Need help building perhaps the biggest repstrap printer ever made!

As the title says, I plan on making a large repstrap printer. I would like it to have a workspace of about 2' by 2' by 2' why so big? You may ask, I plan on having this for a lot of big projects, like when I finish it, I will be designing and printing a Marimba, which is a key percussion instrument. I also hope in the future to be able to print dirt bike trim pieces. What I need help with is I'm new to 3D printing and basically know nothing about it. I feel totally overwhelmed by this printer, I just need someone who feels like they know enough to help me break some of this stuff down and understand it a little better.

I can tell you right now, it is not the best idea to go big right from the get-go, especially if you dont know much about the technology.

I am sure others will point this out, but when you go big you will need to be VERY careful about reliability. Instead of taking a few hours to print, a large scale print can take DAYS! and if it fails 2.5 days into a 3 day print you just lost a lot of time and filament.

That being said, it is not impossible, but it will require a lot of research and design thinking.

What material did you want to print with?

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Building a large printer is not easy not too many people have been successful you will definitely need a heated enclosure. Which brings in a whole other set of problems keeping things cool that need to be inside the heated chamber such as the filament before it gets to the extruder hot end and the motors you're probably going to need water cooling for the hot end cold zone. The printer has to be extremely reliable because you going to print for extended periods of time 24 hours a day multiple days to complete large prints. Something that automatically pauses the print when a roll of filament runs out. I don't know what kind of skills and/or machinery you have but it's going to take a lot. To start off with I would build a small Kit there's a lot to learn. The machine has to be extremely strong it's not just like putting longer rods in a standard machine I might add very expensive unless you have a lot of stuff that you've acquired cheaply laying around. Larger motors which don't work well with the standard reprap electronics is another problem. I don't think the standard belts take heat that well so you're probably going to have to use high lead ballscrews which is what I did mine is only 17" x 14" x 14" . If It was easy they be a lot more large printers out there

Edited 4 time(s). Last edit at 03/20/2014 09:28AM by cnc dick.

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gmh39
What material did you want to print with?

I was planning on using PLA plastic, would printing bigger objects require a different filament?

Quote
cnc dick
Building a large printer is not easy not too many people have been successful you will definitely need a heated enclosure. Which brings in a whole other set of problems keeping things cool that need to be inside the heated chamber such as the filament before it gets to the extruder hot end and the motors you're probably going to need water cooling for the hot end cold zone. The printer has to be extremely reliable because you going to print for extended periods of time 24 hours a day multiple days to complete large prints. Something that automatically pauses the print when a roll of filament runs out. I don't know what kind of skills and/or machinery you have but it's going to take a lot. To start off with I would build a small Kit there's a lot to learn. The machine has to be extremely strong it's not just like putting longer rods in a standard machine I might add very expensive unless you have a lot of stuff that you've acquired cheaply laying around. Larger motors which don't work well with the standard reprap electronics is another problem. I don't think the standard belts take heat that well so you're probably going to have to use high lead ballscrews which is what I did mine is only 17" x 14" x 14" . If It was easy they be a lot more large printers out there

What do you think would be be biggest I could make it without it requiring its own chamber?

I don't have that much experience with PLA but I would guess somewhere around 8" x 8" x 8". And even that would have to be in a fairly good temperature controlled room and a well tuned machine with experience in printing pla shrinks less than ABS but it still shrinks. Most people that have larger than stock machines use it to print many small parts on the same platform

Edited 2 time(s). Last edit at 03/20/2014 11:48AM by cnc dick.

Do you know of any good kits, or models that I can build myself, that's stable, reliable, and accurate? And that have a complete list of parts and programs needed to make and run it.

Edited 1 time(s). Last edit at 03/20/2014 12:32PM by TANelson1585.

What is your budget for this printer?

