Make PCBs with a Plotter

[tggzzz]

Inexperienced people can and will watch the videos, and poorly duplicate what they see. .

Do you have in 230VAC mains wall socket such warning messages, too? 
Nobody puts any metal parts into this socket-because everybody knows it could kill you

Don't make silly arguments: they don't do you any favour. I will assume you are not a troll, for the moment. For a start consider why people buy these http://www.amazon.co.uk/Child-Proof-Saftey-Socket-Protector/dp/B000XRUBBI/ and then consider the more important points...

If you can't understand the fundamental difference, it is this: 230V sockets are familiar, have been around for several lifetimes, and everybody sees them every day of their life. Hence everybody[1] knows they are dangerous, however non-technical they are. Same with gas appliances. Same with crossing the road. OTOH lasers are new and rare and are not understood by "the man in the street". Very few people have the slightest idea of how little laser power it takes to blind you (0.1W laser << 100W light bulb therefore there can't possibly be any danger. Can there? Oh, sorry, I didn't mean to blind you. Please forgive me.).

If you make a mistake with the mains, you suffer. If you make a mistake with a laser, an innocent passer by might be the one that suffers.

[1] I know of a case in W Germany where a young child stuck knitting needles into the live and neutral mains socket. He survived, but his palms were scarred for life.

[Richard Crowley]

Here is another way of using a laser to directly write on the photoresist:

Now, finally a scheme that is actually BRILLIANT!   
There are 10,000s of those cheap laser printers with that kind of technology inside.
I'll have to find someone to translate for me.

[eneuro]

OTOH lasers are new and rare and are not understood by "the man in the street".

My neighbor has 6kW laser for welding and I know him and his family as well as friend who has very little technical knowledge, but nobody lost their sight, while they know that lasers are dangerous and special glasses are needed.

I'm talking about precision laser soldering like in this video and such thing is a few hundred meters away from our yard ready to do precision work when needed, while we know each other from childhood 


Man on the street won't find strong laser in toys shop, so he doesn't have to know anything about electronics, but how to turn on/off his crappy cell phone 

[mauroh]

From several years I'm using a pen plotter to make my own pcb at home, see here:

http://www.mauroh.com/pcbconplotter/pcbconplotter.htm

It is the fastest/cheapest solution I found to use the massive amount of bare copper boards I have.
If I need high accuracy for  a crowded smd board nothing beat the UV light box.

Most probably I'm missing something but I'm not ghetting the point of using the laser plotter instead of the UV light box, although it is clever .

Mauro

[SeanB]

Wonder what will happen if you take a standard HP laser engine and replace the IR laser with the BD one, then build only a single axis platen to run across it. Should be able to do the exposure in under 1 minute per A4 board. You might have to modify the scanner motor to run slower so you do not have to have a 400MHz processor just to keep up, or use the existing processor board as well and have a laser that accepts HPGL as well as PS for the input.

A board printer that does double sided boards at 6 boards per minute.......

[tggzzz]

OTOH lasers are new and rare and are not understood by "the man in the street".

My neighbor has 6kW laser for welding and I know him and his family as well as friend who has very little technical knowledge, but nobody lost their sight, while they know that lasers are dangerous and special glasses are needed.

Ah, the "it hasn't happened to him therefore it won't happen to anybody" argument. Unimpressive. Symptomatic of a lack of critical thinking skills.

Do you also suggest that, because your friend hasn't been knocked down crossing the road, we shouldn't tell inexperienced people to look and listen before crossing the road?

I'm talking about precision laser soldering like in this video and such thing is a few hundred meters away from our yard ready to do precision work when needed, while we know each other from childhood 

So what's your point?

I haven't made any points specifically about your safety practices let alone your friend's.

Man on the street won't find strong laser in toys shop, so he doesn't have to know anything about electronics, but how to turn on/off his crappy cell phone 

Why on earth would toy shops be relevant to the point?

