https://hackaday.com/2020/06/13/rip-danal-estes-developer-of-multitool-3d-printing-infrastructure

What about just putting an index in front of the fan currently used as tool fan?

I uploaded a short video showing this print:

https://vimeo.com/357503565

An alternative would be to continuously extrude a tiny amount of filament on parked heads…

We (at LOG hackerspace) designed such dual extruder using one motor. It is not driven by a Duet, but it should work.

Here is our design: https://wiki.logre.eu/index.php/DondoLOG based on this one: https://www.thingiverse.com/thing:673816 (we changed a lot of things, leading to a much more simple geometry).

Onshape designs are here: Mine¹: https://cad.onshape.com/documents/ab5e4a91e08de464a68c8fa9/w/d1a6bf327030002f2355aebe/e/4fc76c1855ace35a39166ba3 (using aluminium plates) and a derivated, made by a friend: https://cad.onshape.com/documents/44cc3aa0e2de59f4440a6e4b/w/58c86854d8b2aa8e76983bb9/e/82ef35419fb25e023c2c8b7d (using PMMA 6mm).

Feel free to ask if you want more details. Note that the second design is now working (see https://piwigo.logre.eu/picture.php?/1139, https://piwigo.logre.eu/picture.php?/1239 and https://piwigo.logre.eu/picture.php?/1286); I never tested mine...

¹ my design means to me, as it is my very first usage of Onshape (and first time I ever used a parametric CAD software).

David, could it be possible to change the revision numbering and the way releases are managed?

I suggested in another thread to use a.b.c: 'a' for major release (3, here), 'b' for minor release (0, here), and 'c' for bug fixes.

Currently, installing a new release for bugs fix introduces new features, so potentially new bugs: this is not a good thing. One should be able to dissociate bugs fix and new features...

So, after the current release, which should be named 3.0.0, the next one should be named 3.1.0 (not 3.01). And bugs fix should go into 3.0.x (then in 3.1.x...)

Thanks.

Here is a very simple Python script to implement Ian's idea:

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys

for line in sys.stdin:

    # Replace tool changing commands by part changing tags
    if line.startswith('T'):
        num = int(line[1:])
        print "; part %d\n; process %d" % (num, num)

    else:
        args = line.split()

        # Only keep tool 0 temperature commands
        if line.startswith('M104') or line.startswith('M109'):
            args = line.split()
            num = int(args[2][1:])
            if num == 0:
                print line,

        # Default commands
        else:
            print line,

It replaces tool changing commands:

Tn

by:

; part n
; process n

It also remove all temperature commands of tools >= 1.

To use it:

$ ./tool_parser.py <input.gcode >output.gcode

PS: I only checked Slic3r output; Cura output may need additional stuff.

M260 can send data over I²C bus:

https://duet3d.dozuki.com/Wiki/Gcode#Section_M260_i2c_Send_and_or_request_Data

On the I²C slave, just mimic some registers you will write from Duet to take the actions you need.

I recently developped a project using an ATtiny841 as I²C slave (this chip as a hardware I²C slave implementation), working this way. See:

https://framagit.org/fma38/Servo_Node

This is for an hexapod (I will use 6 of them, to control the 4 servos of each leg). But I will certainly use this chip for other projects, like here.

Code in Arduino/ dir is a master example; the real master will be a RPi, running my framework Py4bot: https://framagit.org/fma38/Py4bot

I'm also working on such filament mux, with multiple tools using the same heater, and I didn't have this problem. Could you share your tfree macro, and tell us what commands are skipped?

Hi!

I plan to use 2 fans to cool down the drivers, as my Duetwifi/x5 will be in a box.

Is it possible to create a thermostatic fan, routed to a specific thermistor, without any heater? If not, how should I create a dummy heater for that?

Thanks,

@zapta Yes, it would be nice!

But I guess it would require some custom code on the Duet? Or maybe add some in-between electronic, to convert datas...

Hi!

I just bought a used FLSUN SR, as I have not enough time to work on my CoreXY (this will be for later), and I always wanted to try a Delta

I plan to replace the electronic with a Duet 3 Mini 5+, and put a direct-drive extruder.

Did anyone already make such changes? Any advice?

Thanks,

Nice! I found on some datasheets that a ribbon cables can handle up to 1A, in free air. So, yes, using 2 wires for the power supply should be ok.

What current can handle a standard (28AWG?) ribbon cable?

@dc42 Thanks! I didn't think of twisted cables, it seems the best option.

Hi!

I'm thinking to use a flat ribbon cable to wire the carriage, making a vertical loop above it; any experience with such config, from a mechanical point of view?

I only need power and CAN, as I will use a Toolboard 1LC. For the power, I plan to connect several wires in // to handle the current. For CAN, I don't know if it requires special handling regarding to perturbations: is alternating signal/ground enough? Or should I use a shielded ribbon cable?

Thanks.

@mikeabuilder Amazing, I also have a continuous belt, which turns around a free pulley on the carriage, which I then secure with a screw, to get 2 independant belts!

@mikeabuilder Good point!

@mikeabuilder said in Number of teeth engaged:

Since you are designing, some other things I decided to do that you might consider. My motors are also at the rear corners.

1. Make your idler pulleys from two flanged bearings (I used F606ZZ pulleys with a 10mm belt, which allow a 6mm screw through the hub).

Is it better than Gates idlers?

2. 10mm belt - the costs are not much more and you get much less stretch.

This is something I have in mind for a while. My current printer uses 3GT 9mm Gates belts, as I used gears and linear rods/bushing (16mm!!!) from an old Stratasys printer.

So, when I now see 2GT 6mm belts, they look like toys...

3. Twisted belt configuration. At the back of the machine, where the upper and lower belts cross, if each belt is given a 180 degree twist in that segment, the upper and lower belts can be moved closer together vertically. The center of my upper belt pulley is only 3mm higher than the center of my lower belt pulley. My tallest standoff for any pulley is 3mm. I don't worry about the hubs bending. People will say bad things about twisted belts. I've been running this printer for several months without any issues.

Funny, because my current printer uses the same twisted belts config as yours, with the 180° rotation! I designed a special part, holding a piece of PTFE between the belts, to reduce friction... It works very well for more than 3 years.

4. The only two places that the belts need to be parallel are the segments that connect to moving pulleys - those that move the gantry, and the segments that move the printhead on the gantry.

Yep.

5. If you have access to a laser cutter, I recommend prototyping the corner plates in mdf. I did this and it helped me see several issues that I solved before paying for aluminum. And if you are in the US, check out SendCutSend.com (no affiliation, just a satisfied customer) for inexpensive laser cut aluminum.

I do have access to a laser cutter, and I plan to prototype the entire machine in wood, and also in PMMA as some parts need to be bent. And I will have access to a waterjet cutter for the final parts

Picture of the finished printer without the enclosure:

Nice! Feels solid as a rock! I understand you're not concerned by bending issues!

Thanks for your advices.

@mrehorstdmd said in Number of teeth engaged:

@fma The minimum pulley configuration for corexy is 5per belt including the drive pulley. Every pulley you add increases the load on the motors. If one of your goals is to print fast, you might want to reconsider the belt and pulley arrangement.

I have 6 pulleys, but I don't plan to print fast...

Are you aware that the working segments of the belts need to be kept parallel to the guide rails for the X and Y axes?

Yes, sure! No problem, these segments are perfectly // to the rails.