# Specific 3D Printers, Scanners, & Hardware > Peachy Printer Forum >  Potential resolution

## Morten

Hi! This may be getting way ahead of things but speculating is fun. It occurs to me that SLS is being used to fabricate materials with interesting optical effects like structural color generation in the form of diffraction grating. See e.g. http://www.opticsinfobase.org/view_a...bile%3Dno&org=

Could the peachy or a modified version ever achieve the resolution necessary?

Cheers from Norway!  :Wink:

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## Nahoj

The link didnt work for me...

Cheers from norway to! :-)

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## Morten

Huh, strange - but this is actually much more relevant.

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## Compro01

A bit more accessible explanation of what is being talked about - https://en.wikipedia.org/wiki/Structural_coloration

Basically, micrometer and nanometer-scale features on an object to alter the light reflected to create the appearance of colours, rather than using pigments.

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## Yourtime

> A bit more accessible explanation of what is being talked about - https://en.wikipedia.org/wiki/Structural_coloration
> 
> Basically, micrometer and nanometer-scale features on an object to alter the light reflected to create the appearance of colours, rather than using pigments.


Yeah as I searched it yesterday, I read the same about it and well I still wonder, I can't imagine that peachy printer has that much potential. Please proof me wrong,  I am happy with it already  :Cool:  Would be awesome of course, if this is also in some way possible, when you modify and print it in a specific way.

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## Morten

Well, according to the paper I linked earlier you don't need the extremely complicated 3d-microstructure of a butterfly-wing to achieve at least some coloring effects, simple round dimples or squares/hexagons with diameters and depths of a couple of microns should do it. Perhaps the code that generates the "in between" layers talked about in the last update could be utilized to generate very thin lines in e.g a vase and form a diffraction grating that turns it deep blue or whatever. If control over micrometer features are possible you could map a bitmap to the vase and have ridiculously high-res full-colour printing on it. Not to mention all the iridescence effects possible (use the alpha-chanel of said bitmap to control shininess/sparkles!).

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## Synchron

if this work, i think the next step is to print a cd/dvd inkl. music/film  :Big Grin:

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## Slatye

> if this work, i think the next step is to print a cd/dvd inkl. music/film


The lawyers would have fun with that. Is the audio file that causes a Peachy to print a DVD containing a file which can be decoded into a movie actually copyrighted? And what about the audio file that causes the Peachy to print a DVD containing the audio file that causes the Peachy to print a DVD containing a file which can be decoded into a movie?

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## harpo99999

just think about the SIZE of the datafile to generate the details you are talking about, not to mention the needed superfine control of the mirrors, and then start figuring out how long the prints would need to be for the detail level you want

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## Morten

Stuff like regularly-shaped indentations could likely be automatically generated on-the-fly, you wouldn't need to model the whole thing down to micron-scale just for that. You could use a bitmap as input. Superfine control of the mirrors.. yes, I guess, that's why I was asking. I would like to know what the theoretical /actual size of a Peachy voxel is, or potentially can be  :Wink:  As to print time... given the possibilities I would be willing to wait quite a while for a print that was colored like a butterfly altho it's just made of microscale-structured white plastic.

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## Feign

Regardless of the precision of the mirrors, the laser used in the Peachy is at least half a millimeter wide from what I've seen.  To make an analogy, trying to draw nanostructures in a surface with the Peachy's laser would be like trying to write your name in 10pt font in wet concrete using a bowling ball on a string.  While it's theoretically not _impossible_, it's certainly outside the realm of common sense.

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## Morten

But I don't want to draw nanostructures, I want to draw microstructures. They're a lot bigger. I'm not actually expecting to be able to do this with a stock Peachy, but like I said initially it's fun to speculate. Can the diameter of the laser be adjusted with an iris or a lens of some sort?

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## Davo

> ... would be like trying to write your name in 10pt font in wet concrete using a bowling ball on a string.


