800+ holes x3

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Newz2000
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800+ holes x3

Post by Newz2000 » Fri Jan 27, 2006 8:33 pm

OK, I know some of you have already bumped into this problem and have figured out some way to get around it...

I've got a cool little circuit board with a lot of holes. It's my own little prototyping board and it's just exactly what I've needed but can't buy at the store.

I got my hands on a laser printer, so I'm able to print my circuits now using the toner transfer technique mentioned elsewhere on this board.

However, the usefulness of this board will quickly become eclipsed by the need to drill so many little holes. If the board truly is as useful as I think it will be, then I'll want to make a couple more...

Is there a simple device that will precisely drill hundreds of holes for me while I read a book or do something else?

I have some stepper motors, dead printers, power tools and raw materials. My brother seems to think we have the spare time... Does anyone have some plans or tips on how to do it?

Dean Huster
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Re: 800+ holes x3

Post by Dean Huster » Sat Jan 28, 2006 12:32 am

Matt, designing, laying out, printing, tranferring, etching and drilling a prototyping board at home onto which you can build a circuit is a lot like writing a new word processor program for your computer every time you want to write a letter. Not the best analogy, but maybe you can get my drift here.

It would seem to me that your time and effort would have a far better yield to just lay out the protypical circuit and etch that board. You'll have far-fewer holes to drill, your board will have a much cleaner layout and better chance of success, especially at high frequencies, and you'll save a lot of time and equipment wear-and-tear overall. If you're going to prototype using thru-hole components under those circumstances, just do it on a solderless breadboard.

Dean
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

R.I.P.

rshayes
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Re: 800+ holes x3

Post by rshayes » Sat Jan 28, 2006 12:41 am

You can reduce the drilling to some extent by stacking up several boards and drilling them at the same time. The commercial operations do this even though they have automatic machinery. The additional drilling time is considerably less than the time required to position the drilling head.

You could possibly add two holes that would be drilled out for two bolts, which then can be used to hold the boards in alignment while the other holes are being drilled.

Gorgon
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Re: 800+ holes x3

Post by Gorgon » Sat Jan 28, 2006 3:57 am

Hi Matt,
I don't know your budget or your drilling equipment, but from my experience you tend to break drill bits when getting tired. Stacking boards is a good idea if you use high quality drill bits and some form of stand.

I might be getting old since this type of work doesn't appeal to me.. :D This way you neither use time nor money for unused holes.

TOK ;)
Gorgon the Caretaker - Character in a childrens TV-show from 1968. ;)

Mike6158
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Re: 800+ holes x3

Post by Mike6158 » Sat Jan 28, 2006 4:56 am

Change your designs to use more SMD's
"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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jwax
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Re: 800+ holes x3

Post by jwax » Sat Jan 28, 2006 8:57 pm

Instead of a handful of spare parts thrown together to drill holes, your best bet is to do it right- buy or rebuild a CNC milling machine.
That's the alternative to having a shop do it for you. Drilling hundreds of holes any other way is no fun at all.

Newz2000
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Re: 800+ holes x3

Post by Newz2000 » Sun Jan 29, 2006 8:15 am

all excellent advice... thanks. I have much more interesting projects to work on than this, and my time is much too precious.

Before falling asleep after posting this message, I realized the only workable solution would be some kind of CNC machine, whicn is really too big of a project right now. I've scaled the board down so it only has about 650 holes, so if my brother still wants to do this (it was largely for him) we'll try doing three at a time. I wonder if he can drill 10 holes a minute... :D

Robert Reed
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Re: 800+ holes x3

Post by Robert Reed » Sun Jan 29, 2006 10:10 am

Matt
Aside from the acual drlling , these holes have to be centerpunched ACCURATELY! If you decide to go this route , make sure you use a machinists starter bit. They come in various small sizes and have absolutely no wander.

