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DIY PCB creation... materials needed?


#1

Hello everyone,

I’ve been doing some searching on the forum but couldn’t find too much information on what I’m looking for. Sorry if I missed anything…

I’d like to start creating my own PCBs. I’ve checked many different sites and vendors but haven’t found any complete easy to order package yet. I’d like at least to be able to create my own FEZ Mini/Domino and possibly add some BGA chips to it (I have tons of BGA memory chips and also some processors I’d like to experiment with… though I’m not sure I can get an UltraSparc 3 wired without a multi-layer design) ::slight_smile:

I know what I need as basics to create a simply PCB, but what I’m missing (both information on what you actually need as well as where to get that) is how to make the vias (interconnections between both sides and possibly multiple layers in the future) and how to make the pads for the ICs (both “normal” SMTs and BGA chips). It would be ideal to just order some big “all you need” package and get started without making 20 orders on different sites and then wait several weeks for all the stuff to arrive.

My starting budget would be around 300€ with 500€ being the absolute maximum at this time. I’d really appreciate any pointers and suggestions on this. If you have any suggestions on shops/websites please keep in mind that I live in France so the shop should be shipping international at reasonable prices.

Thanks a lot!

P.S. I’m offering a blank FEZ Domino self made board for the best suggestion posted within the next 5 days (telling me to get my boards made by a professional doesn’t count) :wink:


#2

This group is all about DIY PCBs…

http://tech.groups.yahoo.com/group/Homebrew_PCBs/?tab=s


#3

[quote]P.S. I’m offering a blank FEZ Domino self made board for the best suggestion posted within the next 5 days (telling me to get my boards made by a professional doesn’t count)
[/quote]

Yeah, but what if that is actually the best suggestion ? ;D ;D ;D

Don’t discount someone like DorkbotPDX for small-run options or checking designs. They have the same tolerances as the bigger players but with smaller #s of boards as the minimum.

Anything done fine pitch like BGA really requires a level of dedication that you probably won’t get rewarded for in home production. Depending on the spacing you actually require, you would most likely need to consider not etching but engraving (on CNC) to get the quality you require. Dunno how many $$ that will set you back alone, but its not inconsequential (again to get to a quality point where you’re going to be able to get the resolution you need)

Simplistically vias are just wire between layers whack a piece in and then solder it up :slight_smile:


#4

I’m sorry to say this but:
[ol]You can’t make more than 2 layer boards at home.
You can’t do tracks thin enough for BGA at home.
You can’t do VIAs small enough for BGA at home.
BGA requires a solder mask, with plugged VIAs, else the balls flow away.
To get BGA right you need an x-ray machine for solder joint inspection.
You need through hole plating for domino and mini. This also can’t be done at home.[/ol]

I have been making PCBs at home for the last 20 years. You can use the toner method, but I find that it is a bit sloppy. I use the positive etch resist spray, transparency printed with a laser printer, and a uv light box. With this I can create 10mil tracks, and at a push, 8mil tracks.

The thinnest drills I could find commercially was 0.5mm. This is what I use for my soldered VIAs. I did get some second hand, resharpened, 0.2mm or 0.3mm drills, but they break REALLY easily, and you can only fit one strand, from a multi-strand wire, through the hole.

Also remember, you can’t place a VIA under a chip as you gave you solder a wire through, this leaves a bump which prevents the SMD chip from seating.


#5

I’ve also been searching for the holy grail for years. It can be done at home but the cost of setting up a “factory” for those tolerances will never justify the cost of the number of boards you will make for yourself.

This doesn’t mean we shouldn’t look at the problem differently. Maybe there is a different manufacturing technique like circuit printing emerging?

For diy at the moment my approach is commercially manufactured break-out boards for the fine pitched stuff, installed on diy motherboards with 10 mil sockets. You pay the price in size but gain in satisfaction of doing it yourself.