All that matters is that "man on the street" can - and does - easily obtain them. And some idiots point them at pilot's eyes for a joke, (temporarily) blinding them.

Where someone else's safety is at stake, it is negligent not to include suitable warnings at the earliest opportunity, before the danger arises.

[eneuro]

Here is another way of using a laser to directly write on the photoresist:

There are 10,000s of those cheap laser printers with that kind of technology inside.

http://www.das-labor.org/wiki/LaserExposer
1W 450nm blue Laser diode from ebay (40 Bucks) to replace the infrared one in the printer's assembly.
laser housing and glas lens from ebay (15 Bucks)
It looks like they replaced oryginal IR with UV laser diode and removed optics from rotating mirror providing ONLY glas lens to his new laser module, so somethinglike this happens in this setup:
There is one problem with this: as the beam length varies with the angle of the deflected laser beam, the focus of the laser lens would also have to be adjusted for each beam length. As this isn't done, the laser gets blurry at the ends and the middle of the scanline. But this is not a problem in practice, as the image gets sharp

Anyway, they got really quite good results, but had to add in practice new control software-I was expecting they used oryginal, but of course laser printer is much more complicated and no chance to use oryginal printer software 
So, I do not know, controll of this bloody rotating mirror looks very complicated and it is amazing how they hit PCB with such quite high DPI 
However, if we have to buy this blue laser module with additional lens, maybe it doesn't make sense mess with this rotating mirror, but rather use 2 Axis LinuxCNC to drive this laser vertical (with small angle to avoid see its own laser beam) directly from PC, so we could use existing LinuxCNC software which converts G-Code to drive those stepper motors.
The only problem is probably we'll end with slower UV printing when 2 axis LinuxCNC is used and probably this rotating mirror in oryginal laser printers have hardware advantage, but much more complicated setup.

What about required UV laser power let say for 1 square mm (1mm^2) needed to make proper UV exposition-is it dependent on power of used laser, but what UV exposure profile is needed to make high quality PCBs?
In this How to make a printed circuit board (PCB) using the UV light LED method looks like they managed this by a lot of experimenting 
This instructable shows how to create well done PCB's using Ultraviolet light. It took us about 40 boards before we perfected our PCB, so we will share what worked and what didn't work.

[MrAl]

Hi,

For you guys that are using 'pens' rather than lasers, what kind of pen are you using?
I had started building an xyz table a while back for drawing on PC boards but got involved in other things before finishing it, and never got around to designing a pen yet either.  Any ideas?

[mauroh]

Hi,

For you guys that are using 'pens' rather than lasers, what kind of pen are you using?

Any permanent marker will do the trick.

I like the Stabilo OH Pen

Mauro

[ignamv]

Ever seen what happens to a laser tube if it gets its own reflected beam back in, in phase? 

Increased noise floor?

[nctnico]

Inexperienced people can and will watch the videos, and poorly duplicate what they see. .

Do you have in 230VAC mains wall socket such warning messages, too? 
Nobody puts any metal parts into this socket-because everybody knows it could kill you.

Because this is told to people from a very young age. However there are many dangers you are unaware off in certain situations. Many years ago I had to work in a chemical plant. Before I was allowed on site I had to pass a safety exam. There where many simple things that could go wrong like rooms without oxygen or build up of CO2 due to lack of ventilation.

[eneuro]

I had started building an xyz table a while back for drawing on PC boards but got involved in other things before finishing it, and never got around to designing a pen yet either.

Probably 3 axis machine will be better for UV laser too, while we can make classic trick- before any drawing-let manualy touch four corners of our PCB to ensure that control software will adjust any height differences in the case PCB is not perfectly perpendicular to vertical pen axis.
Additionaly in UV laser tool version we can use bigger angle and let UV laser be reflected from PCB copper in direction which will minimalize beam back reflections and help compensate for PCB not perfectly lying on the table, while in DIY construction it will be difficult make those 3 axis perfectly perpendicular each other.

