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Old 8th Dec 2019, 11:56 pm   #21
Terry_VK5TM
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Default Re: PCB Artwork transfer

Even the CNC used to break them Wendy (especially if you set the z axis speed too high ) and because it doesn't have the auto stop feature, was a real pain to get it back to the point where it broke.

If I only had one or two small ones to do, I had a Dremel in a similar stand to yours but that was worse than using an ordinary drill press for breaking drill bits.
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Old 9th Dec 2019, 12:06 am   #22
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Default Re: PCB Artwork transfer

Hi Terry...I used to break the drills fairly regularly till I re adjusted the slide adjustments and since then.. have been fairly lucky with non breakages.
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Old 9th Dec 2019, 2:21 pm   #23
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FINALLY... Good news.. well for me anyway. One of our members suggested using GLOSSY Photo paper...To be honest.. I was a bit sceptical as I had a few failures with other glossy mediums. However.. I bought a pack on line..and it arrived today, Monday.
I had a quick pcb needed so I decided to try.
The laser printer deposited the artwork and I applied it with a hot domestic iron to the copper... After about 3 minutes the paper was well adhered to the copper. I let it cool, then tried to remove the paper. Soaked in warm water it eventually came off, leaving a residue. Gently rubbing with an old sponge pan scrub, I eventually cleared all the area...... It is necessary to not rush this, as .. as can be seen on the final board, there were one or two holes not etched, probably due to the residue still in the pad holes...
Etching took a little longer than with sensitised board and stupidly I used a piece of double sided board, which slowed down the etch..however you can see the results... it even printed the Lettering and 3 of the drilling pads.. I lost one small area, but for a first time effort I was well pleased...
So in future for quick prototypes, I will be using this method..
Next I will try a SMD IC test.
Photo one shows pre etch after the paper was removed and photo two.. final etch
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Old 9th Dec 2019, 5:53 pm   #24
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Default Re: PCB Artwork transfer

Here is the SMD test. As can be seen.. the middle pads seem to be co joined..and they are, however the large ones with the same pitch are better, however no good for practical use. The SOIC are quite usable though. The other pcb is an audio output stage, slight crashes in places, but again very usable... I must remember to increase some gaps if I use this method.
But overall, after a lot of trial and error.. or "messing about".. I think I have found a usable alternative method of pcb processing, and leave the U/V / photo resist board for final modules.
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Old 9th Dec 2019, 10:02 pm   #25
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Default Re: PCB Artwork transfer

Very encouraging results. Well done.

Have you actually tried the American made professional iron on film ?

I think what happened here is that the manufacturers of it perfected the issues that happen with other iron on systems. With it, when you peel it off, there is nothing to be cleaned away, just the "ink" layer left behind & ready to etch. Probably why it is on a heat resistant plastic backing, rather than paper, so there are no paper fibers to deal with.

https://www.jaycar.com.au/press-n-pe...-film/p/HG9980
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Old 9th Dec 2019, 10:22 pm   #26
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Default Re: PCB Artwork transfer

Something for us "older folks". Lots of years ago, I "acquired" a motor from a tape drive by a well known office tape recording firm.A 12v motor, I added a rectifier/smoothing and a regulator, with a speed controller. Drill was connected to shaft with a connector from a "choc drop" connector .I made many a PCB with this lash up.
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Old Yesterday, 12:31 am   #27
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Default Re: PCB Artwork transfer

As my drawing skills are not that good for anything more complex than stick figures, I'll try to describe a friends drilling setup from many years ago.

The setup basically consisted of a camera at the top pointing down to a small wooden bed.

This bed had a hole roughly centrally located in it and the bed was also able to be pushed down a short distance (think spring loaded).

Underneath the bed was a high speed motor and pulley with a small bearing arrangement through which a pcb drill bit was inserted. A flat drive belt was attached between the motor and directly round the drill bit.

There was also a bright light under this bed, such that it shone up through the central hole, said hole was located above and in line with the drill bit.

My friend would then, using a texta or similar easily removable ink type pen, push the flat bed down over the drill bit and circle on the screen where the tip of the drill bit was.

Drilling consisted of placing the pcb on the bed, lining up pads with the circle on the screen (because of the light shining up from beneath, they were easy to locate) and pushing the bed down to drill the pcb.

