I’ve now built a Root CNC 3 Lite for my Dad. The actual build has been completed, all that remains now is to complete the wiring of the board (we’re using a duet 2 wifi) and setting up of the config.

At some point, I intend to visit a couple of the parts and maybe even look at producing a better 3D model of it. A word of warning, the fasteners list is not correct so don’t follow it too closely.

I will post some videos once its up and running. For now, you just get a picture.

I was asked to produce updated config files for the Anycubic Predator which has been upgraded to a duet 2 board running the latest RC of RRF3.

I have uploaded my files to github and they can be found here. This is for a setup where a smart effector has been fitted. There won’t be too much to change for a stock predator if you wanted to get it to work.

Just a quick short update about the corexy. The little motor I was planning to use for the toolchanging mechanism just didn’t have enough torque.

I have now moved to a mechanism inspired by the Jubilee printer. I’ve remixed it slightly and used bike brake cables instead and my own design of parts.

Above is just a short video showing it able to lock and unlock a tool.

I’m pretty much stuck now until my expansion board comes.

It lives …. kinda.

I have it moving in X and Y. The belts haven’t been tightened correctly yet and I had to add some additional strength to a couple of parts but all in all I am happy so far.

Still waiting on the following:

  • Bed
  • Lead Screws
  • Couplers
  • Duet 3 Expansion Board
  • Locking Pin – I am making this myself

As part of my CoreXY Toolchanging build, I need a number of extruders. I wanted to explore the different options available. As great as the E3D Hemera looks, I can’t justify the Ā£108 cost per extruder (and for my CoreXY I need 6) when I wouldn’t need all the added benefits for every extruder.

I had a look around on my favourite source of parts (Aliexpress) and found the Mellow BMG Extruder. I’ve had my eye on Mellow branded items for a while now as they seem to be up and coming in the cheap knockoff world. They have even cloned the Mosquito Hot End, which so far seems to be reviewing well and at some point I may well order one.

I ordered the Set 2, which comes with the extruder and the motor. Everything came nicely wrapped in a polystyrene box. The main body is injection moulded, as is the larger driving gear. The machining of the teeth on the gears look good and I am generally happy. The purple piece in the photo below held the gear which fits to the extruder in place which I thought was a nice little touch, and is not needed for every day use. The plastic gear has also been mounted centrally on the shaft so rotates correctly when installed. It looks as though Mellow have decent quality control.

In the kit you get all of the tools required to fit the extruder as well as the fitting to allow it to be used in bowden mode. I will be using this extruder in direct mode. There are also two lengths of screws to be used to fit it either directly to the motor or with a mount in between.

I only had one issue with the extruder in that the way I mount it on my machine. The BMG clone when assembled is slightly thicker due to the name badge and the “waves” that have been moulded into the plastic in the front. So I had to spend a little time sanding the front down to get it to fit in my custom mount.

I have yet to print with it (still assembling the printer) but at the moment, the Mellow BMG clone definitely looks like a very good purchase.

As well as building a new corexy for myself, my Dad was interested in a CNC router. He does a lot of woodwork and wanted a quick way to make 3D engravings. So we’re building a Root 3 CNC Lite.

The Root 3 CNC Lite is made out of a mixture of 3D printed parts, 20mm square box section and a number of other vitamins. It uses Nema 17’s to control the motion.

We have chosen to use a 500w air cooled spindle for the cutting and rather than use a ramps board for the electronics, we have gone with a Duet 2 Ethernet.

We have so far received the side panels and base ordered from the online shop and I am busy printing all the required parts.

Once the BOM is confirmed, I will upload. This will give an idea of price and links to where we got the parts from. The BOM on thingiverse is not complete.

My early christmas present has come in the form of a shiney new Duet 3 board. Those of you who have read my earlier posts know that I have used Duet 2 ethernet boards (although they were clones) on both the Anycubic Linear Plus and the Anycubic Predator. They are a fantastic board for the money so it made sense to look towards the duet family for my new corexy.

But why did I choose the duet 3 over the duet 2? Well there are a number of reasons why I have done so.

  • The duet 2 tops out at 10 drivers (duet 2 + duex5). If I populate my corexy with all tools, I would need 12 drivers. The duet 3 should be able to handle at least 24 drivers, so expansion isn’t an issue.
  • The duet 3 can be configured to use a raspberry pi (or other similar SBC) to serve the web control, store the gcode files etc and allow the use of plugins with the reprapfirmware. I have been using raspberry pi’s for a number of years with the smart home system so I have a number of them around.
  • As my bed is 500x500x500, I felt that using 3 nema 17’s to move it would be getting towards the top of its limits. I know that its possible to find nema 23’s that would be suitable for use with the duet 2, I didn’t want to restrict myself. The duet 2 can handle up to 2.4 amps per driver and the duet 3 can handle 4 amps.
  • There are individual tool boards planned that would be mounted to the extruder. This reduces the number of wires to each tool from ~12 to 6 (4 for the canbus and 2 for power).
  • The processor has been increased from 120MHz to 300MHz.
  • Any HDMI screen can be connected to the SBC to run the web interface. You are therefore no longer restricted to the paneldue interface.

Now I’m not saying to go out and upgrade a duet 2 to a duet 3 as for standard 3D printers, the cost can’t be justified. But if you are building a tool changer or a larger CNC machine, the duet 3 is a no brainer.

If you do order a duet 3, the following things are supplied:

  • All connectors and crimps to use every connector on the board.
  • A 26 pin cable to connect the duet 3 to an SBC.
  • The crimps required to connect the power cables.
  • An SD card for use in a raspberry pi. (I haven’t used this as my raspberry pi 4 was already setup with an SSD).
  • A sticker for your machine to show that its using a duet 3.

So far, I have the duet 3 setup with a raspberry pi 4Gb. I have updated it and that’s about as far as I’ve got. I have a couple of motors that I’m going to use for the X and Y. I also have the motor that I’m going to use for the tool changer. I have ordered the Z motors (3 off) as well. I’m still on with building my machine so it will be a while before I actually start doing any electronics wiring. Eagle eyed readers will spot that all those motors above equal 6 and there are only 6 drivers on the duet 3 mainboard. I have preordered an expansion board to give me 3 extruders.

More updates on how the build is going to follow.