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Questions tagged [pcb-fabrication]

About the manufacturing of PCBs (Printed Circuit Boards).

0
votes
1answer
50 views

Surface Mount Adapter PCB With Castellated Holes

I have some prototype boards that I would like to modify. The modification includes removing a section of circuit and replacing it with another circuit. My theory on how to do this is to make an ...
22
votes
4answers
6k views

Different PCB color (is it a different material?)

I have acquired this PCB. The right side of the PCB handles high voltage AC power (250 V maximum,) while the left side handles low DC voltages (24 V maximum.) They are separated, not ...
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0answers
37 views

How to calculate stray capacitance on PCB

I use a 0.4mm spacing between PCB traces (including 0.4mm space between crystal pads and ground) and I believe that's causing stray capacitance. My circuit board is typical (1 ounce copper on FR4 ...
0
votes
1answer
43 views

Whats the purpose of the box in Proteus? [closed]

Like the title suggest, in Proteus 8, there is a box. why is it there? because we can simulate outside the box and it will work, so whats the purpose of the box ?
2
votes
1answer
91 views

For a HASL Finish PCB, Can Gold Plating be done

We have a HASL finished PCB but the pads needed gold plating for wirebonding. Can gold plating be done on top layer of PCB over this? Will there be any reliability issues?
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1answer
73 views

How to safely limit current for DC12v 30a?

I am plating my vias with electrolysis, and I need to safely limit the current so it doesn't go over 30 amps. The power supply I'm going to order is, you guessed it, 12V 30A. I've calculated the ...
-1
votes
3answers
137 views

Which gerber files I need to send to my PCB manufacturer?

My PCB has two layers. I'm using altium and, after to generate the gerber files, I will to generate the drill files and send to a PCB's manufacturer. But, about mechanical gerber files extensions, ...
0
votes
2answers
132 views

PCB etching gone bad

I'm etching a double sided circuit board for my project in electrical engineering but somehow the PCB gets these weird marks and turns out bad. I tried different things like washing the PCB before ...
6
votes
1answer
98 views

High Frequency Characteristics of Solder-Filled Vias

If a via gets plugged with solder, does this destroy its ability to pass high frequency (RF noise) currents? Since there is no longer a surface along which the high frequency currents can travel due ...
4
votes
2answers
61 views

What does Minimum Slot Aperature mean?

Exploring some fab houses and I came across this statement from https://www.viapart.com/PCB/Explain "Minimum slot aperture Mechanical drill 0.6mm The tolerance of groove aperture is±0.1mm" Does ...
3
votes
1answer
62 views

Having different voltage potentials as power planes on the same inner layer of a PCB

I am working on a 6 layer job which placement of the given components in the rather limited area that I have to work with...is driving me a bit crazy. I have no option but to have 2 different voltage ...
6
votes
1answer
165 views

Connecting top and bottom SMD component pads using via

I am working on a 2 layer board and the PCB will be a double sided job. Some components on the top layer will have exact mirrors on the bottom right under them. My question is, for SMD components, can ...
-3
votes
1answer
119 views

PCB Layout validation [closed]

I'd like to know if the pcb layout is ok for the 2 op amps that i use.I'm interested in grounding and if the op-amps have proper layout(not too long loops or poor ground planes). source files The ...
2
votes
1answer
114 views

PCB stackup ambigous percent number

In this stack-up what are those presented in right-side of picture? update: The person who respond from manufacturer told me that is "residual copper ratio". But I think she is misunderstood because ...
2
votes
1answer
265 views

Removing debris from PCB

I have a PCB with no solder mask with a very dense layout and a very fine trace spacing. I didn't get a solder mask because it's still in the prototyping phase, and it's way cheaper. I keep having ...
1
vote
2answers
286 views

Difference between top pad master and top solder mask gerber files?

I generated gerber files to the pcb manufacturer, but I noticed that the top pad master (.GPT) was not generated, the top solder mask (.gts) was. The pcb manufacturer did not complain, but I'm ...
1
vote
0answers
35 views

Strange powerplane layering issue in designspark

I'm trying to order a 6 layer PCB from a fab but they are asking me to resolve an issue with the file and I'm a bit stumped on what to do about it. The second layer of the design I have designated as ...
6
votes
1answer
2k views

Edge-mounted vias… or how is this called? And can PCBs services manufacture it?

