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PCB manufacture

:: EPE Chat Zone ≠:: ≠Radio Bygones Message Board :: » EPE Forum Archives 2010 - » Archive through 08 November, 2011 » PCB manufacture « Previous Next »

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thomass
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Username: thomass

Post Number: 74
Registered: 10-2005


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Posted on Wednesday, 02 November, 2011 - 12:15 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi,

Does anybody know where I can get a single PCB made within the UK?

I want to evaluate a project for school but we do not have the facilities to make PCBís
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joe
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Username: joe

Post Number: 1201
Registered: 05-2005

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Posted on Wednesday, 02 November, 2011 - 02:10 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Thomas,

There are many companies in the UK that can do this for you - search for PCB Prototype on Google. PCBTrain for example.

However, somebody on here may be able to run you off one if your not looking for thru-hole plating or fancy silk screen etc.

How big is it; how many sides ?
What format is your PCB artwork in ?

Regards,
Joe
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thomass
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Post Number: 75
Registered: 10-2005


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Posted on Wednesday, 02 November, 2011 - 03:04 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi Joe,

It's a small single sided board nothing fancy. The board size is 60.96 (w) X 73.03 (h) mm and the artwork is in Circuit Wizard format.

Regards,

Thomas
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joe
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Post Number: 1202
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Posted on Wednesday, 02 November, 2011 - 03:14 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Well, I've personally never used circuit wizard but assuming there's a free download that will print your design, I'll happily run one off for you.

If your interested you can send the file to me at Joe.farr at gmail.com

Regards,
Joe
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thomass
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Username: thomass

Post Number: 76
Registered: 10-2005


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Posted on Wednesday, 02 November, 2011 - 04:41 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi Joe,

Thanks the trail version won't allow you to open any files except the samples a really useful feature.

I can print to a PDF if that's any help or export it to DXF, NC Drill and Gerber format.


Regards,

Thomas
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bruce
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Username: bruce

Post Number: 692
Registered: 04-2008

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Posted on Wednesday, 02 November, 2011 - 05:03 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Thomas,
I'm not entirely clear what you're doing here. Are you trying to evaluate a circuit, or evaluate a pcb? there being a subtle difference.
The reason I ask is that making pcbs isnt always a good idea. This is all a very personal thing, of course, but personally I gave them up years ago. I do make a quite a few circuits, but I use a wiring pen and perforated board ( the board isnt 'perf board' or that hideous disater, vero-board.) I use thin card/paxolin/fibreglass/whatever and drill the holes myself where they're needed. The components are joined using a wiring pen.
I've always thought pcbs are a menace. A hobbyist often needs to 'fiddle', but it's difficult to remove components without wrecking the board. Ironically, you usually end up repairing a pcb with a wiring pen!

Just my $0.02 worth

bruce
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alec_t
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Username: alec_t

Post Number: 731
Registered: 03-2009

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Posted on Wednesday, 02 November, 2011 - 05:54 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

"I want to evaluate a project"
Could you just run a simulation of the circuit? LTSpice (a free download) is a competent simulator.
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muskrat
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Username: muskrat

Post Number: 398
Registered: 06-2009


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Posted on Thursday, 03 November, 2011 - 03:21 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Just my $0.02 worth - @Bruce.
I do everything on PCB. Even my prototypes. I find it easier, neater and is, in fact easier to fault-find in the event something goes wrong. I use AutoCAD to design my layouts, Postiv 20 to prepare and etch the board, and seldom have issues.
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741
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Username: 741

Post Number: 345
Registered: 08-2005


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Posted on Friday, 04 November, 2011 - 01:08 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi Muskrat

Can you give alittle more detail on your PCB methods please?

Say I have some artwork on PDF etc I know roughly what to do but I always thought it was too much trouble.

