Questions tagged [pcb-assembly]
The process of mounting electronic components onto a printed circuit board. This can be done manually with a soldering iron, or automatically using a "Pick and Place" machine.
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Should I worry about the risk of tombstoning?
A colleague has (apparently unsuccessfully :-)) tried to convince me of the risk of tombstoning
in the following situation:
He claims pad 1 for R55 and R59 will lose heat faster during ...
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Securing electrical cables to holes in enclosures?
Suppose I would like to insert data-cables of varying diameters -- e.g., a cable of 5 mm diameter -- into the 6 mm diameter hole of a plastic enclosure. The wires within the cable are terminated via ...
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Why do resistors still use color coding?
I always wondered why color coding is still used on resistors in 2014.
Here is Wikipedia's word on the original reason why :
Colorbands were commonly used (especially on resistors) because they
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What are the 'knuckles' on through-hole LEDs and photodiodes for?
I am using an IR LED and a photo diode, and I have designed the PCB according to the specifications that I found on the datasheet - i.e. hole sizes for the pins being 0.6 mm. However, on these ...
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Which of these marks signifies Pin 1 on the STM32F (LQFP64)?
I'm using the STM32F105, in a LQFP64 package. It has two circular markings, on opposing corners of the IC. This picture is for a different ST ARM, but the markings and silkscreen are similar:
The ...
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Sizing SMD components for Hobbyist Kits
More components are only available in SMD packages.
For hobbyist assembly the options are to buy breakout boards or
solder SMD.
Since components are usually packaged in a couple of SMD
package ...
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Is PCB testing of all nets after assembly required?
That is my first time asking an assembly house to produce 200 units of a PCB (and not the usual 3 or 5 PCBs). The assembly house came back to me saying that the testability of the board was bad and ...
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Replace SOT-23 (5 pin) package in production with wire
I have found a hardware bug on a board design after many PCBs have been manufactured but not populated. I can fix the problem by removing a SOT-23 component and putting a wire across two of the pads.
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Questions on mass-production soldering
Wave soldering
I am trying to understand how wave soldering works. Unfortunately the Wikipedia article has has left me unsure about the process:
Is the entire board with its components quasi-...
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What are these spots on the PCB that are by the mounting holes?
When you look at the board, there is a weird part of the PCB right of the top left mounting hole. There is also another one above the top right mounting hole.
****...
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Soldering heatsink pad on bottom of IC
I am attempting to make a board for the tlc5951 24-channel led driver to drive an 8x8 rgb led array. I have made what I think is a good eagle library for the sop-38 package, but I am not sure what to ...
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How to reliably secure stranded wire in terminal block?
My 18AWG stranded wire continues to come out of the terminal block it's screwed into. What are some ways that I can more reliably secure this in an industrial environment?
Strip extra wire and loop/...
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Double-sided Assembly
I'm going to assemble a prototype PCB which have components on both sides. I have access to a reflow oven with profiling control, solder paste and stencils (from OSH-Park)
In the reflow process for ...
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Single- vs double-sided PCB assembly costs
I'm working on a new design (still laying out the components) and I have a chance here to reduce the size of the PCB by roughly 40%-50% if I use the other side for a QFP-100 IC (so it's heavy and will ...
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Is it advisable to use lead-free PCB and solder paste on a first SMD assembly job?
I am sending my first PCB design to Sunstone for manufacture and I need to decide whether to order the board finish lead-free. All of the components are lead-free, and I have not decided on solder ...
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Is there a standard PCB Array Size for PCB Assembly?
I am planning on use various PCB assembly houses to get my boards PCB assembled. To minimize process costs, I am told it is best to panelize/array the PCB such that there is multiple boards per array, ...
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Half-etched fiducials Vs through-cut fiducials
While making PCB, I added 8 fiducials (fids) marks so that pick and place machines use these marks as referent points on the PCB to position the surface mount components (Packages) during assembly.
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Why did Axial Capacitors Fall Out of Use in the Industry?
When inspecting the boards from electronics made in 1980s and earlier, one distinct feature is the extensive use of axial, electrolytic capacitors as power supply filter. Axial ceramic decoupling ...
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How do I solder headers so that they always stand straight up?
When soldering headers, usually single and double pins, I flip the board over so the pin rests on the surface and then solder them. They never come out straight. It would be great if someone has ...
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How to secure cables to a PCB
What is a good way to secure cables to a PCB?
There are some good advice in the following post, but the application is slightly different:
Securing electrical cables to holes in enclosures?
In this ...
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When and why use triangle solder joints
I found these triangular solder joints in a 24v power supply. Why are they made as triangles? This is the first time I have seen it and I was unable to google anything about it.
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Designing Pick-and-Place-friendly CAD library parts
I'm working on a PCB design with surface mount components to be manufactured by a PCB assembly shop. I'm using CADSTAR, and I had to populate the library with some components, from scratch. I'm new to ...
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OK to connect boards perpendicularly like this?
Are there any disadvantages in using the following method to accomplish a perpendicular board-to-board connection?
(i.e., any disadvantages in terms of
board manufacturing capability/cost
assembly ...
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Feasibility of PCB edge plating?
How feasible is it to edge plate a PCB or at least a portion of one? I've seen it done but as I understand the outer edge is only cut after plating at most fab houses. Is this something that's ...
