PCB LASER CNC

[oldschool]

Hy

I am thinking to build smal cnc with laser of 500mw to1w  with 405nm to exspose photoresist on pcb plates. But cant find some stuf on internet wich are bothering me.

I have read that laser shoud have over 30Khz somthing becose it cut nicer. So dc laser is of the question or what? What is pwm or tll in lasers? I thinked that lasers are dc powered not high voltage high frequency, at least form ebay for 30 dolars.

Next stuf is how to program this beast. If i use target 3001 program for drawing pcbs, how to convet in some usful file that for exsample mach3 program can read it. If i understand corectly laser cuting goes up and down over the whole board with litle steps. I understand g code ( i work on cnc machines) , but how do you convert picture from target to this kind of movement of the machine. Is there eny programs for this or how it is done.

I woudbe realy hapy if somone can give me an advice or two.

Thank you wery mutch.

What have i done.

 - i looked on the internet
 - i ask on another forum replies zero
 - i looked for cnc kontrolers online and pricing
 - i loked at the you tube where i found some videos
 - ask frends
 - buyed 3 nema steper motors loking for more powerful controler or polulu stuf

[Domagoj T]

May I ask why are you doing this?
If you need a DIY way to produce PCBs, toner transfer is much easier, cheaper, faster and more accurate.
If you are doing it because you will end up having a CNC laser too, well, you're not going to cut much more than paper with 1W.

As for how to do it, you can either convert the traces to BMP image and do a raster engrave job, or covert GERBERs to gCode to do vector job.

[jeremy]

I have read that laser shoud have over 30Khz somthing becose it cut nicer. So dc laser is of the question or what? What is pwm or tll in lasers? I thinked that lasers are dc powered not high voltage high frequency, at least form ebay for 30 dolars.

I am guessing that what you have read refers to ablating (vaporising) the copper, where you would likely use a Q-switched laser that operates at something like 30kHz. These lasers are quite large, need water cooling and cost something like $50k  LPKF makes some machines that do this which are more like $100k.

Just exposing the photoresist with a laser diode driven by DC should be fine. Make sure you get a single mode laser (for 405nm, usually only found in blue ray drives) for the smallest spot size.

[janoc]

There are some projects on Hackaday that did this - both a laser plotter and actual laser printer for exposing photoresist.

However, apart from having fun with lasers (and burning your eye out) this isn't a very practical method of making PCBs. It is very slow (realize that that tiny laser spot has to pass over every single spot of your board!) and very very sensitive to vibrations from your gantry (or whatever rig you use). Also perfect focusing and intensity control of the beam are a must (otherwise it will bleed outside the intended trace). When laser cutting or engraving 0.2-0.5mm is not a problem but with PCB tracks 0.1mm error can make the board unusable already.

The Hackaday project didn't use a 500mW module from China but one of those Bluray laser writer laser assemblies that come with focusing coils and all that - that is actually essential unless you only care about very rough boards with huge traces (but then you probably could just draw the tracks with a sharpie as well).

A better method is to either make transparencies, or, if you don't want to mess with those, some people hacked cheap LED  projectors by replacing the light source with an UV LED.

[ptricks]

I tried this method of doing pcb. I even built the MPCNC machine off thingiverse.
The problem you are going to have is that PCB boards are not 100% flat and so when you focus on one part of the board and get that nice clean line from the laser and then the laser moves across the board the line thickness will vary from wide to smaller.  The machine I built ended up being great for cutting wood or engraving but not PCB.

I still use the pre-sensitized PCB board method which is really really easy if you ever do it once.

[oldschool]

Hy

I dodnt have a lot of information about laser printing pcbs. I found a few internet sides last two days and programing seems to go from gerber files so this is doable.

To me it was nice option to exspose pcb with tiny laser dot. I wontet to have laser stationary and xy table moving on linear rails hiwin. So that vibration can be avoided.

I thot that laser had straight beam not conikal. This is interesting. I saw 3 laser converting in one dot on the pcb this must be realy triky to maintan.

Ok, if i understand corectly problem are mainly laser beam stability becose of vibratins and geometrikaly changin vertical aksis in z direction becose of bended pcb, time konsuming production and ayes hazard.

This is bad. vibration on mill are pain in the ass. I loked china co2 laser gantry and mirors and so on, to me it seems realy simpel 60w machine. Beem stability isthe worst as i see it. How can you mesure z ofset for compensation, like with plasma cuting(i read aticle of hack day, totaly insane, probably the equeipment cost a fortune).

It seem that is is waist of money nerves and time.

If i is so then is beter way to draw pcbs with tiny marker on cnc, a lot of wideo about that. And pcb s are cheap. I am buying pcb with fotoresist and foil on it (blue color), like they are from gold. For my hoby with no smd s and realy tiny stuf this wou be ok.

