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interesting way to do home boards

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large_ghostman

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Obviously a slightly more powerful laser should speed it up a great deal, but kind of clever thinking to do it that way. Nice finish as well

 

large_ghostman

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Apparently black paint can used as well with a normal laser, personally I would use the spray stuff you use for glass etching with a laser. Then again this is only for quick test boards, I still dont think home boards on the whole are now worth doing.
 

large_ghostman

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The black paint has some down sides, the one above is simply UV laser. I think a normal high powered laser with the right coating would be better. There is a molly something coating you put on glass to etch with a laser, I would personally start there. The 40W cheap lasers would do that board in under a min. The trick would be in finding the right spray on coating, for those that still make boards and have a cheap laser it might be an option.

DONT USE a laser on bare copper!! Unless its is rated for it!!! Some lasers have copper mirrors in ;)
 

Daniel Wood

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Looks good. My one concern would be a possible blanket of copper particles a few microns thick that didn't get picked up by the laser and/or etching process.
If a solder mask could be applied and then burnt off, that would be great!
 

large_ghostman

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Looks good. My one concern would be a possible blanket of copper particles a few microns thick that didn't get picked up by the laser and/or etching process.
If a solder mask could be applied and then burnt off, that would be great!
The first is using normal photo resist, the laser just does the UV work. All home methods have quality issue potential, but if you need a quick test board it might be an option/

My two older sisters live near Horbury in Wakefield :D, well is actually in Lupset
 

MrAl

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Hi,

What is the power rating of the laser in that device?
 

tomizett

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Funnily enough, I was discussing a similar principle with a colleague the other day. We have a laser cutter/engraver at work, and we where discussing using that to vapourise a layer of resist before etching.
If we get around to giving it a go, then I'll let you know how we get on.
 

large_ghostman

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Hi,

What is the power rating of the laser in that device?
I dont know, I will post the other videos up. All I know is the first one uses a UV laser and normal photo resist board. The others I saw used 40-50W lasers to burn off black paint from normal pcbs and then thay are etched like normal. BUT I have seen some moly something or other (I forget) in a spray can, this is sprayed on glass so a 40W laser can engrave the glas by eating away at the coating.

EDIT I think the UV one is 150 mW
 

large_ghostman

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Some more for you, looks like its possiable with normal laser from around 15W!!! even some been done with arduino! The price of cheap cnc is really low these days, so it comes down mainly to finding the right focal point and coating to laser off.





Also done with 25mW (real slow) and needs red light room! But seems that laser pcb is practical to some extent

 

large_ghostman

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Whatching the first video just above again, the guy does a couple of double passes!! See the quick flash of red light go up into the optics? Not a good idea, yiu shouldnt see any laser line just the red dot on the work area.
 

large_ghostman

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Funnily enough, I was discussing a similar principle with a colleague the other day. We have a laser cutter/engraver at work, and we where discussing using that to vapourise a layer of resist before etching.
If we get around to giving it a go, then I'll let you know how we get on.
If its a non UV laser make sure the focus point is bang on the coating, use a non reflective coating and if you see the red laser line STOP!!! I bet you know all that already, but in case others dont
 

tomizett

Active Member
Our laser is an infared CO2 type - commercial machine so it's pretty safe, thankfully.
It will probably take a bit of experimentation to find a suitable coating. I must admit I've not watched the video above properly yet (with the sound on) but I am I right in saying he was using a UV laser to expose a conventional photoresist board? In which case I suppose the additional passes are about getting enough exposure, given that you'd normally have to do several minutes.

We do shiny stuff all the time in out machine, engraving serial numbers on stainless plates (stainless I think, but they could be plated - it's not actually my job, so I've never looked very closely). You have to spray them with some (very expensive) magic paint to de-shiny them and absorb the heat, otherwise - as you allude to - it will just scatter and the laser won't touch it.
 

Triode

Active Member
Funnily enough, I was discussing a similar principle with a colleague the other day. We have a laser cutter/engraver at work, and we where discussing using that to vapourise a layer of resist before etching.
If we get around to giving it a go, then I'll let you know how we get on.
I've used this method before. We just use black spray paint as the resist and burn it away with a laser cutter. Rustoleum matte black works well, and you apply it very lightly. Then we'd just put it in the etchant solution of choice. I usually used the muriatic acid and hydrogen peroxide one.
 

tomizett

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Thanks Triode... seemed like it should work, but nice to know someone's had some success.
 

large_ghostman

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Copper is the problem, not because its a shiny metal, but because if you look up laser absorption copper is very high at reflecting red lasers. Way way higher than metals. Apparently its used as the optics in metal cutting lasers. I will try and find the you tube channel about laser copper mirrors. It also has the spray stuff on, they use it to coat glass for laser etching, I am willing to bet that is ideal for resist on copper.
 

large_ghostman

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This guys channel is a good source of info.

 

large_ghostman

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Mosaic my leisure battery has sat for 18 months from new, now its dead and not holding much of a charge!!! Cost alot as well :(, any advice from the battery maestro?
 
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