Large Format Dowell to Duet conversion
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Hi there I was wondering if someone can help me please - I have a really big (120018501600 xyz) printer from Dowell 3D in China (http://www.dowell3d.cn) which I am using to print the biocomposites we have developed into outdoor construction panels to make our ‘Green Camp System’ - basically 3D printing ecovillages from sunshine. Scroll to the bottom of the home page for journal entries about the development of the 3D printer and prototyping thus far: www.create.green
I replaced one of the two filament extruders that came with the printer with a Lily Pellet Extruder ( https://www.recycl3dprint.com/support/documentation ) that was working fine but I have burnt out two of the custom Dowell Motherboards that run custom Dowell firmware.
It is very frustrating that as soon as I get the printer working the mobo burns out and there is basically ZERO support from China and ZERO doccumentation that comes with the printer. Basic things like auto PID tuning do not exist and it is time to switch electronics provider!
The gantry is a good system with four independent z axis motors that actively move as the print is printing to keep the bed level which means there is pretty complex wiring but we think we can do without this feature as I’m printing large panels with a 3mm nozzle but if you have any ideas how we can include that I would be very grateful. The microstepper controller for these larger stepper motors is Microstep driver 9-42v. But as you can see from the attached picture it doesnt have a model number on the front.
The XY gantry motors are larger: (XY gantry motors 57cm23 https://leadshineindia.com/products/leadshine-hybrid-stepper-motor-57cm23 ) and there is one for x movement and one for Y. The microstepper controller for these larger stepper motors is Rtelligent Microstep driver Dm542.
Would the Duet 3 Mainboard allow us to drive these x, y and 4x Z stepper motors without the microstepper drivers or would we still need to use the microstepper motors? I have read the specs and it says the Trinamic drivers have a microstep function that is quite high. Would we even need the extra microstepper drivers? Maybe for the large x y motors as these are 5A?
We also need a driver for the extruder which is a total of 7 stepper drivers and I note the new Duet 3 main board only has 6. Would an extension board allow us to have additional drivers simply working with marlin firmware?
Also can we run an auto mesh-level function on reprap please?
Hope to hear back from you so we can buy both the mainboard and the extension soon.
Many thanks
Charles
p.s: Since time of writing this I have now ordered the Duet 3 Main Board and will buy the expansion when I can afford it next month.
Attachment(s)
Pic of the microstepper driver without any part name on it -
@charles-fraser thank you for choosing Duet 3.
You should be able to run those XY motors directly from the Duet 3 main board. For the extruder, you can either use one of the drivers on a EXP3HC expansion board and drive the extruder motor directly, or you could use a EXP1XD board to connect the existing driver to. If you do that then the firmware will not be able to control the extruder current (except to turn it on/off) so that current would still be fixed at the value you select on the driver.
Yes you can do mesh bed compensation, if your machine has a suitable Z probe.
Duet WiFi hardware designer and firmware engineer
Please do not ask me for Duet support via PM or email, use the forum
http://www.escher3d.com, https://miscsolutions.wordpress.com -
@charles-fraser I think you could upgrade that printer with a Duet 3 MB6HC, it can surely drive that Pellet Extruder (80W AFAICS) and those NEMA23 motors without extra stepper drivers. The stepper drivers on the MB6HC can drive stepper motors up to 6.3A but you'll have to cool them if you go anywhere near that range (> 3.8A). Mesh-level compensation is supported as well.
Duet software engineer
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@dc42 thanks so much for the feedback. Just to clarify: if I use either of the expansion boards I can’t change the Amps on the pellet extruder motor? How do these drivers change the speed of the motor then? My assumption is that to increase or decrease speed the driver is varying a signal that varies both volts and amps? Or does it just vary the speed of the pulses? I’ll order the larger of the two expansion decks as we might add an additional extruder to add a flexible material as a sealant material one day.
Many thanks!
Charles
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@chrishamm great info! Thank you so much. I will defo run a very powerful fan over the mobo and expansion board. Do you know of a suitable model that will plug into the board please? Many thanks again, Charles
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@charles-fraser said in Large Format Dowell to Duet conversion:
it just vary the speed of the pulses?
