Kossel XL V-Slot 2020 complete BOM and build instructions

Hi all forum members,

I'm a proud owner of a Prusa Mendel i2 that over the past 3 years has suffered quite a few modifications (Z lead-screws, quick-fit carriage with dual J-Head hot-ends, and auto bed leveling, for the most relevant changes).

Right now I'm envisaging the build of a Kossel XL using V-Slot 2020 extrusions but I'm unable to find a full and comprehensive BOM and build instructions.

Can anyone please point me to the "official" (if there is such a thing) set of STLs for the printed parts, a comprehensive Bill of Materials and, if possible, the respective build instructions ?

Thanks in adavnce

If you are going to build a large Kossel, then I strongly recommend you use metal corners. Robotdigg make some expensive cast ones, but there are some cheaper sheet metal ones being developed - see the delta printer Google group for more.

I recommend you use modern 32-bit electronics. Less vital but still worth using in a new build are 0.9 deg/step motors for the towers and 24V power.

I've described a design and listed a BOM for a printer with these features in my blog at [miscsolutions.wordpress.com] and the two succeeding blog entries. The printable volume is 300mm diameter by 480mm high, and the power supply, electronics and mains wiring is now all under the bed. I think at least one person has adapted it to use Openbuild V-slot extrusion.

Edited 2 time(s). Last edit at 09/01/2015 09:10AM by dc42.

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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].

Thanks dc42.

I'll take a good look at the links you sent.

My first idea was to go for the regular Kossel XL but moving from 1515 to 2020 extrusions to increase the rigidity of the frame and reusing as much elements as possible from my i2 (motors, electronics, endstops...).

You definitely want 2020 or larger extrusions on any delta bigger than a Mini Kossel. As for re-using parts from your i2, I advise against it unless you have access to another 3D printer. It's very useful to have a second printer available when a part on the first printer breaks, or you find you didn't print it quite right in the first place when assembling it. You could probably use the same motors and extruder (although 0.9deg/step motors are better for the towers of a delta) and endstop switches, but if you are using 8-bit electronics then be aware that it struggles to do the delta calculations fast enough. If you have a graphical LCD attached, you won't be able to use Marlin to drive it and a delta printer. 32-bit Duet electronics is only $50 from Replikeo and not only has the processing power to run a delta, it provides a web interface, SD card, fast native USB port, easy configuration without rebuilding the firmware, fast delta auto calibration (using a Z probe), and software-controlled stepper motor currents.

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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].

Thanks for your clear and informative answer.

I fully understand the interest in having an existing and operational printer while in the process of building the Delta. I started my path into 3d printing by building a repstrap with everything I had available (wood, drawer slides...) and that allowed me to fabricate the pieces for the first iteration of my i2.

I've got both a graphics and a text based LCD for my Ramps. Do you think the text based LCD will not significantly impact the ability of the Mega to drive the Delta? I would like to keep as much as possible of my previous investments for the Delta. As it is a hobby the budget has to stay under control.

You say that 0.9 s/d steppers are best for the Delta towers. Does that mean that 1.8 are not good or just that the resolution will not be as fine as using 0.9 s/d ?

Thanks in advance.

You can certainly use 1.8deg/step motors, and most delta kits use them because they are cheap. But with the Z steps/mm being so much lower for a delta than for a Cartesian printer, and the incremental torque per microstep being so low, deltas benefit from 0.9deg/step motors in a way that most Cartesian printers don't. So I recommend 0.9deg/step motors if you are starting from scratch and having to buy the motors.

It's certainly possible to drive a delta and a text display with a Mega, but you have to find the right compromise for the delta segments per second, and you may also spend a lot of time trying to get the calibration right.

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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].

I agree with David,
The 8-bit Arduino/Ramps combo is definitely at the edge when using it for a delta.
1.8° steppers can be used. With "decay hacked" DRV8825 drivers you can improve their movement.
But 0.9° steppers are only 2EUR more/pcs. That shouldn´t be a dealbraker.
And the decay hack for A4988 drivers ( you should use them for 0.9° and 8-bit ) is much easier or even not necessary.

Instead of using expensive metal corners, I would use diagonal struts, were possible.
-Olaf

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o_lampe
Instead of using expensive metal corners, I would use diagonal struts, were possible.
-Olaf

Diagonal struts are certainly another option, if you don't mind them getting in the way. There are also less expensive metal corners on the way, see [groups.google.com].

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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].

Quote
dc42

Quote
o_lampe
Instead of using expensive metal corners, I would use diagonal struts, were possible.
-Olaf

Diagonal struts are certainly another option, if you don't mind them getting in the way. There are also less expensive metal corners on the way, see [groups.google.com].

Thank you for the link, I filled the form for interest.

I think those along with 20*60 extrusions will do wonders for deltas.

When I read the original thread he they were designed for 20*40 at max which makes it a bad choice if you plan to use linear rails, but this development is just great!!

Quote
dc42

Quote
o_lampe
Instead of using expensive metal corners, I would use diagonal struts, were possible.
-Olaf

Diagonal struts are certainly another option, if you don't mind them getting in the way. There are also less expensive metal corners on the way, see [groups.google.com].

Dave just for interest Robotdigg now do Alloy corners to take 20x40 extrusion though they would be rotationally stiffer if they rotated the Verticals by 90 Degrees.

Doug

Thanks for all the pertinent answers.

I think I'll ponder on this Kossel XL build some more time before committing to it. In particular the issues related to the reuse of the steppers and the controller.

On the other hand I may start to procure the basic frame elements like the extrusions, fasteners, and the remaining vitamins... and even start printing the plastic parts.

Again thank you all.

You might want to take a look at the ultibots site-- they sell a v-slot kossel 250 kit, and have a thingiverse page (with BOM and STL's) for it as well: [www.thingiverse.com]