I don't really have a set budget, but I could probably put in as much as $1000 of I needed to, although I'd rather stay on the cheaper end, if there is a good printer that's cheaper

First, welcome to the club and get ready to be consumed for a while. There is no free lunch here, whether you're buying a machine and learning how to print, or designing and building from scratch, then programming the firmware, then learning to print.
Your first chunk of time should be spent reading, researching, reading, and researching. +1 vote to buying a small kit. you would benefit greatly and it's all there, somewhat recipe like.

My $0.02 on the marimba (i own one), is to invest in wood working equipment and do the frame from wood. You're obviously willing to invest time and money, and the keys are not printable anyway. Good DIY plans available online.
The motorcycle trim pieces might be better suited to vacuum forming over a wood form? Buying from web is also cost effective.

To build your own machine, of your own design or others, you should have some experience in 3D CAD software. It helps.
You will also need a good set of tools, be mechanically clever/handy, have an abundance of uninterrupted chunks of time, and a fair amount of cash.

From my perspective,you can build big just as easily as building small. I've built two distinctly different large machines, one made of sheetmetal and the other 80/20.
The designs were done in Solidworks, each taking around 100 hours or so. Construction, debug and tuning/programming takes about same.
Costs for each design are in the $2k-$3k range.
The sheetmetal design can be reconfigured for cable driven CoreXY, GT2 belted H-bot, and standard belt driven cartesian (current state).
There are no build blogs on either sadly. Thingiverse the word Mitus for some of the 80/20 parts.

I'd suggest using cartesian designs, 80/20 aluminum, linear bearings, GT2 belting, NEMA 17 motors and an all-in one electronics package. The hotend has been my biggest issue.
Keeping it smooth running, both in the pinch wheel area and the hotend have caused me grief. My longest prints are only 8 or so hours, with various jams, clogs, failures etc.
Many issues are my own, since it's all been custom. There are many hotends on the market that work, so don't go custom is my advice.
I have a NEMA 17 with the screw/nut, 400mm long, lifting my z-axis, which is a 1/2 glass plate and 2.66mm sheetmetal. The single motor is lifting it with authority, and it weighs just shy of 40lbs, so it's plenty strong.
Kysan 1040095 is the model number for that motor.

Constructing a large flat build plate is more challenging than you may think. my 1/2 glass is tempered and not flat at all.
With the Marlin firmware recently, they've added some auto leveling, but it requires complexity in other areas, like z-axis endstops attached to servos.

Prepare for PLA printing mainly, for the size of part you're talking about and no heated enclosure. If you can get PLA working on a custom machine, adding a heated enclosure will be easy for you.

This is an all consuming hobby.

Hey I print motorcycle parts! I can tell you this: You can't print anything the fuel touches, even if you coat it with po15 or something like that. Also you're really going to want to print with ABS if you're trying to do anything like a side cover or flap. A 2'x2' heated bed would take an ungodly amount of power though. Like 50-100 amps I'd guess.

If you want to go big, the mendel90 is where you want to be. Building an enclosure won't be expensive, maybe $150 for 6 sheets of 24x24 acrylic and some hinges. Look up fish tank construction for that part. There are easy ways to bond the sheets very very perminantly.

A 2' cube of build volume will be basically impossible, but I like your idea of going big. Not sure if you can pull it off for a grand but it won't be too much more than that.

Coincidentially, I also used to play the marimba and attempted to build my own out of PVC. It worked, but not well. There are very specific plastics with the acoustic qualities you need and I would wager that neither ABS or PLA will give you the sound you're looking for. PVC is more ridgid than either and it sounded pretty rough. A printer would be great for..say...mounts or parts for a pedal damper system but the fact is 3D printed materials are not great for voluminous parts as you've described.

Best of luck.

EDIT: davew_tx, those look fantastic. I restore old cymbals in my free time so I first read that as 80/20 bronze and though you were crazy. Hahaha.

Edited 1 time(s). Last edit at 03/20/2014 04:04PM by SamS.