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[img]https://lh6.googleusercontent.com/-SR5C ... 180136.jpg[/img]

Uhh.. I don't know what to think of this... Coolest thing ever? Or so many problems you'd want to smash it?

Can that thing actually stay true at that size?

Tinyhead wrote:Uhh.. I don't know what to think of this... Coolest thing ever? Or so many problems you'd want to smash it?

Can that thing actually stay true at that size?

Maybe, if he puts diagonal supports across the corners, or just use big sheets of plexiglass. Looks like there'd be enough clearance.

That door is tiny. Does it go to a kiddy room?

barry99705 wrote:

Tinyhead wrote:Uhh.. I don't know what to think of this... Coolest thing ever? Or so many problems you'd want to smash it?

Can that thing actually stay true at that size?

Maybe, if he puts diagonal supports across the corners, or just use big sheets of plexiglass. Looks like there'd be enough clearance.

I hadn't notice before, but that's not the standard 1" x 1" T-slot either. Still... The word 'ballsy' comes to mind.

yea i got my 1500mm vertical and 1000mm vslot in.. i had to test this

im actually cuttin the 1000 in half and using those for the base/top cross beams.

this is the actual size with reference to the standard glass plate
[img]https://lh5.googleusercontent.com/-kXFq ... 203340.jpg[/img]

Good God Man! It's a Super Kossel!

The calculator says that with 500mm horizontal beams, you'd have a printable radius of 360mm. That's a biggun'.

Does the kossel design scale well? Are you aware of any additional gotchas when scaling up the mini kossel design?

I have a few questions for you on this setup.

How are you going to overcoming the inheirent problems with resolution when sizing up like this? The steppers have of course got a certain step size and when a larger arm such as this is leveraged it is going to move a larger amount than with a smaller sized delta.

Are you planning on printing with filament or do you have some other experimental output medium in mind? Build time, curl, seperation, maintaining heat over the entire part.....this should be a very interesting project!

The 3D printer that takes one full year to print a full sized object...

Are you going to use an engine block for the heated plate?

This will be cool to see you get this going. I am considering retrofitting a plasma table (4' x 4' x 6") and using a large extruder output to print big stuff with low resolution. Your printer may approach that size!

coool!

The resolution question is a good one. I suppose it would stand to reason that a mini kossel would be more precise than a rostock max, at the expense of a smaller build volume.

So two things I noticed.

(1) When the Rostock switched from 16 tooth to 20 tooth GT2 pulleys, didn't that effectively reduce the resolution of moves by 20%
I'm looking around the net, and it appears that the 16 tooth pulleys are still available

(2) Would it be safe to assume that if you were using 0.9 steppers, that you would gain approximately 50% in print resolution?

Accuracy is a really complicated subject, theoretical minimum moves aren't really an indication of overall quality.

The original Rostock had 15 tooth pulleys an but only a maximum of 8x uStepping, later they shipped 20 tooth pulleys, but the later Rambo boards support 16x uStepping, for a net gain in resolution.
HOWEVER uSteps aren't real resolution improvements, they are designed to smooth motion out, when a motor is at a uStep it does not have it's full holding torque, and with significant resistance to motion, movement between full steps can be jumpy.

Then there is the fact the with arduino controllers, the CPU available is marginal and your approximating what should be quadratic moves with straight lines, often way too few segments.

FWIW I would guess most of our printers have more slop than anything like the finest possible positional movement making the hole thing moot.

Flateric wrote:I have a few questions for you on this setup.

How are you going to overcoming the inheirent problems with resolution when sizing up like this? The steppers have of course got a certain step size and when a larger arm such as this is leveraged it is going to move a larger amount than with a smaller sized delta.

Are you planning on printing with filament or do you have some other experimental output medium in mind? Build time, curl, seperation, maintaining heat over the entire part.....this should be a very interesting project!

I think it depends more on the angles than the size.

Remember, its not a lever arm, its a push-pull on the end not a twist.

The steppers have a set resolution, but the distance traveled is determined by the size of the pullies not the length of the uprights. So if one side movesfrom bottom to top its going to take more steps on a taller upright, the effector itself will travel further because of it. So if the stepper on one axis moves one step the effector isn't going to move twice as far just because the machine is twice as big.

If there was ever a delta to need a Kraken....RELEASE IT!

some progress

[img]https://lh6.googleusercontent.com/-W3ND ... 233523.jpg[/img]

What's the world record for longest single print? You and John Oly might be going head to head on that one.

Jimustanguitar wrote:What's the world record for longest single print? You and John Oly might be going head to head on that one.

"Took three weeks to print my life sized Scarlett Johansson statue!"

[img]https://lh3.googleusercontent.com/-MdQB ... 212809.jpg[/img]

So for determining arm length, should i be aiming for a angle when the nozzle is on the edge of the print radius? i noticed the max is almost horizontal at the edge.

I believe the optimal length is an angle of 60 degrees from the horizontal with the effector in the middle of the platform.

I'm designing my own sooper-kossel right now, and when I get to arm length, I'm going to try out somewhere between 5 and 15 degrees from horizontal at the point opposite each tower at max radius.

But... Here is something else I've been trying to solve for...

What if you want to have that max radius for both extruders? I haven't figured out a way to hold onto the build plate in such a way that there's no interference with the not-active extruder. Wouldn't it be cool if you could hit that 11 inch perimeter with either extruder?

im rolling mag arms on this for quick tool change. i wont have dual extruders

I'm on the same track as you are, I've ordered a 3rd extruder so I can quick change between single and dual.

I wonder though, if you get that set up before me, if you end up having to recalibrate the arm_radius when you switch between effectors.

I ended up tracking down a "doming" issue and it turned out my arm_radius was off by almost half a millimeter.

I'm wondering if our effector prints are accurate enough to where we won't have to worry about it.

as long as you use the same material and have a super simple design that would eliminate your variables for effector offset you could minimize your chance of having different delta radius. that being said, once you measure the delta radius for one end, it shouldent change so you could just write it in marker on the side also.

here are my rod arm lengths used with traxxas mag ends
3/8 x 3/8 n52 cylinder mags

bubbasnow wrote:here are my rod arm lengths used with traxxas mag ends
3/8 x 3/8 n52 cylinder mags

full rod lengths.JPG

rod end wire.JPG

rod end.JPG

Which STL did you use to print the Rod Ends?
Which slicer did you use?
Aren't I nosy?