Printbed size: what do you actually use?

After running a standard Prusa for a long time, i am building a second/new printer now. This new printer only uses parts that i designed and will basically be my personal Prusa version.

For Repraps there is the question of how big do you want your printbed to be, there are some pros to bigger and smaller:
- bigger bed gives the possibility to print larger but especially more things
- smaller bed makes the printer more compact
- smaller bed makes the printer faster (less weight)
- smaller bed makes the printer more sturdy
- smaller bed makes the heated bed use less power

I print mostly in ABS, which is even with a heated bed limited in size due to warping. i succesfully printed something the size of 190*140*30mm but that took an extreme amount of effort.
Also i prefer to keep the printing time relatively small: 4hours max or so. With extremely long printing times there is just a too big chance that something goes wrong halfway.
With the new smaller nozzles the detail has gone up greatly but the printing time per volume also went up.

So i am strongly thinking about making the bed smaller than 20x20cm. Maybe something like 12*18cm?

What do you guys (and girls) think what would be a useful / efficient size for a printbed nowadays?

Edited 1 time(s). Last edit at 03/05/2012 12:38AM by north90ty.

The biggest piece I have printed so far has only been 100 x 100mm..But with that said I think a size of 150 x 150mm would be the smallest bed size I would personally want. I do think that the 20cm x 20cm size we have right now is good, but printing a continuous piece of that size is definitely going to be hard to prevent warping around the edges

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Kreativ-e
Tinkerine Studio

95% of the time I could've used a smaller build plate, but when you need it it's so very convenient just to be able to print 30 copies of the same small part, without having to reload the machine all the time. Many people use the Prusa PCB heatbed, and it's a good tradeoff for size.

The main concern I'd have if you scale down the printer to a smaller build plate is the build height would decrease as well.

If you build a standard size Prusa, why not have two beds? One small for day-to-day printing, and a large one to clip on top of it if you do production runs? I have yet to see someone build a solution with two heater coils for the bed, but it would be feasible if you can avoid the glass cracking.

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-Nudel
Blog with RepRap Comic

A typical print is 75mm x 75mm x 25~40mm. Bigger is better and I would suggest a wide 400mm x 200mm x 200mm working area for a single extruder. This build area would drop to some to 300mm x 200mm x 200mm with a dual extruder setup.

99% of parts you are capable of printing decently will fit within 8x8, and 90% will fit within 6x6.

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www.Fablicator.com

I don't often print large things, because the larger the print the more precise my bed level has to be. Getting it level enough to do a full bed print is a time consuming pain. However, without a mendel sized bed I wouldn't be able to print the three part plates for [www.thingiverse.com] . Also, I'm working on designs for objects that would be very hard to do without the full 20cmx20cm bed, like [www.thingiverse.com]

Even if you don't print to the full 200x200 size of the HBP, the heated margin surrounding smaller prints might be preventing warping at the edges and corners.

It is much more difficult to get a level, flat, and temperature even surface reliably on a 200x200 than it is on a 100x100. Power requirements are dramatically larger as well.

Maybe my opinion would change if I was interested in printing plates, but I think the sweet spot is somewhere between 100x100 and 200x200 and probably closer to 100 than 200.

As for the size of the parts I print.. 99% fit on my 100x100, but it does feel a bit cramped.

Thanks for all the input!

What about a not square print-bed? For example 12*20cm? In general the very large parts are only large in one dimension.
I think it would help a lot to reduce the lenght of the x-axis, to make the Prusa more sturdy. I know quite a few solutions have been posted with sturdier frame-vertices or crossbars to tackle the same problem. By reducing mainly the x-axis size the build-height isn't reduced.

an asymmetrical build space actually makes no sense in printing real life products than a symmetrical one. Everyday products are usually not uniform in shape. I would say its a good idea

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Kreativ-e
Tinkerine Studio

I regularly use over 75% of my build surface on my Prusa's 200*200mm bed. Usually printing multiple parts rather than single large pieces. It really isn't difficult to get it level enough to print over the entire surface, even using 0.2mm layer height. Much lower than this and leveling would be a pain though.

My next build will be a MendelMax with something close to 300*300mm build area, and 200mm or so in build height. It's not infrequent that I would like a larger area than I have on my Prusa Mendel, and I frequently want a larger build height.

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My MendelMax has a build area of 305 x 305 and I have been using about half of it most of the time. That's also right on the limit for 8mm rods, if anyone else is planning to go as large as 300 x 300 then do think about using 10mm or 12mm rods.

For new machines, I'm thinking about a build area of around 200mm x 150mm - The 200mm being in the X axis, so Dual extruders can both cover a decent build area, and single extruder can accommodate any long parts. It also makes the Y axis shorter so it's easier to fit on a desk with a filament spool holder at the back.

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[richrap.blogspot.com]

What is the minimum size build volume that is able to print every printed Mendel part, even if it needs to print the largest parts one at a time?

Is it true that any Mendel part can be printed with a build volume of 97 mm x 69.5 mm x 34 mm (3.82" x 2.74" x 1.34") ?

Those dimensions come from:
* the X carriage lower: 97 mm x 62 mm x 34 mm
* the Y motor bracket: 86 mm x 69.5 mm x 18 mm
Is there any other printed Mendel part that doesn't fit in this build volume? (Do any of the latest RepRaps on the front page of [reprap.org] require a printed part that doesn't fit in this build volume?)

I see that all the parts for a Wallace RepRap ( [reprap.org] ) fit in 3 plates, each with a build volume of 100 mm x 100 mm x 70 mm (4" x 4" x 2.8").

Can a RepRap really print parts all the way to the edge of the print bed? If not, how much margin is typically used -- edge of part to edge of raft (r), and edge of raft to edge of print bed (b)? (So to print some L by W part, the print bed must be b+r+L+r+b long, and b+r+W+r+b wide).

What is a good name for a page on the RepRap wiki that discusses "bed size" and "build volume" and the advantages and disadvantages and non-obvious implications of choosing some particular sizes?

("Able to print every printed Mendel part, even if it needs to print the largest parts one at a time" is the main goal of the Bonsai RepStrap [reprap.org] . It was also alluded to in the "Baby sized reprap" thread [forums.reprap.org] ).