About the manufacturing of PCBs (Printed Circuit Boards).

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PCB Cleaning for Manufacturing

We produce PCBs in quantity on an automated line. We then have been washing them en mass in a spray-washer that looks like a dishwasher. It uses a saponifier with water to dissolve all the crud on the ...
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2answers
396 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 ...
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4answers
333 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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1answer
81 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
52 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 ...
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1answer
43 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 ...
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45 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 ...
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3answers
132 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 ...
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40 views

Fabrication outputs options are not available in my Altium 13.0

I am using altium 13.0 and just finished very first my pcb layout. I want to now generate the gerber files but the fabrication output options are not showing up. I even tried clicking the "get more ...
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3answers
2k 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 ...
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3answers
92 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 ...
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3answers
472 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 ...
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3answers
790 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 ...
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3answers
116 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 ...
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1answer
93 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 ...
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0answers
53 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 ...
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2answers
793 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 ...
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36 views

Making PCB for PL2303 at home

I'm new here and this is my first question/post. I'm trying to print a PCB for UART-USB bridge IC PL2303HX (package SSOP28). I designed the board in eagle and printed it using a common HP laser ...
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1answer
65 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 ...
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1answer
58 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 ...
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2answers
107 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 ...
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33 views

Convert Gerber files to scaled PNG's for A4 size paper

I need to export GERBER files to PNG's or PDF's so that I can print it on a A4 size paper and not loose the scaling, obviously to avoid mis fits of chips and components. I have gerbv installed on ...
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32 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 ...
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5answers
1k 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 ...
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1answer
103 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 ...
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1answer
90 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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1answer
208 views

Silk-screened 'buttons' on a touch-tone phone?

I've been taking apart a recent, standard touch tone phone with the aim for automated dialing via a separate MCU with transistors activating the contacts (Smirk. An assistive technologies project ...
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62 views

fiducials on a panel

have a little question about fiducials: My Layouter/My Boss likes to use 3 fiducials on the panelframe and one fiducial on each individual board in the panel. My job is to build the program for the ...
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80 views

What to look for in a CNC PCB router?

When shopping for CNC routers for milling PCBs, there are some specific tools and others that seem to be fit but are meant for other types of works (typically engraving wood or advertisement). For ...
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5answers
211 views

Correct way to define board outline?

I'm a student and am almost ready to have a PCB I designed fabricated, but I'm confused about how the board outline should be defined. Here's what I currently have: I also have a 20mil keepout ...
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2answers
571 views

Eagle - non solder mask defined (NSMD) pads

I am designing a PCB layout in Eagle and in the datasheet of my modul it is said that "Non solder mask defined (NSMD) type is recommended for the solder pads on the PCB". Does it mean that there will ...
4
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3answers
1k views

PCB opaque coating for anti reverse engineering?

Im trying to find a coating for my PCB in order to protect it from reverse engineering. I want it opaque, non-conductive and with a low thermal resistance. Basically I do not want that someone ...
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71 views

Should courtyard information be included in gerber files for manufacture?

I just used 4pcb's free DFM checker and it doesn't like the fact that the courtyard line widths on my board are 1.968mils (what Altium generated in the IPC component wizard). It's also complaining ...
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274 views

What is the black thing on the circuit [duplicate]

What is the black thing on the below circuit? Is it used to hide the IC (or other components) that is used on the circuit? What material is it?
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5answers
206 views

How to order a custom PCB

I need a tiny PCB for a tiny IC. Is this something I have to design in autocad? Do I have to go to a shop to print it for me? Ultimately I want to be able to flux solder the IC on the tiny board so ...
4
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1answer
145 views

LED module design considerations for an aluminium board

I need to design a LED module something similar to below. Could anyone who is experience tell me if there is any SW (or tools) to determine how to place the LEDs to have a good and evenly ...
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1answer
57 views

What is the recommended exposure time for presentisized positive photoresist board? [duplicate]

What is the recommended exposure time for presentisized positive photoresist board using UV light, fluorescent light, CFL bulb and (will it also work with LED light)? How do we also determine if the ...
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1answer
95 views

How multi layer PCB are connected

I've been watching videos how to make PCB at home and I understand the process. But none of them shows how 2 sides are connected, I see on some PCBs there are some circular end points, so it must be ...
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1answer
115 views

Twisted pair coil embedded on a PCB

Has anyone tried twisting very thin wires(of order 100 microns) and then sandwiching it in between 2 layers of a multilayer PCB? I have a problem of EMI and looks like twisted pair is the only ...
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1answer
91 views

Question about a dimension in this IC package drawing

this is the first time I'm making a PCB layout, so I'm not too familiar with datasheets. The picture below shows a diagram for an IC I'm using. The datasheet says all dimensions are in mm. However, ...
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2answers
99 views

What are the plated holes on this PCB for?

In the top left corner of this snapshot, you can see a bonafide test point, TP12. Slightly down and to the right of TP12 you can see an exposed copper pad, also likely a test point. What I am ...
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2answers
77 views

Inkjet Printers+lamp+unused pcb can It work? [closed]

So suppose I have design x Can I print design x inverted onto paper, shine a lamp on it above unused pcb and make a printed pcb? Sorry for my ignorance Cheers!
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1answer
75 views

Hole diameters in PCB software - finished or tool size?

Should I specify the diameter of holes on my PCB as before plating (tool size) or after plating (finished)? Michael Leonard says finished Olimex says tool sizes Pcbex says finished ... Thank you ...
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2answers
134 views

How to measure the PCB size?

Can somebody share me your methods measuring the PCB size in CAM Software ? In PCB house ,we always measure the size according to the centre of outline and get the final size of the unit board or ...
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1answer
141 views

PCB Open Via Issue

I am recently bump into a problem where we found a certain percentage fallout of the open via. This is my very first time seeing this kind of problem and don't really have an idea why. It comes back ...
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1answer
106 views

How to determine dielectric constant and loss tanget of a PCB board at a specific frequency?

I need to know dielectric constant (relative permittivity) and Tan loss of a FR4 board at 2.45 GHz. The specification of the manufacturer is as it is below: Dielectric Constant: Test method ...
2
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1answer
132 views

Is it bad to route a trace edge of a rectangular pad?

I got a quick friendly critic from someone in production for the below trace that I should not route the trace from the edge of a pad. What he said that it would create an extra force to the trace ...
2
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1answer
204 views

Ways of PCB Etching other than Photosensitive Spray or Toner Transfer

Toner Transfer is not an option for large quantity or quick production and in my area I could not find any photosensitive sprays. I tried with screen printing emulsion, but it does not stick with ...
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4answers
869 views

What is the purpose of holes on edge of the PCB?

Here is a photo of one of Texas Instrument's RF EVMs. Please pay attention to edge of the PCB that has multiple tiny holes. I marked 3 of them with a red circle on the photo. What is the ...
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2answers
354 views

Altium can't output NC drills file?

I'm about to send my gerber files to OSH park however I'm having trouble generating the drill file in Altium 14.3. The output file is some other format than the Excellon / NC Drills file that the fab ...