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Newbie questions about a bigger reprap

Posted by poogle 
Newbie questions about a bigger reprap
July 11, 2010 12:39AM
Hi, I just read about the reprap concept and its absolutely perfect for some things I've been wanting to do but never had the right tools, but for the things I want to make (various small-scale model buildings) the basic mendel is too small.

So my questions are, how hard is to increase the print area? I was looking at around 400L x 700W x 300H (mm).

At this size, would keeping the print layers hot enough to bond with the next be a problem? What temperature is needed for it to still work?

Does printing on a larger area require different software?

No doubt there are probably other aspects of concern that I don't know about, so please post any info you could. If anyone knows of a blog or page with more on this topic could I get a link please? I searched around and read a few topics on the subject but they all seemed to be about increasing print time / extruder volume more than anything else. I really wouldn't care if it took a week to print so that isn't a concern, just actually being doable without serious modifications to electronics/motors etc.

Failing that I'll just make a smaller one and make each building as a series of components then assemble later, but it would be so much better to make them as single pieces.

Thanks for any advice smiling smiley
Re: Newbie questions about a bigger reprap
July 11, 2010 10:43AM
Search Apollo Mendel, it's been talked about. But the issue is the fastest extruders go 80mm/s which means that size of printer will have to print for DAYS to use it's build area.

To give you an idea, the larger Mendel parts take 1-2 hours to print, and they would fit in your palm.

You can modify the RepRap software and hardware to print on larger scales, but some of the basic tech dev work has still to be done.

Go download Heekscad or Openscad and draw it out. I would love to see what your version would look like!

Re: Newbie questions about a bigger reprap
July 12, 2010 02:36AM
Thanks for the info smiling smiley
Re: Newbie questions about a bigger reprap
July 13, 2010 03:44AM
current electronics and software should be fine for that size, I think your biggest problems will be mechanical stiffness and print time. Also, a heated bed would be extremely power hungry but by no means infeasible.

Wooden Mendel
Teacup Firmware
Re: Newbie questions about a bigger reprap
July 16, 2010 10:43PM
I think that'd be cool and wanted to encourage you. I can imagine some cool objects to print that need a big space but have a modest volume, or just patiently printing a large volume.
Re: Newbie questions about a bigger reprap
July 19, 2010 08:50AM

I'm guessing that your buildings will be hollow.

If the is the case then I would assume that while there will still be time issues, the actual 'running length' printed (i.e. extruded) will not scale in ratio from the current mendel parts. A mendel part has infill (of some amount) which takes time to print and could be reduced for this consideration.

As for the heating, would the 'heated room' solution help? If it did, I would expect the printer parts to be made out of a higher temp material, e.g wood or steel to avoid the issues Nophead had.

Just my 2c worth.


Chris A
Re: Newbie questions about a bigger reprap
July 26, 2010 10:48AM
Sounds like a really good idea. The increase in scale would bring about some challenges but would open up a lot of opportunities when perfected. Just some things I've thought of here about some issues:
A heated room (convection?) would probably be the best idea rather than a heated platform. That would definitely heat the build more evenly and not just on the bottom, which is way better for larger objects where the heat can't transfer through the material as far as you get into more and more layers.
The correct material would have to be chosen for a long build time under constant heat. I'm not sure how a lot of plastics work under heat for a long time but I would think most would eventually start to bake and get brittle after a while under heat. I'm sure a lot of people have a whole lot more experience with this than me. I'm just starting out building a Reprap Mendel machine (not complete yet).
In any case, if it can be done on a small scale, it can be done larger! smiling bouncing smiley
Re: Newbie questions about a bigger reprap
July 27, 2010 01:47AM
What sort of ambient temperature would be the ideal range?
Re: Newbie questions about a bigger reprap
July 27, 2010 09:25AM
The ideal temperature is just below the glass transition of the plastic, so about 80C for ABS, 45C for PLA.

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