That's great. I tell people it's like signing a check with a caulk gun, but I may borrow this from you.  :Smile:

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## Yourtime

> Regardless of the precision of the mirrors, the laser used in the Peachy is at least half a millimeter wide from what I've seen.  To make an analogy, trying to draw nanostructures in a surface with the Peachy's laser would be like trying to write your name in 10pt font in wet concrete using a bowling ball on a string.  While it's theoretically not _impossible_, it's certainly outside the realm of common sense.


I agree with you and I like the analogy, but he also said modified peachy, theroetical is it possible to use a more thin laser to reach the micrometer level?

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## IsThisSparta

I agree that the laser looks about .5 mm wide, but I hope and pray that the focused point at the center is bright and small enough to do this

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## Anuvin

The laser point is determined by the user. The user can place a cover on the laser, and poke a hole the size they like. What's the best way to put the tiniest hole in a piece of soda can?

(The aperture disk in the beta kit is essentially a disk of thin aluminum)

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## bovalis2037

But by changing this aperture would it affect any calculations the team has done and already built in to the printer? 

For example if they said to poke a hole with a tooth pick rather than a pin the aperture would be different, and the laser would cure different amounts of resin than initially expected and change the wall size of the print. If you were to somehow make the hole smaller than initially expected the laser could possibly be moving to fast for it to actually solidify any of the resin.

Our am I just going crazy waiting for this thing to get here

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## Anuvin

I don't think so. However, I don't think anyone knows yet how small a laser point you can use to cure resin. Another test to add to the list.

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## Morten

This printer http://oldworldlabs.com/product/owl-nano/ seems to use a laser and (10x?) lens to get to .1 micron - why couldn't we mount a peachy on a microscope? Vibration dampening is probably a concern but a laser can demonstrably cure resin at far higher resolution than we need to do structural color  :Smile:

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## Feign

The OWL printers use a rather complex lensing system to reduce their laser footprint.  After watching someone's beta assembly video, it looks like there's plenty of room in front of the Peachy's laser for a small lens stack.  Just making a smaller aperture would not necessarily make the beam tighter, as you start getting dispersive lensing effects at very small apertures for physics reasons that I can't remember the names of.

Of course, that would be something for an upgraded or modded Peachy.

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## Pete

> Just making a smaller aperture would not necessarily make the beam tighter, as you start getting dispersive lensing effects at very small apertures for physics reasons that I can't remember the names of.


diffraction is the one you're looking for.

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## rylangrayston

> But by changing this aperture would it affect  any calculations the team has done and already built in to the printer? 
> 
> For example if they said to poke a hole with a tooth pick rather than a  pin the aperture would be different, and the laser would cure different  amounts of resin than initially expected and change the wall size of the  print. If you were to somehow make the hole smaller than initially  expected the laser could possibly be moving to fast for it to actually  solidify any of the resin.
> 
> Our am I just going crazy waiting for this thing to get here


Very very good point bovalis2037
We  are really focused on making the peachy printer hackable, built TO  be  modified, there are many many things that users will want to change that  will effect any default calibration.. Thats why there is no default  calibration per say... instead every time you make a peachy printer you  calibrate it! We are shipping with not only software to print with but  also software to calibrate with, That way if you build a different  printer for better or worse it still has a great shot at working!

Since this is a problem that im very passonate about solving ill get into it a bit  :Smile: 
There are 3 basic ways we are doing this:

1 . The printer always draws a bit of a warped shape with its moving laser beam, there are many stacking and unpridictable reasons for this, so  we have been implementing a way for you to create a specific profile for  each of your peachy printers.  It applys various transformations to unwrap you unique printer. 

2. Cure Rate calibration print-- (as you mentioned) If a  larger aperture was used or a different laser power or even an different  resin was used then the amount of light needed per volume of cured resin  would be different. To calibrate for this we walk you thru doing a print  where every layer is progressively cured less and less, once this print  is complete you tell the computer at what height the printer did the  correct amount of curing and the software correlates that with the  settings used on the layer at that height. 

