Questions about making circuit boards

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Mike6158
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Questions about making circuit boards

Post by Mike6158 » Sun Jan 02, 2005 4:30 pm

If I am doing something for myself, silkscreened artwork isn't a real issue (though it would be nice.) Does anyone here have a method to easily add silkscreened artwork to a board that you make at home?<p>Commercial boards have a transparent green coating on them. What is it and can I use it on my boards?<p>Now the fun one. I have a board design that I would like to put in an enclosure. It's small. Like 1"w x 2.25" L x 3/4" deep. The enclosure would need to give me access to a double row 18 pin header.<p>Now the last one. I'm not sure how to word this. You know the RC receivers that you connect servo's too? That's the way I want my pin header to look only they use 3 row headers and I only need a 2 row header. Speaking of J-connectors (I was getting there). Does anyone know where I can get 2 pin "J" type connectors preferably with 12" of lead wire already on them?<p>I think that's it.
"If the nucleus of a sodium atom were the size of a golf ball, the outermost electrons would lie 2 miles away. Atoms, like galaxies, are cathedrals of cavernous space. Matter is energy."

russlk
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Re: Questions about making circuit boards

Post by russlk » Sun Jan 02, 2005 5:06 pm

Look at Mouser or DigiKey for an enclosure. www.mouser.com or www.digikey.com

Mike6158
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Re: Questions about making circuit boards

Post by Mike6158 » Sun Jan 02, 2005 5:34 pm

Yeah I looked there but I'm looking for something specific to my board design. I guess a stock housing of some kind might work but I want this thing to look decent. Professional...<p>Board dimensions- 1" x 2.75". It has a double row 18 pin header in the middle of it. The pin header needs to be recessed but accessible so the housing would be about 1/2" deep? There are mtg holes in the 4 corners of the board so standoffs for those holes would be nice. I'm probably asking for way too much...
"If the nucleus of a sodium atom were the size of a golf ball, the outermost electrons would lie 2 miles away. Atoms, like galaxies, are cathedrals of cavernous space. Matter is energy."

Mike6158
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Re: Questions about making circuit boards

Post by Mike6158 » Sun Jan 02, 2005 5:44 pm

This is on the order of what I was looking for. Their smallest case is still too big though...<p>OKW<p>[ January 02, 2005: Message edited by: NE5U ]</p>
"If the nucleus of a sodium atom were the size of a golf ball, the outermost electrons would lie 2 miles away. Atoms, like galaxies, are cathedrals of cavernous space. Matter is energy."

Mike
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Re: Questions about making circuit boards

Post by Mike » Sun Jan 02, 2005 6:26 pm

If you don't mind a black silkscreen, then it's simple to do. Just mirror and print the silkscreen onto standard paper using a laser printer.<p>Then, use an iron to melt it to the board. Although not neccesary, I usually spray the top side of the board with clear spray paint for a nice finish.<p>The time to iron it depends, so you will have to experiment with it. I haven't made a silkscreen lately, so I can't even remember how long I heated it for.

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philba
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Re: Questions about making circuit boards

Post by philba » Sun Jan 02, 2005 9:33 pm

I use toner transfer for the etch resist and the legend print (aka silk screen) as well. A couple of tips that helped me: <p>after you've etched and drilled the board, clean it again (I use acetone - works wonders). Then take 600 git sand paper and give the legend side a good roughing up. The toner will adhere better with more surface area. I use a laminator instead of an iron but keep the iron good and hot. For an iron, 3 minutes is usually enough. The best paper I've found is regular inkjet paper (but run through a laser printer). I do a hot peel of the paper - just pull it off when its still hot. The legend isn't quite as dark as it could be but it looks ok and is a lot less work.<p>By the way, the green stuff is soldermask. Not really necessary until you start doing reflow soldering.