As you can see, the through-holes (vias) are at the border of the inner cutout. (rendering is wrong of course, as vias are not cut) I imagine a manufacturer first prints the board and then cuts it, ...
7
votes
2answers
100 views

Component designators on multi-pcb projects

I am currently working on a project that goes over multiple PCBs for the first time and realised that i don't know what the "standard" or best practice for component designators over two (or more) ...
4
votes
1answer
64 views

Is this possible to make a module with both castellations and LGA?

I am trying to decide on a pinout methodology for a module that will be assembled board to board on a bigger PCB. considering the pros and cons of LGA vs. castellations(cut half vias), i was thinking ...
0
votes
1answer
247 views

Creating a slotted & plated through-hole in EAGLE: where to draw milling outline

Problem summary I want to create a rectangular slot in my PCB for this component. Do I draw the milling outline on the footprint library or on the board after placing the component? Does it matter? I ...
1
vote
0answers
45 views

How to solve via on pad without plugging?

There are some vias on pad in my design. I've read some articles and know that these vias should be plugged to avoid solder wicking. However, the board house told me that they can't provide a plugging ...
5
votes
1answer
598 views

How to plug PCB into PLCC Socket

I have an IC that I need to replace by a small PCB. IC is currently plugged in the 44-pin PLCC socket. Is there a way I can keep this socket in place? That is, can I somehow "plug" this new PCB (which ...
0
votes
1answer
132 views

Vias not connected to ground plane

I recently designed my first 2 PCBs. Both have a 5v copper plane on the top layer and a ground plane on the bottom layer. I use short traces and vias to connect top components to the ground plane. ...
2
votes
1answer
232 views

Can Silkscreen Go Directly Onto Copper PCB Layer? (No SolderMask)

Hi I am wondering if a PCB silkscreen layer can be printed directly onto a copper layer without a solder mask. I don't see this often but I have a design for which this would be useful. Has anyone ...
0
votes
2answers
88 views

In PCB DFM process; manufacturer have highlighted Gullwing Issue. What is Gullwing?

In PCB DFM process; manufacturer have highlighted Gullwing issue saying "Gullwing is not optimal robust SMT process. What is "Gullwing"?
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votes
1answer
85 views

In PCB DFM analysis; manufacturer highlighted TOEPRINT ISSUE. What is component TOEPRINT?

PCB manufacturer have highlighted component TOEPRINT issue. Issue Statement: "Component is too close to another component TOEPRINT." What is mean by TOEPRINT?
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votes
3answers
60 views

Equivalent Characteristic Impedance for Different Trace Widths

Suppose I have a PCB trace that needs to be impedance matched, but the trace width changes as it travels from its source to its destination. Something like this: The 5mil trace would have a certain ...
1
vote
0answers
87 views

Reversed silk screening on EasyEDA

Just a quick one. I'm not sure if the text should be mirrored on the bottom layer of EasyEDA. It seems okay in the 3D preview, but when I upload the gerber to JLC their preview shows it still reversed....
-1
votes
1answer
66 views

EAGLE GERBER files nit opening in CAM 350

I have chinese factory that I need to assemble PCB. They cannot open eagle gerber files, only altium how to fix
3
votes
2answers
140 views

Is it feasible to remove non-functional via pads on outer layers

During PCB design & manufacture it is common to remove the via annular rings on internal layers where the via is not connected to anything, so called non-functional pad removal. Would it be ...
1
vote
3answers
185 views

PCB plated through hole short-circuit

We have a board built in the thousands, and several have (apparently) short-circuited a plated through hole (PTH) to an adjacent pour (see photo, note the other thermal damage is probably due to ...
4
votes
1answer
251 views

What part type is denoted by SKx? [closed]

I’m fairly well versed in component labels like C1, R12, U72, etc but while taking apart a small external hard drive I found a component which looks to be made of ceramic labelled SK1. Now, crystals ...
1
vote
1answer
61 views

Accidentally Pasted Beyond Origin in Altium

I'm new in Altium and I accidentally pasted some pads and components(the ones at the bottom corner) from another pcb file but I wasn't aware of it at first because it didn't show on the sheet on the ...
4
votes
1answer
217 views

SMDs on bottom side of board with THT components?

