UV lightbox cheap equivalents?

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demonicpicaxeguy

Senior Member
down here in australia about the only place you can get it is in officeworks but last time i looked the cheapest as $49.00 for a packet of 25 and it's a bit of a rip off compared to my paper solution, i'll post one of my good pcb's tonight when i can get access to the scanner again

i am at the moment looking at building a light plotter by making a milling machine attachment for my milling machine with a laser pointer and a few layers of pcb material to "chop" into the beam and give me a small dot
all i've got left to take care of is linear encoders which i'm waiting on part for
 
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Dippy

Moderator
Blimey. Do you have 'Staples' down under?
I bought some of their Laser/Photocopier transp sheets and they worked fine.
None of it is cheap however.

I guess someone will be trying felt pen on clingfilm next ;)
 
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demonicpicaxeguy

Senior Member
Dippy said:
Blimey. Do you have 'Staples' down under?
I bought some of their Laser/Photocopier transp sheets and they worked fine.
None of it is cheap however.

I guess someone will be trying felt pen on clingfilm next ;)
Click to expand...
try not to chuckle too much but for the first couple of pcb i literally drew on a piece of perspex with a black marker, i had to go over it several times, and it worked quite well
 
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kevrus

New Member
On the topic of track sizes, ive successfully used inkjet onto tracing paper down to 0.4mm for use with a surface mount 28x1 and ds1338 rtc...haven't tried anything smaller yet
 
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Dippy

Moderator
I've just managed a 1 micron track with the artwork written in Unicorn's blood using a quill on toilet paper.
 
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Dippy

Moderator
Oh the blue-eyed one.
Darn it! I've only got the red-eyed one.

On a serious note, when someone can do several home-brew PCBs of, say, 100mm x 150mm covered in intact <0.3mm tracks then I'll say "Well done Sir!".
And if someone can do half a dozen, complete with resist and ident and drilled for under a tenner and within a week then I'll send you my artwork :)

Anyway, back to the plot. Job done yet? Nails done yet?

Off on a tangent.
I recently had some dental work done and the denist used a bright violet light thing to cure the stuff. Apparently not UV. Shame, I was hoping for a tan on my tongue.
(No need for paragraphs on safety please, it was just an observation.)
 
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demonicpicaxeguy

Senior Member
Dippy said:
On a serious note, when someone can do several home-brew PCBs of, say, 100mm x 150mm covered in intact <0.3mm tracks then I'll say "Well done Sir!".
And if someone can do half a dozen, complete with resist and ident and drilled for under a tenner and within a week then I'll send you my artwork :)
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hmm.. normally i would do a single sided 100mmX160mmX1.6mm fr4 pcb with traces of 0.2mm and a 0.2mm gap for $27.50Aud which is $13.52Gbp that includes drilling up to 100holes (0.75mm - 10mm) within a week..... it'll spend most the time in postal transit but i could probably do it for 10Gbp without too much hassle
here's the last exposure i did - the three white particles is just crap the glass on the scanner,
 
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Dippy

Moderator
That's really neat dpg, good stuff.

Why aren't the pads very circular? Not important, just wondering.

For larger pads&drill-holes I always use smaller holes for home-brew, just for better drill centering if drilling by hand.

I think , again for home-brew, I'd be tempted to fatten the tracks slightly and 'neck' them just before the SMD land - just in case of tiny printing 'hole' pitting the artwork. Sod's Law right on a thin track.
Anyway, thats just me being picky. Just my peculiar preferences.

Nice job. We'll have to start a gallery :)
 
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Mycroft2152

Senior Member
DPG,

Nice board!

Let's be honest, how much did it cost to put together the equipment to make the board?

Definitely not a piece of glass and the sun...
 
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demonicpicaxeguy

Senior Member
thanks, i'm not too sure why the holes don't turn out to be rounder, it may have somthing to do with the laser printer and it's resolution but i've never had any complaints, i normally do them a lot smaller for drilling component leads but these particilar ones are for some bigger pins so i'll be using a bigger drill anyway,

mycroft,
for that pcb we're talking around $3 per board
for a 160X100mm single sided pcb, we're talking a total manufacturing cost of $15.00 _+ $0.50 and after profit a total $27 which down here isn't a bad price for prototyping quantities considering there isn't any "one time setup fees" and free postage within Australia

as for the rest of the equiptment i've maybe spent $100 to $150 which i've already made back
 
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Mycroft2152

Senior Member
DMG.

I am sure others would be interested.

Please describe your setup (photos?). That will give a good perspective on what is actually takes to make a quality board.

Myc
 
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kevrus

New Member
On a serious note, when someone can do several home-brew PCBs of, say, 100mm x 150mm covered in intact <0.3mm tracks then I'll say "Well done Sir!".
Click to expand...
My apologies if I went off on a tangent, I just mentioned it as i thought it may be of interest to people with inkjet printers and I would be the last person to attempt to impress others...apologies again
 
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alband

Senior Member
First try for everything :cool:

1min in UV (a la CD case)
about 1min in developer (done by eye)
and about 20min in my very week etchant. Although this is clearly a pain and I need to buy some more acid at some point, it was very useful while the last bits of copper were wearing away (1st photo)

So that's it, very nice (for my standards, I'll await your views) PCB made in about 30mins for under £50 :D

Thanks for all the help in this long thread, it has been much appreciated! :)
 

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alband

Senior Member
Andrew Cowan said:
It's getting better.

