New to reprap, want to build and source my parts

Hi everyone. I've been reading about reprap for about a year now and finally decided I want to build one of my own.
I would like to source my own parts to be cost effective.

I'm deciding between and mendel i2 or i3.

I was also wondering if increasing the print volume would be as easy as using longer and thicker smooth rods? I would like something like 1 meter x 1 meter x 1 meter. (thats really big i know)

Any advice?

Your rods may need to be about 4X the "normal" diameter. The same would go for the material in the frame (if an i3). If you are going to print ABS you will need a heated bed. As a rough guess the heated bed will need about 2.5KW to heat it.

You are trying to handle 25X the bed area and 125X the print volume.....

If a large print on a normal printer takes 8 to 24 hours, your large print will take one to four months.

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Don't in any way take that to be a negative, far from it. You just need to know what you are getting into. I'm thinking about something similar done as a Delta

I would just need thicker and longer frame material and rods? No different electronics or software? I plan to have a heated bed, and powering it shouldn't be a problem. I ofcourse wont be printing 1 meter ^2 cubes, but i just need that availability for prints that may be larger than your average print area.

As long as you have a 220V 15A power source and the solid state relays to control it, all you would need to do is to design a heated bed from scratch that will accept that sort of power. I'd guess that a reasonable design could be done for less than $1,000 for the bed. I'd do an isolation transformer to keep it safe. If your design is not to heavy it should work. You essentially are putting the innards of an electric oven on the carriage....

You would need to go with larger motors (NEMA-23's) and high power controllers. Those are fairly easy to come by. Figure $30 each for the controllers and $40 or so for each of the motors. You would need to design custom mounts for all of them. The X carriage will be heavy enough that dual drivers for the Z motors is likely a good idea.

If you have a 220 circuit for the heated bed, the power for the motors should not be to hard to come by. Figure a 48V 600W supply. It's probably overkill, but they are pretty cheap ($135 or so). The software and firmware should be standard stuff. You likely will need a fairly heavy (thick) piece of ground glass for the bed.

Instead of a 1/4" aluminum plate for the frame, you would be looking at a 1" thick piece. It would need to be wider (2-5X) than normal.

I suspect that you could do it all for $3 to 5K in parts. There are some issues like belts that would need to be figured out, I suspect that the normal stuff would not be up to the task.

Needless to say, other than the extruder, everything for the printer would need to be scaled up and fully re-drawn. That's not quite as hard as designing all the parts from scratch, but it's not easy.

Whether the printer comes in under 300 pounds or not - you'd have to do some math. I'd bet that by the time you get it bolted to it's support structure it's going to be pretty heavy. It's also not going to be very fast.....

My original idea was to upscale too. Maybe not 1 meter cubed, but I was thinking of 350 or 400mm.

In the end, I decided to build a standard sized prusa out of parts that I sourced myself. It was a great learning experience, and I can tell you now that I'm glad I didn't go big. The 200x200 size is almost never a limitation, and if it is, it is generally along only one axis and I can always rotate 45 degrees to get a bit more length.

Thanks for all the info! I didn't anticipate so much cost of just expanding the bed. I think I should play safe, start with something standard or close to it. I try to see how much a standard size would price out..

On a standard sized printer, it's very tough to beat the price (or quality) of a kit. One mistake on a part and you have pretty much blown any cost advantage you might have.

Of course if you have a bunch of 8mm chrome plated hardened shafting just sitting there doing nothing ....

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You pay for most of this stuff by the pound. Weight goes up as the cube of dimension. Double the size and you increase the weight 8X... You pay for it in cash, and you pay for it in things like deflection and acceleration as you go into the design. Correcting for those things makes for more cash needed.

After paying postage costs I doubt if you will save anything over a kit. I would have a look at the mendel90 aswell.
If you are going to go for a larger machine later perhaps starting with a mendelmax 2 is a possibility?

I'm managing to find everything for less than kit prices. It may have to do with location. If you are close to someone who sells very competitively priced kits, I guess it would be hard to beat.

It also depends very much how good you are a sourcing parts...

BTW, for the i3, the biggest issue is the aluminium frame. You might be able to do a very nice job yourself with 1/4" plate and a jigsaw. Aluminium is easy to cut.

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Yvan

Singularity Machine

It depends on what you want. I realize I could have done it cheaper buying a kit, but I wanted to search the parts out on my own - to pick and choose from the options. Yes I made some mistakes, but that was all part of it. As someone else said here, for me it wasn't the destination, it was (and still is) the journey.

One non-trivial issue with sourcing all the stuff is getting it wrong. There's a lot of 'this and this work only with that" going on between various parts. Making one mistake that way can be expensive.

A good thing to look at - do you already have an inventory of metric nuts and bolts? If you happen to have a bigger inventory of inch stuff, sourcing the metric costs real money. If you live in a metric country, they could be nearly free. One good example - go down and look for a 2mm metric bolt that's 12mm long. If that's a "got those on the shelf" thing - you have an unusual stock of parts.

Quality is a tough thing to judge. You can certainly see a range of kit prices. My guess is that there are also a range of quality to those kits. Can you source the parts in a $300 kit for less than the parts in a $1200 kit - yes. Is one over priced - yes. Would I be afraid of what I'd get in one of them - yes. Can you pay $600 to ship a $600 kit - yes. What works for me may not work for you.

There's a reason you don't see a lot of cubic meter machines. I am getting close on a 3.3 (+ or -) cubic foot machine. The electronics, motors, hotends, gears and even some of the linear parts are the same or similar. But let's take a look at your z axis to start... You need bigger motors for that size, which means bigger drivers. The cheaper ones will eventually bring trouble. So the driver I am using (Mass Mind) is $35, and you must assemble it your self. Then there is the frame. Mine is of welded steel, and weighs close to 200 lbs. There are more than a few different ways to go about it, depending on what you want your output to be. If you want to do, for example, vases, lampshades, tableware, etc, you can get away with a very tiny bit less rigidity, than if you want to do highly accurate models, robotics and body parts, as do I. Your hotbed at one square meter will certainly be at least around $800 +, I am still working through the intricacies of sourcing mine. I can tell you that at that size, you will have a hard time ordering in lots of one. Even the frame for my build bed has around 180 parts, including fasteners, and that alone took a month to build. Machining and welding will almost certainly be necessary to produce a number of the parts you will need. My build envelope is about 10 times that of the average printer. Yours is about 8 times the size of that. I do think it can be done, but I would only suggest that you think about your printer as a number of subsystems, and then analyze what you will really need to make each work, by itself and then as part of the whole, before you begin selecting parts and components. You must also keep in mind that as things become larger the parts become longer. The issue of stiffness is magnified as this happens. You will have to stray from the original design, if you are going to have a machine dimensionally stable enough to give you your desired output.