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Estimating Assembly Cost
I've got a project BOM costed out and I know my PCB costs. Without sending my project out for quote I'd like to be able to estimate the assembly cost by number of SMT components placed and the number ...
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Any tricks to attaching a wire or pin to a testpoint?
More and more often, I find myself needing to tear apart a device to seek out and connect to serial pads. These pads typically give me access to the underlying operating system for research or ...
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Connecting 10AWG wires to PCB
I have 4 wires 10AWG stranded, that I need to connect to a PCB that I'm designing. They will be in a high vibration environment, so direct through hole soldering may not be the best solution.
I've ...
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Is it practical for firmware to be uniquely identified in production
Are there systems available in large scale manufacturing that allow a unique serial number to be programmed into the firmware or some free memory space for each PCB that comes through?
I've found ...
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PCB fabrication vs PCB assembly
What is the difference between PCB fabrication and assembly? Some companies like Golden Phoenix list that based on the size of PCB, it outputs a quote.
Mine was 2.1 x 1.6 inch. It outputted 29 pieces ...
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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?
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Centroid of component for pick and place machine using Eagle
Just finished designing a PCB and sent the Gerbers off to my board house (Bittele) and they have requested that I also provide them with a pick and place file.
Using Eagle, I ran mountsmd.ulp and ...
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Solder paste stencil application
I am trying to do reflow soldering with a stencil for the first time. I have done some reflow soldering before, but every time I manually applied the paste using a small syringe + needle. These ...
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Rule of thumb for surface tension when placing components on the secondary side of a board
I've been working on my first multi-layer PCB design, and have been placing a variety of components on the secondary side of the board (mostly decoupling capacitors and QFN ICs). However, some of ...
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What kind of breadboard and prototyping board do I need for this right-angle DB25 connector?
What kind of breadboard and prototyping board do I need to fit this right-angle DB25 connector?
I'm new to soldering and don't know what the standards are. Additional information on this subject ...
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How do PCB fabrication houses make PCBs?
I know the different ways of making PCBs at home, but I can't seem to find a lot of information on how board houses professionally make their PCBs. Is this how they do it?: http://www.youtube.com/...
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Very low stacking height PCB connector
I need to stack two PCBs together, but the stacking height is extremely critical. In terms of board-to-board connectors, the best I could come up with was SAMTEC GFZ series.
What other solutions can ...
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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 ...
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adhesive glue before soldering
Before I solder very small electronic parts on PCB board, I want to find some needle point sized injector to inject tiny glue fix the parts, then do the soldering.
Some manufacturers used that, but I ...
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How do I find the center of a part when making a footprint for a component that will be used in a centroid file?
Often the footprint I need is not in the existing libraries and I need to make my own. For example one of the dozens of micro USB footprints.
When I make a footprint and then send for assembly at ...
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Moisture Senstive Devices - Shelf Life
I have a bag of DAC7512N digital to analog converter from TI. They are still sealed in the original packing, however the caution notes denote "calculated shelf life in sealed bag: 24 months" and the ...
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Unknown SMD component - PCB Designation question
I have a board we are trying to repair. We are unable to get any technical documents from the manufacturer, no schematic or BOM for the board. This has multiple switches, think metal dome you press ...
user388256
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PCB Assembly: Specifying Jumper Configuration For Assembly House
I want to send a board off for fab + assembly soon which will include various jumpers in 2 or 3 pin configurations. For example, see this picture below (sorry about quality). I'd like to specify the ...
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I am building my own distortion pedal but every time I connect it to a 9V power source it does not seem to work?
I am trying to build my own distortion pedal. I initially built this on a breadboard and connected it to a 9V power supply and it seemed to work fine when I connected it to my electric guitar. So I ...
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Conformal coating of shielded RF modules
What is the best practice to protect a circuit with shielded RF modules?
I have a feeling that conformal coating is difficult since the shield is not sealed.
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PCB Silkscreen Marking
Today, I came on a PC board and the silkscreen marking have TG on it. What is the component for TG?
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What kind of failure would I see in moisture sensitive parts?
I am reflowing a design using an electric skillet. When the uC and LEDs arrived they were in moisture sensitive packaging. They were in sealed bags with moisture indicator cards. After I opened them I ...
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Soldering wire directly to a PCB through hole vias, what is acceptable proximity tolerance?
The wire gauge is 16 AWG. The hole size is 63 mil, and the overall via diameter is 98.5 mil.
What is the minimum spacing between two of these for voltage levels of 0-12V and 0-160V circuits?
I think I ...
user298907
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Clarifications about PCB assembly
I just finished designing my PCB, I printed it and assembled it. Everything seems to be working fine after some tests. However, assembling the load cells and power cables was really complicated and ...
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Building using single sided PCB proto-board
I have a prototype board like this one:
Note that mine does not have the arrows/numbers on the side. Looks like a cutout from the middle section.
It only has golden circles on top. So far I'm used ...
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Can I mount LTC6102 on breadboard?
LTC6102 is a shunt resistor current sensor with the following datasheet:
http://cds.linear.com/docs/en/datasheet/6102fe.pdf
The package Description has come on page 24. If everything is in mm, then ...
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