3. drips and  containers- We are making an easy to use program where you let the drip  feed run from one height to another. After entering the hights int the computer it counts the drips and  tells you how many drips per mm there are in your setup.

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## bovalis2037

Im soo glad what I said made some sense. Thank you for explaining! 

Now does that mean that I will be able to (in highly improbable theory) be able to print my own apertures?

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## Anuvin

You probably could, but it would be challenging. If your resin is clear or semi transparent, it won't work. But if you have opaque material, sure. Probably just simpler to poke a hole in tin foil or whatever though.

On the other hand, I bet it prints a little hole in a disk really well. Perhaps one could print sequentially finer and finer aperture disks, which would be really cool.

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## bovalis2037

Thats exactly what I was thinking! The more fine I get my aperture the more fine I can print one and it then becomes a cycle.  Im sure that the accuracy would increase but after a certain point it would be negligible.

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## rylangrayston

> Thats exactly what I was thinking! The more fine I get my aperture the more fine I can print one and it then becomes a cycle.  Im sure that the accuracy would increase but after a certain point it would be negligible.


 :Smile:  There is something very appealing to me about cycles like this. I keep joking with everyone about the idea of printing a record, on which is encoded a "song" which when played into a peachy printer, prints another record.
And of course Im very excited to try printing a peachy printer with a peachy printer (Peachy RepRap) . 

I have no clue how well these things work in actual practice but I can tell you that the resin blocks uv light very well.  Im sure you can print a large aperture, but i don’t know how small you could print one.

What ever happens be sure to post because others (like me  :Smile:  ) will really enjoy seeing the process !

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## bovalis2037

I will!! But I wanted to print a record! One of my friends and i were working on some software to convert super high quality mp3 files to record "bumps" as we've been calling them. And i kept telling him that i have full faith in the peachy cause of its insane z axis resolution. I am still soo shocked at how clear and glass-like that column was in update 13

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## Morten

So is the cured transparent resin transparent to UV light as well as visible? Because I'm thinking about printing lenses now  :Smile:

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## mike_biddell

Printing spectacles would be brilliant for the 3rd world (and ours for crazy specs). Wonder how you convert an eye prescription into a 3 dimensional lens? The optician can do it, so we just need to know how !!!!

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## Feign

> diffraction is the one you're looking for.


Considering that the original subject of the thread was using diffraction to create colored prints, I'm a bit embarassed to not have remembered it.




> I have no clue how well these things work in actual practice but I can tell you that the resin blocks uv light very well.  Im sure you can print a large aperture, but i don’t know how small you could print one.


You've mentioned before though that you can fill a hollow print and it will cure under sustained UV, which would suggest that the cured resin isn't completely opaque to UV.  I'm sure it's too opaque to make into a focusing lens for the laser though.

I think most glasses-wearing watchers had the lens printing idea after seeing the column print video.  I look forward to running some tests to see what kind of refractive index the resin has and just how smooth it can print with that sub-layer interpolation that was talked about.

I think that it would be easier to write an equation to directly generate lens cross-section based on z-axis and focal point than it would be to make a parametric lens model and use a slicer.  The machine that grinds out the lenses for the optomitrist already uses a CNC process that might already be very similar to g-code.

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## nka

> So is the cured transparent resin transparent to UV light as well as visible? Because I'm thinking about printing lenses now


Not sure what you're trying to do, but I dont think you'll be able to print lenses. Those need very high precision and polishing to be acurate.

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## Feign

> Not sure what you're trying to do, but I dont think you'll be able to print lenses. Those need very high precision and polishing to be acurate.


No reason not to try it...  Besides, a quick delve into Wolfram Alpha suggests that there are indeed relatively simple functions for determining a lense geometry for any given z-value.  Meaning that someone could just have the Peachy graph out the function at high speed rather than running the G-Code, with each drop changing the z-value.  Effectively making each drop a seperate layer.

Also, I remember reading that the resin tends to stick in the tiny crevices where layers meet, giving a slight smoothing effect.

