Introduction...

Hello,

I am Adam from Hungary. I live in Italy for the moment to work on a project in order to create and replace organic objects using the material polycaprolactones. For the moment I use CAD models from CT X-Ray files, create them with our Objet polyjet machine at the uni, stamp the model in a silicone mould and inject polycaprolactones in order to create the part. However, the process is too long and I have a lot of difficulties with the contribution of polycaprolactones and silicone. I can only use gravity casting to pour the priorly created gel (olygomer) phase of polycaprolactones, because the melting point of the polycaprolactones would be too high for the silicone mould to resist. This process is extriemely long and the final model undergoes about 10% of shrinkage, so it has nothing to do with stamped geometry :-)) All in all, the projet can not be continued in this way...

Anyway, the RepRap project is fantastic, so congratulations to all who strated and created everything so far!

I definitely would like to join the community, however I have more experience in material science than in machine building. It is time to practise machine building, ay? :-)) I have read through the step-by-step process of creating the machine, and I can not wait to start. However, I have read in the forum, that you are going to set up an internet shop in Europe as well to make it easier for Europians to order. What do you suggest me? Wait until this is going to be ready or start ordering from the states? And does anyone have an idea how much toll costs on these items?

Thanks is advance,
Adam

Hi Adam, welcome.

I'm just another RepRap user, not part of the organizers... but I'm trying to get involved in bringing the cost down.

I think eventually the assembly of a RepRap will require less sources and less work. To the point where people will be offering completed kits and ultimately printing it for you using their RepPap. I personally find the PCB electronics soldering to be a slow step, but so far haven't seen anyone offering to do those for other people. I encourage you to express the demand.

I think the cost right now is still up in the air a bit as some of the parts are just now becoming easily available (not having to make "RepStrap" "printed parts" yourself from blueprints). And there will likely be supply problems.

I am going to visit Zach in NYC next weekend, and I intend to review this issue myself to see exactly what the next gen cost is looking like. (I'm starting to get the impression that the intermediate next-gen is "Arduino+McWire", but I'm still figuring that out, And future is future). I think right now it is more than what used to be quoted on the wiki. I think the Wiki used to say USD$400 but now says EUR

Edited 3 time(s). Last edit at 12/02/2007 11:27AM by RoundSparrow.

Hi Stephen,

Thanks for your answer. I am just looking at Ardunio's web page and other PCB creator's sites. Last summer I rebuilt a CNC machine where I used the following servo controllers:

[www.granitedevices.fi]

Do you think they would work with this system as well? I know they are pretty pricey but I can get some discount and they work very well also on the software's side.

And, there is something I do not really understand: why would I order standalone PCBs and wires and solder them up if I can order complete ones from Ardunio?

Thanks,
Adam

Hey Adam,

well the Arduino is just the brains of the system. You need to hook boards up to it that actually do the things such as drive steppers, motors, extruders, etc. those are the things you need to solder yourself.

That granitedevices driver would definitely work, although it is probably overkill. you could drive it with an arduino, as it takes step/direction inputs: (Command inputs: step/direction pulses)

Hey Zach,

Ok, I meant I could use Arduino instead of creating the Power and Communications board, is that right? But, you say in your answer:

"you could drive it with an arduino, as it takes step/direction inputs: (Command inputs: step/direction pulses)"

Have I misunderstood something? Or I really can use Arduino as a servo drive as well?

Thanks,
Adam

Hey Adam,

What I meant is this: both this board and the Stepper Driver board both the same type of digital input: step/direction. This means that on a hardware level, they look and function identically from the perspective of the Arduino.

That means you could use these components in place of the Stepper Driver board. You would need to supply your own motor, and you would still need the rest of the components in the system (power/comms, arduino, pwm driver, dc motor driver, etc)

With the current Arduino setup, you need 2 arduinos, which means you need a power/comms board to create the token network.

once i get caught up with all the things that are going on right now, i plan on fitting everything onto one arduino board. that will simplify things quite a bit. until then, you'll need two arduinos to run a full reprap.

>I can only use gravity casting to pour the priorly created gel (olygomer) phase
> of polycaprolactones, because the melting point of the polycaprolactones would >be too high for the silicone mould to resist.

That is odd. What temperature were you using for the polycaprolactone, and what kind of silicone mold material are you using? It sounds like you're using a heat-vulcanized silicone mold material.

I know that people use silicone molds to cast pewter and tin, and I think a good silicone mold should be able to stand up to at least 300C temperatures.
[www.smooth-on.com]

e.g. this RTV silicone molding putty mold:
[www.miniaturemolds.com]
can take 425C.

The caprolactone we've been working with melts below 100C, around 60-80C. My process has been more one of 'Place caprolactone object or granules into a vessel, pour boiling water over capa, remove gooey lump of capa from water, hand shape it, reheat with more boiling water if necessary, and then hand shape it or press it into a mold.' Press-molding, technically.

It sounds like you were pouring liquid capa into a mold. What temperature were you doing that at?

You may be interested in our: Pisa, Italy / Italy general RepRap User Group forum.
[forums.reprap.org]
If you want a your_city, Italy forum,
request one here:
[forums.reprap.org]