About the manufacturing of PCBs (Printed Circuit Boards).

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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
45 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
80 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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60 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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49 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
92 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
89 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
33 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 ...
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1answer
104 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 ...
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1answer
73 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
703 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
61 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 ...
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3answers
251 views

What is the best way to plate VIAs?

My local hackerspace has a CNC machine. I can give them my Gerbers and they can print out the PCB. The machine does not plate VIAs. I need to do this after the CNC machine is finished. What is the ...
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1answer
426 views

How to select FR-4 board thickness

The PCB manufacturing house that I use says the board thickness between 0.4mm and 1.6mm are the same cost (I have 2 layer design). What is the benefit of having thinner or thicker board thickness for ...
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2answers
268 views

Mounting hole on a PCB

Here is a picture of 3 mounting holes on three different PCBs. The red one is what I prepared on Eagle CAD and used "hole" button on the left side menu , something like this: Do I need to use ...
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2answers
99 views

PCB Panelization tool/SW and adding test connections

I prepared 4 different PCB layouts on Eagle CAD and generated Gerber files. As I can see Eagle CAD doesn't have any option to panelization. Is there any free tool/program that can allow me to ...
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2answers
295 views

Why we need the PCB Panelised for assembly?

I have a PCB finished in invidividual size for customer but they gave me comment that it can't be used by their assembly vendor and ask me make the new batch for them, When we make the board in 2 up ...
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3answers
102 views

Does ferric chloride etchant “go bad” after some period of time?

I have some old circuit board etching solution (ferric chloride) that is unused but a few years old and has not been in a temperature controlled environment. It has been sitting, all but forgotten, ...
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1answer
91 views

PCB assembly cost per-board

I know this question might get closed because of being opinion depended but I couldn't find any answer from google or any other search, so I decided to ask it here. For clarity of question I want to ...
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1answer
160 views

Suggestions for in-house PCB/FPC lab? [closed]

We are a hardware startup based out of Greece, looking for in-house PCB/FPC fabing solutions/equipment. LPKF's ProtoLaser U3/S look great but they cost $140K and $70K (if I'm not mistaken) ...
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2answers
255 views

Gerber - is my understanding of solder mask layer (GTS / GBS) correct?

I've just had a PCB manufactured for me, but it seems like the solder mask is only applied to where the copper is. I'm trying to figure out if it's my fault or not. According to my understanding ...
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0answers
70 views

Is 3dBi PCB etched GSM/GPRS Antenna Possible?

Is it possible to design a GSM/GPRS antenna that has a gain of 3dBi? if not, what is the maximum gain possible with a PCB GSM/GPRS etched antenna? I'm thinking of a PCB sized 11cm long and 5cm width. ...
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1answer
75 views

Why should PCB design be mirrored before toner transfer?

I am currently designing a PCB to make with the toner transfer method for the first time. I was reading a guide that said to mirror the image before printing it to the paper. However it seems that the ...
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2answers
144 views

What Gerber file extension is used to specify PCIe edge connector plating?

I am designing a PCB in Eagle using the mini PCIe card format and am not sure how to specify finger plating the board edge connector to the PCB fabricator. These plating regions are specified in Eagle ...
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1answer
72 views

What fedex paper to use for toner transfer

I am very new to creating PCBs and I am planning to make my first one in the upcoming weeks. I noticed that all the instructions and tutorials called for using a laser printer which I do not have ...
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1answer
274 views

Any better alternative to produce PCB than UV etching

I hope this is an appropriate question to ask it here. I work for a small start up company that has a limited budget. We have UV box, etching tank, etc from manufacturer like Mega UK. Our problem ...
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4answers
442 views

Why did my homemade PCB turn out like this?

I did a first experiment with the UV-lamp + Transparency + Presensitized-Board method. Using a randomly drawn pattern, this was my (promising but unsatisfactory) result: What could typically be ...
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3answers
410 views

Solder Mask and Pad Area (SMD vs NSMD)

I have been trying to figure out the "right" way to size pads for surface mount components, and I have found some conflicting wisdom floating around the internets. Lets say I have this hypothetical ...
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4answers
672 views

PCB, pads with holes but with different nets on top and bottom sides

I need pads with holes in by PCB, but the top and bottom side of the pads need to have different nets i.e. the top and bottom sides must be isolated. Here is the picture Is this possible to fabricate ...
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2answers
1k views

What is the use of the golden like coat on this circuit?