Basically, yes. The current setting would be done on the external driver itself if you chose to continue to use it. The current would basically determine the amount of torque the motor has, but it's also put in balance with heat generated by the motor and the amount of back emf that gets generated at high speeds. It's a complex thing.
For motors that are directly connected to the Duet you can set the current in software. That's the main difference that we're pointing at. For external drivers the Duet has less control over what they do.
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The best fan for cooling would depend a bit on your electronics enclosure. If you have the space, a 120mm Noctua fan blowing at the edge of the board so it can blow across front and back would be a good option.
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@charles-fraser said in Large Format Dowell to Duet conversion:
@dc42 thanks so much for the feedback. Just to clarify: if I use either of the expansion boards I can’t change the Amps on the pellet extruder motor?
If you use the EXP3HC expansion board to drive the extruder then you will be able to adjust the current from the software. If you use the EXP1HC and the existing microstepping driver then the current will be controlled by the switches on the driver as it is now.
Duet WiFi hardware designer and firmware engineer
Please do not ask me for Duet support via PM or email, use the forum
http://www.escher3d.com, https://miscsolutions.wordpress.com -
@phaedrux cooli I use noctua on my threadripper, thanks
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@dc42 thank you! I guess it would be best not to use the external stepper motors then
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Hi dear @dc42 & @chrishamm @Phaedrux
The Duet 3 mainboard and 3-E-3HC expansion board have now arrived. I have begun labelling the wires of this massive printer and have crimpped together the connectors for the motors: 4X Nema 17 (z axis) and 2X Nema 23 (X and Y axis).
I am going to use the expansion board to drive the nema 17 motor for the pellet extruder. I will also get the daughterboard that can handle the K-type thermocouples as that is what both the extruder and the bed use. Q1: Can the daughter board manage 2X thermocouple please?
I have the extruder on a mosfet that takes the load from the PSU directly to increase efficiency.
I also have the massive mattress sized bed on a relay that when banged (bangbang mode) opens a gate that powers the bed directly from the mains supply. That thing is a beast and we had to build a special power supply from the mains because it would melt all my plug sockets on the wall.
My main question is: what kind of power supply unit do I need to provide enough power for all of this? I am looking for a 1000w supply and can’t seem to work out if my current PSU is fit for the task. Also it goes through this little relay that takes power frolm the mains and routes it to the psu, the bed relay, the on-off switch and two inputs to the board. I provide pics below. Please could you advise me on how to wire all this together and if I should get a new more powerful or different psu. It says 24V on it but no 12V and the Duet 3 says 12V on it. But does the little on off relay transform that somehow. I cant work it out. I have supplied more pics below
Many thanks,
Charles
From 12 o'clock clockwise around that is On off switch (yellow, blue, brown), Mains Power (brown blue (the earth is connected to the frame of the printer - is this safe?), then power to the PSU (blue brown), then 5v in brown blue, then signal blue brown. Where should all these go in the board please?
p.s: Once I work it out I will print this new housing with the fans and higher risers for the boards. I have those ordered.
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@charles-fraser said in Large Format Dowell to Duet conversion:
Q1: Can the daughter board manage 2X thermocouple please?
Yes, each daughter board handles 2 thermocouples. Keep the thermocouple wires away from stepper motor cables, or else shield them.
@charles-fraser said in Large Format Dowell to Duet conversion:
My main question is: what kind of power supply unit do I need to provide enough power for all of this? I am looking for a 1000w supply and can’t seem to work out if my current PSU is fit for the task.
As you are using a mains- voltage bed heater, the PSU need to power only the Duet itself (which needs very little power), the stepper motors, and any low-voltage heaters. Do the pellet extruder heaters work from low voltage, or from mains power via a SSR? I can see one SSR in your photo: does it control the bed heater or the pellet extruder heater(s)?
The Duet 2 is usually run from 24V. The 12V marking you can see on it is probably by the voltage selection jumper for low-current OUT ports, or for the auxiliary 12V output.
