Gina

Thanks Dave That looks like a nice fan - think I'll get one. The Duet Wiki says to cool the back of the board rather than the front though. I can scrounge a long Nema 17 motor from my Titan printer when I rebuild it. It uses 60mm Nema 17s for X, Y and Z drives and these big motors are not needed for the XY drives. Think I'll use a cooling fan anyway.

This shows another problem with the print bed mounting. But in spite of this the correction still works.

Been reading about fan controls on the Duet WiFi control board. Fan0 is used to control the Parts Cooling Fan as usual but the water pump, which corresponds to the hotend heatsink cooling fan can, with advantage, be run from Fan1 which defaults to a thermostatically controlled fan operated by the hotend temperature. The result is that the fan will always be when the printer is switched on and will remain on when the hotend temperature if above the set value. With subsequent print runs the fan comes on when the hotend reaches the set temperature in the fan control GCode. The fume extraction fan can also be controlled by Fan 1 as fumes are only generated when the filament is hot. That leaves the Duet cooling fan and the lighting with just one controlled fan left. If the remaining Fan control is allocated to the lighting, that leaves the Duet board cooling fan which is required if the Z drive motor is on. I'm reluctant to have the board cooling fan running continuously, though a larger fan running at reduced speed should be both quieter and longer lasting. Anyway, I would rather have this cooling fan on whenever the Duet power is on to prevent the possibility of the Z drive being used without the fan running. Another possibility might be to use a larger (and therefore more efficient) Nema 17 motor on the Z drive so that the Z motor driver could be run at less than 2A and not need the chip cooled. I would prefer to reduce the motor current anyway regardless of cooling needs.

Wanted the 24v 15A PSU that was powering the 24v bed heater for my Giant printer so I've swapped the bed heater for a mains voltage one controlled by SSR and have connected that instead. Titan is now using the mains voltage bed heater and printing fine. Bed heating is now much quicker. About a minute instead of four minutes.

I think I shall have two 3D printed boxes, one for the Duet control board with cooling fan and another to contain a mains switch, bed heater SSR and the buck converter. May arrange the second box to cover the end of the 24v PSU where the terminals are and have all dangerous voltages safely enclosed. The mains wires to the bed heater pad are well insulated and the aluminium bed plate is earthed to the frame (and frame connected to mains earth). The parts enclosed by the second box are shown with a dashed red line.

The Duet cooling fan can be run in parallel with the water pump and fume extraction fan. If I had the remote power off function I originally thought of all these could have been "always on" except when the power was turned off. To control them now they must be connected as a controlled fan and turned on at the start then turned off at the end of a print run.

Looking at a box for Duet WiFi control board. Since I'm running the Z drive at 2.4A (the maximum the Duet allows) I think a cooling fan might be a good idea for the Duet board. A 30mm or 40mm fan directly behind the Z driver chip should be sufficient. It will need a design change for the box.

There's a part completed miniature one about 35mm diameter. Printed in green ABS. I may make one a bit bigger in ASA (UV resistant) in my Giant printer in time...

New power wiring diagram with 24v PSU. 12v for the water pump, fume extractor fan and LED lighting strip is obtained from the 24v supply via a buck converter. The 24v PSU provides power to the Duet WiFi controller board which controls all printing functions including the hotend heater, parts cooling fan and heated bed via an SSR (Solid State Relay) from the 240v AC mains supply, plus water pump, fume extractor fan and LED lighting strip. I would have liked to have controlled the water pump and extractor fan separately but the Duet only controls 3 fans (plus 2 always on).

I have all the telescopes I require and more - maybe I should sell some

Trying something... Yippee At the bottom of the photo is a foot steel rule (30cm) to show scale.

I am now looking into how to arrange the PSUs and Duet control board plus a few other odds and ends.

I'm afraid there won't be any more photos as I appear to have used up my allocation on SGL I didn't realise there was a limit or I might have been less lavish with my photos and videos. EDIT - Later... Found a way round it using Dropbox - slightly more to do but at least it works.

Here's a photo of most of the printer. Above is a mess of wires and water pipes, a couple of power supplies, the Duet control board and spool of filament on stand. All this needs tidying up and sorting out.

Still experimenting with settings but ...

Adjusted nozzle height 0.4mm lower and first two layers were fine but but the spiral vase wall went wrong.

Filament not sticking to bed properly so I've given the bed a thorough clean and reapplied PVA slurry. Now trying printing again.

Bed connected up and heating. Trying a print run

Extrusion test done.

That's all the calibration finished - next to connect up the rest ready for printing.

Z probe calibration next. Had to screw the Z probe in a bit to make it higher before calibration would work. Two things need setting roughly right before Z probe calibration will work - level bed (or XY frame in this case) and Z probe height relative to nozzle. There is some tolerance on these but not a lot.

Decided to have another tweak of the Z drive rods and this is the result. I think that is as far as I can go - the errors now are mainly the plate not being quite flat. This is with the bed cold - I shall repeat with the bed hot and see what difference I get.

A bit more tuning and I think this should be good enough. RMS error less than 0.25mm.

After a bit of fine tuning.

Here are the Automatic Calibration Results before fine tuning.