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Can Duet 2 do these things?

Posted by leadinglights 
Can Duet 2 do these things?
June 13, 2019 01:37PM
I am looking to replace the controller and firmware in an experimental 3D printer I have been working on for some years now. Previously I have purposely used an Arduino/Ramps setup running Repetier firmware: The reason for this is to so that anything I accomplish can be replicated at a low cost by others. Sadly, info from the Repetier forum or even on this forum when asking about Repetier firmware seems to be pretty much unavailable.

Having followed several threads and deckingman's blog about his wonderful multi-material printer I see that the spirit of experimentation has not died from the universe and I find myself willing to change horses mid-stream - albeit with some kicking and screaming. (Arduino/RAMPS should be good enough for a 200mm X 200mm X 150mm cartesian printer even with bells and whistles - but hey, pedestals are made to be toppled)

Before I spring for a Duet 2 Ethernet I need to find out if solutions to interfacing needs that I have either exist or if requests for these to be accomodated in future software have a chance of success.

Specifics:-
A piezo nozzle contact probe that I have been working on has two outputs: One occurs only if a clean contact has been made which meets several criteria; the second if a contact is made but does not meet these criteria - this will allow the nozzle to be lifted to avoid damaging the print surface. Is there anything already in the firmware to support this already? Since this also detects soft plastic on the nozzle tip it would be nice to have a way of re-probing several times until a good contact is found. Some details on [reprap.org]

A two headed printer mechanism with its own stepper controller. This needs one line to select one head or the other - say high would select the left hand head and low would select the right hand head. An output line would be raised during the change to signal the controller (Duet) not to feed filament. Will this need software or are there already M codes to do this?. Some details on [reprap.org] and a video on [www.youtube.com]

Minor bits:
Heated chamber. This exists only in experiments and CAD designs but consists of a chamber under which the build stage which moves in both X and Y. Requirement is similar to the print head change mechanism, 1 line to raise/lower the chamber and one tosignal when the move is complete. Some details on [reprap.org]

Vacuum hold down on build stage. This works very well but a way of stopping the print in the event of vacuum failure is needed. Video of the first one at [www.youtube.com] and latest one on the current machine at [reprap.org]

Thanks for any advice/info etc..

Mike
Re: Can Duet 2 do these things?
June 13, 2019 02:29PM
It sounds like you need a much quieter way to get a vacuum. I would think that the large surface area means you only need a couple PSI less than atmospheric pressure to achieve the hold-down. You could probably get that very quietly using a centrifugal blower with a brushless DC motor. With a BLDC, about the only way the vacuum would fail is if power failed, and your printer is going to stop anyway.

Here's a printable blower, using a motor from a hard disk drive, that might be able to do the job if you connected a hose to the input side instead of the output.


Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: Can Duet 2 do these things?
June 13, 2019 04:11PM
Quote
the_digital_dentist
It sounds like you need a much quieter way to get a vacuum. I would think that the large surface area means you only need a couple PSI less than atmospheric pressure to achieve the hold-down. You could probably get that very quietly using a centrifugal blower with a brushless DC motor. With a BLDC, about the only way the vacuum would fail is if power failed, and your printer is going to stop anyway.

Here's a printable blower, using a motor from a hard disk drive, that might be able to do the job if you connected a hose to the input side instead of the output.

Hi DD,
I do like your blower and may try it out for a near field cooling pump. For a vacuum I think it would not be strong enough - my original noisy pump pulled down to about 1/10 of atmospheric pressure but even the quiet cheap one [www.ebay.co.uk] does a creditable 1/2 atmosphere.

Mike
Re: Can Duet 2 do these things?
June 13, 2019 05:44PM
Quote
leadinglights
A piezo nozzle contact probe that I have been working on has two outputs: One occurs only if a clean contact has been made which meets several criteria; the second if a contact is made but does not meet these criteria - this will allow the nozzle to be lifted to avoid damaging the print surface. Is there anything already in the firmware to support this already? Since this also detects soft plastic on the nozzle tip it would be nice to have a way of re-probing several times until a good contact is found. Some details on [reprap.org]

That's not currently supported, but wouldn't be difficult to implement, and I would certainly consider implementing it.

Quote
leadinglights
A two headed printer mechanism with its own stepper controller. This needs one line to select one head or the other - say high would select the left hand head and low would select the right hand head. An output line would be raised during the change to signal the controller (Duet) not to feed filament. Will this need software or are there already M codes to do this?. Some details on [reprap.org] and a video on [www.youtube.com]

That should already be possible, by using the M577 command within the tool change files.

Quote
leadinglights
Heated chamber. This exists only in experiments and CAD designs but consists of a chamber under which the build stage which moves in both X and Y. Requirement is similar to the print head change mechanism, 1 line to raise/lower the chamber and one tosignal when the move is complete. Some details on [reprap.org]

Again, I think M577 meets this requirement.

Quote
leadinglights
Vacuum hold down on build stage. This works very well but a way of stopping the print in the event of vacuum failure is needed. Video of the first one at [www.youtube.com] and latest one on the current machine at [reprap.org]

You could use M581 to trigger a pause when a vacuum switch indicates loss of vacuum.

HTH David



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Can Duet 2 do these things?
June 14, 2019 05:54AM
Thanks David,
I will try to get the sensor controller hardware, software and specifications on Github in the near future so that exactly what is needed is clearer.

In the meanwhile, I have two more questions:

Does the duet have support for external I2C - may be helpful for reconfiguring/calibrating the Z sensor controller? If there is, is it 5V compatible?

Does the Duet support 20 chr X 4 line displays, again at 5V. This to postpone extra costs untill I have everything working.

Mike
Re: Can Duet 2 do these things?
June 14, 2019 06:38PM
Quote
leadinglights
Thanks David,
Does the duet have support for external I2C - may be helpful for reconfiguring/calibrating the Z sensor controller? If there is, is it 5V compatible?

It does have external I2C and supports the M260 and M261 commands. The signals levels are 3.3V. You can buy 3.3V to 5V bidirectional level shifters. Caution, I2C has no noise immunity, error detection or error recovery protocol, and should not be used over distances of more than a few cm.

Quote
leadinglights
Does the Duet support 20 chr X 4 line displays, again at 5V. This to postpone extra costs untill I have everything working.

No. The Duet Maestro supports both RepRapDiscount-style 12864 displays and PanelDue colour touch screens. The Duet WiFi and Ethernet support PanelDue only. But most Duet users don't use a display at all because the web interface used on a PC, tablet or smartphone (or all 3 at once) is so powerful.

Edited 3 time(s). Last edit at 06/15/2019 04:28PM by dc42.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Can Duet 2 do these things?
June 15, 2019 07:28AM
Thanks for the info David, however it does make it unlikely that I will be using the Duet 2 as the time to make the necessary mods is too great a commitment when taken with other constraints - like already having to make an all new enclosure to hold the Duet 2. Picture below to show that even the RAMPS is cramped.



If I pick up a delayed high temperature Delta printer I will almost certainly use a Duet there.

Mike
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