I am facing is that the boards are meant for production (1,000 qty in the initial ...
1
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1answer
154 views

How do I make a through-hole via? [duplicate]

Using a simple PCB with copper on both sides but naturally in between, is it feasible for a hobbyist to make through-hole vias like this: It seems there is copper in the via itself, isn't there? If ...
3
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2answers
1k views

Place a component on specific height above the PCB

what I have as a big issue is the following layout with two connectors. The problem is that the connector K201 (in right bottom) is very close to the frame. This frame will the attached to a device so ...
5
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4answers
850 views

Clear material for UV Box

I have constructed an UV light box using the innards of a commercially available finger nail drying unit consisting of 4* 9w tubes. (should be more than enough). I have had very poor results in ...
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2answers
1k views

What constitutes a Via-in-Pad?

Would any of the via's in the picture be considered a via-in-pad? or is it only if it's dead center of the pad?
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1answer
1k views

What are “slash sheets”, and how do they relate to PCB substrates?

I am trying to specify the stackup for a PCB. Previously I have used whatever the board house considered to be their "standard" stackup. This time I am looking at using FR-408 (pdf) because of its (...
6
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1answer
4k views

What are the recommended trace width and clearance on homemade PCB's?

I know that there are multiple processes and lots of variables regarding homemade PCB manufacturing. Using the right tools it is possible to achieve professional levels. I'm concerned for students ...
2
votes
2answers
3k views

Using a CFL ballast to power 9W UV tubes

I would like to build a low-cost home UV exposure box for PCB manufacturing. Recently my attention was brought to these dirt cheap UV bulbs which are used in manicure drying lamps. I have the ballast ...
5
votes
3answers
1k views

Is it possible to create a double layer PCB by gluing together two single layer PCBs?

I'm really in a hurry with a university project. I need to finish the first prototype of an electronics board by the end of the week. It's a through hole board, no SMD. Having just single sided ...
19
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4answers
6k views

Why are vias bad?

I am designing a PCB with EAGLE and saw that it was trying to limit the amount of vias through the PCB. Why do you want less vias? Why are they bad? Do they bring extra manufacturing cost or is it OK ...
2
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4answers
327 views

PCB design few questions

Quick couple of questions, I am designing my first PCB and want to have a few boards prototyped with OSH Park. For a board I will be manually soldering components to, will I need to include a tCream ...
9
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3answers
3k views

SMD Crystal solder(?) problem and any recommended test procedure

I use a 32.768 kHz SMD crystal (datasheet) for a MCU. Here is the layout part of the crystal. Here is a view from an actual PCB I mounted the components by hand-soldering, and produced about 30 ...
8
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3answers
1k views

How to cut costs when fabricating large PCBs?

I've looked online at PCB fabrication companies, and they invariably price their boards according to the size of the board as the primary factor. Why is this? The physical board itself isn't that ...
0
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3answers
312 views

Printing the self designed PCB

I have designed the PCB on Eagle. Most of the components are SMD pakages. This is for the first time i have designed the PCB. I want to print this PCB in the industry (Chinese industry) but i have no ...
0
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1answer
343 views

PCB - High current PTH

Some power boards are failing a high current (lightning) test where an MOV lead is used to transfer the current to the bottom of the board - see MOV lead and pad attached. The issue seems to be that ...
1
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0answers
110 views

0.8mm PCB for a PSU circuit

I am working on a PSU that converts 230 VAC to 12Vdc (0.1 A). The board has the necessary clearance and creepage distances. Would it cause any safety issue (IEC60950) if the 0.8 mm (or 1.2 mm) thick ...
9
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2answers
4k views

Air gap on isolation space

The below photo belongs to a PSU. I wonder what was the reason of placing air gaps on the 8 mm isolation. Is it to improve the isolation or provide a thermal relief (although there is no component ...
1
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3answers
2k views

Print PCB on copper using Altium

I've been trying to print and make my own circuit using Altium (print it on film paper, iron it on copper-coated plastic and then dip it in Ferric Chloride etc.), using Gerber files. Only problem is, ...
0
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1answer
121 views

Symmetry in routing

I'm moving a design to an 8"x6" panel, and got thinking as I drew the route layer(white). The cutouts on the right two boards will be routed out. The left cutout will stay with the frame. During ...
3
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1answer
823 views

From what pitch should I consider ENIG finish

My design (4-layer, FR4, 1.6mm) has a couple of ICs with 0.5mm pitch pads and some LEDs with 0.4mm pitch pads, very small LEDs. Should I consider ENIG (more expensive) or will HASL do the job? I read ...
0
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2answers
1k views

PCB design cost for 0.4mm pitch bga, 0.1mm drill hole, 4-layer routing using via-in-pad [closed]

I am doing a development board for a IC with 36 WLCSP package. My PCB layout has 16 via over pads, minimum 0.1mm drill holes, 4-layers. I need to fabricate my PCB. And I could not find a exact pricing ...
1
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1answer
362 views

BOM/OPL parts help before PCB fab

I am completing my first official PCB project. I am outsourcing the PCB fab to Seeeed Studio. I was wondering if any of you might be able to shed some light on my issue. I am using their PCB ...
15
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5answers
7k views

Anything bad to place a via on a pad?

Once I mistakenly placed a via on 0603 pad and didn't have any problem on soldering. I am routing another board now and I could save some space by placing some vias (0.3mm) on a 0603 pad. I wonder if ...
2
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1answer
1k views

Understanding PCB layer stack-up shorthand notation [2:(1(2+345*67)*16):7]

I was given a PCB layer stackup specification like this: [2:(1(2+345*67)*16):7] For an 8 layer blind via setup. Could someone provide a reference to decode this ...
2
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1answer
502 views

Should PCBs be rinsed after being cleaned with IPA?

A lot of people recommend using 99% IPA to clean flux (and other stuff) off PCBs. I haven't been rinsing off boards after cleaning with IPA as to my knowledge it's not corrosive, but I'd like to hear ...

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