Pen tool might be usefull too, but looks like very difficult to fill eg. solid 100mm^2 area with perfect pen coverage, so it might be usefull for simple projects where ONLY small percentage of PCB copper area is used in final circuit 

Do you have any "patents" for this-to fill large copper area with pen plotter? It looks like we shoud have at least two pens exchangable, but it leads to need for 4th axis or need to change  pens before PCB drawing is finished...

[tggzzz]

Inexperienced people can and will watch the videos, and poorly duplicate what they see. .

Do you have in 230VAC mains wall socket such warning messages, too? 
Nobody puts any metal parts into this socket-because everybody knows it could kill you.

Because this is told to people from a very young age. However there are many dangers you are unaware off in certain situations. Many years ago I had to work in a chemical plant. Before I was allowed on site I had to pass a safety exam. There where many simple things that could go wrong like rooms without oxygen or build up of CO2 due to lack of ventilation.

Precisely.

I hope eunero won't write similar things again. He hasn't responded to my response, so maybe he does have his tail between his legs OTOH he has made other statements about his neighbour with a 6kW laser not having problems

[eneuro]

I hope eunero won't write similar things again.

I do not have time to write twice the same.
Better focus howto achive smallest possible 1W UV laser beam in custom CNC machine and howto calculate optimum expousre time for given UV laser power per mm2 of PCB to get perfect results with this method

BTW: I f you feel frustrated UK weather, fly to Cyprus right now perfect temperatures... it will help you enjoy life and see light sources much less dangerous if you feel warm and heat from the sun at winter and let you forget about rainny windy days in UK 

[nctnico]

I'm with tggzzz on this one: the first 3 issues to solve when working with harmfull and dangerous radiation are:
1) safety
2) safety
3) safety

Figure out how to make the enclosure in a way the UV cannot get out, research which eye and skin protection to use, read how to operate an UV laser safely, read about safety interlocks, etc. The people with the 6kW laser probably have a machine where all of this has been adressed properly. Cool they have a 6kW laser and know nothing about it but no doubt someone else did the hard thinking for them! Now just hope they are not going to mess with the safety interlocks and so on.

I don't know where I read this story but here it goes: at some point a Chinese restaurant owner found it more practicle to have a microwave oven with a slot in the front so they wouldn't have to open the door all the time. Just shuffle the plates in and pull them out. Result: a couple of employees lost their hands / fingers and one women got permanently blind (the slot was as the same height as her eyes).

[MrAl]

Hi,

My reply is mostly for posts #33 and #36, in regard to using a 'pen' of some type.

Well in using a magic marker even by hand i found that it gives up at some point, where the ink dries a little at the tip and has to be 'restarted' on some clean surface before resuming the line drawing, even by hand.
Is there a better marker than the 'Sharpie', the fine point?

For larger areas i would do them by hand with a large tip Sharpie.  I would not sweat that part because the line drawing is the most tedious to do by hand, not the 'fill in' with the larger marker.  I would just draw a 'box' around the area to be filled, then later remove the board from the machine and fill in by hand.  I dont need production quanities and dont mind filling in a little.  I do like making larger areas when possible though so it saves on etchant solution.

So, did you have this problem too when using a Sharpie or are the other markers that much better that they always write perfectly?

[mauroh]

Well in using a magic marker even by hand i found that it gives up at some point, where the ink dries a little at the tip and has to be 'restarted' on some clean surface before resuming the line drawing, even by hand.
Is there a better marker than the 'Sharpie', the fine point?

Very nice description
What I noticed is that the "ink dries a little at the tip and has to be 'restarted'" only if the tip overwrite on a dried paint on the board.
This can be slightly reduced minimizing the overlaps and slowing the plotting speed.

On large surface to be covered, it will be good to avoid the final drawing of the outline of the area.