Also: How fine-pitch an SMD can you make work, and do you do double-sided?
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muskrat
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Post Number: 399
Registered: 06-2009


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Posted on Friday, 04 November, 2011 - 05:48 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@741
Once the artwork is ready, I print onto overhead transparency on my inkjet printer (high quality, photo paper setting, greyscale only and anti-aliasing - all settings on my Canon IP4300).
I clean and spray the board with Positiv 20 or Cramolin Positiv Resist.
The board must be perfectly clean and 'wettable' before spraying the photo-coating.
I use a piece of glass to sandwich the image, ink-side down, against the coated board and expose to UV light for the required time. Depending on the lights used this is the only major variable. Exposure tests would have to be run on the lights available.
I have used 'black light' tubes (around 20 minutes) to higher power UV sources (3 minutes or less)
The developer is a solution of Caustic Soda in water. 8 to 10g/litre.
Once completely developed, it is rinsed and etched in warmed Ferric Chloride.
On the SMD side, I have only experimented as I am only now getting into SMD design (I know - way behind the times!) Tests have include 0802 devices and TSSOP packages with excellent results.
This does, of course, assume that the printer produces acceptable quality artwork with no 'creep' of the ink.
You also have to design the artwork the right way round. When designing through-hole, the CAD system is set up to design looking from the component side so that the printed artwork can be placed against the coated board ink-side against board.
I have not tried double-sided yet, as I haven't had the need. All the stuff I do for the farm is fairly simple and I would rather use a couple of jumper wires than go to the expense and hassle of double-sided.
I believe my friend Joe Farr has experience with double-sided production.
It sounds like a lot of work, but the results are worth it.
Once I have all my stuff together, ready to make boards, I can turn out up to five boards an hour with ease. If they are fairly small, that number increases.
My set-up is crude but effective!!
As long as a lot of time is spent checking and double-checking the layout, the rest is easy and will be (hopefully) fault-free.
The only major hassle with this method is dust! Specks of dust can leave little spots of unexposed coating resulting in little copper dots on the board.
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741
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Username: 741

Post Number: 346
Registered: 08-2005


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Posted on Saturday, 05 November, 2011 - 10:57 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Many thanks, very encouraging, especially "TSSOP packages with excellent results".

Basically I accept that very fine pitch and maybe vias are off-limits to home-brew, but there any many times I'd like to do better than veroboard.
Example: Display with 1mm pitch pins <--> 0.1" pitch pins.

Obviously I can't justify £37+Vat+Carriage~=£50 from PCB Train for that kind of thing.
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741
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Post Number: 347
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Posted on Saturday, 05 November, 2011 - 11:28 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

One nice thing about SMD is 'no drilling' :-)

I'd be interested to see your TSSOP test if you have a photo, also your 'setup'.

My guess is that etching may be hard to make consistent (that was why I posted a question about pH meters in an earlier thread). Do you simply keep inspecting the board and do you use bubbles or agitation to keep the FeCl sloshing round?

Regarding dust: perhaps a shot from a can of compressed air imediately prior to laying down the artwork would help.
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muskrat
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Post Number: 401
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Posted on Saturday, 05 November, 2011 - 02:59 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

My setup is very basic. The developer is in an ice-cream container. The FeCl is in a plastic tank with air bubbled through it and has an aquarium heater to warm the solution.
The dust problem is not so much at the exposure stage, although it does happen, but rather when spraying the photo-resist. As soon as I have sprayed the coating the board is placed in a dark , dust-free enclosure to dry.
If dust settles during the spraying exercise, those dreaded spots will appear!
I'll dig out some examples and photograph them for you.
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istedman
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Username: istedman

Post Number: 225
Registered: 05-2005


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Posted on Saturday, 05 November, 2011 - 03:13 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi,

A simple test board recently made with a 0.65mm TSSOP device, made @ home.

Fine pitch SMT

I find SMT boards quicker to assemble than through hole. There is less drilling, all parts are mounted and soldered on one side (no flipping of the PCB to insert then solder the part).

If you start with SOIC parts, which have 0.05"/1.27mm pitch and 1206 size discretes, then move on to smaller parts, you will succeed.

Youtube and Sparkfun were two good websites for information on SMT soldering when I started, watching videos helps immensely.

@Thomass

What are you building?
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thomass
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Post Number: 77
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Posted on Tuesday, 08 November, 2011 - 08:59 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@istedman

I'm building a PICAXE training board which uses a PICAXE 18 series chip. It has various inputs Ė couple of push switches, a LDR and a thermistor. For the outputs it has 4 LEDís, a speaker and a couple of spare ports which you can connect other devices to.

I found the project on TES and the author sent me the PCB layout files, hence why I wanted to get a single PCB made. Joe Farr very kindly made the PCB for me.

I will upload a picture of the finished board later

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