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## mike_biddell

Feign..... have googled printing lenses...... people are already on the case..... it could well be a goer. No problem polishing the finished article with a little jeweller's rouge. Obvs, for spectacles, some research required on translating a prescription into lens geometry.

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## Anuvin

Sure, that crystal clear column has got me convinced the peachy can print all sorts of crazy things! Time will tell, and the sky is the limit.

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## rylangrayston

> Effectively making each drop a separate layer.....
> 
> Also, I remember reading that the resin tends to stick in the tiny crevices where layers meet, giving a slight smoothing effect.


From what i have seen i think the peachy can do lenses. Standing over the printer watching it print the heart really gave me that impression for the first time.
Warps and bubbles aside it has a really smooth surface and it was printed face up (the hard way with steep walls reaching first out and then back in)
The two reasons you mentioned in the quote above are exactly why its doing so well at it already but let me also note that a drip may seem like a digital sort of increment but 
when you actually watch it closely each drip  spreads into a long continuous  stream of water running in the hose. I keep bugging the engineers at peachy saying the water actual enters one atom after another :P
I think the truth is that altho we think of it as printing in layers ( and we treat it that way in software) its really printing a really long spiral.

Also by dipping a print in resin and curing the smooth layer of resin over and over you quickly get a seemingly perfect gloss finish. 
We didnt do that in any of our prints yet tho. They actually came out this smooth without dipping 


fdc0630bf7379cf3f53d14824b054871_large.jpg
3fd04d54221c7945338e8b55a3af3f8b_large.jpg

I think there are still some big suprizes that need to be accounted for before you could ever use the peachy for making even a pour camera lenses, but already it looks like it can make a toy magnifying glass with a bit of TLC. 
more pics at https://www.kickstarter.com/projects...c/posts?page=3

Also these prints are all rather small and I would expect we will run into many newly needed solutions (problems-lol sorry that how I think. )  as we try bigger prints.

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## Morten

Mind-blowing to think we can do lenses. Even a toy microscope would be a great achievement. What I was wondering is whether the cured form of the transparent resin is transparent to the UV laser (I'm guessing it's not) because if it is, then I could print a 50x microscope, mount it on the Peachy and have 50x the resolution (and a much smaller print). Then, I can do printing on the micro-scale, allowing structural color and other fun stuff, mabye. Hey, we're all desperately awaiting pictures of the first prints, speculating helps ease the suffering  :Wink:

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## jjmouris

I don't think it will work like that. Being able to print a lens or in high resolution does not mean you can use that to print a printer with even greater resolution. It is not just made out of cured resin, there are parts made out of different materials that we currently can not print and do effect the outcome.

Secondly dipping prints into resin to smooth the surface does not improve the resolution. So your lens will become smoother but not more accurate. In fact it will become less accurate and may not do what it is supposed to do. Trying to adjust the drawing you feed the printer may work but without the resolution / accuracy you will not get repeatable results.

Warping and bubbles worry me a bit.

Bubbles we can potentially get rid of by treating the resin with a vacuum before printing to expand and raise any small bubbles to the surface where they will pop. A technique comely used in composite manufacturing. Thinner resins will help here.

Warping however is mainly due to the shrinking of the resin as it cures. A greater wall thickness results in more warping, important if you are after a very accurate surface. It may be best to print the side of the surface you want to be accurate first with a very small spot of laser light and then run the laser inwards line by line to build up the wall thickness. Or after the first outline is done, increase the size of the spot to increase the speed as which you can build up the wall thickness. All of this is assuming we are printing layer by later when as Rylan points out it is more of a dynamic affair with the constant drips raising the fluid continuously within each "layer". A resin with ultra low shrinkage is the easy way to skin this cat.

J

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## glauco

> I keep bugging the engineers at peachy saying the water actual enters one atom after another :P
> I think the truth is that altho we think of it as printing in layers ( and we treat it that way in software) its really printing a really long spiral.


