printing techniques for VERY small, intricate parts

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twicx
Posts: 105
Joined: Fri Jan 11, 2013 1:26 pm

printing techniques for VERY small, intricate parts

Post by twicx »

Hey again,

So following my little jam issue, the printer seems to be running smoothly again, albeit 5 degrees hotter than before :p

Now I have one last issue. I've all the main parts of my building printed, ie, floors, walls, stairs etc etc. All thats left is this major nightmare of a facade. It's REALLY intricate, and I've tried a few things to print it well, but to no avail. This is as much about how I'll split up the model as it is the printer itself.

This is the facade:
Image

Now, I have to print this at 1:500 scale, which means that if i take just the front section, in Repetier, it looks like this:
Image

So, here's the issues. The whole facade is curved. No part of it is flat. Even that tiny piece needs a big raft, which is a problem. On normal quality, the walls of the facade are too thin, and break apart when I try to separate the facade. When I try High quality, the raft is too dense, and although the facade is thicker, the same problem happens. I've also tried production, but that was the worst. I've tried smaller parts with no support, and it's not been so good either. The only thing I haven't tried, mainly cos it's a last resort is to print each column of cells without the support on high quality, and then glue them together after.

The problem is the facade, if you took a vertical section through it when it's flat like in repetier above, is curved, so it would need a raft on the left and right.

What I'm just wondering is if anyone here has any tips on how I might be able to solve this, whether it's to do with chopping up the model differently, or maybe something in settings. One thing I've noticed is that on normal quality, instead of filling in the walls, it just prints them as two lines, with a small gap, ~0.5mm between them. A raft on normal quality with denser walls might just do it, but the configuration for any of the slicer settings is so confusing that I wouldn't know what I'd be looking for.

Any suggestions? Also, hand making it is not an option :P

angryangel
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Post by angryangel »

perhaps you can print it flatand heat it up and bend it over the surface you need to apply or you print a block with the surface you need and bend it along that

satoer
Posts: 436
Joined: Mon Oct 01, 2012 8:00 pm
Location: Netherlands

Post by satoer »

I don't think this is doable on a extrusion 3D printer. You probably need a powder 3D printer for that. To print this with the Felix you probably have to go with Angryangel advice. Print it flat, and bend it. PLA is easy to bend in shape, just submerge it in hot water and bend it in shape.

Edit: Maybe you can print a "inside" solid version of the shape and bend the flat grid against it as a guide.

Another solution I can think of is this (I don't know if this has been done before): Inverse the shape and print a mold of it in ABS. Fill this mold with 2 component epoxy and wait for it to cure. After its been harden out, submerge the part in acetone to dissolve the ABS leaving the epoxy shape.

But: You need to print with ABS because PLA doesn't dissolve in acetone. And you need to make sure epoxy doesn't also dissolve in acetone.
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twicx
Posts: 105
Joined: Fri Jan 11, 2013 1:26 pm

Post by twicx »

ok, angryangel's idea is interesting. Printing it flat and "wrapping" it around the building would actually be my best bet.

Good news on getting my finals ready, submission is friday, I'm second to present on monday, and I'm ready to print. My model is the last missing piece of the puzzle. I've to finish off the context, but i'm handmaking it out of card, and it's 2/3 done, so by my estimate, i've all afternoon tomorrow, all day thursday (literally, I'll be pulling another allnighter for that one) and friday morning to get this done. Red bull is my new best friend.

Now, for the really tricky bit, I have this all drawn up in rhino/grasshopper. The challenge now is to see how to develop/unroll/flatten the curved surface so I can apply the cells and get it set up for print.

Anyone familiar with grasshopper/rhino? How the hell would I even go about doing this?!

twicx
Posts: 105
Joined: Fri Jan 11, 2013 1:26 pm

Post by twicx »

Update:
All i need to do now is to figure out my little problem with grasshopper as explained here: http://www.grasshopper3d.com/forum/topi ... ed-surface

Surface morph is a nightmare.

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