L. Daniel Rosa
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Re: 800+ holes x3

Post by L. Daniel Rosa » Sun Jan 29, 2006 10:18 am

If you ever have a fab house make a PCB for you, see if you can include one or two copies of your prototype board in any unused space that you've already paid for. That's what I did on a promotional deal a couple yars ago.

Forrest
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Re: 800+ holes x3

Post by Forrest » Sun Jan 29, 2006 11:05 am

The real question is how much time do you want to spend imaging, etching and drilling the PCB's? In my experience, you'll probably spend 10-15 hours to build 3 PCB's and it will probably cost $30 in materials (PCB laminate, photo paper, etchent and drill bits). By comparison, www.batchpcb.com will charge you $10 per order plus $2.50 per square inch to build the PCB's for you.

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CeaSaR
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Re: 800+ holes x3

Post by CeaSaR » Sun Jan 29, 2006 11:42 am

What about the CNC machine article in the December issue?

CeaSaR
Hey, what do I know?

Newz2000
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Re: 800+ holes x3

Post by Newz2000 » Sun Jan 29, 2006 11:43 am

Originally posted by Forrest:
In my experience, you'll probably spend 10-15 hours to build 3 PCB's and it will probably cost $30 in materials (PCB laminate, photo paper, etchent and drill bits)...
Well, this is nowhere near the types of times I've seen. I spent a total of 2 hours creating the design, a good portion of that time was adjusting it so that I can get three on a board.

It typically takes me about 1 hour to etch a board, and that includes the trial and error of printing the circuit out. I bought a batch of PCB material (30 pieces) for $15 - shipping included - so that totals $0.50 per board, but with three of my proto boards on each piece that means the cost is actually more like $0.17 for each proto board.

Photo paper and toner costs me about $0.25 per sheet which again gets divided by 3 which is about $0.08. Therefore, if you figure the cost of the etchant, which I don't know how to estimate, the total cost of the boards is under $1 each, assuming a break a drill bit in the process of producing each. My total time (not counting this discussion) will be 3 hours + the time to drill the boards. If I can drill three in 1.5 hours, that will be a total of 4.5 hours for 3 boards or 1.5 hours and $1 for each proto board.

I am an optimist, so if we double each of those figures, we're at 3 hours and $2 per final board. Seems to be a good deal because I get the final product instantly.

I agree that the batchpcb product has a very compelling price... but I think I can still do it cheaper in my "free" time, since this is still just a hobby.

Newz2000
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Re: 800+ holes x3

Post by Newz2000 » Sun Jan 29, 2006 12:10 pm

Originally posted by CeaSaR.:
What about the CNC machine article in the December issue?

CeaSaR
I knew I saw that article somewhere, but couldn't find the mag where it was. After looking through my stack, I noticed Dec was missing... a quick hunt turned it up (no, not in the bathroom) and I think that will be a perfect reference. Thanks for the tip.

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Re: 800+ holes x3

Post by Forrest » Sun Jan 29, 2006 8:40 pm

My prices assume you'll need to buy a box of photo paper ($10), and a set of tungsten carbide drill bits ($10), a bottle of etchant ($7) and some PCB laminate ($3). It typically takes me 3-4 hours to image, touchup, etch, clean and drill 1 PC board.

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haklesup
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Re: 800+ holes x3

Post by haklesup » Mon Jan 30, 2006 11:55 am

The $ and labor are adding up.

At some point you will see that sending out for 2-6 layer boards is not such a bad deal. one vendor I checked is offering $25 per board at (QTY 1!, 2 layer) shipping, tooling, silkscreen, soldermask all included. Similar deals are to be had at a bunch of vendors as long as you stay within the "proto" specs. (usually >10mil holes and >7/7 mil space/trace, no gold, no routing.)

Its not hard to get a batch of 5-10 boards for under $130. Unless you plan to make a real lot of boards over time, this should be less than a CNC machine of any size.

There's nothing like doing it yourself but at some point it gets tiresome and inefficient.

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