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My Icepick-delta is up and running

A project log for Icepick Delta

A highly experimental open-source 3D printer with a rock bottom bill of materials

TTNTTN 11/30/2014 at 05:514 Comments

I got it running! With the help of this link and this link,

I managed to figure out how to change the firmware to deal with the non linearity of this type of delta (my fork of marlin on github). I haven't yet got bed leveling working, but it doesn't seem to be working on the normal marlin firmware either.

So far it prints very nicely at low speeds (30 mm/s, 0.1 mm layer height, pla, 0.5 mm nozzle, 3000 acceleration set in firmware) EDIT: Looking back it wasn't actually doing 200mm/sec, as the arduino couldn't calculate the moves fast enough.

At higher speeds the limitations of the design become apparent ( 200mm/s, 0.2 mm layer height, pla, 0.5 mm nozzle, 3000 acceleration set in firmware)

EDIT: Looking back it wasn't actually doing 200mm/sec, as the arduino couldn't calculate the moves fast enough.

The ratio between the steppers and the upper arms is 1:14. Ideally it would be in 1 to 20 - 50 range. As long as the machine runs slow and the microstepping can really make its effects apparent. I wouldn't say that there's any fatal design faults in the icepick, but that 1:14 ratio is a bit of a snag. I have some ideas about using braided fishing line and some very small pulleys, if used, the big pulleys could be much thinner. Another alternative may be to increase the size of the main pulley, and cut off a piece off the bottom which isn't required, but increasing the pulleys may make the design a bit too bulky.

Ideas are welcome! Leave them in the comments below :)


Discussions

3dreplicator wrote 01/21/2015 at 14:06 point

Hello! What might be the disadvantages of the use of reducer, such as this:

http://www.thingiverse.com/thing:8460

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TTN wrote 01/21/2015 at 18:30 point

Mainly backlash, I think the slop in the drive will increase as it gets used more and more. And at the moment I'm happy just getting it running as it is as my todo list is a bit long. I still want to try one out at some stage.

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Bonapartista wrote 01/02/2015 at 08:52 point

I was also anoyed with small gear ratio and microstepping. So i decided on doing it little differently. Goal was to work with half steps or at least 1/4 steps for smoother stepping and to keep as much torque as possible. Instead of pulleys and gears I'm using fine pitch screw 0.35mm which means for every half step i get 0.8um movement of arm. Since i make hifi screws and nuts for laser industry i can make it near zero backlash or make a 0 backlash nut. I'm going for precision since i'll do it with laser. But can't figure out how to make your firmware work with replicatorg or any other host. Did you use replicatorg?

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TTN wrote 01/21/2015 at 18:45 point

Sorry for not replying earlier, I must have missed the notification.

I've been using Marlin up till now, but getting Repetier working at some point is on the todo list. I've got a modded version of the firmware here: https://github.com/TTN-/Marlin/tree/Marlin_v1 I'm using Pronterface as the host on the pc. So far I've been running on a Ramps 1.4 board, A4988 stepper drivers with 16x stepping.

But if your arms are moved in a linear motion by the screws, (if I'm picturing it correctly) the math isn't going to work on it, as the math assumes that for every step, the arms will move x distance no matter what position the arm is in, it always moves the same distance, which wouldn't be the case if it was setup similar to this, screw rod wise:

http://reprap.org/mediawiki/images/thumb/8/89/Trap_concept_1.jpg/475px-Trap_concept_1.jpg

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