From the unetched copper at the edge, I think you need more even etching - agitate or bubbles?

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The stuff on the left edge is because it was an un-even cut so didn't get enough UV. The large diagonal chunk at the bottom is actually th edge of the board (perhaps I should have put it on something that wasn't copper coloured :rolleyes:)
 
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Dippy

Moderator
Wey-hey, you're getting there. Much better.

Same comment as before to someone else; for home-brew, don't have your drill sizes too large. Pointless. Make drill sizes smaller - after all you ARE going to drill them!
Smaller holes mean more copper and better centering for hand-held drilling.
 
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alband

Senior Member
Gurgh, I know. I remembered you saying that before and was going to change these one. Clearly I forgot except for when I looked at the artwork on the acetate and thought "damn".

Both reasons for making them smaller have come about :(
 
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Mycroft2152

Senior Member
Dippy said:
Wey-hey, you're getting there. Much better.

Same comment as before to someone else; for home-brew, don't have your drill sizes too large. Pointless. Make drill sizes smaller - after all you ARE going to drill them!
Smaller holes mean more copper and better centering for hand-held drilling.
Click to expand...
I usually make the holes as small as possible, just a "dimple" in the copper to help position the drill bit.

Myc
 
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Dippy

Moderator
alband, when you supply artwork to PCB manufacturers they usually request NO drill hole in artwork. Obv they use carbide drills in very high speed drill heads, but as Myc says: use sharp drills.

In all my boring years of making proto boards I have only ever ripped up a pad once (during drilling) and that was on some funny cheap unbranded board where the copper-to-board adhesion was poor (more pads came off during soldering).
If you ever suffer that problem then its the drill-bit, the board or you ;)

Also, if you only have a small ring of copper then overlong etching can weaken it as the etchant gets behind the photoresist to the edge of the copper and eats inwards under the resist. This applies to thin tracks too.
 
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SilentScreamer

Senior Member
Personally I like using a dremel since its faster and I find it far easier to move between holes. I have used a "proper" PCB drill at school, its better, but not enough to justify buying one.
 
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Andrew Cowan

Senior Member
Axminster said:
Not suitable for Dremel 300 series.
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Grr. Still - I like axminster - their customer service seems second to none.

Bank account - not good. Still recovering after after purchasing an (Axminster) milling machine. Saving up to convert it to CNC :).
 
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eclectic

Moderator
Andrew Cowan said:
Grr. Still - I like axminster - their customer service seems second to none.

Bank account - not good. Still recovering after after purchasing an (Axminster) milling machine. Saving up to convert it to CNC :).
Click to expand...
In that case (Dremel 300 from original posting):

1. If you own a Milling machine, then you're half-way there.

2. Buy a Multitool that fits the stands.

e

PS. Which Miller?
 
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Mycroft2152

Senior Member
Good choice! You will be able to mill meta with that.

Start saving your pence.

Plan on spending twice its cost to computerize it.
 
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alband

Senior Member
Hello all again,

I would first of all like to re-emphasise my thanks to all that helped with this thread, as having the ability to make my own boards has just been another degree of freedom.

I recently acquired a USB hub expander/mug-warmer. It is pretty useless at both applications; it is USB 1.1 so can't really be used for much more than charging stuff and I haven't got a clue how they expected at thick mug resting on a hot piece of metal to stay very ware.

However, the metal does get quite hot (problem being the mug thickness) and after dissecting it, I've found it works using two hot, resistor like components. Using some clever calculations (or rather; dumbly poking at it while it was on and judging by the colour of the resultant burn :confused: what was I thinking???) I reckon each component reaches about 120deg. They each rest on the metal disk and are thermally joined with what must be thermally conducting grease.

I had the idea that this could be used as a low budget heating element for the etching process, which is still painfully slow, even with the addition of more ferric chloride. Now, I had a few ideas of getting some scrap metal in a pan shape and attaching those little resistor heaters to it then shoving that in the etchant, but before that idea could develope I realised the metal would be eaten away. If I used a plastic, it would melt, if I used metal it would corrode :confused: So first question: any other ideas on what material could be used as a heating element in an etching tank that wont melt/corrode? btw, thought of glass - it would work perfectly, but I'm not really in the glass-blowing business.:eek:

Now, while I was looking for answers on the web, I came across this instructables. The chemical process is summarised on page 4.

What are everyone's views on it? Looks intriguing, but I'm surprised it isn't more popular or well-known give it is that good.

Any thoughts/ideas on either topic would be appreciated as usual.

Thanks,
David.
 
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SAborn

Senior Member
Hi David,

I have been making PCB's for many years and have tried many methods.
What i use to use was an old electric frying pan with water in it and sat the container of etchant in the water bath. This worked well and i could set the temp on the dial.

But now days i just grab a 1/2 bucket of hot tap water and stick the container of etchant into the hot water while etching is taking place.