I can guess at the reason for one of the two blue relays (to latch power to the PSU), but not the other one. Can you trace a schematic of the relay board?
Duet WiFi hardware designer and firmware engineer
Please do not ask me for Duet support via PM or email, use the forum
http://www.escher3d.com, https://miscsolutions.wordpress.com -
@dc42 Hi there, thanks so much for your reponse.
Both the extruder heater (80w) and heated beds are on an extermal mosfet and relay as indicated in the attached schematic.
I have drawn up the wiring I have managed to put together so far with little green questions marks where I don't know where to put those wires or have some questions. Any advice would be super appreciated. Many thanks, Charles
schematic attached
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For the bed heater the inputs of the SSR would come from a heater output on the Duet3. Since the SSR uses a low voltage signal input, it doesn't matter so much which heater out put on the Duet3 you use. There is a high power heater output (out_0) in the covered screw down terminals that would normally be used for a high powered heater, but you could use a regular output like Out_1 as well.
The thermocouple board would go onto the Duet3 itself.
https://duet3d.dozuki.com/Wiki/Thermocouple_daughter_board
https://duet3d.dozuki.com/Wiki/Connecting_thermocouplesYou should also reference the wiring diagram, getting started guide for duet3, and the duet3 hardware overview.
https://duet3d.dozuki.com/Wiki/Duet_3_Mainboard_6HC_Wiring_Diagram
https://duet3d.dozuki.com/Wiki/Getting_Started_With_Duet_3#main
https://duet3d.dozuki.com/Wiki/Duet_3_Mainboard_6HC_Hardware_OverviewFor the protective earth connection, it should be going to your PSU as well. Connecting the metalwork of the frame is also a good idea in the off chance that a high voltage connection makes contact with it. Keeping the high voltage wires isolated and protected is also a must.
See what other questions you have left after reviewing those documents.
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Thank you so much. I will have a look again. If you could please quickly explain where to connect the 5v in and signal connector to that little on off relay that would really help. Thanks again! Charles
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@charles-fraser The power supply is 350W as stated in the name LRS-Wattage-Voltage. You can also calculate the wattage by multiplying the output voltage (24V) by the amperage (14.6A). It should be more than adequate to drive the Duet 3 MB6HC mainboard and a (number of) expansion board(s).
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@charles-fraser said in Large Format Dowell to Duet conversion:
X & y end stop, is this wiring correct:
I'll try and direct you to existing documentation as much as possible.
https://duet3d.dozuki.com/Wiki/Connecting_endstop_switches
Duet 3: connect the switch between the IN and GND pins of your chosen IO_x connector.
Can I assume these are normal microswitches? It looks like you've connected the endstops to 3.3v and GND. The red wire needs to move down one spot to the
IO_#.inpin.@charles-fraser said in Large Format Dowell to Duet conversion:
The ‘3D Touch v3.0’ z probe (cheap version of BL touch) has an extra ground I don’t know what to do with.
Some people leave it disconnected, some people daisy chain it to the existing ground at the bltouch, some run an entirely separate wire for it and connect both grounds to the same pin on the board.
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@phaedrux I thank you
I will check / change all that. Yes they are just simple end stops. Only two wires coming from them.
The thing I really cant work out is how to wire the on-off switch relay board as per the question marks that come off the wires coming out to the left of that relay board in my “schematic” above. It needs a 5V in and a signal input from the duet. Please advise!
Sorry about all the questions just the best I have made before is some resonant LED circuits and a PC.
Many thanks
Charles -
@charles-fraser said in Large Format Dowell to Duet conversion:
It needs a 5V in and a signal input from the duet.
I'm not super savvy when it comes to relays etc but I think what you want is an external 5v supply for the relay to power it, and then the signal would be coming from the duet using the PS_on function M80/M81 see here: https://duet3d.dozuki.com/Wiki/Power_Wiring
Where does the current printer get the 5v for the relay from?
@charles-fraser said in Large Format Dowell to Duet conversion:
Sorry about all the questions just the best I have made before is some resonant LED circuits and a PC.
Nothing like diving into the deep end.
.