Questions tagged [pcb-fabrication]

About the manufacturing of PCBs (Printed Circuit Boards).

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59 views

8-layer Stackup: 3 cores vs 4 cores

For a new project I am looking to use 8 layers and I am currently figuring out the layer stack I want to use. As for usage, I will most likely go with: Top GND Plane 1 Signal 1 Power plane 1 Power ...
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2answers
32 views

Eagle Drill vs. Diameter Parameters when making Through Hole Parts

I am working on making footprints in Eagle for a through-hole connector I want to use. I am running into some issues as I try to determine the appropriate diameter and drill size I need for the ...
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1answer
164 views

How to evaluate the reliability of a PCB-printing service?

I had a talk with a friend the other day who told me that he had many issues with PCB-manufacturers in China (copying his product, long delivery times, bad quality) and that he had to sell his company ...
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1answer
2k views

Intriguing obsolete(?) PCB manufacture techniques in this old MSX

Browsing Wikipedia (as one does), I have stumbled upon this picture of a circuit board¹: Now, when you look at it, there are several things that stand out as being interesting and different to today'...
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1answer
28 views

Clearance between hole and power plane after removing unused via pads

After removing unconnected via pads and repuring copper fill, the clearance between the via hole and the fill will be defined by the rules, but the pours will be closer to the hole. Does this bring ...
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1answer
77 views

PCB Panelization Impact

What is the impact on a PCB design if it is panelized? I received a message from a PCB manufacturer: In your order, the quantity of boards is large and the boards are quite small. Can we panelize ...
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4answers
86 views

Securing mod wires to PCB

I have done a few mods to a PCB with 36 gauge mod wire. Obviously this wire is so thin that it only takes a few bends back and forth to break it. What is the best way to secure this in place on the ...
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3answers
2k views

Why do some PCBs have exposed plated perimeters?

I've seen a number of PCBs, largely high speed and RF boards, that have exposed copper, either at the perimeter of the entire board, or in various sections, often with stitching vias. I've never ...
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2answers
1k views

What is an acid trap

I've heard about acid traps and that they are something from the days of yore. But what are they and how are they created?
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1answer
52 views

PCB Thickness Variability

How much variability is there in the thickness of a standard PCB? Let's say I order a 1.6mm FR-4 board. Will the actual thickness range 1.5mm-1.7mm? 1.4mm-1.8mm? 1.59mm-1.61mm? What is the (...
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2answers
110 views

Reasons for using no conductor finish on PCB

Some PCB manufacturers, such as Eurocircuits or PCBWay, offer the choice of no conductor finish (vs ENIG, HASL, Immersion Tin, OSP or others). Since this option is not often chosen, it raises the ...
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1answer
61 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 ...
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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
54 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 ...
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1answer
45 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
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1answer
98 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
80 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 ...
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3answers
161 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, ...
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2answers
148 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 ...
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1answer
119 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
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2answers
62 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
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1answer
67 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
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1answer
194 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 ...
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1answer
121 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
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1answer
117 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
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1answer
271 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 ...
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2answers
454 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 ...
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0answers
42 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
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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
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2answers
107 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
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1answer
70 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 ...
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1answer
400 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 ...
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0answers
49 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
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1answer
606 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 ...
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1answer
157 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. ...
3
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1answer
304 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 ...
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2answers
96 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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1answer
102 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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3answers
67 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 ...
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0answers
96 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....
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1answer
68 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
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2answers
163 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 ...
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3answers
194 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
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1answer
257 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 ...
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1answer
67 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
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1answer
223 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
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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
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4answers
385 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
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1answer
74 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 ...
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1answer
89 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 ...