Itty Bitty Double Extruder

[clough42]

The power board discussion likely warrants it's own thread. If this is for the community, consider posting a schematic and proposed layout for review.

Of course, not everyone will want to use an ATX supply.

Agreed. I derailed my own thread.

Back to the Itty Bitty Double Extruder: Has anyone besides RobH2 gotten this up and running yet? Any problems printing any of the parts?

[TopJimmyCooks]

I'm thinking about switching to ATX since so many accessories need 5V now. I don't like that it doesn't fit as well on the frame of the printer, and they are a lot more expensive. Especially if you spring for one with the nice modular cabling. In the meantime I'm going to try running an RC Battery eliminator if I pick up anything else that needs 5V.

I'm considering trying a heated enclosure, because i need it for fume extraction at a minimum. I get headaches if I'm near the printer when it's going. If I do that it will be a good excuse to move the meanwell 12V supply to that and get something new for the printer.

[bobe99]

I just created a fork and branch of Marlin with my firmware changes: https://github.com/clough42/Marlin/t...v_double_bitty

This is a fork of Beckdac's fork of Marlin, which contains Roxy's auto-bed-leveling code.

It's a work in progress, so you should expect changes.

I only modified two files:

• Configuration.h: https://raw.githubusercontent.com/cl...onfiguration.h
• Configuration_adv.h: https://raw.githubusercontent.com/cl...guration_adv.h

You will likely need to tweak the servo endpoints and the Z probe offset.

Right now, I'm doing the extruder offsets in Slic3r, so it isn't set up in Marlin. RobH2 has played more with the Marlin side and may have some input here.

The changes I see which are specific the dual extruder (ABL support ignored) are in Configuration.h:
#define MOTHERBOARD 34
#define EXTRUDERS 2
#define TEMP_SENSOR_0 1
#define TEMP_SENSOR_1 1
#define HEATER_0_MAXTEMP 280
#define HEATER_1_MAXTEMP 280
#define DEFAULT_AXIS_STEPS_PER_UNIT {80, 80, 4000, 644.2}

I saw a change in Configuration_adv.h, but I'm not sure if it's extruder related (?):
#define DEFAULT_STEPPER_DEACTIVE_TIME 150 // Makerfarm default was 60

[Stuartknight1]

I'd definitely be interested in a full kit at some point, but at the moment I'm still getting to grips with my basic 10" i3V

[AbuMaia]

I saw a change in Configuration_adv.h, but I'm not sure if it's extruder related (?):
#define DEFAULT_STEPPER_DEACTIVE_TIME 150 // Makerfarm default was 60

That's to keep the X and Y steppers from deactivating during a G28 after a tall print. It can take the Z axis more than a minute to home, and if any of the steppers deactivate, that stepper's "home" info is lost, and a subsequent G29 Auto Bed Leveling will fail.

[TechMasterJoe]

That's to keep the X and Y steppers from deactivating during a G28 after a tall print. It can take the Z axis more than a minute to home, and if any of the steppers deactivate, that stepper's "home" info is lost, and a subsequent G29 Auto Bed Leveling will fail.

so when you get setup max your Z hit home z and a stop watch then set DEFAULT_STEPPER_DEACTIVE_TIME
to the the stop watch + say 15 to 30 sec just to be safe
sounds like a good idea
i plan on doing something like this http://youtu.be/jguPioUpYtc?list=UU9...nutKg06BitOByg
as well

waiting on http://www.stamps.com/shipstatus/sub...99561698334613 (extra hexagon 1.75mm hotend)
plus belts from mcmaster

on a side note (as posted on thingiverse)
I'm using a custom built SMPS yes designed and built by me a long time ago (about 6 years now)
for more then a few reasons witch i wont get in to mostly because i have it and i can run it at just about any voltage i want

[AbuMaia]

so when you get setup max your Z hit home z and a stop watch then set DEFAULT_STEPPER_DEACTIVE_TIME
to the the stop watch + say 15 to 30 sec just to be safe
sounds like a good idea

That's exactly what I did.

[printbus]

...It can take the Z axis more than a minute to home...

I think the numbers are far worse than that. The stock HOMING_FEEDRATE is set to 50 mm/minute, so an 8-inch printer will take four minutes to home full scale 200mm in Z, up to six minutes for 300mm on the 12-inch. I've previously doubled the HOMING_FEEDRATE to 100mm/min, and just timed full-scale Z home to still take 2 minutes 5 seconds on my 8-inch printer to validate the data. I've tested higher Z feed rates, but I found my Z-motors get pretty skippy at just over Z travel rates of about 2.5 mm/sec. I've left the DEFAULT_MAX_FEEDRATE for Z at 2 mm/sec in order to ensure margin. I could probably get by with a Z HOMING_RATE of 120mm/min to match the 2mm/sec max feedrate.

Yes, doubling the HOMING_FEEDRATE also doubles the rate used where the Z motors are moving slower for the more accurate part of the homing. I haven't seen any issues with this on my non-ABL printer. If I had, it wouldn't be hard to refactor the firmware ratio for the slower part of the movement. Making adjustments in ABL firmware would be a bit more complicated since the HOMING_FEEDRATE factors into a lot more movements for ABL.

I'm starting to think that especially the larger printers are screaming for a retrofit of 8mm ACME lead screws instead of the M5 threaded rods. At 2mm pitch vs 0.8mm pitch for M5 rods, the Z feed rate should be able to go up by a factor of 2.5 with the ACME screws.

Apologies to clough42 for continuing the sidebar discussion.

[lemming]

Hi

I'm guessing the gears should be printed in PLA.

Should the rest be done in ABS or PLA

[TopJimmyCooks]

Generally anything near the hotend should be ABS rather than PLA. So the fan shroud, x carriage plate, main block and the double groove mount plate should be run in filament able to withstand higher temps. I printed the rest in PLA.