As you are using Sound, Light and Heat to produce things, exactly like Nature does according to occultism and some brazilian scientific strands, is very possible that your printings are printing like a spiral, exactly like the Nature does. Take a look man, you have three active factors (Sound, Light and Heat) and three passive factors (Water, Resin and the Drawing itself). This is literally the duality being manifested by the trinity.

Very congratulations man, you broke a lot of barriers between metaphysics and pratical uses.

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## Spelljammer

I would say that the Peachy has the potential for huge resolution. At 16 bit res., that is about 4.3 Gigapixels. Printing a 4 inch square object would yield about 1.5 micron resolution. Using 40 ounces of salt water per 1 inch rise in height would yield about 1 micron resolution on the Z axis.

And as far as laser spot size, increasing speed or decreasing power for a given speed, effectively reduces the spot size.
laser.png

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## chipphydes

With regard to the poking a hole in foil, I would like to suggest you look at camera pinhole lenses.  These have been used for years to produce incredibly sharp photographs with no blurring.  The smaller the hole, the sharper the image.  Just a thought.  Google "camera pinhole lenses".  Prices vary.

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## Spelljammer

I don't like the pinhole idea because it limits the light that passes through, *substantially*. And 20 mW is barely enough for decent speed prints. I prefer the lens approach. This one on ebay has a focusable lens. At least this way you get the full 20 mW instead of about 3 mW through a pinhole.

http://www.ebay.co.uk/itm/405nm-20mw...item58ae5e9eed

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## Anuvin

The laser is focusable. It looks just like the one you posted. It doesn't focus enough. 

Also, as the print level moves, wouldn't you need to refocus?

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## Spelljammer

Anuvin, sorry, all this talk of pinholes in foil led me to believe that the laser wasn't able to focus without it. You are right that there is a need to refocus with layer height. Although, it seems good for an inch or two. And moving faster over a given spot, but hitting it more often (so that it can still cure) has the effect of tightening the focus...but there are limits. This brings us back to the floating laser idea...

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## Feign

The floating laser base, hydraulic build platform, and floating build resevoir (my favorite of the three) all give the Peachy a fixed focal point.  If we're getting to the point of microstructures though, lensing turns out to be absolutely essential.  I did a quick browse through Wikipedia about diffraction and found that (according to the papers linked on the first page) while reflective diffraction needs structures to be in the order of 10x the wavelength of the light you want to exhibit as the viewed color, aperture diffraction becomes a problem at the aperture being below about 6-7x the wavelength of light passing through it.  The problem becomes not one of lase size, but of how much resin is partially cured by light scattering and refracting within the resin itself.  In the macroscopic scale, this has no effect on a hard ridge, but microscopically, it would cause any corners you make to be deeply rounded off by partially cured resin.

Granted, having a microtexture of gently rounded divots might also have interesting optical effects, just not the deeply iridescent coloration of sharply etched silicon.

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## chipphydes

I brought this up because the low-end lasers have horrible "spot" size and shapes.  At least a camera pinhole lens with a given aperture size you can get an idea of the resolution possible.  When I get my Peachy Printer, I plan to replace the laser with a circular focus laser diode module.  Very high cost but I will know exactly what the spot size is.  Ultra fine resolution is my goal.

I do like the floating lens approach as it should be adaptable to any light source (some modifications, of course).

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## chipphydes

Has anyone thought of using singlemode fiber optic cable as a way of cleaning up the laser output?  Not only is the diameter of a single strand the diameter of a human hair, the cable is flexible and very energy efficient.  With sufficient length, the laser could be firmly mounted to one end and the other end could be attached to the floating laser base.

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## Anuvin

@Spelljammer - You know I love that floating laser design. Honestly, the hardest part of the floating laser? Finding a container with perfectly straight sides! So far, I have 2 part baseball card boxes and aquariums. Let me know if you find any good containers to use for a floating laser.

@Feign - I am hoping we can put some of your research into practice soon. I have no idea if we will be able to really get the laser that perfect. Lots to deal with - Mirrors, aperture, focus, and probably lots more. All problems we can overcome, but it will be a hard fight. Can't wait for everyone to have one so we can get ideas like this rolling.