One thing i found is if the etchant (ferric chloride) is too strong it takes longer to etch and i needed to add 50% water to the solution to get a faster etch.
Try a small sample diluted first with a scrap bit of board before you dilute the lot.

As for heaters to go into the etchant im not a fan of this but the glass fish tank heaters is often used by many people.
To me its just more crap needed and messy so i will stick with my bucket of hot water.
Others report they put there etchant in the microwave and heat it first but i also dont like the idea of doing this.

My bucket of water give me a etched board in 10-15 minutes and the bucket takes care of any dribbles or minor spills so stops all those nasty stain marks that you get from ferric chloride.

I use UV leds mounted on the carriage gutted from an old bubble jet printer and controlled by a 08m picaxe to scan the leds back and forth over the board for exposure and get perfect results every time.

One good tip........ I print my artwork onto plain paper with the printer set to high quality.
Then i wipe cooking oil over the back of the paper with a tissue, this makes the paper very translusent and works very well with either bubble jet or laser prints.
There is no need to store the artwork as its easier to print a new one when you need it again.
If it has been a few days since oiling the paper it pays to print a new one anyways.
Try it as i think you will agree it works better than any other method and better than transparent clear sheets. At a fraction of the cost.
 
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alband

Senior Member
Hmmm,

Some great tips there I can try next time. I especially like the paper-oil solution; should improve artwork quality no end.
I still don't want to waist those little things though, perhaps the best solution would be to attach them to a metal heat sink, then use that to heat a water bath on which I can keep etchant warm. A heat sink is quite a large chunk of metal though.

How about: Two flora cartons, sump rectangle of metal at the bottom of one with the heaters attached. I ill thin water, then sit the second carton on top with etchant in.

Any thoughts on that instructables?
 
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Dippy

Moderator
I know nothing about chemistry but it looks interesting and potentially dngerous.

I have been making PCBs for 758 years and use the traditional etchants.

"Toss in the PCB" - a rather casual approach when using hazardous chemicals.

So, if oxygen regenerates it (subject to enough acid) then it should be automatically regenerating in my Bubble Etcher.
The trouble is that it sounds like it'll attack most common metals which could I guess include internals of bubble and spray etchers. I'll give it a miss.

Why don't the Big Boys use this method?

Have a go and report back. I don't trust much on Instructables.
Complex chemistry articles are sometimes written by economists.

While you are at the shop don't forget a face mask and gloves. This could be nasty esp mixing alk and acid.

If you intend to do a lot of etching I would thoroughly recommend saving your pocket money and buy a proper Bubble Etcher. Typically £200.
 
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SAborn

Senior Member
If you so desire to use your little heaters then attach them to a old pot or saucepan / frying pan and use them for a water bath, as the thermal conductance of a water bath compared to a base element is far better for lower heat applications below boiling point.
Although the hotter the water the faster the evaporation rate.

If you are interested i done an artical on how i make PCB's here.http://www.thebackshed.com/windmill/articles/MakingPrintedCircuitBoards.asp

It is just a basic show of how to use photo resist board.
I skipped the bit on etching as figured anyone can dunk it into a solution.
You might find a few more tips there.
 
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alband

Senior Member
@ Dippy: So the general opinion is better the devil you know + if it ain't broke don't fix it?

@SAborn: Nice knowledge of thermal stuff there, that's definitely saved a good deal of effort.

How heat resistant is epoxy glue (once set of course). The heaters are effectively small resistors so the metal legs will short if I just dunk them into water. So I need something heatproof to cover the legs with (assuming normal plastic coated wire will be fine further from each heater)?

Thanks,
David.
 
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Mad Professor

Senior Member
I am also looking at making my own UV Exposure Unit.

I have just been able to get my hands on 6x 8W UV tubes.

I don't know if the UV light is in the right wavelengh.

The tubes are clear and read "Germicidal 8 Watt UV Lamp".

Can you tell if they are upto the job and how meny tubes I will need per side.

I have looked on maplin and megauk sites, and it seems that 2 or 3 tubes per side will do the job

I still have no way to connect or power the tubes yet.

I am in two minds, to buy two 16/24watt ballast units, or 4/6 high freq mini fluorescent lamp holders.
 
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eclectic

Moderator
alband;131305 How heat resistant is epoxy glue (once set of course). The heaters are effectively small resistors so the metal legs will short if I just dunk them into water. So I need something heatproof to cover the legs with (assuming normal plastic coated wire will be fine further from each heater)? Thanks said:
@David.
This is NOT advice, simply links to Datasheets.

Araldite, and I assume most other Epoxies:
http://www.bostik.co.uk/diy/faqs/group/10

&#8220;electronic&#8221; grade Silicone:
http://www.rapidonline.com/Tools-Fasteners-Production-Equipment/Service-Aids/Sealants-Coatings/Silicone-adhesive-sealant/34295/kw/silicone

A &#8220;real&#8221; etching tank:
http://www.rapidonline.com/Tools-Fasteners-Production-Equipment/PCB-Equipment/Etching/PCB-Etch-tank/29472/kw/etch


Ec
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