#6

@ realiser,
What are 10 mil sockets? 100mil maybe? 10mil is 0.254mm…


#7

Well I started with single sided pcb production a while ago.
Using a old flatbed scanner and a face tanner resulted in a uv lighting rig.

A cheap (damaged) vase from a local store and a fish tank air hose + fish tank air pump resulted in a bubble etch tank.

This rig cost me around 25 dollars. (20 euros).
It is very possible to create a double sided pcb with this rig.

The double layer trick would be to print the two layers, etch them to both sides and then connect them.
You might experiment with through hole connections to get things done easily.

That’s all I can think of right now.


#8

I should say 0.1" pin spacing - so just good old “pin headers” or “IC sockets”.

Like this… http://www.pyroelectro.com/tutorials/diy_breakout_pc_board/

This is just a random link I Googled but turned out to be pretty cool :slight_smile:

The point is it is very difficult to produce a PCB yourself with the resolution to handle BGA or fine pitch SMD chips. With a commercial break-out board to hold the chip, it is then easy to have a DIY motherboard with 0.1" pitch to host it. It might not work as expected - especially with RF and high frequency stuff, but it is a start.

Through-hole plating is another kettle of fish. The most DIY friendly technique I’ve seen is to use silver-based heat element repair fluid… The stuff they use to fix your rear window defroster on your car. That can be squeegeed into the vias and apparently make nice through-holes. Never tried it myself.

You can also do it like the pros and do actual THP with the chemicals and electro-plating, but what makes that possible is the ability to drill your holes BEFORE you etch the board. For that a CNC drill is a requirement. I guess you could also do it by hand on an exposed or toner transfer board but I’ve never tried.

Right now, my area of interest is direct inkjet printing. The theoritcal resoluton of this is 1200 dpi - but I’d be happy to get lower. Right now I’m printing directly onto PCB but I’m struggling for the ink to stay put in a uniform manner over the entire board. Still experimenting with this.


#9

@ realiser,
0.1" is 100mil… :slight_smile:

I have used silver varnish, see my capasitive keypad for the CANXtra on th ewiki. It’s a pain, and I didn’t even squeegee. Tried that before and it didn’t work so well. Resistance is also quite high and you can use it for power supply.

Are you printing etch resist onto PCB or are you printing the conductive layer?


#10

First of all thanks a lot everyone for your replies… I learned two valuable lessons:

I shouldn’t post my crazy ideas at 4am on a normal workday, especially making offers I’m unable to keep.

Second I shouldn’t get too ambitios in my projects where I usually like to spend a lot of money with very little return…

That being said I decided to start slow and get a basic kit to start doing some basic boards. From what I understand I cannot do anything wrong as in buying something that needs replacing if I want to do something better.

As for the vias to interconnect two sides, I also now found a solution albeit an expensive one… I found the machine to insert the vias for 207€ but it requires special headers (80€ each) for different sizes of vias. They offer 0.6, 0.8, 1.0, 1.2 and 1.5 mm vias. Plus a box of vias is 20€ per size. If I get all possibilities that would be 707€ so the first two questions are: Is it worthwile to get this solution or is there something significantly cheaper? Which size(s) should I get (first)? I was thinking to get 0.6 and 1.2 mm at first and then see if I might need others for specific things. Would you agree?
Here are the links to the product (it’s in German but you see the pictures…):
Machine itself: http://tinyurl.com/cvnlbhd One of the heads: http://tinyurl.com/cmcgovb and the vias: http://tinyurl.com/blw3ygc

For the finer spaced stuff and BGAs I will probably go for professional breakout boards for now and look into that again when I got some confidence in making my own basic PCBs. My idea initially was to make my own breakout boards and not order one for every new chip I encounter (I get a lot of stuff from “old” hardware at work). Or maybe I can create the layout for a multi-chip breakout board and then send it in for production. There are not a lot of companies in France that do that for individuals but I’ve recently made good experiences ordering materials from China so maybe I can get them made there.