@Chipphydes - I like the way that laser diode sounds. Got a link on that? An optic cable would be great, that is a fantastic idea! Isn't it also kind of expensive, and tough to ship? Perhaps that will be an option for Pro backers and as a DIY hack, maybe an add-on. No matter what happens, that is an idea worth investigating, for sure. Got any more insight on lasers for us?

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## chipphydes

Anuvin

Try this for laser diodes http://www.digikey.com/product-searc...-diodes/524333

Try this for singlemode fiber cable http://www.l-com.com/fiber-optic-bul...on-style-cable

I look at something like this for a DIY hack or on a Peachy Printer Pro.  However, if it works well and is cheap enough it could be adapted now.  Just a thought.

We need an experienced optical engineer in on this thread to come up with something that can be used at a price we could all afford or tell us we are barking up the wrong tree.
.

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## Feign

Chipphydes, from what I understand, the resin needs UV light to cure.  Specifically in the  300nm-350nm wavelength.  The laser diodes you've provided aren't in that small a wavelength.

It's kind of part of the reason so many people were thinking that the Peachy couldn't possibly be under $100.  Where the Peachy team is getting UV lasers for an affordable price is kind of a mystery.  Likewise, most kinds of glass are pretty good at blocking UV rays, Coming up with focusing lenses that will work well for the Peachy might be harder than we expect.  Hence the pinhole attenuator rather than a compound lens.

Thankfully, UV photography is a thing, so there are whole forums that have talks about what camera lens sets are permissive to UV light.  Somehow I doubt there is much info on fiber optic cable in the same vein.

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## Morten

Love where this thread is heading, lots of interesting info and ideas! 

Another way is to use a beamsplitter, maybe? My soundcard has 5.1 channels, enough to control 4 mirrors. Perhaps split the beam into one larger and one very tightly focused beam, you could create a "Pheachy Hydra" and use the small beam for surface details and the large one for volume curing.

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## nka

No need to have more output on the card. You just need to use a different frequency (i.e.: 10-15 Khz = Kit 1, 20-25 Khz = Kit 2).

The Peachy Pro have a focused laser, but I dont know what they are using. Rylan seems pretty good at finding cheap stuff  :Smile:

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## Spelljammer

I thought it uses a 405 nm laser. Glass doesn't block much until you get to the shorter wavelengths. 405 would pass completely through. So, a glass lens would work fine, even down to about 325 nm or so.
input_optics_graph.jpg

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## Feign

I see glass does better at letting UVb pass through than I would have expected...  A 405nm laser?  I thought photopolymers needed UVb to cure them, which is a bit below that, and that's just barely at the edge of UVa.

Is the resin y'all are using a special formula for the Peachy, or is it standard Maker Juice?

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## chipphydes

Feign,

I just checked and the laser is 405nm.  This is known as UVA/VIS as it is at the top of the ultraviolet range and the bottom of the visible range.

Anyway, there are plenty of 405nm laser diodes : http://www.digikey.com/product-highl...er-diodes/3447

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## Anuvin

SubG or SubG+, I can't recall which. But it's just the standard stuff. Cures up to 420nm, it says on the bottle.

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## Feign

Well, I'm happy to be corrected like that!  My research into photopolymers was clearly incomplete.  So this stuff will cure with a regular blacklight (or blacklight LED), then.  I'll have to get some of this to see what other things I can do with it while waiting.

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## Anuvin

I am a bit lost. Is 420nm more or less ultraviolet than 405nm?

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## Pete

405 is closer to what you would consider UV, 420 is more toward the visible blue/violet spectrum.

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## Pete

605px-Linear_visible_spectrum.svg.png
Visible spectrum vs wavelength (nm) from Wiki

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## Anuvin

Okay, I should have just looked that up, but thanks for clearing it up. So the resin will cure up to about half of the visible UV spectrum.

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