minimum printer to build a printer

hello; my first post here, just signed up today. Have searched both this forum and google for an answer but could not find. Found much discussion about repraps replicating new repraps, but I'm wondering about simplest way to make that first reprap. What is the minimum kit to build a very basic printer that will be able to build most parts for a better more capable printer? It seems to me that most of the parts to be built on that first printer for the second machine are not high complexity 3D models, so would not require a highly capable printer. Ideally be able to use most of the parts from that first printer in the better second printer (ie motors). Perhaps leapfrog with rough parts to start, then better parts on the second printer to make a third.

I did read about repstraps, but did not find a minimum requirement to build a second printer.

I'm not so much looking to be cheap, but rather I am intrigued about taking this path.

Has anyone done this?

Edited 4 time(s). Last edit at 06/16/2015 09:36PM by hBaz.

It's an interesting question, and I don't know what the answer is. Build volume is often a major factor, it being a lot easier to build an accurate small printer than a large one. You could download the STL files for the printer of your choice and run through them to find the biggest part - that would determine the minimum build volume for your starter printer. Material would be the next question. If PLA would do then you might get away without a heated bed in the starter printer, but if you want ABS parts then the heated bed is likely a must have. You may end up finding that your starter printer is pretty close to what you had in mind for the second one.

Overall, you're probably looking at spending a lot of effort for not a lot of gain. The printed parts for most printers are a pretty small percentage of the total cost. Sets of parts for a Prusa i3 sell for about $30 on Ebay. On the other hand I relate to your comment about not doing it for the cost savings. I'm currently working on a repstrap because I like making things and have the tools. But I do find myself looking at the slow progress and wondering what on earth I was thinking!

Repstrapping is it...

The only thing you really have to be concerned with is bed size and build height. Will all the individual parts I want for the 2nd revision fit on in the build area. The parts wont be prety, but nothing drilling and filing cant make close enough.

These days there isnt much point in restraping, unless you want to... I did way back when, but that was because back then a set a plastics cost over $900USD!!! There was also no such thing as kits, and ebay had about 4 hits on the keyword reprap or 3d printer

[dustsreprap.blogspot.co.nz] if your intersted (many many advances have happened since then)

Edited 2 time(s). Last edit at 06/16/2015 11:04PM by Dust.

It seems to me these days that its easier and quicker just to get a bag of bit off ebay than build a bootstrap.
To build a bootstrap you'll need something to replace the plastic parts with, and pretty much theres not a whole lot of the final printer your not going to end up needing for the bootstrap.

I guess the question is, what is the minimum viable printer?

Lets look at the most basic design a box based prusa i3, it actually has more printed components than a frame one, so actually you'll want to build something out of some cheap material.

Extruded aluminium seems a favourite, and a wide range of fittings are available, and i've seen some designs using lego, mechano and so on as part of the build.

there are some absolute must haves before you start that you just can't get round:

electronics, a cheap ramps kit will do for now, and you'll also need at least a ATX power supply you can hack into powering it.You'll need somthing to use as endstops, this isn't too hard, bog standard microswitches will do.
Nema steppers, no matter what you are trying to build it out of, you'll need at least 5 of these.
Smooth rods and bearings. Dont cheap out on the rods! you'll need them in the future! bearings are ten a penny and its worth getting at least enough for the stock i3 build.
A hot end, and some kind of extruding mechanism.

What you can skip:
heated printbed, if you aim for PLA as your first material you can skip the heatbed.
a large print area, it might be best to keep it small, work out the largest component you'll need to print and aim for a touch bigger than that.

The main challenges to building a repstrap as far as I can see are:
Cost vs a kit, you may well end up spending more than just buying a bag of bits!
Build suitability its got to be study, so the material you use has to be strong enough to lug itself around
Firmware, you won't have any standard values to put into marlin, so you'll have to research this and calculate it all yourself.
Holding a 180 to 190 degree hotend with melting or setting fire to anything. Yup.

When I bought my kit, I knew it was going to be my bootstrap to greater things, but I did order thing I new I would need, so I went for alu frame, a e3d hotend and a heated bed.
I've since upgraded it with a auto bed leveling system, since I had a solid platform to start from it made life so much easier.

Question really is... Do you want to pri t plastic or tinker endlessly with a home built printer...

If it is to print plastic there are inexpensive complete prusas with metal fram for $350 which is less than sourcing parts for the same printer.

I would just strongly recommend a kit for newbs. Unless you have advanced skills.

I like you wanted the challenge of building from scratch.
I had a small cnc router so I routed out a printer from 5mm plywood using files from Printrbot.
Printrbot uses a laser to cut the parts.
It would actually have been easier to use a scroll saw to cut out the parts.
It depends on your skill levels and existing equipment but you have to put no value on your time as it will take longer and not save any money.
In the long run I could have spent a lot less mony for a completed printer but what woul be the fun in that.