Mike6158
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Re: Questions about making circuit boards

Post by Mike6158 » Mon Jan 03, 2005 6:45 am

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by philba:
I use toner transfer for the etch resist and the legend print (aka silk screen) as well. A couple of tips that helped me: <p>after you've etched and drilled the board, clean it again (I use acetone - works wonders). Then take 600 git sand paper and give the legend side a good roughing up. The toner will adhere better with more surface area. I use a laminator instead of an iron but keep the iron good and hot. For an iron, 3 minutes is usually enough. The best paper I've found is regular inkjet paper (but run through a laser printer). I do a hot peel of the paper - just pull it off when its still hot. The legend isn't quite as dark as it could be but it looks ok and is a lot less work.<p>By the way, the green stuff is soldermask. Not really necessary until you start doing reflow soldering.<hr></blockquote><p> :( I've just had an epiphany... I so don't know what I am doing when it comes to making boards. I can make them but I can play a guitar too and you won't ever see me on an album cover (point being I'm not very good at it). This is frustrating. I've gotten pretty handy at designing circuits and boards over the last month. Progamming is coming slowly but it crosses over to what I do so at work so that's not going to be much of an effort to learn. It's all a waste of time (save for the entertainment factor) if I don't learn how to do boards efficiently.<p>So, all that said, if you don't mind (other thoughts are welcome too), could you please go over the different ways to fab boards. Right now I use a UV lamp (with the right wavelength). My mask is clear acetate run through a copy machine at work. Exposure time is about 10 minutes. Then I develop it. Then I etch it. Drilling we've already covered. I'm waiting for bits but I think that will go ok.<p>(1) What do you mean when you say you use a laminator? You mean one of those things that you make ID cards with?
(2) What do you mean by toner transfer? Frankly I'm not happy with the UV method. Too much margin for error when making the mask. At least the way I've been doing it there is.<p>Mike<p>PS- Thanks to everyone for the replies.<p>[ January 03, 2005: Message edited by: NE5U ]</p>
"If the nucleus of a sodium atom were the size of a golf ball, the outermost electrons would lie 2 miles away. Atoms, like galaxies, are cathedrals of cavernous space. Matter is energy."

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Re: Questions about making circuit boards

Post by Engineer1138 » Mon Jan 03, 2005 10:13 am

Mike: I haven't tried toner transfer, but I have made dozens, if not over a hundred PC boards over time. My preferred method is the one you're doing: photosensitive board and clear film. It gives the most consistent quality I've seen over other methods like direct resist, tape, and screen print. I haven't made a board in a while, but I could easily get nice 10mil traces for going between pads. Suggestions:
Time everything you do so you can reduce the operation to a repeatable process. Record the wattage of the light and the distance above the board.
Make sure to use a heavy piece of glass to press the film down to the board when exposing.
Standard double sided foam tape is just the right thickness for making double sided boards: align the registration marks, and use 4 pieces of the tape to hold the component & solder side layers together.<p>As far as the silkscreen goes, you can pick up a silkscreen kit at most art stores and make a screen the same way you develop a PC board: using a light sensitive screen resist. You can also save a bunch of money by doing this yourself: the cost of a DIY screen frame, chemicals, and a squeegee is quite a bit less than what the art stores sell the kits for.<p>But ask yourself if it's worth doing all that when you can get PC boards for $10 from Olimex (www.olimex.com).

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Re: Questions about making circuit boards

Post by Mike6158 » Mon Jan 03, 2005 10:55 am

Thanks. I haven't checked out Olimex (I will) but I have been looking at board shops. Kind of hard to beat them. Especially if I'm going to do 10's of the same board. $10 is pretty cheap all things considered.
"If the nucleus of a sodium atom were the size of a golf ball, the outermost electrons would lie 2 miles away. Atoms, like galaxies, are cathedrals of cavernous space. Matter is energy."

