Cloning reprap prusa parts in 30 mins LINK

Has this been posted yet?

[i.materialise.com]

Looks interesting

cheap repraps parts for everyone?

Hopefully it works out; my first repstrap was a cast Darwin back in 2008, and the cast parts really don't hold up like the printed ones do. I'll be more impressed with this when they show that the cast Prusas actually work well.

The parts really only need to hold up long enough to print a set of plastic parts. As long as they can do that it should still faster to produce a batch set of molded parts and have each machine print out a set of replacement parts for itself than it would be to print each set out directly. Certainly it will get the students printing more quickly.

madscifi Wrote:
-------------------------------------------------------
> The parts really only need to hold up long enough
> to print a set of plastic parts. As long as they
> can do that it should still faster to produce a
> batch set of molded parts and have each machine
> print out a set of replacement parts for itself
> than it would be to print each set out directly.
> Certainly it will get the students printing more
> quickly.

Pity about the waste of plastic in that scenario.

i think it's definitely possible, i sell resin polyurethane cast parts but you must go with the higher shore d rating , the description of the resin i use TC802 reads 'suitable where ABS like strength is needed'

but still you might find there are certain parts that might benefit from being printed like prusa x carriage bearings, the extruder body..

i think if you think along the lines of casting all the parts you can, and working out a way to make the load bearing parts stronger you can cut a lot of cost and time and still deliver something that will last a long time.

resins for art/jewelry/special effects will warp pretty quickly though especially in contact with heat. the TC802 can be 'post cured' which means after casting and while still in the mold putting it in the oven for a long time and then it reaches full capabilities and can deal with higher heats. so while it would be a bit much to put a full prusa kit in molds in an oven for 12 hours or whatever, it is however feasable to cast 50 small gears for the extruder and post cure them.

//don't try this in your eatin' oven

madscifi Wrote:
-------------------------------------------------------
> The parts really only need to hold up long enough
> to print a set of plastic parts. As long as they
> can do that it should still faster to produce a
> batch set of molded parts and have each machine
> print out a set of replacement parts for itself
> than it would be to print each set out directly.
> Certainly it will get the students printing more
> quickly.

No the parts would need to hold up long enough for:

a. the person to figure out what they are doing
b. the person to get the machine calibrated enough to print parts
c. the person to get what ever parts they are just dieing to print
d. the enough get ALL the replacement parts (which basically means a complete clone)

So no, low quality parts are a recipe for dropped RepRaps.

c.

---

repraplogphase.blogspot.com

Ok, ok, so almost nobody likes the cast parts... ;-)

I'm not convinced that printing plastic parts is necessary, nor am I convinced that cost effective casting materials can be found that will stand up to long term use. I simply don't know enough about the subject to have a meaning opinion on the matter.

I'm also not suggesting that anyone should be selling low quality parts, or handing them out to strangers either, for that matter. However, I can imagine that in a educational situation where there are a lot of students that all want a 3d printer "right now," parts that are adequate to the task of allowing each student to print out a complete set of new parts, especially since there would be a strong support structure provided by the instructors and other students, would allow each student get started more quickly than would be otherwise possible. If the parts are inadequate for the task then the approach will be quickly abandoned as something that is more trouble than it is worth.

In reality I suspect that if the cast parts are not useful long term, the approach will be abandoned anyway simply because it is annoying to put something together only to have to completely disassemble and rebuild it a day or a week later. I agree that in the general case of selling or giving away parts they should be robust and able to stand up to long term use, for some reasonable value of long term.

What I do find amazing is the concern expressed by some on the open3d site (in the comments) that the cast parts will lower the price that sellers can get and thus decrease the amount of development work done by the sellers. I strongly suspect the sellers of the expensive commercial products feel exactly the same about the Reprap project as a whole. This simply is not an argument that ends well for the rest of us.

What about molding using a stronger material? I think that a good option is epoxy, better yet if mixed with something, like epoxy granite, or fiberglass, etc.

I don't see the problem with cast parts. I have a hard time imagining that the frame vertices are going to break after some short interval due to extreme degradation. I can imagine the extruder gears or motor pulleys wearing at a faster rate. That's easy to replace though, and quick to print. It just doesn't seem like the main frame pieces are likely to fail even if the cast plastic is not as strong. What are the failure modes of the cast polyurethane? Does it just become brittle after a few months and crumble? I find that unlikely. It seems like the most likely to fail parts are also the easiest and quickest to replace. Am I way off?

Bryan