New to Fab, resolution question

Hello everybody. I was wondering if I could use a RepRap setup with some tweaks as neccessary to obtain a resolution of <10 microns and with drops less than 10 microns in diameter? Thanks a lot.

The quick answer is probably no.

The target resolution of the machine is 100 microns. To get 10 microns step size with the same mechanical setup you would need to add 2000 step shaft encoders and modify the firmware to handle these and also generate PWM to do 10 times microstepping. Theoretically you would then get a step size of 10 microns but I doubt the machine would maintain any sort of accuracy at that resolution due to belt slack and the fact it has a relatively flimsy scaffold type construction.

I have a machine with a 6 micron resolution XY table but it uses seriously chunky metalwork, dovetail slides and ball screws in addition to shaft encoders and microstepping.

For 10 micron drops I guess you would be talking about inkjet technology but I have no knowledge of that.

What is you planned application?

Edited 2 time(s). Last edit at 09/05/2007 07:12PM by nophead.

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[www.hydraraptor.blogspot.com]

I plan to make scaffolds out of polymers which I believe cells may someday be seeded to. Would you have any links to modifying ink jets to do this? I know they have done some cell printing with ink jets. Any help is appreciated. Thanks a lot!

Sounds great. I figured the cells would be buried in the substrate that was printed, but I know next to nothing about biology.

Have you considered trying to work in Jello?

Unfortunately, the way consumer inkjets work is they boil a small bit of ink, and what comes out is basically the splatter. At least, that's the version I'm aware of.

Good luck with your project. I'm 32 and know already I'll want a new knee in a few decades. Preferably one that's manufactured to original spec, not some silly thing made of titanium and ceramic.

I just bought a really neat book on DIY inkjets:

[www.amazon.com]

and intend to run a student project soon on putting one in a RepRap head...

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best wishes

Adrian

[reprap.org]
[reprapltd.com]

Hi Adrian,

... maybe there is a chance for an 'oldstyled' needle-printhead in a reprap too?

I'm thinking on a conversion from an normal needle- (or thermo-)printer, where the needles penetrate a thin sheet of material, which laminates continuously on the feeding-roll ...

Then the fabbing process can be very fast (dependant on the speed of the laminating) and the processing is reduced to the boundaries of the slices.

The slices wouldn't be orthogonal, either (this must be handled by the STL-Parser), but the Z-stage is reduced to fixed distance-rolls over the topmost foil-surface ...

Ciao, VDX

Interesting idea. What sorts of materials had you in mind? And how would you make the thin strip of the required?

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best wishes

Adrian

[reprap.org]
[reprapltd.com]

Hi Adrian,

> ... What sorts of materials had you
> in mind? And how would you make the thin strip of
> the required?

I think 'normal' foils of thermoplastics, which i can by on rolls of hundred meters and more, should be fine ...

The laminating could be with a solvent/glue or with a heating roll ...

The needles of the printhead should be sharpened like little knifes for better perforating - i tried to laserweld hardened steelneedles with the same diameter as the original printerneedles (it runs well, but in the weldingzone the metal is recrystallized), so i think i can modify old printheads for testing/prototyping manually.

The main benefits are simplicity, accuracy and speed - the limit is either the printing or the laminating.

If you remember the speed of the old 24-needle-printers like the NEC P6, then i estimate that a complete slice on the roll need 1 minute or so.

If the foil is 100 micron thic, then there would be nearly 10 minutes for a millimeter or 4 hours for an inch, but this inch is a tubular volume around the roll-axis, which can hold many different parts with an accuracy of nearly 100 microns !

And with a faster printing process or a scanning cutting laser instead of the print-head there can be a really serious speedup ...

Ciao, VDXpeng

interesting idea... please play with it and let us know how it goes!

... if someone has a thermo-transfer-printer or -FAX, then he already has an 3D-capable setup!

In the thermotransfer-process a transfer-foil coated with a thin sheet of coloured thermoplastic is aligned with the paper and a moving printer-head with heatin resistor-pins melts the outputted pixels through the transfer-foil, so the melted thermoplastic can stick to the paper ...

If i repeat this process in a endless loop, then i can stack slices to an 3D-object.

The only thing to make is a movable laminating roll for adapting the height of the assembled slices and a endless proces for coating (and proper removing) the close-looped transfer-foil with a thin slice of thermoplastic.

Maybe the coating can be made with a solvent of thermoplastic powder and some liquid, which fast-dry on the transfer-foil?

Viktor