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philba
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Re: Questions about making circuit boards

Post by philba » Mon Jan 03, 2005 1:30 pm

toner transfer is another way of making PC boards (vs the way you are doing it). Basically, you print artwork on some sort of coated paper (like inkjet paper, magazine paper, photo paper, ...), lay it toner side down on a copper clad blank and heat it up to the point that the toner melts. The toner will stick to the copper and form an etch resist. Some use a clothes iron but you can also use a regular document laminator (hot laminator) for this. The laminator is pretty nice but an iron will work too. Etching is as you've already been doing. <p>Here are some links to look at:
http://www.extremecooling.org/ec/module ... =73&page=1
http://myweb.cableone.net/wheedal/pcb.htm
http://www.fullnet.com/u/tomg/gooteepc.htm
http://www.infiltec.com/seismo/pcb-home.htm
http://geocities.com/pdmtr/<p>a google search on toner transfer will turn up a lot of links.<p>So photo vs TT is the next question that always comes up. <p>Plusses of TT:
- very inexpensive to do. materials needed are very cheap, uses regular copper clad boards (non-sensitized).
- specialized equipment is not necessary though one could argue a laminator falls in that category
- because the costs are cheap, one can experiment with out much waste.<p>minuses of TT:
- 8 mil features is the lower limit.
- takes some experimenting to get right.
- larger boards are difficult, especially with an iron (though a laminator increases the size - I've done 6x6 boards).<p>plusses of photo sensitive/uv: (I'll probably miss some so help me out)
- very fine detail possible
- double sided is somewhat easier to do
- larger boards are pretty easy<p>minuses:
- needs specialized equipment (exposure lamp and frame, clamping system for double sided)
- materials cost more (pre-sensitized boards, developer)
- more steps - artwork to acetate, expose, develope, etch<p>I can't say one is clearly better than the other. I know one can produce professional quality results with either system.

Mike6158
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Re: Questions about making circuit boards

Post by Mike6158 » Mon Jan 03, 2005 2:55 pm

OK... Since I already have the hardware I guess I'll stick with photo. It's a PITA to transfer the image to acetate. Only because I have to do it in my office at work (via 1200 dpi laserjet printers). My home laserjet is too wimpy. The traces are semi-transparent (can't do 600 dpi) when it's done so I don't even waste my time anymore.<p>I'll check out the links... just in case :D
"If the nucleus of a sodium atom were the size of a golf ball, the outermost electrons would lie 2 miles away. Atoms, like galaxies, are cathedrals of cavernous space. Matter is energy."

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Re: Questions about making circuit boards

Post by Mike6158 » Wed Jan 05, 2005 11:43 am

Time to resurrect this and say thanks to everyone. I just punched about 30 holes on no time with a Dremel and a little press. I used my 4" magnifying work light (as suggested). I'm using a #59 bit that I bought a month or so ago from Jameco. It seems to be holding up ok for now. My eBay bits should be here next week so I'll try to save some holes to give them a try.<p>Etching... Well... Let's just say that I learned something. Like don't heat your developer up... I have a couple of copper boards now. Anyone know how to put the resist back on :D<p>[ January 05, 2005: Message edited by: NE5U ]</p>
"If the nucleus of a sodium atom were the size of a golf ball, the outermost electrons would lie 2 miles away. Atoms, like galaxies, are cathedrals of cavernous space. Matter is energy."

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Re: Questions about making circuit boards

Post by upsmaster » Sat Jan 15, 2005 1:46 pm

the pretty green is a solder mask for wave soldered boards... maybe you can draw your logo and have a office supply make a stamp for you, then you can get any color of ink. you can conformal coat your boars with spray can technology after your finished but it covers everything and makes shooting trouble hard and replacement of parts will mess up the finish.
joe

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Re: Questions about making circuit boards

Post by Mike » Sun Jan 16, 2005 4:42 am

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Engineer1138:
But ask yourself if it's worth doing all that when you can get PC boards for $10 from Olimex (www.olimex.com).<hr></blockquote><p>Where can you get the 10 dollar PCBs? All I see are $26 and $33, for single or double sided. If they really are $10, thats definately a much better deal than making your own, because a board is, say, $4, Etchant is about $1-$2 per use (assuming ferric chloride), the paper is $.50. So thats 6.50, and since PCBs are such a pain to make and never come out close to the quality of professionally made ones, 10 bucks is definatly worth it.

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Re: Questions about making circuit boards

Post by hp » Sun Jan 16, 2005 7:09 am

The cheapest service I have seen would be futurlec's (http://www.futurlec.com/PCBService.shtml). They used to only accept protel files but now they accept eagle and gerber formats.<p>Harrison<p>[ January 16, 2005: Message edited by: hp ]</p>

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