I'm designing a PCB for factory production and I'm not sure if placing SMD components on the bottom side of the board, which also contains THT components (pin headers and buttons, they're all on the ...
11
votes
4answers
1k views

When are fiducials needed?

On a single-layer board with no through-hole and no machine placed components, is there any need for fiducials (for example to route the board outline)? Board house has asked for permission to add ...
4
votes
4answers
343 views

What PCB Plating do I need to use Exposed Copper Pads with Pogo Pins?

I am designing a PCB that will have some Mill-Max pogo pins make direct contact with exposed copper pads on the PCB. This will have many connects and disconnects, think hundreds to thousands. I know ...
2
votes
1answer
67 views

How long can a brand new PCB last before additional protective coating is required if any?

I have just made several PCBs for a large project using the photoresist method. (I ran the boards through sodium silicate developer then through ferric choride) I then rinsed off all chemicals and ...
0
votes
1answer
88 views

PCB inside a parallel port cable case

I designed a PCB to fit inside the case of a parallel port connector cable. It will be soldered, internally, to the pins of the cable connector. I already did a first version, I printed it on paper in ...
0
votes
1answer
84 views

PCB key contact [closed]

Hi! anyone knows how to design a pcb like this in the photo with eagle? Someone has a guide to do it? I don't know how the resistor should be placed. It is basically a pcb for a synth, the key ...
1
vote
3answers
133 views

Best way to flatten PCB again after cutting with utility knife

I cut my presensitized PCBs down to size with rulers and a utility knife when I need a custom PCB. I noticed every time I cut one, the cut is always clean, but the copper on the board at the same ...
4
votes
2answers
312 views

Can I place an electrolytic capacitor close to a solder point on a two sided pcb?

I’m designing a pcb, which is going to be installed inside a metal chassis. To minimize space I will make it a two sided pcb. (See pictures) Because there will be parts mounted on the top face of the ...
0
votes
1answer
226 views

Photoresist PCB - Traces always gets washed away with developer

I have a positive acting presensitized UV-curable PCB board (link). I'm using the manufacturer-provided developer. Supposedly, the parts that get exposed will get washed away by the developer. ...
2
votes
2answers
415 views

Through hole components on a PCB

When prototyping diy PCBs, we would run a small wire from the underside of the board to the top and solder on both sides, wherever there was connection on both sides of a THT component, so there was ...
2
votes
1answer
120 views

Manufacturing PCBs for DDR3 memory

I'm currently designing a 4-layer PCB for a SOC (Allwinner A33 to be precise, 0.8mm-pitch BGA) with one DDR3 chip. Per DDR3 routing requirements, the traces need to have 50-ohm impedance. Also, they ...
0
votes
0answers
111 views

cause of photoresist removal after etching

I just tried to do a new PCB today with the photoresist method but what is very strange is that after etching it, I rinsed the board with water and wiped it dry, but as I wiped it dry with toilet ...
2
votes
2answers
130 views

Bubble etching versus rocker tank

I make my own PCBs and etch them in a homemade bubble tank. The tank has failed after a couple of years largely due to the etchant slowly eating it's way through some of the materials (glues, pipes, ...
0
votes
0answers
70 views

how does multilayer PCB Press/lamination machine work or bond the layers?

I just know the components involved in this process of bonding layers: Vacuum hot press to remove air bubbles, Piston Press to apply pressure and some temperature device to create the temperature. i ...
0
votes
0answers
43 views

Curly PCB lines [duplicate]

I was checking out this Raspberry Pi 3B when I turned it over and found that there are these curls made out of the printed material near the microcontroller. Why have these been made?
10
votes
4answers
2k views

My PCBs etch all bad! (sodium persulfate)

I've recently started having problems with etching my PCBs. I use a permanent marker to do the traces and etch them in a stainless steel cup, heated with a tea light (small candle.) The PCBs come ...