General Questions - Large Format Printer
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Greetings,
I am in the process of building a very large format 3D printer (1,800mm X 1,800mm). I am looking for some advice to see if the Duet 3 is a good choice for my controller. I am completely new to this hardware, could anyone help know if this is suitable?
Extruder (Two Stepper Motors)
- Two Bondetch QR-M Extruders (https://www.bondtech.se/product/qr-m-extruder/)
- Mosquito Magnum+ Liquid Cool (https://www.sliceengineering.com/products/mosquito-magnum-plus-liquid-1-75?variant=43671175397617)
- RTD Pt1000 thermistor
- Two 50 Watt heaters
X,Y,Z Motors (3 Servo Motors, 4 Stepper)
- Y Axis (2 Step/Dir Servo Motors)
- X Axis (1 Step/Dir Servo Motors)
- Z Axis (4 Stepper Motors - Slaved together, all corners of 1,800mm stage have a lead screw)
- 7 Limit switches (4-Z, 2-Y, 1-X)
I am planning on using CURA as a slicer. Does my configuration seem to be outside of the bounds of what the Duet 3 can handle? I would really appreciate board recommendations.
Thanks!!
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@Snyggis Duet 3 will handle that; it was designed with CAN FD expansion specifically for this kind of machine. It can be achieved in a number of different ways; it depend on how far apart motors and other inputs/outputs are, and how easy you want to make the cabling. See here for a list of current Duet 3 boards, mentioned below: https://docs.duet3d.com/en/Duet3D_hardware/Duet_3_family
I'd probably recommend using a Duet 3 Mainboard 6HC as the main controller, and connect the Z motors directly to it. For the extruders, 2x Duet 3 Toolboard 1LC would be suitable. For X and Y motors you could use either 3x Duet 3 Expansion 1XD boards, or, If you haven't already bought the motors, you could use 3x Duet 3 1HCL boards with large stepper drivers for closed loop control. These are more tightly integrated into the Duet Ecosystem than external servo drivers would be.
There are various other combinations you can use, for example using a Duet 3 mainboard 6XD as the main controller, driving the X and Y external servos, and use a Duet 3 Mini 5+ to drive the Z motors if they are not too big. If you are going to slave all 4 Z motors together and use an external driver, this could connect to the 6XD directly. If the extruder is one block with two extruders, you could use a Duet 3 3HC rather than the toolboards, for more current capacity and input/outputs.
All the boards can be located close to the motors, and only need to be supplied with power and CAN FD, to communicate with the main controller. This greatly simplifies wiring on large machines, and the risk of interference and cable losses.
Ian
TronXY X5S with Duet 3 MB6HC and Roto toolboard : Cartesian bed-slinger with Duet 3 Mini 5+ WiFi and 1LC : RRP Fisher Delta v1 with Duet 2 Maestro : Polargraph with Duet 2 WiFi
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Thank you for the great advice.. I have been reading through the documentation much more and am getting a better handle on things.
Is there a reason why I wouldn't just use the 6XD for the 4 Z motors, and use the two extras for the two extruder steppers? I did purchase the servos already - they are ClearPath all in one motors. Seems like I would need three 1XD boards to run these. Do you know if I can use the fault output on the servo to stop the machine through the 1XD board?
Can you help me understand the benefits of using boards close to the motors? Each board needs CAN distributed to it. This is CAT5 cable, right? Also whatever power the motor needs. Is that typically easier than distributing the cable for motor power or potentially encoders?
My bed heater is also going to be very big, probably running off 220V. Would it make sense to use one of the thermistor inputs on the 6XD, set it up to run PID control, and use the DC control output to drive an AC solid state relay?
Scott
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@Snyggis-0 the 6XD is for driving external motor drivers, not stepper motors. To drive stepper motors, use a 6HC. You could use one 6HC to drive the four Z stepper motors and the two extruder stepper motors.
To drive the three servos you can use either three 1XD expansion boards or three of the outputs on a 6XD. The 1XD is limited to about 100k step pulses/second whereas the 6XD can manage around 500k/sec subject to the timing requirements of the external drivers.
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@Snyggis-0 said in General Questions - Large Format Printer:
Is there a reason why I wouldn't just use the 6XD for the 4 Z motors, and use the two extras for the two extruder steppers?
The 6XD only has external driver connections; it can’t drive the Z steppers directly, as it has no onboard stepper drivers. For the same reason you can’t run the extruder drives from it. The 6HC has 6x stepper drivers, so you can connect 4x Z motors and 2x extruders to that. However, using CAN toolboards for the extruders will save a huge amount of wiring; it’s not just the extruder motors, but the heaters, fans, temperature sensors, endstops, filament monitors etc that can connect to the toolboard rather than be wired all the way back to the main controller.
I did purchase the servos already - they are ClearPath all in one motors. Seems like I would need three 1XD boards to run these. Do you know if I can use the fault output on the servo to stop the machine through the 1XD board?
Yes, you can configure an input on the 1XD for fault/alarm, as well as connect endstops and monitor motor temperature. See https://docs.duet3d.com/en/Duet3D_hardware/Duet_3_family/Duet_3_Expansion_1XD#configuration-examples
Can you help me understand the benefits of using boards close to the motors? Each board needs CAN distributed to it. This is CAT5 cable, right? Also whatever power the motor needs. Is that typically easier than distributing the cable for motor power or potentially encoders?
For can cable recommendations, see https://docs.duet3d.com/en/User_manual/Machine_configuration/CAN_connection
Generally, CAN cabling reduces cabling cost and complexity. It can also help reduce problems with interference and voltage/signal losses that can happen with long cable runs. Finally, it’s easier to change out components, without having to rip the whole machine apart each time to rewire. I’m sure there are other benefits, too!My bed heater is also going to be very big, probably running off 220V. Would it make sense to use one of the thermistor inputs on the 6XD, set it up to run PID control, and use the DC control output to drive an AC solid state relay?
Yes, you can’t run 220V through the Duet, so using an SSR is necessary for mains beds. See https://docs.duet3d.com/en/User_manual/Connecting_hardware/Heaters_bed
Ian
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I can understand using Servo motors for the Y-axes. Because they have to boss around a big cross beam.
But why for the X-axis? Ist the toolhead so heavy? I'm sure, a simple NEMA17 is strong enough to move a dual toolhead around.I'd consider using servos for the bed, if that's what moves in Z-direction...
