Topic: Modified Solidoodle 2 Pro suffering Y-axis shift -- help!
Hi,
I have a heavily modified Solidoodle 2 Pro:
* Standard controller board (Sanguinololu) -- fitted with TI DRV8825 drivers and a 60mm 12V fan for cooling
* Keenovo silicone mat bed heater (the heater resistor was one of the first things to fail!)
* Horizontal filament spool mount on the back panel (Tarwin's -- https://www.thingiverse.com/thing:34284)
* Several Lawsy mods -- extended filament guide, XY carriage, cable chain
* E3D V6 extruder and Jigsaw (Mdroman/Wardjr/Lawsy version -- https://www.thingiverse.com/thing:431363) with carriage-mount part cooler fan
* Direct drive Y axis -- http://tomhorsley.com/hardware/solidood … irect.html
* GT2 belts throughout, 20 tooth gears
(This is just a summary -- there's a full list of mods on http://wiki.philpem.me.uk/3dprint/solid … ent_setup)
I was running at 250000 Baud for comms to the controller, but had a lot of "checksum error" messages and printing stalls (printing stopping dead mid print), so I've switched back to 115200.
I'm running 1/32 microstep on the TI drivers. Current for the X and Y axes is up against the motor limits (as defined by Vref at least).
Now, while this setup (on a good day) will produce lovely parts, with perfect circles where demanded, I have a problem where the Y axis will suddenly skip during printing. This is markedly worse when the filament spool (E3D ABS filament, 750g) is less than half full -- the E3D spools seem to be tighter towards the centre.
I've found that the Y axis still binds slightly at four points in its travel, but nothing I've done has helped with that (not even the linear bearings on the Lawsy XY carriage). The 6mm back rod is brand new (the original had rust spots).
Do the two pulleys which carry the Y belts need to be in a specific position (rotationally with respect of the grubscrews) to each other? The binding seems to line up with times when the Y-shaft is in a specific position. I can disconnect the motor shaft coupling and still have the same binding.
I'm at my wits end now... I have a printer which prints almost perfectly (at the cost of losing 15mm of Y travel for the part fan), but I can't leave it alone because half the time it
What should my next step be to fix this?
Reduce microstepping?
Increase Vref (motor current)? (I'm already up against the motor specs)
Different filament mount? (does a top mount put less stress on the carriage?)
Thanks
Phil