Advice on new large delta build with parts i already own/have on the bench...

* I am working on a large delta build and could use some input.
* Frame: Open builds store 3x 1500-2040, 3x 500-2040 upper, 6x 500-2020 lower, RobotDigg xxl corners, .
* Running Gear: Robot Digg 1.8 degree nema 23 motors with Robotdigg nema 23 dampers, rails/wheels running on the support towers. Pulleys are GT2x32 6.25 bore (sizing??),
* Opto-Endstops,
* Bed: 300mm aluminum heat spreader and rubber hpb element.
* Power: 350w 24v led type power supply.
* Effextor/Extruder: UtilBots UMBEE magball effector/direct extruder from shapeways in black stainless steel modified to support ir sensor board (I also have FST kits on the bench but haven’t decided which to use)
* Diagonal Rods: 6x500mm 9mm od 6mm id wrapped carbon fiber tubes as effector rods. (length? i dont mind giving up height on this size build and i can always cut them back, i know the 60, 62 and 80% guidelines, but the trend seems to be getting closer and closer to horizontal extrusion length)
* UMBEE uses 43mm wide ball spacing between rods and i believe a 43 mm effector offset. carriage offset should be around 25mm
Electronics: I chose (and may regret) the ramps-fd v1.2 on and arduino due with a choice of steppers (I have A4988, DRV8825, and MKS TMC2100) i was going to use the 2100’s. a Gikfun AT24C256 I2C EEPROM, Reprap Ramps1.4 RRD Fan Extender for pwm on fans, with the Ramps-FD display adapter and a repRap discount full graphics smart controller. or the RepRap MKS TFT28 V1.2 smart touch screen controller with Bluetooth and Wifi.
* Firmware: most familiar with repetier (it colored my choice of electronics, but i have read that though it supports 32 bit, it doesn’t really take advantage of it)
* i also have other power supplies and a 24v relay w/heat sink lying around.
*
* I would welcome thoughts, comments, caution and advice etc. with the understanding that this is what i already have in the bench and i haven’t cut anything to length yet…

* Many thanks in advance-


* MMS

I'm assuming the Nema 23 and the 32 tooth pulleys are items you already have. If I were you, I'd go for a 16 tooth pulley, and if possible, nema 17s. Unless, of course, you're using nema 23s with a .45 degree step, then the pulley config is about right.

I already replied to the very similar comment that mshievitz left on my blog. But as this is a better place for this type of question, I'll delete that comment and my reply. This was my reply:

- If your horizontals are 500mm, then 300mm diameter is way too small for the bed. Your printable diameter is potentially about 450mm. I recommend making the bed about 30mm greater in diameter than the printable area and the heater diameter, so that you have room for bed supports and bed clips outside the heater and the printable area.

- Don’t waste your time trying to use DC power for this size of bed, go for AC mains power like I did.

- 43mm is IMO too narrow a spacing between the rods for a build of your size, I suggest between 1/5 and 1/7 of the rod length, for better rigidity and reduced sensitivity to build errors.

- I won’t comment on your choice of electronics as you probably know my views already.

- You can probably complete the printer with the parts you already have, then upgrade the bed, rod spacing, and if necessary the electronics.

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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
I already replied to the very similar comment that mshievitz left on my blog. But as this is a better place for this type of question, I'll delete that comment and my reply. This was my reply:

- If your horizontals are 500mm, then 300mm diameter is way too small for the bed. Your printable diameter is potentially about 450mm. I recommend making the bed about 30mm greater in diameter than the printable area and the heater diameter, so that you have room for bed supports and bed clips outside the heater and the printable area.

- Don’t waste your time trying to use DC power for this size of bed, go for AC mains power like I did.

- 43mm is IMO too narrow a spacing between the rods for a build of your size, I suggest between 1/5 and 1/7 of the rod length, for better rigidity and reduced sensitivity to build errors.

- I won’t comment on your choice of electronics as you probably know my views already.

- You can probably complete the printer with the parts you already have, then upgrade the bed, rod spacing, and if necessary the electronics.

If he has 500 horizontals, and can print up to about 450mm, what would his diagonals be?

Quote
3DRapidClone

Quote
dc42
I already replied to the very similar comment that mshievitz left on my blog. But as this is a better place for this type of question, I'll delete that comment and my reply. This was my reply:

- If your horizontals are 500mm, then 300mm diameter is way too small for the bed. Your printable diameter is potentially about 450mm. I recommend making the bed about 30mm greater in diameter than the printable area and the heater diameter, so that you have room for bed supports and bed clips outside the heater and the printable area.

- Don’t waste your time trying to use DC power for this size of bed, go for AC mains power like I did.

- 43mm is IMO too narrow a spacing between the rods for a build of your size, I suggest between 1/5 and 1/7 of the rod length, for better rigidity and reduced sensitivity to build errors.

- I won’t comment on your choice of electronics as you probably know my views already.

- You can probably complete the printer with the parts you already have, then upgrade the bed, rod spacing, and if necessary the electronics.

If he has 500 horizontals, and can print up to about 450mm, what would his diagonals be?

I would need to work it out to be sure, but off the top of my head, about 500mm.

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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
3DRapidClone

Quote
dc42
I already replied to the very similar comment that mshievitz left on my blog. But as this is a better place for this type of question, I'll delete that comment and my reply. This was my reply:

- If your horizontals are 500mm, then 300mm diameter is way too small for the bed. Your printable diameter is potentially about 450mm. I recommend making the bed about 30mm greater in diameter than the printable area and the heater diameter, so that you have room for bed supports and bed clips outside the heater and the printable area.

- Don’t waste your time trying to use DC power for this size of bed, go for AC mains power like I did.

- 43mm is IMO too narrow a spacing between the rods for a build of your size, I suggest between 1/5 and 1/7 of the rod length, for better rigidity and reduced sensitivity to build errors.

- I won’t comment on your choice of electronics as you probably know my views already.

- You can probably complete the printer with the parts you already have, then upgrade the bed, rod spacing, and if necessary the electronics.

Just a bit on this Mine is a very similar size with 500 mm sides and my arms are 520 but I think they need to be shortened a little so I thinks Dave's estimate of 500 is pretty close.

Doug

If he has 500 horizontals, and can print up to about 450mm, what would his diagonals be?

I would need to work it out to be sure, but off the top of my head, about 500mm.

On my 500mm diagonals using the 25000 plates, the Onyx (310mm) bed aligned the mounting screws right on the slots in the diagonals. They may be thinking 300mm to keep the bed entirely inside the triangle. To get to 450mm I'd have to have the bed going outside the triangle by close to 70mm on each of the three sides. I can post a picture if it would help.

On a large delta build the circular part of the printable area does extend outside the frame, unless the carriages are unusually thick and/or the effector is unusually large (either will prevent the nozzle getting close to the towers and will therefore reduce the build radius).

Edited 1 time(s). Last edit at 12/14/2015 05:53PM 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].