How big is too big?

Hi, I have read a lot about how big printers are generally a bad idea, but how big is too big? I am considering building a printer with a 200x400(don't really know the hight yet) build volume. I am hoping I can use the Prusa i3 design, but that might not be a good design for my size? I would love some feedback/thoughts on my project.

X- and Z- carriage should be fine, but I worry about the large mass of the print bed. I'd recommend an ultimaker-style design. Remember, lower moving mass == better. Take a look at the Eustathios and the Ingentis.

While I have not built a large format machine myself, I have been doing a lot of reading oand it seems there is a thread every day with this subject or some variant almost every day. That being said make sure you look into the other threads

First off, build cost for scale up is not linear, its much closer to exponential. Some machines more so than others.

It seems that moving heated bed designs (prusa, mendel) are less than ideal for large size because as the weight of the heated bed increases the stronger its carriage and motor and drive system need to be making it expensive heavy and slow.

Stationary (or mostly stationary) heated bed designs (delta, corexy, Hbot) seem to scale up a little easier, but still suffer complications with frame rigidity, and long print times (compare printing 1 cm cube vs. 10 cm cube), etc.

For these reasons and several others, the advice is almost always to focus on building several small machines and splitting the work up into pieces, it is faster, more flexible for different jobs, and more cost effective.

Any 3D printer is too big if you are building it just for the sake of it being "big".

First decide on what you really want to print and make sure you understand the ins and outs of 3D printing using FDM technology.

Then also make sure you understand that it may not be worth building a $2000 printer to print a dozen or so plastic parts per year with a total value < $200. Just use a printing service.

If you have determined that you really need to build your own 3D printer, design your own or use one of the existing Open Source designs for a 3D printer, with the correct dimensions for your printing needs.

An ultimaker-style design would be ideal because of the low mass, stationary bed and therefore lower footprint. I only have one problem with it. I want to have two separate x-axies for dual extrution as demonstrated in this video: [www.youtube.com]. I don't think an ultimaker design could encorperate this?

To clarify, I'm not building a big printer for the sake of it being big. I have a prusa i3, but some of the parts I print are simply too big (almost always in just one direction) for my 200x200 build platform. I'm planning to put two regular heated beds beside each other to have the option to print parts that are long in one direction.

Edited 1 time(s). Last edit at 03/31/2015 01:15PM by TnTd.

I agree with andrewBCN. It's always possible to split a part and print it in multiple parts then gluing them together. If large parts are 50% or less of the overall parts you print, you'd rather stay with a small printer.

It's possible to build a printer of any size. Your money is the limit. You just want it to be well engineered. As you're talking about the Ultimaker's or Prusa i3 design, you should be wise that printers are not scalable. I mean, if you increase only dimensions you're wrong. When you increase the lenght of one axis, you must recalculate each component in relationship with that axis. From feets to head. That means you need to rework a large part of the printer. Maybe redesign parts, buy bigger components, and so on.

The idea of a 400x200 will allow you to reduce the cost compared to a 300x300 or bigger print bed. It will be more manageable and the project will take less time in front of your CAD program ! To me the CoreXY is maybe the best building principle for biger printbeds, because the weight of the bed is not a factor.

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

Marty Rice did a double size bed on a RepRap Wilson. Video showing it and the process here: [www.youtube.com]

You would be able to do something very similar with a Prusa i3.

I'm not saying it's the best way to get a bigger size, but it would be a quick way of doing it if you already have an i3.