Would buying a laser engraver be a good idea for these purposes?

Thread Starter

HalfMadDad

Joined Jun 10, 2016
30
Hi Everyone

I repair circuit boards for a living and it would be a lot easier for me if I had a wide variety of stencils.

I would like to create small circuits to teach my kids more about electronics too. Do you think I could buy a laser engraver to cut little stencils to work with solder paste for repairing boards?

Do you think I could also cut little stencils for applying etch resist to copper clad boards to create small SMT friendly boards at home?

Thanks for reading

P.S yahoo used to have a home brew circuit board group but it seems to have died. Is there a good discussion place for this sort of thing? is allaboutcircuits the right place?
 

Tonyr1084

Joined Sep 24, 2015
4,048
This is a good place to get lots of information and ideas concerning electronics, PCB design and manufacturing. The people here will give you a plethora of ideas and opinions. Sometimes those opinions may contradict each other, but that's what makes life so colorful, the contribution of differing viewpoints on a wide variety of issues.

Regarding your proposal, I would assume (I said "Assume") you could use a laser to etch circuits, but I would imagine it would be costly and time consuming to make circuit boards. They're called PCB's or PRINTED circuit boards because they are typically lithographically printed, then etched. To do the same (or similar) with a laser would make them LECB's (Laser Etched Circuit Boards). Perhaps on very small scales LECB's would be cost efficient both from monetary and time considerations; but larger projects would definitely take a lot longer to etch. Hence, much higher costs.

The idea of using a laser to repair PCB's stands some merit (in my opinion). Especially where modifying the circuitry is necessary, i.e. cutting a trace and adding jumpers to reconfigure the circuit paths, perhaps to correct mistakes made on the printed circuit plan.

As for whether it would be better for SMT versus PTH, I don't think you'd see much difference there. With PTH you have to drill, whereas SMT (generally speaking) doesn't require drilling, except in the case of multi-layer PCB's; excuse me, LECB's.
 

Uilnaydar

Joined Jan 30, 2008
118
A laser engraver would be great for doing bulk repairs on single sided or 2 layer PCBs. (Actually, if you could "burn through" a multi layer PCB accurately there'd be no limit). Make a jig on the engraver, program it to etch in the locations you want to cut traces and add mod wires until your hands are completely coated in dried super-glue. Heck, if you could burn off the mask only, it would make landing mod wires much easier than the x-acto blade scrape action. If the jig is accurate, the ability to repeat the process would be great!

I don't play etch-a-pcb anymore, there are way too online sources for cheap prototypes to mess around with. However, I don't see a reason why laser cutting opaque plastic film couldn't make fairly accurate photo resist masks.

I could also see this being used to make solder paste stencils, which would be nice.

With that being said, there is enough justification to buy the item <evil grin>. I think I even talked myself into purchasing one.
 

shortbus

Joined Sep 30, 2009
7,363
Somewhere I read that lasers don't give good results with copper/PCBs. Seems that the copper reflects too much. The common methods of etching PCBs using resist and a bath, can also be used to make stencils for solder paste also. The model railroad and aircraft guys do things like making parts by etching quite often, on thin hard to machine parts.
 

Thread Starter

HalfMadDad

Joined Jun 10, 2016
30
Hi Guys
Thanks very much for the help!

I wasn't thinking about burning the etch resist right off the board, that sounds like a good idea. However the point about copper reflecting too much is a good one too. I could try both.

If I can make little stencils, I can also make little stencils layouts to connect up a few SMTs.

Thanks again
 

Uilnaydar

Joined Jan 30, 2008
118
I remember seeing an article about using flat black spray paint as the mask and then using the engraver to remove the black paint... etch and start drillin'. I'd google it but I need to go harass my co-workers now.
 
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