Printing DNA sugested by amirjabri

In this Thread http://3dprintboard.com/showthread.p...ter-Team-Print
amirjabri suggested that we try printing DNA

"Hey Ryan, congrats on the progress keep up the great work!!! I found some cool molecules like dna which would be a challenge for any other !
http://www.sharecg.com/v/62551/galle...l/DNA-Molecule "


I think thats a great idea for a few reasons..

1. it has lots of islands that start with nothing under them so to print this we will have to make lots of suport material, and figure out the intricacies of support material done by peachy printers.
2. This print has huge amounts of over hang, so its a great opportunity to show how the peachy printer dosent need suport material for suporting over hangs it instead more often needs it to seed islands.
infact Id rather call it seed material, I think that’s more descriptive.

Not sure if the term seed material is coined yet if not here is a definition.
Seed material: A type of support material in 3d printing. Its purpose is not to provide additional structural strength instead it is only added to provide a place for an island to start printing off of.

3. DNA is cool

Last night I downloaded the dna stl.

After viewing it for a while I realized that there are alot of problems with that exact stl.
Its seems to have inconsistent gaps between many of the molecules and the task of adding seed material would be very large without making instances of each molecule.
Looks like it will be much faster just to start modelling this from scratch.....

Blender time...
Attachment 3928 .. Attachment 3930....Attachment 3931...

Attachment 3932..Attachment 3933

Little more work almost ready for a first test..
Attachment 3934

Ok I like to fail fast so Im going to stop here and print what I have re-modled so far, that way the rest of my modelling can be informed by what the printer does.

Time to slice:
Wow I love Cura, every once in a while software just dose something unexpected and beautiful..
http://m.youtube.com/watch?v=_AbHWfM...e_gdata_player

http://m.youtube.com/watch?v=_AbHWfM...e_gdata_player

now we throw this Cura's g-code at the printer and wait for a few hours...

alright printed quite well for a first go
- this is 27mm tall
- it took a few hours to print with the 100 dollar kit( no special mods)
- it has aprox 2700 layers
here are some pics

Attachment 3935 Attachment 3936

One thing I notice is that the seed material is much more attached than I want it to be.
Im going to make the slender bit of the seed material longer and longer for each set of spheres, as they go up, so i can test what a good distance is. I want it to be very easy to break off.
Im just puling each set of 3 down a little more than the last set like this:

Attachment 3937

Ok I have re-sliced and sent this off to the printer again, once Iv tested and got the seed material breaking of easily ill continue modelling the rest of the DNA.
For now Im glad Im only printing a small bit of it, this way the prints are nice and quick, allowing me to learn from and fix problems much faster.

Oh if anyone wants to join in on the modelling that might be rather helpful. Or If you just want to check it out, here is my latest .blend file:
https://drive.google.com/file/d/0B_7...ew?usp=sharing

How did it go? :)

It went well, I wont be at the shop for 2 days now, and I forgot to take a pic of it that next morning.
The support material was just slightly connected( just like i wanted ) on the second or third set of spheres up,
but the z height of the print was quite off( making the print shorter than it should have been) so ill run another test again when I get back.

Wow Rylan, i never imagined how involved it is to come up with a support structure or I probably never would have suggested it! It is very impressive so far what you are engineering to make this possible! Would be cool to be able to write a python plugin that would add support structure for such elaborate models automatically! My coding skills definitely aren't up to par but I would love to print out all sorts of molecular models!

I think it would be pretty straightforward to write a script that added support/seed materials but before that can be done the team need to know how much seeding is needed in each situation so it can be as tiny as possible. I think trial and error is going to be the only way to gather that information.

The fact that this print requires us to do work, that further increases the printers function is why it makes sense to take it on.
It may seem like lots of work but keep in mind that all iv done is model a few spheres in blender, extrude tails on them, most of the work is done with modifiers and instances. If it wasn’t for features like array in blender this would truly be alot of work.

I think its very posible to automate this... just look at what circuit board routers do!
but just as chayat says some trial and error will be needed so we can figure out what the exact goals of the automation code would be.

well here is the next print ( that worked ) I had one failed one the other day dew to dipper problems:
Attachment 4074 Attachment 4075 Attachment 4076

Attachment 4077 Attachment 4078

I love that last pic :)

This print is 4cm tall and has 4000 layers.
I think pigment in the resin shorten the depth that the laser cures in to the resin and could give us greater height resolution.

Attachment 4079Attachment 4080

A little further investigation here, the last 3 sets of seed material broke of rather easily, it felt about like breaking a tiny piece of egg shell with your finger nail.
Back in Cura I counted how many layers of thin material there were in the second last set, looks like about 50 layers of material that are quite thin( altho it dose gradually get thinner) 50 layers at 100 layers per mm thats a .5mm gap between the thick part of the seed material and the actual object.
I think the desired gap could be very different for pigmented resins.

With this new experience next ill move on to modelling the rest of the dna.

Quote:

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Originally Posted by rylangrayston

I think pigment in the resin shorten the depth that the laser cures in to the resin and could give us greater height resolution.

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Could we emulate this in clear resin by running the laser at the weaker strength? (Is such a thing even possible?)

Quote:

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Originally Posted by Yarharhar

Could we emulate this in clear resin by running the laser at the weaker strength? (Is such a thing even possible?)

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Good Idea!
Turning down the laser power or the exposure per volume of resin could help! I think it would mean a softer print, but that's is ok because its easy to cure the resin fully after printing. There are likely dies that can be added that block uv light while still being transparent to visible light, that could help also.

perhaps a fluresecent dye so the camera(eye) used to monitor the printing can also see the refraction products from the beam