He became very proficient and could drill even a fairly large pcb in a very quick time.
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Old Yesterday, 9:44 am   #28
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Default Re: PCB Artwork transfer

Quote:
Originally Posted by Argus25 View Post
Very encouraging results. Well done.

Have you actually tried the American made professional iron on film ?

I think what happened here is that the manufacturers of it perfected the issues that happen with other iron on systems. With it, when you peel it off, there is nothing to be cleaned away, just the "ink" layer left behind & ready to etch. Probably why it is on a heat resistant plastic backing, rather than paper, so there are no paper fibers to deal with.

https://www.jaycar.com.au/press-n-pe...-film/p/HG9980
That's marketed in the UK as 'Press 'n Peel'.

At the Jaycar link, it appears to be $35 AU for a single A4 sheet, which the website seems to indicate. If so, that's a staggering £18 GBP a sheet. ($AU = £0.52 GBP).

It's widely available in the UK, both on eBay (typically £4.52 for a single sheet + £1.45 postage) and from Amazon £15.90 for five sheets, (so £3.18 per sheet), plus postage unless on orders over £20.00 of for Amazon Prime members:

https://www.amazon.co.uk/Press-n-Pee...92068730&psc=1

That looks frightfully expensive to me, even if a user can put several PCB layouts on one sheet. It explains why so many people try other papers or methods first. Many people on internet suggest that thin glossy magazine paper works best as once the design has been ironed on, the paper is much easier to remove than for example glossy photo paper. It does seem counter-intuitive to use magazine paper on which there is already print, and to print onto it with a laser printer, but of course, the ink on the paper is printers' ink and the laser printer applies toner.

I wonder how many users forget to reverse the artwork before printing it and ironing it on, and end up with a perfectly printed PCB which is a mirror image of what they actually need? Oh dear!

True, the Press 'n Peel and iron on technique obviates all the faff of needed a UV box (which can be cheaply made from a fly killed or ultra-bright UV LEDS), and for developer, but the UV negative resist dry film that I use typically costs £3.38 for a 1 M x 30cm reel, which equates to 17p for an A4 sheet. It takes 2 teaspoons of developer (cheaply available 'soda ash) to develop a PCB.

If I had a laser printer and no UV light box, I think I'd be opting for magazine paper.

Really, all that matters is that we each find a system that works for us, and share our successes (and failures!) with kindred spirits on the forum.
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Old Yesterday, 10:43 am   #29
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Default Re: PCB Artwork transfer

$35 for 5 sheets David.

Roughly £3.60 a sheet.
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Old Yesterday, 11:15 am   #30
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Default Re: PCB Artwork transfer

Hi David. My experience of the Magazine paper was totally negative.. in as much as some toner would be left behind, no matter how long the heat was applied... I put it down to the ink already deposited....thats why I opted for plain glossy photo paper.
A roll of coated acetate also arrived, which I have not tried yet.....I need to get my head around its use...as it was only about £3 its obviously not the material you suggest.
30cmx1M/Roll PCB Photosensitive Dry Film.
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Old Yesterday, 2:34 pm   #31
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Default Re: PCB Artwork transfer

Quote:
Originally Posted by Wendymott View Post
Hi David. My experience of the Magazine paper was totally negative.. in as much as some toner would be left behind, no matter how long the heat was applied... I put it down to the ink already deposited....thats why I opted for plain glossy photo paper.

A roll of coated acetate also arrived, which I have not tried yet.....I need to get my head around its use...as it was only about £3 its obviously not the material you suggest.
30cmx1M/Roll PCB Photosensitive Dry Film.
Re the toner transfer method, I've no experience of it, but I've looked at quite a lot of internet comments and youtube videos just out of interest, and there doesn't seem to be a consensus of what paper consistently achieves best results. As with other PCB techniques, I don't think it's helpful when the tracks are needlessly thin and pads needlessly small. A lot of people who use toner transfer seem to end up touching up areas where the toner hasn't adhered.

As to the negative UV dry film technique, it comes with no instructions, or in incomprehensible 'Chinglish' which is quite bizarre and no help at all.

I've mentioned the process before on the forum, but can't find the link, so I'll outline it again below.

The method and processes can be viewed on youtube at this link:

https://www.youtube.com/watch?v=2hQfGtSFe_0

The UV dry film resist has a thin transparent protective sheet on each side.