I have build nice box with uv actinic lights form filips realy nice. Wood, transfomators, lights, aluminium plate, even timer is in the box for time seting and so on. I realy like it. But this problem with laser printers is eating my nerve. I wont to buy3020 phaser, but i dont now if it will print on plastic.

So it seems laser is realy pain in the as. i didnt now this. Milling is poisenus becos of fr4 in air as i hear. Toner transfer was stil problematic when i looked for pcb manufacturing solution. People were loking for right printer, becose of holes in traces and so on.

Than you for your time to exsplain to me this laser pcb exsposing problems.

[Domagoj T]

Yes, toner transfer can leave porous traces, but it is something that can be solved.
After I transfer the toner to the PCB, I run the board one more time, but this time I apply this foil to it:
https://www.ebay.com/itm/50-Sheets-A4-Gold-Silver-Transfer-Foil-Paper-Laser-Printer-Machine-Hot-Laminator/302139903497?hash=item4658f10e09:m:mwoIMq8LAKZUeFXvNeQH3tQ

It sticks only to the areas where there is toner and fills all the little holes that the toner alone didn't cover.

[janoc]

Hy

I dodnt have a lot of information about laser printing pcbs. I found a few internet sides last two days and programing seems to go from gerber files so this is doable.

To me it was nice option to exspose pcb with tiny laser dot. I wontet to have laser stationary and xy table moving on linear rails hiwin. So that vibration can be avoided.

That won't eliminated all vibration, you would still get vibration by coupling through the chassis. Of course, it would depend on the construction of the machine.

I thot that laser had straight beam not conikal. This is interesting. I saw 3 laser converting in one dot on the pcb this must be realy triky to maintan.

Cheap semiconductor lasers like the module you likely wanted to use output slightly divergent beams. Also air dispersion plays a role. See here:
https://www.edmundoptics.eu/resources/application-notes/lasers/fundamentals-of-lasers/

Furthermore, the reason for needing the focusing is not only the beam being divergent but also that a beam that gives a "dot" of e.g. 1mm across is of little use when you need to draw features down to e.g. 0.1-0.2mm. So you need to focus the beam down and maintain that focus during printing (otherwise the width of the "line" will change). Which is kinda big deal because of the aforementioned vibrations, the surface of the copperclad not being totally flat (it never is), etc.

This is bad. vibration on mill are pain in the ass. I loked china co2 laser gantry and mirors and so on, to me it seems realy simpel 60w machine. Beem stability isthe worst as i see it. How can you mesure z ofset for compensation, like with plasma cuting(i read aticle of hack day, totaly insane, probably the equeipment cost a fortune).

It seem that is is waist of money nerves and time.

That's a completely irrelevant type of machine if you want to expose PCBs. CO2 laser produces infrared light and such machine is vastly overpowered for this job. Also, those machines are laser cutters, if the beam isn't perfectly focused you get a slightly wider/narrower cut (or it doesn't cut at all if it is too defocused) but that's all. That's not at all comparable with exposing boards. There you need a laser assembly that is more akin (both construction and accuracy-wise) to something you would find inside of a laser printer or a bluray writer, not a 60W laser cutter!

If i is so then is beter way to draw pcbs with tiny marker on cnc, a lot of wideo about that. And pcb s are cheap. I am buying pcb with fotoresist and foil on it (blue color), like they are from gold. For my hoby with no smd s and realy tiny stuf this wou be ok.

I would say forget the CNC - the marker comment was only to say that if you would be happy with such poor resolution, you could draw it using a felt tip marker by hand, not on a CNC. Using a plotter (that's what your CNC is) is a very slow and inefficient method.

If you have a laser printer then learn to do toner transfer - by far the easiest and fastest method. If you don't, then buy dry photoresist film (it is a lot cheaper than pre-sensitized boards) and learn how to do it using transparencies.

I have build nice box with uv actinic lights form filips realy nice. Wood, transfomators, lights, aluminium plate, even timer is in the box for time seting and so on. I realy like it. But this problem with laser printers is eating my nerve. I wont to buy3020 phaser, but i dont now if it will print on plastic.

You don't need to print on plastic (I guess you mean transparency films). Tracing paper is more than enough and most printers will manage to print on that.

So it seems laser is realy pain in the as. i didnt now this. Milling is poisenus becos of fr4 in air as i hear. Toner transfer was stil problematic when i looked for pcb manufacturing solution. People were loking for right printer, becose of holes in traces and so on.

Than you for your time to exsplain to me this laser pcb exsposing problems.

