Prototyping Surface Mount Components??

I don't think the picture is quite as bad as you paint it. Sure the via holes on this board aren't drilled perfectly, they didn't need to be here, but the SMT part of things was fine. I had no poor tracks or pads. The chip is a TQFP, the tracks 8 thou mostly. This was made at home in not a lot of time at all, just a quick prototype. Excuse the blurred photo.

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Steve

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Steve
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You must be joking.

You've only got one project to work on? There's _nothing_ productive you can do while waiting for a board? That firmware just writes itself, does it? Those old products all support themselves? Documentation just appears out of nowhere?

Must be nice...

;)

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Reply to
Grant Edwards

I regularly do multilayer boards at home. Once you have a through plaiting setup, this is relatively simple. As a rough estimation you can say that you need a total processing time of one hour per layer. So, a 4 layer takes 4 hours and so on.

Obviousely a through plating setup and a CNC drilling machine cost some money, so for the average hobbyist this is not an option. I made my own througplating machine and hence could save a lot of money I otherwise would have to spend to buy one. Smaller CNC drills are relatively cheap these days so at least for me it was worth the investment.

Personally I think making your own boards is having a lot of advantages apart from the prize argument only. But while we are talking about prices, there comes a break even point with increased complexity in that prototyping prices for multilayer boards (especially those >6 layers) seem to rise exponentially. Another point is the fact that even when I do my boards myself many kind of work can be done unatended.

Elsewhere in this thread you mention also the time one has to wait up until externally made boards arrive. This is a very valid argument and the waiting time significantly varies depending on where you live. At the risk of outin myself of not being perfect, this becomes a real issue if you discover some sort of error or find some important optimisation (i.e. because of space constraints etc.) once the board arrives.

Just my 2¢ of course.

Markus

Reply to
Markus Zingg

The keyword is planning. I have several pcbs drawn in different stages, and while one gets manufactured, the others proceed in whatever they need. Don't forget at one stage, they need firmware, they need PC software, they need sales efforts, and so on.

Rene

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Rene Tschaggelar

I've always been interested in having a go at doing PTH in my workshop. Looks a bit complicated from what I have read to date, how feasible is the process from an amateur perspective?

Steve

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Steve

Basically the biggsest hurdle is getting the propper chemistry. These days it should not really be so difficult to buy it from one of those suppliers who deliver board shops. In europe Bungard is one of them, but there are others.

What's left is to have the needed number of tanks and following the instructions given with the chemistry. Ok, you also have to use photo resist laminate instead of already coated base material so as the holes remain covered at the final etching stage but that's about it. Apart from this using photo resist laminate also is having advantages like cheaper base material and also the option to simply start all over should you discover that the exposing and developement process did not worked well enough.

I made a webpage some time ago which showes the station I built. It does not have to be so fancy though.

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There is a tradeoff between simplicity of the station and the chemistry quantity needed. Since here in europe chemistry is relatively hard to get and expensive, I tired to make the tanks as narrow and small as possible to still being able to process double sized euro boards. If you can get the chemistry easier, there is no reason why one should not use containers like they are widely and cheaply available i.e. to store cerials.

After a couple of years of useage of above presented station, I'm now revising it and part of this process will be to TRY to vacume form the tanks. If I manage to do this, I will consider selling kits of the station. In other words, the biggest work is makeing the tanks but again, if you can get hold of the chemistry at a reasonable price you can make your live a lot easier by using ready made containers of slightly bigger size.

HTH

Markus

Reply to
Markus Zingg

Thanks for all that information and the useful website, that is a really neat machine you have built there! I looked at the Mega UK website and noticed their chemistry is quite expensive. I didn't think there was anything particularly unusual is used in those solutions, and wonder if detailed formulae are published anywhere. Maybe it would be possible to make the chemistry up more cheaply from basic chemicals.

Steve

Reply to
Steve
[snip]

There is, there's a german forum where someone posted formulas. I don't have the link at hand right now and also must admit that chemistry is somehow "black art" to me.

Personally I prefer to pay the - ok expensive - chemistry but at the same time being sure it works well. If you want, this is now me using the same argumentation of those not makeing their own boards but with regard to the chemistry :-) I really don't have to make EVERYTHING by myself :-) But I agree, one can save some 300-400 buks this way. Remember, if well treated, the chemistry once bought lasts VERY long - especially in prototyping/hobbyist envireonements where there is not a high number of boards processed. My initial chemistry partially still works, that said I replaced one bath ever since.

Markus

Reply to
Markus Zingg

That's useful information thanks, it's not so bad if you can keep the reagents for a long period, I had thought they might go off quickly like so many other things we use.

Steve

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Steve

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