Custom builder wanted.

ok so its a full sheet of aluminium, we are waiting for price on the sheet, get that tomorrow, but a company i work with in town, because i am a currier and bring them all there steel, said they would do all the work to the metal for $250 CAD he said aluminium shouldn't be that much. ill post pictures of the frame once i have it built.
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| | <--- rough picture of the machine, it will stand with the bed 2" off the ground, and have an above bed height of approx 2" we are achieving this by going 1.5ft + 2 inches from center, CUT, bend 2" in and down, place holes along length of short bent section to match sheered off section. bolt on sheered off section with spacer to give true 600mm width. we are leaving the sheets at there 4ft length though and using the extra room to mount motors and electronics on. we will 3D print carriages based off a Prusa for our Gantry unit.

RPearce: OK I wrote, then deleted this post as I saw you already had a machine from previous posts you made but in simple terms it said...

Dont do this project until you had experience of another machine, so save your money, get a normal machine and gain some experience with it. Othyerwise I would suspect you will waste your money on a project that is likely to fail, cost you money and you will get bored and frustrated with it. If you get a normal printer and spend some months with it, you will be able to print some plastics kits and sell them to raise some money, whilst giving you more time to save from your day job income.

I just dont want to see you make a big mistake on something that is more likely to fail if not thought out and carefully planned.

Edited 2 time(s). Last edit at 01/22/2016 10:23AM by Mutley3D.

I don't understand the purpose of this armor plate base?
Lots of weight, no flatness, no adjustability



Drilling thru 1/4" metal to mount anything a real chore.

Perhaps a piece of MDF --- with screw inserts if necessary

Please get a crayon and a napkin and do some sketching
Get some cardboard and knife and scissors (the ones with the blunt ends)
and cut and fold up some pieces and make a 1/4 scale model.

Sketchup and openscad free software

Quote

Drilling thru 1/4" metal to mount anything a real chore.

Oh, it's not that bad. 1/4" alum is pretty easy going, and it holds a thread nicely. If I had the money then big chunks of metal for the non-moving parts would be an appealing direction to take. 3x4' is a bit big to get on the drill press though, so that's a negatvie. I'd love to be able to weld - a steel box frame made out of square section tube would be plenty rigid

Edited 1 time(s). Last edit at 01/23/2016 06:09AM by JamesK.

$1200.00 wouldn't even cover the labor. Not mine anyway.

All I wanted was for someone who knows what's in a prusa and other repraps to build a parts list. And if people know where to get good deals on parts. Oh well, I'll just build it all my self and hope I get all the parts the first time.

Quote
RPearce
All I wanted was for someone who knows what's in a prusa and other repraps to build a parts list. And if people know where to get good deals on parts. Oh well, I'll just build it all my self and hope I get all the parts the first time.

You can only create a useful parts list if you have built/constructed the machine to begin with, that's how BOMs come into existence. They are the product of constructing a new machine, not the premesis.

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

Prusa i3

[reprap.org]

It doesn't have a 1/4" bottom armor plate?

$600 gets you a kit but not 600x900x600

Gave you a design that might work
[forums.reprap.org]
but you wanted $1000 worth of aluminum plate

Please get a crayon and a napkin and do some sketching
Get some cardboard and knife and scissors
and cut and fold up some pieces and make a 1/4 scale model.

Sketchup and openscad free software

Quote
RPearce
All I wanted was for someone who knows what's in a prusa and other repraps to build a parts list. And if people know where to get good deals on parts. Oh well, I'll just build it all my self and hope I get all the parts the first time.

Quote
RPearce
All I wanted was for someone who knows what's in a prusa and other repraps to build a parts list. And if people know where to get good deals on parts. Oh well, I'll just build it all my self and hope I get all the parts the first time.

You really underestimate the engineering required to scale something from a standard Prusa i3 with a moving Y-axis at 900mm lengths. Tolerances become quite difficult as you get larger and so does weight with a moving bed. A prusa was never designed to scale up the large. If anything a Triple leadscrew CoreXY would be the far better choice. Don't rush.

Be specific. If you try to spec it out, you won't be able to make your budget. Large machines are not cheap. You can go "YOLO", but a fool and his money are soon parted. I'm trying to help you out.