Anyways thanks a lot for all your suggestions, sorry I can’t go through with offering that free board just yet but maybe sooner or later I might get to that :slight_smile: And yes I promise I’ll think a bit more before making these kinds of postings again :-[ ::slight_smile:


#11

For the vias, I would save my money and just drill a hole that a piece of solid copper wire will fit into snuggly then solder on both sides. If that wouldn’t work for the board then it’s off to Dorkbot…


#12

@ Errol, I’m printing resist - like this:

I use a Canon ip4600 with CD tray.

@ Xykon - as Ianlee said, vias are as simple as putting a wire through and soldering top and bottom. Not a big deal - just labour intensive.

Some more links from my ventures in this space…

http://www.pabr.org/pcbprt/pcbprt.en.html

http://www.colinmackenzie.net/electronics/14-pcb/25-thru-hole-plating-diy-printed-circuit-boards

http://www.thinktink.com/index.htm


#13

This is the way I’ve been doing my PCB’s for 2 years.

Parts needed:

-PCB with photoresist (single/double sided - available in different sizes) from online shop
-one Mercury-vapor lamp with the outer shell removed - emits a lot of UV (used this because I already had it hanging around) or any other UV emitting source.
-layer files are printed at a local print shop on transparent plastic sheets
-some chemicals depending on what you can find or allowed to buy :slight_smile: (sodium hydroxide, iron chloride, isopropyl alcohol).

After I cut the PCB at desired size, I expose it (different time and distance depending on the PCB complexity), develop it (in sodium hydroxide), etch it (in iron chloride), clean the remaining photoresist (with isopropyl alcohol) and drill it (vias at 0.5mm, the rest depends). The best I got is 0.2 mm traces. I generally use 0.33 mm for digital signals on small PCBs (0.25mm if the pads are really small). The smallest parts I use are 0402 SMDs and 0.5mm pin space packages. If a part is smaller that this, there are big chances the part or the PCB will get destroyed in the soldering process.

I just made this days a custom board for the EMX module. If anyone is interested, I can post some pictures.


#14

Once again thanks everyone for your suggestions. I’m reviewing my plans right now on what I really need and what is available to purchase.

I just talked to the exclusive distributor for Sparkfun and Schmartboard in France and he assured me that he’ll get me any item from those two even if they are not listed on his shop website if I order enough items.

I’m also looking into PCB production in China since I recently had some very successful dealings with a Chinese vendor for electronic equipment like a BGA reballing kit which was top quality and low price. I’ll let you know if I find any good offers for individuals.

I’m still planning to get into the PCB production “game” sooner rather than later but I’m not as crazy about it as I’ve been two days (or actually nights) ago. It seemed so easy on YouTube but the more I read about it the more I realized how much effort it actually is if you want more than just a few blinking LEDs…

I might still get that machine for the vias I linked earlier as I’m not too much into labor intensive work but rather to spend a few Euro to get an easy and fast method. And since I’m visiting my parents for x-mas in Germany I might take the opportunity to get it as it’s a lot more expensive in France. I’m still looking into liquid conductors as well but once again it seems not to be as easy as pushing copper bits into the board. The question is probably just if 0.6mm is small enough which is the smallest they offer for the machine.
As for the actual image transfer I’m still looking into different options. There is PCB in a box which looks easy enough but they don’t seem to have a dedicated reseller in France so I’d constantly have to order internationl for refills. I might rather go with the more traditional method of using a UV lamp since that’s available at conrad.fr. Either way I’ll take the weekend to look over things again and probably start ordering next week. I’ll let you know how it goes…


#15

we are always interested in Pictures… no need to ask … :smiley:


#16

Here is a project I’ve made some months ago.

All the PCBs are made by me. There are some other projects on my blog.

I’ll put some pictures with the EMX board when I get home later today.


#17

This is pretty neat for a DIY PCB. Impressive.


#18

@ godFather89 What is the link for your blog?


#19

@ Architect: http://andreiprojects.blogspot.com/


#20

Interesting. Following