Questions tagged [pcb-fabrication]

About the manufacturing of PCBs (Printed Circuit Boards).

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1answer
127 views

Can resistive traces be created on a PCB?

I'm assuming that copper traces on a PCB have negligible resistance. Is it possible to put a trace on a PCB that has some greater amount of resistance? The amount of resistance would not need to be ...
3
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1answer
127 views

PCB etching not working: everything etched

I tried to etch a PCB with the photoresist method, using sodium hydroxid as developer and ferric chlorid as etcher. I think the problem is in the development phase. Although reading a lot about ...
3
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2answers
2k views

Which surface finish for edge connector plating to increase number of mating cycles with sliding spring contact?

I'd wish to insert a small 12x33mm PCB into a USB slot multiple times a day. Because of that high number of expected mating cycles, the surface finish of the edge connector should be chosen wisely. ...
4
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2answers
554 views

How safe is using non-RoHS parts?

I was wondering the safety of using non-RoHS parts for hobby projects. I already use non-leaded solder, but some of the parts I have are not RoHS compliant. How much would I, and my family, be exposed ...
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1answer
71 views

PCB strip from manufacturer

When we manufacture certain PCBs, where 50ohms impedance matching is required the manufacturer provides a small PCB strip along with the actual PCB. What is the actual purpose of this?
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0answers
18 views

How do I design a circuit with overload and shortcircuit protection for a multi-usb type c powered hub only?

I am planning on getting a number of raspberry pi 4, for now we will say room for 5. They have usb type c connectors on them, and can receive 5v at 5 amps. Therefore the total amps is 5 ports * 5a ...
84
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6answers
5k views

Looking for circuit board material that can be dissolved

We are working on a product where the entire device needs to be dissolved in liquid after the device has operated and the device is no longer usable or desired. This is a down-hole application. The ...
7
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1answer
105 views

Black Pad. Will heat remove the gold from an ENIG finish?

I have a batch of new PCBs with ENIG (electroless nickel / immersion gold) surface finish. My assembly house has had two unsuccessful attempts at populating the boards. We're trying to troubleshoot ...
2
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3answers
135 views

How do I reduce cost for a circular PCB shape?

I'm designing an electronic product that has a circular housing. There needs to be a PCB inside this form. In order to reduce costs as much as possible for high volume production (5K-10K), what shape ...
5
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2answers
874 views

GND plane and vias on a two layer PCB

I'm trying to build my first two-layer PCB layout using this example schema: I'm using SMD elements, which I would place on the top layer. Also I would create a ratsnet area as GND on the top layer. ...
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3answers
42 views

What does Construction and Standard/Alternate within the PCB Fab Industry?

In the Constructions Column, it indicates AxB. By the looks of it, B is referring to the woven glass material.See pg 7. What is the A in Constructions (AxB) and why would anybody care ? What does ...
27
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6answers
16k views

High PCB copper thickness: What are the pitfalls?

We need to carry high currents on a PCB (~30Amps sustained), so we are likely to order our PCBs with high copper thickness. So far we've only used 35 microns (1 oz) in our designs, so 'high thickness' ...
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2answers
694 views

SMD footprint design: Heavy copper, pad width smaller than pin width?

I'm working on a high power board that's using heavier (4oz) copper. I have an IC on this board in a 0.8mm pitch QFP-32 package (no other package options available). The IC's datasheet says the pin ...
1
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1answer
46 views

KiCad: “No fooprint for automated placement”

I just finished my first PCB with KiCad. Now, I need to produce it and I need the Pick and Place file. When I try to generate footprint position files the software produce the message "No fooprint for ...
2
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5answers
237 views

Review PCB Design

I've created a PCB design for the first time ever, but I would like to know if I've made any mistakes that will result in a broken board or short circuits in the near future. I've encountered people ...
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2answers
69 views

Efficient assembly/fabrication of PCBs differing only in solder jumper configurations

I have a PCB design with solder jumpers which need to be bridged to select specific functionality - say A and B. Half of the PCBs are going to have A and the other half B bridged. Is there an ...
2
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2answers
120 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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1answer
250 views

THS6002 “Dual Differential Line Drivers and Receivers”. Output: 15 MHz

I made ​​a PCB with the THS6002 chip "Dual Differential Line Drivers and Receivers". I copied the application example of figure 59 in the datasheet (page: 34), with three differences: the transformer ...
3
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2answers
44 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 ...
0
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1answer
165 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 ...
1
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2answers
112 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 ...
2
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2answers
178 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, ...
2
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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 ...
2
votes
2answers
1k views

What is the general rule of thumb regarding UL's creepage clearance regulation?

I've read a whole bunch of material but I'm still quite confused regarding creepage clearance, specifically: How to calculate the minimal clearance on a PCB board? How to calculate the width of the ...
8
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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
82 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 ...
16
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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 ...
3
votes
1answer
346 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 ...
2
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4answers
102 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 ...
8
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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?
2
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1answer
54 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 (...
22
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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 ...
0
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1answer
74 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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0answers
109 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 ...
1
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0answers
422 views

Problem isolating vias. Solder mask offset

I detected a shortcircuit between two vias in one of our PCBs. The shortcircuit was caused because an offset on the solder mask leaves part of the via's ring "half opened". When the PCB was assembled, ...
0
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1answer
47 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 ?
-1
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3answers
190 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, ...
2
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1answer
99 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?
0
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1answer
87 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
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2answers
621 views

Custom/DIY Metal-Core PCB?

I would like to fabricate a slight enhancement over the metal-core PCB's shown here: https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=6071 Specifically, my application requires 2 LED's of ...
0
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2answers
165 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
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1answer
132 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 ...
2
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1answer
3k views

Altium trace length vs signal length

I've seen both of these in the PCB tab when editing the PCB board in Altium Designer.. what are the two? I thought I new, but I have fully routed traces with signal lengths of 0 as well as signal and ...
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 ...
-1
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2answers
103 views

can 2 3mm leds fit within a 5mm bi-color led without bending wires?

After creating a circuit calling for a bi-color common-anode LED, I checked places for stock, and to my dismay, all they wanted to sell common-cathode bi-color LED, but the funny thing is I can order ...
3
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1answer
86 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
215 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
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1answer
123 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
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 ...