We are men here, carpe diem will work instead of Yolo, anyways I know what it should look like and that's all that matters, we will start buying parts soon. I am going to get the beds and heaters done first. Then work on gantry units. Still trying to figure out the trolley system for the gantry. Making a system that rolls smoothly on a 1/4 face and keeps level is a bit of a challenge. Good thing we plan to use auto levelling probe like the Printrbot simple metal we currently have in service, but is down until our E3d head gets here which is going to be a whole new challenge for a new thread.

Closest thing I can find, but imagine that gantry goes up and down as well. This is of course about 3-5 times larger then the printer I'm making but same basic design concept.

Quote
RPearce
Closest thing I can find, but imagine that gantry goes up and down as well. This is of course about 3-5 times larger then the printer I'm making but same basic design concept.

That is a CNC machine. Not a 3D printer. The gantry is fixed in height, but the cutter can be moved up and down a few inches.

very much a CNC machine

from its home page

[oneoceankayaks.com]

also note the price "Complete mechanical, electronics, software system under $16,000."

Edited 1 time(s). Last edit at 01/26/2016 02:58AM by Dust.

Maybe try this mostly (3d) printed CNC [www.thingiverse.com] which can also be extended to be used as an 3d printer [youtu.be]

While I agree that Pearce lacks the skills for this build, that style machine can work for 3d printing. You can print all the way to gantry height depending on how the Z stage is set up.

Pearce. I have to be honest. You will waste money. Look up the flatness specification on that sheet and tell me if you think that ia suitable for 3d printing. You either need a much more expenaive tooling plate or to have that shop face mill it. Also, be careful trying to run bearings on the sheared face of that aluminum. If its not perfect then the workpiece will have the imperfection imparted onto it.

I wish you luck, but i think you are in trouble here. You are about to learn a lot on thia build attempt, but you will learn even more and save some money if you heed the advice of guys who gave done it all before.

Here are some rough sketches.

I'm going to take the Prusa I3 gantry and make it work for my application. The trolley will be interesting and I'll need the exact OD of those little roller bearings but otherwise shouldn't be too bad haha.

Basic bed design made from 3 pieces

I'm going to be doing some double posting but it's my thread so deal with it.

Just as a data point for you to use, I found a place where you can get a 4' x 8' 1/4" tool plate for about $400. Shipping is another $300. So before you get too far into the project, you might want to rethink your budget per printer. Just from what I have quickly guesstimate, that $1200 might be good for a single printer. But I'm pretty sure it will be a lot more.

Ok so rough drawing with the gantry, going going with 2 travel motors on belts, 2 elevation motors with threaded rod, and 1 travel motor on belt for the head just like a prusa.


I've only worked with the Prusa I3 and printrbot simple metal. I'm using a metal bed like this because my simple metal uses a metal bed roughly the same thickness, and it has a probe for auto bed levelling because I hated that about my prusa I could never get the damn thing to level off and work properly so I sold it and bought the Pb been happy since but now I need a much larger machine.

Anyways this works out to having a physical surface area of 3ftx4ft. Which is great because I can mount everything on the back nicely and there is lots of room for my trolleys and motors with out messing with the original 2ft width by 3ft length by 2ft height.

I may get the tops machined for a perfect rolling surface, I was also looking at sheeves I think they were called, used as pullies for rope. This might work for the top bearing however they were rounded so I would need square ones. Either way I still have to get my trolleys figured out.

A company in town quoted me $500 cad, for the sheet of aluminum plus all the shearing and punching.

If you go with 1 motor for Z and link the two sides with a belt you'll cut a little weight off the gantry and avoid any problems with the Z screws getting out of sync.

I'm thinking about rebuilding the X axis on my prusa-alike, partly because the current arrangement produces a lot of flex in the nozzle position (in Z). For a 2' width you'll probably need to look at 12mm rods (which will sadly add a lot of weight). Spacing the rods as far apart as possible should reduce the amount of movement in the nozzle for a given amount of flex, so I'm thinking of a layout with one rod front low and one high rear, effectively placing them across the diagonal of the carriage cross section.

Good find on the price for the aluminium! Care to share? I could really do with a new metal supplier.

I&M metal in Saskatoon idk if you wallet the same deal as I got because I am one of there transporters for metal they bring in and out. But that's also a cash deal. Hell it's probably a pay for materials and put cash in the bosses pocket kinda deal.


