Mounting Laser, Cool Air, Tang Knife & Spindle Fan Hat To Z Axis – Duet CNC Controller P6

In the previous video I wired and programmed the CNC Spindle Inverter Drive but in between that and this one, I made some amendments after realising the analogue current signal generator I had bought was rather choppy.

I’ve now just wired the 0-20ma and zero-ground to the ACI and analogue ground on the VFD. So I should be able to turn this on now and programme the VFD. I’ve changed option 6 to 3 which is to use the alternative frequency input from the ACI but the only problem I have is when I flick the selector switch…

You can see the frequency is oscillating. It also feels like an overcomplicated way to do something quite simple.

 – so I wired a manual selector switch which allows me to control the spindle RPM with an analogue voltage form the Duet or via a potentiometer – without having to programme the behaviour into the VFD. Instead I wired a manual selector switch which allowed me to control the spindle RPM with an analogue input from the duet or via a potentiometer without having to programme the behaviour into the VFD. This is the new wiring diagram which you can pause to have a look at.

The front of the control box looks a little bit different now as well. Now the two-stage latching selector switch, instead of toggling between two inputs on the frequency drive – physically sends a signal either from the duet controller or the adjacent potentiometer to a single speed select input of the VFD. If the potentiometer signal is selected, a yellow pilot light illuminates to remind me of the current input state. I also added a safety key switch for the Opt Lasers engraving module which I’m planning to commission at a later date. That has a red LED pilot light because it’s dangerous.

I also tinkered about with a few things, starting with mounting the 3D-printable tangential knife. This is secured onto a 3D Printed plate that is attached to the side of the spindle mounting brackets. The Tang knife is on the same Z axis as the spindle, so I’ll have to manually remove any router cutting bit from the spindle when going between the two tools. That said I still haven’t got this working. I’m still hoping either Vectrics introduce a tang-knife setting in their software, or someone develops the kinematics for this kind of movement for the Duet.

I also increased the height of the mounting adapter for the extraction hood. At the moment I’m using this hose that came with the extractor from Axminister but I want to swap this out for a clear and more flexible one at some point.

Additionally I also designed a spindle fan mount – which I did in fusion to use a 92mm fans to cool the router spindle.

And it will be wired so that whenever the VFD is on the fan turns on as well.

This works by pushing air through the spindle from the top to keep it cool – especially at lower RPMs. I initially wire this to operate using the VFD onboard relay circuit but later changed it so it would turn on and off via a signal from the duet.

Now I’ve wired the cable up through here, and via a relay module – this relay module here. 24v goes into the normally open terminal and the common goes up to the fan and the ground comes back over here.

I think the current firmware still hasn’t got spindle status object model – so I’m relaying on this command to be in the start and stop files. This is the wiring diagram for that as well.

While I am sorting out the Z axis – I also made and installed the mounting plate for the Opt Lasers (with an s) plh3d-6w head, and a flexible lubrication nozzle. I’m not sure what I’ll be lasering, but I’m planning to only use the nozzle for cold air feeds – which is particularly useful when router cutting acrylic.

Instead of 3D printing this plate, I decided to use the CNC machine to cut one out and again demonstrate the workflow I’ve been able to design around the duet controller. There’s a lot of stages but they are relatively simple to execute and edit if needs be.

I’m now able to use the PanelDue touch screen to do most of my stages – include moving to a stationary probe location and to perform a probe cycle which sets the tool tip to zero along the z axis which happens to be on the wasteboard.

Not sure why it says print there – well it says print because this was primarily a 3D printing platform but it’s clearly functioning for CNC too.

There are two stages to the cutting job – the first making countersunk shapes with a V-bit for the mounting machine screws – which I had to do twice to get to the right depth. This is followed by profile cuts with which included making a recess for a raiser-block to increase the height of the lubrication nozzle mixing / mounting section. It’ll look a bit cluttered on the Z axis, and I’ll lose wasteboard capacity when going between the different tools, but I also want to try set this up on the controller as it’s own boring challenge.

I had been sent the original laser head back in 2017 – and only used it a handful of times including to decorate some pencils on a much older CNC machine. The company have offered to send me a newer version to review – and amazingly that will be backwards compatible with the docking adapter that I’ll be mounting to the plate I’m current cutting out.

I’m now cutting out part two of the plate gcode file. I’m using a two flute straight cutting tool which leaves a lot of the dust within the cut. I know my dust extraction hood, well it’s not as good as Marius Hornberger’s one but who knows maybe I’ll improve that someday too. That said it seems to be getting most of the dust that is in the air and any extraction is better than no extraction.

There’s not much more for me to say so I’ll leave you with assembly process. The air nozzle is the blue creaky thing. In the next video I’ll talk about the wiring and set up of the laser engraver module and how I set up the offsets between the laser… spindle and tangential knife.

Actually there is something else to add – If you would like to support the channel and content like this please consider becoming a patreon or better still buying my CNC manual for the Moot One desktop machine. The links to which will be in the description of this video.

Thanks again for watching and you’ll catch me in the next one.