[josey.mathew]

hi
another q for the project i mentioned before
is there any polymer which is available in powder forem and which soldifies when some liquid comes in contact with it
Thanks a lot for your help.

[eugenedakin]

Hi josey.mathew,

Chuckle... I have a good memory, but it is pretty short...

What type of properties are you looking for (hardness, temperature stability, material compatibility (stable in water), etc...

This might help us narrow down some of the options.

Sincerely,

Eugene

[josey.mathew]

hi
what  i was luking for was a polymer which would be resonable hard (but not brittle) at room temperature. It should be stable at romm temperatures and it should not be soluble in water or any other common solvents in households..
Hope such a material exists !!

[eugenedakin]

Hi josey.mathew,

Hmmm... I was thinking along a different line... sorry.  I was thinking of a polymer which dissolves in water.  Most polymers need to be extruded.  I wish that I could help more, but unfortunately, I don't have any other ideas.

I wish you the best in your search.

Eugene

[P]

hi
what  i was luking for was a polymer which would be resonable hard (but not brittle) at room temperature. It should be stable at romm temperatures and it should not be soluble in water or any other common solvents in households..
Hope such a material exists !!

How about something like bakelite or melamine formaldehyde.   OK, the MF resin is soluble in water to start with but this is how you get it as a liquid to start with  -  you set it in a mold with an acid curing agent and it cross links to make a hard polymer like bakelite.

Alternatively, how about some kind of silastic molding compound?  Starts as liquid  -  mix in curing agent and it sets (maybe too springy for your application - not sure)

What is the application here? It may help if we knew what it was intended for.

regards,

P.

[josey.mathew]

hi
i dont think both the previos replies solve my problem bcause everything is liquid !!!
wht i wanted to build is a material printer so it deposits a thin layer of resin(it should be a powder or a high visious liquid) and on it a layer of catalyst(a low visous liquid) is deposited only in regions where the polymer has to form Any ideas ?

[P]

This is called lithography.   

Can you cut a template and then screen print your resin onto the material. Why must it be a powder?   You could have any polymer (which will stick to your material) and screen print it onto the material through a template. you then will only have the polymer on the desired areas of the material. You can then leave it to dry.    OR - as you just suggested - you can coat the whole thing with a high viscosity MF resin and apply the acid cure through a template  -  again the areas exposed to the acid will set hard and the rest could be washed off (I wouldn't do it this way though - I'd just paint the liquid resin on through a template and let it set  -  much easier).


Being honest  -  until I know what you are doing exactly I can't prescribe any particular polymer system.  e.g. You said it mustn't be brittle, but how flexible does it need to be? -  once on the material, does it need to be really flexible?    Are you printing to a T-shirt or something? Or is it a banner?

If you MUST have it in powder form for some reason  -  how about painting the material in the areas you want the polymer to stay on with glue. Then sprinkle the powder over and shake  -  you'll be left with your pattern stuck on.

There are probably a dozen ways to do this  -  but to suggest the most suitable I need to know what the application is.


Regards,

P.

[josey.mathew]

hi
what i want to build is a model printer that is it takes a 3d image from the computer and prints it from a polymer
how i plan to do this is to build the material layer by layer that is i cut the original 3d figure into layers using software and then print the layers
the steps will be

1. a layer of a polymer powder is depostied
2. the curing agent is deposited in this layer only in regions where the plastic should form
3. another layer of powder is deposited
4. and so on
.
.
in the end the extra powder is sucked out for further use and i get the 3d object !!

[josey.mathew]

hey
wht is up ?
when i have explained my pro in detail i dont get any replies 
have i broken some forum rules by posting engg. questions   

[Borek]

No, you are OK. It is more like - we know what you want, we have no further ideas at the moment.

[P]

Yea, sorry - I go home at the weekends and don't get to post.

Also - what you want is not easy.   I thought - a long time ago - that it it might be possible to do some 3D lithography with some kind of gel cube which would react to light (just like in a 2D UV resist).  You could then project a 3D hologram into the gel and get the areas where the hologram is showing to crosslink.  Then disolve away the outer unexposed bits and you have a 3D object.   Sounds simple...

Good luck.


PS:  Multilayer VLSI Circuits are made in a similar way to what you are describing, but on a micro scale.  You spin coat a Si wafer with a photo/e-beam sensitive polymer (like polystyrene ir PMMA - depending on if you want a negative or positive resit) - expose it to your e-beam or UV pattern and develop the template - The circuit is then etched onto the wafer. The process is repeated to get multiple layers.