As for the print head, the diagonal approach might work, and if I use a probe and tell it to check height at 300mm (centre) it will be able to calculate the sag and take it up.

I'm thinking a Bowden feed is mandatory in keeping as much weight as possible off that head.

For elevation you will have to explain that a bit better to me as I am failing to grasp how that would be achieved.

I've spent "a little" time in both sheet metal shops and in a machine shop. I do it all from modeling, reverse engineering, to machine mods, programming and setup, both on the sheet metal side and the machining.
Your plate will not be flat enough. Not only will it not be flat after you put your bends into it, but 1/4" material won't be strong enough to maintain its own flatness on an uneven surface. Milling one side of a piece of 1/4" plate will cause it to warp more as you take the "skin" off one side you change the stress in the plate.
For the size you want, to keep things rigid enough to work you need beefier stuff. You will just waste money going down the road you are on.

Well if I go alot thicker I won't be able to lift the damn things, plus I have to ship it to the US after we get one built.

We will figure something out for getting the surface flat enough.

Best of luck then.I know you don't know me from anyone, but flat out just ignoring things that don't fit with your idealized world isn't the way to succeed.

Ya, koko is right. The physics of the matter are always true whether or not you ignore them. Auto tramming can help but it only goes so far.

I would mill the plate flat and braze some one inch aluminum angle to the underside of said plate. That takes care of flatness and the rigidity issue of a quarter inch plate over that kinda span.

By the way a 6 square foot quarter inch thick plate is about 15 or 20 lbs if memory serves me right. Then probably 5 lbs of angle if you stiffen it properly. With this much weight moving you need to start thinking about belt elasticity, desired acceleration capabilities (big plus quick is expensive) and the motors and drivers needed to get there.

I dont think you need to build a moving bed. The gantry could move instead.

And we havent even talked about the entire problem of adhesion (ignoring your inevitable non planar problem for a moment) on a 2 foot long print.

I believe the OP has been talking about a fixed bed/moving gantry, so bed weight isn't an issue from a kinematics perspective.

I mill things of that size to the flatness needed for this operation regularly. Without a decent vacuum setup to hold it down, you can't even think about milling a piece of 1/4" aluminum that size. When you turn off the vac, the plate will warp like you won't believe, the faces will be parallel (although I suppose concentric would be more applicable since they will be arcs at this point) but nowhere near flat. Brazing stiffeners after milling would not be the right way to go, if anything you would add the stiffeners on and THEN mill the top flat.
Then there's the press brake that will bend the sheet, the OP mentioned this before. Sadly this too will produce some error. When you put a bend in the edge of a sheet, the face will bow. How much bow depends of a few factors including the alloy of the sheet, grain direction, bend radius and weather or not the press has a "crowning" function, and if the operator knows how to adjust or use it. With 5052 in 1/4" and over the length described, with radii appropriate to the sheet (it's not a sharp bend if you don't want it to crack) it would be more than a layer height or two.
Making anything that size that flat is a challenge, and not an impossible one. It takes time, planning and some cost, which the OP was trying to keep under a certain number. If you want to do things on the cheap, you are going to have to put in a lot more work before you even consider what material to buy, and not buy stuff before you have thought the whole thing through. Otherwise you wind up spending twice, one is your initial budget, and again when you do things the way you needed to in the first place. Might be the voice of some hard earned experience talking....
OP what firmware are you planning on using which takes warp/twist/bow into account when leveling the bed?

Edited 1 time(s). Last edit at 01/26/2016 04:28PM by Koko76.

it seems a lot of you missed the part where i said moving gantry stationary bed. never the less bed isn't moving, only the gantry is, if this machine doesn't move fast i'm fine with that. and i didn't plan on milling the giant surface, on the edge where the trolley will ride so it rides smooth. the plan was to use PrintrBots, system that the simple metal uses, but change some of the values for the larger bed of course.

doesn't have to move faster then say 40mm/sec
accuracy to within .5mm would be preferred but 1mm is tolerable.

ill build it, figure out what doesn't actually work and go from there, nothing much else i can do.

What size nozzle and layer height do you want to use? That will determine how flat the bed needs to be.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].