The steps are as follows:

• Cut a piece of film to the size of the PCB and attach a piece of Sellotape to the corner of each side of the protective film to peel one side off. One side will peel off - the other will stay on. (It doesn't matter which side peels off).

• Place the UV film onto the PCB, smooth it out and pass it through a laminator a couple of times to ensure that it adheres to the PCB with no air bubbles in it.

• Place the artwork on the PCB in the usual manner and expose it in a UV light box. (Note: The artwork must be NEGATIVE – not positive). The exposure time is approx 45 – 60 seconds. To create a negative, open the PCB artwork file in ‘PAINT’ then usin the ‘Select’ option and with the mouse, 'lasso' the image, then right click on the image and a drop-down menu will appear. The bottom option on that menu is ‘invert colour’. Select that option and left click, when it will invert the colour to create the negative. Click on ‘save as’ and rename the image ‘PCB negative’ or whatever.

Any black areas of the UV mask which aren't exposed by the UV light will be dissolved away by the developer. Any clear areas of the exposed PCB will remain on the PCB once developed. The opposite of course, of positive resit techniques.

Developing:

• Peel off the second protective clear plastic film from the exposed UV resist layer and place the PCB in developer, consisting of a solution of 100 ml of water to 1 – 2 grams of Sodium Carbonate (also known as ‘Soda Ash’), so 1 Litre of water requires 10 – 20 grams of sodium carbonate. (1 gram is 1 level teaspoon, which is 5ml).

• Agitate until the exposed areas of the PCB have dissolved, then rinse in water.

Etch the board and when fully etched, remove the resist with meths or acetone. If the etched board is place in a shallow container and just covered with acetone, the resist will wrinkle up and float free of the board.

As the film is light sensitive it must be kept in a lightproof container such as a mailing tube.

A 1 metre x 30cm roll of negative resist UV dry film typically costs £3.00. EG:

https://www.ebay.co.uk/itm/124002347436

There are UK suppliers of the film too, but a little more expensive.

The film has the merit that you only need to cut a piece off the roll the size of the P CB. If the PCB doesn't turn out as expected, you can just place it in acetone to completely remove the UV resist, then apply a new piece of film and make another attempt.

When I first stated using the film, I didn't find it that easy to smooth out every air bubble then when passed through the laminator, the film was sealed to the PCB compete with a few bubbles. It isn't quite as simple as the youtube video seems to suggest.

1 KG of sodium carbonate is typically £5.50 post free on e-bay:

http://www.ebay.co.uk/itm/300980297463

I have to admit that it's more involved than the toner transfer method if people have success with that. But for anyone who doesn't have a light box and only wants to make the occasional PCB, toner transfer is clearly an attractive and cheap option with much to commend it once consistent results are obtained.

For me, I've been in it for the 'long haul', making my own PCBs for sixty years, initially using rub-down transfers and Fablon film, but have used a UV light box for maybe 40 years. Pre-sensitised board were expensive and I often ended up with useless offcuts, so gave up on that and used positive resist self-sprayed UV lacquer. Then in 2016 I discovered the negative UV film, which was a notable improvement on UV lacquer.

Some may find this all a rather tedious nuisance to be avoided, but for me, it isn't a chore or I wouldn't do it. It's a facet of my home-brew projects which gets me out of bed each morning.

The pics below are:

1) A PCB which has been exposed and developed. (about 1 min to expose, and 1 min to develop).
2) The PCB after etching, with the resist still in place.
3) The PCB with the resist removed by placing in a dish of acetone for 1 min, ready for drilling.

Hope that's of interest.

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Make the most of today - get interested in something.
Shake yourself awake - develop a hobby.
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Old Yesterday, 2:37 pm   #32
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Default Re: PCB Artwork transfer

Quote:
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$35 for 5 sheets David.

Roughly £3.60 a sheet.
That makes more sense Terry!

When it said 'quantity 1' I did wonder if it meant 'one pack' rather than 'one sheet'.

Cheap enough to give it a go, especially if several PCBs can be printed onto one sheet to make best use of it.
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Old Yesterday, 4:42 pm   #33
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Default Re: PCB Artwork transfer

I can certainly see the merits of your preferred method David.. Lots to try..
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