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Topic: Scaling up 3d printer for larger items

What would be some of the problems one will run into building a 3d printer and trying scale up the printers size in order to scale up the printers ability to print larger, taller items? For a contour crafting application.

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Re: Scaling up 3d printer for larger items

No real problems... everything is just bigger and costs more....

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Re: Scaling up 3d printer for larger items

You can but there are some limitations.  If you go too big you will need large motors which the electronics can only deliver so much current also you have to take onto account sag of smooth rods. I am working on a 2ft cubed h bot design though so its not impossible.

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Re: Scaling up 3d printer for larger items

power supply, cable length, tangled wires and motor upgrade(print is too heavy and cause missing steps)

Solidoodle2 with Ceramic tile heated bed http://www.soliforum.com/topic/2544/my- … eated-bed/
"1kg should last for an while" is a lie!

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Re: Scaling up 3d printer for larger items

All of the size increase problems can be mitigated with .... more cost. I built a 4' x 8' plasma table with nema 23 steppers and just cables hanging from the ceiling could have very easily added a bigger z axis and a couple of bungee's for a large scale 3dprinter and the actual cost of the complete machine wasn't that bad... well all things considered wink

6 (edited by REdington 2013-04-09 22:48:46)

Re: Scaling up 3d printer for larger items

The biggest problem with going larger is speed. You need to keep the mass weight on the moving parts light. I built a 300mm (aprox 12" square) cube printer scaled up from the ORD-BOT Hadron design. Still tweaking on it but it does a super job so far. I have a QU-BD extruder modified with PFTE barrel and a bearing spring lever tensioner. I'm working on a duel head Bowden extruder to put on it. I use precision acme thread rod instead of the crappy and sometimes bent all thread that a lot of printer are built with.

The ideal 3D printer would be that just the head moves (Bowden style extruder) and either move the table or the head carriage up and down for the Z axis.

One thing to think about also is the larger the print, the more shrinkage you will have and cause cracking in the print. Also is print times. I printed a large vase for a trial print that took over 30 hours. It was 11 1/2" tall and 10" in diameter.

Rodney

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Re: Scaling up 3d printer for larger items

Yeah the print times would start to get excessive smile but with all the other 'enlargements' lets double or triple the extruder orifice and keep the times reasonable... you lose some detail but only in the relative sense of the word as your x-y plane accuracy/addressability is still the same and z would be controllable.

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Re: Scaling up 3d printer for larger items

Personally I think the main problem with big printers....BIG print times.

Can you imagine how bad you would feel if 25 hours in to a print something happened. With the amount of potential problems we can have it is a risk I'm not keen on exploring at present.
I would rather find a better way to join several prints than go big.

Maybe when the whole scene matures and you can press print and walk away knowing the item will come out perfect every time I'll look again at going big, but for now, 6x6x6 is just fine for me.

But hey, don't let me stop you from creating something great....as long as you post pictures smile

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Re: Scaling up 3d printer for larger items

I am in the final stages of building a large printer.  Don't ask me why....  I think the biggest challenge will be flatness of the bed.  It needs to be within a few thousandths of flat.  Mine will print a 21" cube.  I milled the bed flat, but I am not sure it will be good enough.  About all I have left is wiring it so I should find out soon.

I am using Nema 34 steppers on the y and z axis and a Nema 23 on the x.  I am using a ramps 1.4 controller.  Instead of using the traditional stepper driver modules, I hacked the step and direction signals and feed them to standalone stepper driver modules.  Speed may be an issue.  I put together a test circuit wit an Arduino to move each axis.  I didn't do any analysis on motor size.  I just used some motors, drivers, and precision ball screws I already had.  I could reliably move the axis at 100mm/sec.  I'm not sure if I can tune it up much faster than that though.

I did a couple of novel things relative to mounting the extruders.  It has dual extruders.  Each one is mounted on its own bearing block on a miniature linear slide.  In other words, the extruders are on independent carriages.  One extruder is attached to the ball nut.  The other extruder "sticks" to the first with magnets.  That would be for traditional dual extruder mode.  The second extruder can be pulled apart from the first and a 10" beam connected between them.  In this mode, you could print the same file out both extruders at the same time and print two parts at once. 

I'm not sure where I'm going to get a 24x24 piece of flat borosilicate glass.

10 (edited by adrian 2013-06-20 05:07:25)

Re: Scaling up 3d printer for larger items

tmccafferty wrote:

I'm not sure where I'm going to get a 24x24 piece of flat borosilicate glass.

Most glass manufacturers and suppliers have it or can special order it. You will probably find the local Glazier can supply as well - and the bonus there is if you normally have a chat about what you want something for, often those guys will more than help you out price wise (at least in my experience... ). The pain is its, compared to standard glass, a right royal PITA to cut and requires special processes.... so expect to deal with a reasonable cutting price.  You can purchase a larger sheet and have it cut down to 24x24 ...

But Borosilicate itself, is actually quite common...

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Re: Scaling up 3d printer for larger items

Not trying to hijack this thread.

I saw a youtube vid where some one claimed mirror squares could be used.

Is this a bad idea?  Granted the mirror solution should hold the glass, yet the vid also recommended covering said glass with Kapton tape.

I am an open book, write on my pages that I may learn the wisdom that you posses.

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Re: Scaling up 3d printer for larger items

Depending on how thick your metal bed is, how it was produced (ESPECIALLY if it was cold-rolled thin at any stage of production), and what sized mill cutter you used, this could be a HUGE headache for you. If at all possible, you should REALLY use a face mill with carbide inserts, and you should have the metal annealed. Probably very expensive, though.

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Re: Scaling up 3d printer for larger items

the only thing is with a bed that big unless it is attached in more than a few spots it will warp when heated.  My onyx heated bed is flat but when its heated it bows a little mainly because its only attached on the outside.  I am bonding it to the mounting plate with hopes of curing it.

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Re: Scaling up 3d printer for larger items

just go with a delta type design. a plain jane rostock already gives 200x200x400 build area. and depending on how meticulous you are during construction, can deliver insane speed and accuracy.

im sure you could double or tripple that build volume without needing too much more in the way of larger motors. will be needed of course, but the end effector could theoretically stay the same size with everything else growing around it. im sure nema 17s from the stock design could easily run a printer several times larger. 600x600x1200 build area anyone?

personally though, i think you would be better served by enlarging just one axis and focus on making it rigid and moving bits as light as possible for speed, to enable you to plate up more parts at once. and while the rostock offers that double height build area, i think a double x or y area would be more useful.