Hope someone will come with a suggestion for a perfect ink that solve this issue.
At the moment I can live touching up a bit the plotted board before the acid bath.

Mauro

[tomizett]

Hi All,
A little while ago I got hold of an old Tally wide format dotmatrix printer - after pondering what to do with it for a while I decided that it should become a PCB plotter.
In the same way as the original poster, I plot directly onto copperclad (the Stabilo OHpen is my favourate - I found it to give thicker coverage than the Staedtler). Part of my motivation was to avoid the additional expense of photoresist versus plain copperclad, as well as the additional scope for error in the exposure process.
My ideal machine would be a mill which would cut tracks directly and do the drills, thus completely eliminating chemicals and their attendent mess/ploution etc. I'm using FeCl by the way - takes an age without a heated etch tank, and I think that a better result could be achieved with a faster etch - this giving the etchant less chance to soak through the resist pen.

The results a just about aceptable, but certainly beat no PCB at all! I do everything on a 0.1" grid, doing only through hole work so far. There is quite a lot of backlash in the "paper feed" axis, which is really the limiting factor for acuracy, while the finest pitch is limited by the thickness of the pen tip.
I re-used the original motor driver ICs, but built my own control circuitary. The MCU on the plotter handles the primative PEN UP, PEN DOWN, MOVE XY actions, and a host programme on  the PC hands out the instructions. As this was a bit of a quick lashup, the easiest format for me to read in was DXF (drawing exchange format) so I'm currently doing all my PBC layouts in a general purpose CAD package!

I've just taken some photos of it to share with you, but I'm damned if I can get them off the camera. I'll do it at work tomorrow and upload them then.
Interesting thread (interesting forum)... Thanks.

(edited for typos)

[balu]

Hello All,

I’m back and I have made a new PCB with my plotter. This PCB is just for a simple splitter and amplifier which I need for a PoC. The first picture shows the plotted PCB. I use a Staedtler permanent Lumocolor pen (Size: F, 0.4mm). The second picture shows the PCB after etching with the leavings of the color of the pen. The last picture shows the final PCB (white spots are reflection of light).

[Refrigerator]

Nice ! 

[PCBaby]

Hello.
I know the topic is 120+ days old, but I didn't want to start a new one for exactly the same subject.

Did anybody here have a recent experience with the below type of products, which seem to correspond exactly to the title of the topic ?

https://agic.cc/en/education_hobby

and

https://agic.cc/en/industrial

Solutions allowing direct "conductive ink" printing seem to exist now.

[C]

HP7440A plotter
This does support hardware handshake.
will support XON/XOFF if programmed

You might like
[urlhttp://www.retrocomputing.net/parts/hp/colorpro/docs/docs.htm][/url]

[CaveMannDave]

Very nice description
What I noticed is that the "ink dries a little at the tip and has to be 'restarted'" only if the tip overwrite on a dried paint on the board.
This can be slightly reduced minimizing the overlaps and slowing the plotting speed.

On large surface to be covered, it will be good to avoid the final drawing of the outline of the area.

Hope someone will come with a suggestion for a perfect ink that solve this issue.
At the moment I can live touching up a bit the plotted board before the acid bath.

Ink jet?
Lots of them around.  Adapt for flat bed and change ink/travel speed for good coverage.

What about Vinyl cutters?  Small, cheap, programmable.
Cut RubyLith or similar material on backing substrate, peel waste and transfer to copper.

Or spin-coat copper with resist, engrave isolation (Think: Fine servo Z axis to JUST touch foil), then etch.

Cheers,

Dave

[Gyro]

Here's one I knocked together when I was young and enthusiastic, it's good for front panels too. Needless to say I haven't used it in ages. 

P.S. Just as a side-note it's based on a very old manual drafting tool which used various width scribers to remove ink from a coated acetate sheet for photo etching. It was completely manual - the operator actually had to turn the X and Y knobs to move it!