The below PCB belongs to a wireless access point. Could anyone explain what are the golden-like part of the circuit that is indicated by the red circles(ish)? What material is it? What is the the ...
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32 views

In pin-through-hole, how much bigger should the hole be than the pin? [duplicate]

I've been etching circuits. So I ask: how much bigger should the hole be than the pins I intend to put them in?
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2answers
97 views

Lead solder toxicity after cooling?

Now I am sure that most people have read discussions on the possible hazards of handling solder and how your supposed to wash your hands after handling it. My question is, after soldering something, ...
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133 views

Multiple Layers per Page Printed on Altium Designer

I use Altium Designer for PCB design. Usually, before ordering prototypes with a better finish, I make my own boards at home, as many do. I'm playing with the Press-n-Peel sheets for the tonner ...
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2answers
206 views

Creating printed circuit boards (PCBs) which aren't flat

I would like to create a printed circuit board (PCB) which is not flat and which is not shaped into a square, but don't know how to proceed. Can Cadsoft Eagle create such a board? If so, how? What ...
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1answer
85 views

Is a ceramic heater good to use in an etching process?

I use Sodium Persulfate as an enchant at a maximum temperature of 50 C. My experience with glass heaters is that they break if they are not fully submerged or if they are removed while it is warm ...
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3answers
126 views

Creating with BGA

I have a project that I've begun to work on, it's sort of an embedded PC type project, with a iMx6 arm processor. However, since this is a (potentially) commercial venture, we can't use prebuilt ...
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2answers
863 views

Making PCB with DVD Writer

Maybe sharing this idea after building a prototype would be much better. As many of you know, there is a technique to make a PCB with laser CNC. You spray a matte black paint onto PCB, and burn that ...
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1answer
227 views

What kind of PC board coating is this?

I recently came into possession of two large (approx. 3x4 ft) copper-clad fiberglass boards from a junk sale. These boards are consistent with typical printed circuit board material (thickness, ...
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51 views

Why is all my photoresist stripping?

I got presensitized positive boards from Injecterall, but I'm using Datak chemicals (positive developer and etchant). I used Datak boards before and the process was very smooth. This time, after ...
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2answers
88 views

Non-glass heating element for an etching tank

I have been using below glass heating element (the part name is ET20) on my etching tank. The problem is that the glass is too gentle that breaks very easy for many reasons, I already needed to ...
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1answer
77 views

PCB Trace Orientations [duplicate]

When inspecting a PCB earlier today it occurred to me that all traces you find on modern PCB's are confined to 45 degree increments with respect to the (typically square) board edges. What is the ...
3
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1answer
414 views

PCB design: the setting of the test point and the use of variable resistor

I am designing a PCB circuit and meeting two problems: My design includes a two-stage MFB band pass filter. To make sure the center frequency of the filters is the same, I need to add a variable ...
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2answers
282 views

Which layer of PCB is used to identify cut-out of individual boards within a panel?

Let's say I'm using a software like EagleCAD to create a panel with a few copies of a design (or even different designs). There is a "Dimension" layer (mapped to an Outline layer, e.g., GKO), but ...
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2answers
208 views

Is quality China manufacturing possible without being there? [closed]

I'm looking for some help with manufacturing in China with respect to PCB fabrication and assembly, plastic injection molding and metal forging/brushing. Common wisdom in our days is that one HAS to ...
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1answer
95 views

How many of these UV lamps do I need for PCB fab?

I want to build a PCB UV exposure unit. It will be in a wooden box, it will have lamps and a glass above them. Basic design. For the lamp drivers I will use the circuit from the neon lamps at home. ...
3
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1answer
128 views

How to choose PCB manufacturing technology/factory?

I have sent some PCB designs to factories for prototyping. The price, however, varies greatly. Some ask 200USD for a four-layer 5cm*10cm PCB prototyping. While some only ask for 50USD. I assume that ...
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4answers
2k views

Are acid traps real? (2014)

Some people online say that acute angles in trace routing will cause these problems: "Acid Trap" - PCB etchant gets stuck in the corner, and eats away too much, causing open circuit "Peelable" - ...
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1answer
77 views

adding limiter to reduce distortion in audio amp

I got this schematic from adafruit. But at high volumes, it exhibits distortion. A guy from Maxim Integrated referred to include a diode-resistor network(BAV99 and R-100 Ohm) b/w C22/C23 and R8/R9(to ...
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3answers
266 views

What rules and tips make automated assembly easy?

What rules and tips make automated assembly easy, rather than unnecessarily difficult or completely impossible? In particular, if I have a circuit board that works fine after hand assembly, some ...
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5answers
645 views

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 ...