Well, manufacturing anything takes time and quite a bit of trial & error if you want to master it. If you don't want to worry about this stuff, don't manufacture boards at home and pay some board fabricator to make them for you. It is not expensive anymore. Just then you have to pay both in money and waiting time instead of elbow grease 

If you still want to try the laser way, have a look at this project - it is probably the closest to what you wanted to do:
https://hackaday.com/2017/07/14/laser-exposing-pcbs-with-a-blu-ray-laser/

Or this (basically a laser printer for making PCBs - probably the best approach if you want use laser):
https://www.youtube.com/embed/G9-JK2Nc7w0

and another one like that:
https://www.youtube.com/embed/fi4P-Bwc6g8

[sairfan1]

Working on almost same project my first target is to mill pcb and then through laser cut 3mm acrylic sheet,
I choose planet cnc, good thing about it is you can directly import gerber file to mill pcb they also support installing laser but i did not study yet,

[KL27x]

Toner transfer was stil problematic when i looked for pcb manufacturing solution. People were loking for right printer, becose of holes in traces and so on.

People want toner transfer to be cheap/free for some reason. If you are serious about making good PCB you might consider spending a little. HP printers seem to work well for toner transfer. You can buy excellent transfer papers for a dollar a sheet.

"Holes in traces" might not be the printer, though. There are various reasons for holes, including transfer method and etchant.

If you are willing to spend the time and money to build a laser CNC PCB exposing machine, I think you could spend that time and money in toner transfer and/or UV resist and end up with better capability.

[oldschool]

I must realy admit, to read your replys is real inspiering. Truly. I lern from your post more as in last few month browing the net.

Fackt is that, lasers are realy pain in the ass. I have cnc laser machine in budy s house but co2 tube broke becose of lackof colent. Sooo,.. i coud put laser diode there but i think it wont work. Vibratins are huge for smal objects to print.

If i wont to build laser it seems it is realy pain in the ass to build it corectly. And if i think that laser must print on clad bord from half an hour to few hours is time consuming too.

A lot of option to consider. I love laser it is sexsy but,... it can eat my nerve a lot too. Specialy if i took this diode https://www.ebay.com/itm/405nm-500mW-Focus-Dot-Engraving-Laser-Module-12V-Adapter-Violet-Blue-Diode-Carve/321910367592?hash=item4af35a6568:g:9V8AAOSwLwBaeUOX or similar without fokusing laser and so on. I watced some videos form you tube.

Tones transer is nice option in fakt i try it once yers ago, but printer problems kiled it. Comercial paper from comershals like interspar, hofer und sutch and print it. Didnt stik, holes, this that. I read on the forum some peole use a lot of time to master it, with right printer those days.

I can buy coper clads for realy cheap as left overs from industry production of pcb s. so i found this video https://www.ebay.com/itm/405nm-500mW-Focus-Dot-Engraving-Laser-Module-12V-Adapter-Violet-Blue-Diode-Carve/321910367592?hash=item4af35a6568:g:9V8AAOSwLwBaeUOX

If understand corectl this person uses aduino bord with some caind of sheeld gerb on witch he ataches steper moter drivers and then steper motors with power suply and usb cable to the computer. Ok i found this https://www.ebay.com/itm/3D-Printer-Kit-CNC-Shield-R3-Board-Stepper-Motor-Drive-Limit-Switch-for-Arduino/263837593803?epid=23021788194&hash=item3d6df230cb:g:CN8AAOSwBqZb3Q13 or https://www.ebay.com/itm/CNC-V3-Shield-UNO-R3-for-Arduino-Compatible-Board-4x-TI-DRV8825-D3U1/132300836009?epid=2190523849&hash=item1ecdbe8ca9:g:0rkAAOSwRJ1ZmHPh.

I have build cnc mill form scrach, i mean elektronik part totaly, drivers power suplys, contorelrs and so on. But how do you program aduino to work. If i understand corecty you must upload to aduino some code or program to work, then you need program to make somthing. I am not familiar with this type of sistems, ( i now that whole world is using them adn so ob enbeded systems).

i think i will avoid laser ploter becose if i undestand corectly i need realy good rails suports an so on, and laser fokusing thing, to me is money not good  spend. I will ratehr wait and build sturdy machine then i can put on it laser and spindle and so on with proper servo control.

But this flomaster ploter cnc marker thing can be build for cheap and fast. this woud work. Only problem is i am not familiar with aduinos  . (i have nukleo at home, try it twice i didnt get nowere, it woud me nice to heve soem turtorial for the thing)

Naice day to all and thank for your answers.

[oldschool]

https://www.youtube.com/watch?v=ud75Zdolh-M

[Canis Dirus Leidy]

Well, there is a really big (417 pages) discussion of such machine from shit and sticks Chinese laser diode and DIY mechanics (former inkjet printer plus stepping motors) / controller (STM32 based plus webcam). But it's in Russian.