Hi guys. I wasn't sure which subforum to post this in, but I guess here is best as it's modding and experimental. Although I ponder about red lasers now it wouldn't really belong in the red forum if someone suggests other colors so here goes...
I am after advice and guidance relating to lasers for neatly slicing through plastic film like the thick stuff used for transparrancies/overheads in laserprinters/copiers. I am trying to cut stencils for use in electronics soldering (solder stencils) and after trying drillbits and other milling as well as hot-needle type cutting (just gets full of gunk from cutting!) I ended up starting to look into lasers.
I've read up on protecting my eyes and such and have a few laserpointers up to the 50mW range already (and am very carefull about where and when I use em, mostly chasing seagulls off the lawn in the wee morning hours).
Putting my EE training and experience to good use I started by picking apart one of my derlilict dvd-rw drives (a SH-S223) where I quickly found a dual-diode assembly whithout the traditional slug, but instead a huge heatsinky thing with the red diode molded in together with it's IR brother using a common Cathode. I got it running with a simple linear regulator type constant-current drive and have tested it up to 227 mA so far.
By modifying the heatsink I managed to make it match the diode-slug from a 5mW red laser so I could reuse it's frame and twist-focus lense.
It's hard to focus when you avoid looking at the beam, reflections and spot but I managed to go by smoke on a non-reflective dark surface and have it fairly well focused at 3" with no noticeable burn-danger 1/2" infront and back of this point.
This is good for me as I intend to put it in my cnc machine where I only want to cut through the suspended film but not scribe patterns in the base table. (MDF burns!)
Attached are some images resulting from testing with sharpie-coloring the plastic sheets. It's mostly fast swipes and it's obvious that slower move can cut the plastic but it's not very clean. Images had to be rescaled to 800x600 so they have about 418 pixels/mm for scale. Film is only 0.1mm thick and it appears so is the focal point of my beam when approx ok focused. If I could cut with that accuracy I would be a very happy man. It would be accurate enough for my smallest details like the really small pads on some chips.
When it comes to the machine operating I will probably have to run slowly so best not to be in room while it works. It's too tempting to look at it.
I'd like a ref to a good place to buy some RED blocking shades/goggles but I am quite dissapointed in the OD 2+ stuff being sold all over. It seems I could get OD 4+ for same money, but I need to find somewhere that ships to Norway.
I'd also like tips on how good the goggles need to be vs the power of the laser even though I think I want 4+ regardless.
If anyone knows how far I can push the diode from that SH-S223 I'd be thankfull.
I have started with RED laser for a few reasons. It is my understanding that red lasers are direct-type laserdiodes and as such will have little stray frequencys. This should make it safer in regards to blink reflex and optics focusing what is really there and not focusing something else another place too. There may however be good reasons to use something else, so I am all ears...
As a final comment I will note that I won't post detailed images of modifications and such here as I don't want any kids starting to reproduce this from their old dvd burners. I have a certified lab to work in allowing me to do these mods without ruening the diodes and other parts but most kids won't. (Luckally...)
I am after advice and guidance relating to lasers for neatly slicing through plastic film like the thick stuff used for transparrancies/overheads in laserprinters/copiers. I am trying to cut stencils for use in electronics soldering (solder stencils) and after trying drillbits and other milling as well as hot-needle type cutting (just gets full of gunk from cutting!) I ended up starting to look into lasers.
I've read up on protecting my eyes and such and have a few laserpointers up to the 50mW range already (and am very carefull about where and when I use em, mostly chasing seagulls off the lawn in the wee morning hours).
Putting my EE training and experience to good use I started by picking apart one of my derlilict dvd-rw drives (a SH-S223) where I quickly found a dual-diode assembly whithout the traditional slug, but instead a huge heatsinky thing with the red diode molded in together with it's IR brother using a common Cathode. I got it running with a simple linear regulator type constant-current drive and have tested it up to 227 mA so far.
By modifying the heatsink I managed to make it match the diode-slug from a 5mW red laser so I could reuse it's frame and twist-focus lense.
It's hard to focus when you avoid looking at the beam, reflections and spot but I managed to go by smoke on a non-reflective dark surface and have it fairly well focused at 3" with no noticeable burn-danger 1/2" infront and back of this point.
This is good for me as I intend to put it in my cnc machine where I only want to cut through the suspended film but not scribe patterns in the base table. (MDF burns!)
Attached are some images resulting from testing with sharpie-coloring the plastic sheets. It's mostly fast swipes and it's obvious that slower move can cut the plastic but it's not very clean. Images had to be rescaled to 800x600 so they have about 418 pixels/mm for scale. Film is only 0.1mm thick and it appears so is the focal point of my beam when approx ok focused. If I could cut with that accuracy I would be a very happy man. It would be accurate enough for my smallest details like the really small pads on some chips.
When it comes to the machine operating I will probably have to run slowly so best not to be in room while it works. It's too tempting to look at it.
I'd like a ref to a good place to buy some RED blocking shades/goggles but I am quite dissapointed in the OD 2+ stuff being sold all over. It seems I could get OD 4+ for same money, but I need to find somewhere that ships to Norway.
I'd also like tips on how good the goggles need to be vs the power of the laser even though I think I want 4+ regardless.
If anyone knows how far I can push the diode from that SH-S223 I'd be thankfull.
I have started with RED laser for a few reasons. It is my understanding that red lasers are direct-type laserdiodes and as such will have little stray frequencys. This should make it safer in regards to blink reflex and optics focusing what is really there and not focusing something else another place too. There may however be good reasons to use something else, so I am all ears...
As a final comment I will note that I won't post detailed images of modifications and such here as I don't want any kids starting to reproduce this from their old dvd burners. I have a certified lab to work in allowing me to do these mods without ruening the diodes and other parts but most kids won't. (Luckally...)
