D-Bot 3D Printer

[Gina]

After yet more reading through the list of posts on the Duet forum, I found this :-

Quote

And I love the WiFi, I have 3 Duets - 2 Wifi's and an older 0.6 with ethernet.. I hate having to run a network cable to the printer with the 0.6 ethernet as well as worry about moving it around and pulling on the cable etc.. that said once its in place its fine.

I took one of my WiFi printers into work to show it off, was really easy to just find a spare power outlet, connect to the work wifi (with a macro I prepared in advance) and bam away it goes.

But, we have very reliable strong Wifi at our work, and I have a fairly decent one at home as well (ubiquiti unifi), although I also had no troubles using it on a cheap tplink router with built-in wifi as well. as has been said if you have poor or congested WiFi then the ethernet is probably a safer bet.

 

[tekkydave]

I thought about getting the Duet Ethernet but decided on the Wifi instead and set up a spare BT Homehub WiFi router in the office. This is also connected via Ethernet to the rest of my network so I can access the Duet from anywhere in the house. Our main BT router is downstairs and the Duet will connect to it but the signal is marginal.

Edited January 19, 2018 by tekkydave

[Gina]

And I thought BT HomeHubs were supposed to have exceptional WiFi   Well that's what they say in their adverts   I was quite satisfied with mine when I was using it but the fibre optic one supplied by Gigaclear works alright throughout the bungalow and observatory.

[tekkydave]

The Home hubs are pretty good - I can get a signal halfway down the garden, but I wouldn't want to rely on it. My weather station RPi outside is connected via the regular house Wifi and seems to manage.

Upstairs it seems to be marginal (-60 to -70db) and the Duet only has a tiny antenna so I didn't want to rely on it, especially once the Duet is put in a case. The signal from the office router is consistently -30db.

We can't all have the luxury of fibre right to our doors, Gina  . I'm getting 42Mb/s download and 20Mb/s upload speeds which isn't bad when you consider the last half mile of cable is a twisted pair

 

[Gina]

I didn't mean to gloat Dave - just comparing routers.  The Genexis router I have now has been found to have a poorer WiFi signal but mine is alright so far.  Your speeds are perfectly acceptable I would say and far better than most get with twisted pair wet string.  I would have settled for that (compared with 2-3Mbps d/l and 0.3Mbps u/l).

Been tackling the wiring up of my Mini printer today.  Fiddly job with the tiny crimps in the multi-way connectors.

[Stub Mandrel]

5 hours ago, Gina said:

And I thought BT HomeHubs were supposed to have exceptional WiFi  

A bit like the 'if only everything in life was as reliable as a Volkswagen' advert which omitted to mention the reliability of a Volkswagen was no more than average at best.

[tekkydave]

I've added some extra idlers to increase the contact area between the z drive belt and the pulleys (photos to follow).

I have also removed the front L&R wheel sets as I think having wheels at all 4 corners was over-constraining the z axis. It moves up & down perfectly on the 3 leadscrews now so only needs constraining on the back edge. I may also remove the front bar I added if it proves ok as it is just dead weight now.

Both of these changes together has allowed me to increase the maximum z axis speed from 120 to 180mm/min. This also improves the piezo z probe operation as the faster you can hit it the better.

[Gina]

Getting there then Dave

That seems a very slow Z axis speed Dave.  I have mine at 600mm/min but it's still much slower than my Titan printer and I shall be increasing it.

Edited January 21, 2018 by Gina

[Dave_D]

On 19/01/2018 at 15:17, Gina said:

And I thought BT HomeHubs were supposed to have exceptional WiFi  

*correction 'And I know BT HomeHubs are exceptionally crap'

[tekkydave]

1 hour ago, tekkydave said:

I've added some extra idlers to increase the contact area between the z drive belt and the pulleys (photos to follow).

I have also removed the front L&R wheel sets as I think having wheels at all 4 corners was over-constraining the z axis. It moves up & down perfectly on the 3 leadscrews now so only needs constraining on the back edge. I may also remove the front bar I added if it proves ok as it is just dead weight now.

Both of these changes together has allowed me to increase the maximum z axis speed from 120 to 180mm/min. This also improves the piezo z probe operation as the faster you can hit it the better.

Some pics. The new idler arrangement:

Gap where wheels used to be:

 

[tekkydave]

55 minutes ago, Gina said:

Getting there then Dave

That seems a very slow Z axis speed Dave.  I have mine at 600mm/min but it's still much slower than my Titan printer and I shall be increasing it.

Yes, I wish I could get it faster, although its not an issue in normal operation. It might be down to the weight of the z carriage & bed, especially as it is leadscrew driven (more friction). The bed is 300x300x6mm cast aluminium so not light.

[Gina]

Ah yes.  That is some bed!  Very heavy.  My Titan uses a 300x300x3mm borosilicate glass plate with silicone heater pad stuck to the underside - 24v 360W.  So it's very much lighter than yours.  And the Mini is only 200x200mm again with borosilicate glass plate but 12v 220W heater (which I might replace with a mains version).  I agree, no operational problem with slow Z drive, just needing more patience

[tekkydave]

I might remove the bed to see what speed I can get

The z motor is quite powerful (54N.cm) but the belt gearing is 3:1. Also the leadscrews are 1mm pitch single start. This gives me a 9600 steps/mm overall using 16x stepping. Not sure if changing anything will have any effect on the top speed.

[Gina]

That is quite a high steps/mm by may be needed for a heavy bed.  My Z steps/mm is just 401 on the Mini.  No idea what the maximum speed might be on NEMA 17s. 

The Duet sure makes the machine "silent running"   Noisiest thing is the cooling fan on the hotend and that's pretty darn quiet   The ease of changing settings is a sheer joy after all the fussing about with Marlin.  All my 3D printers will be using the Duet.  Best thing since sliced bread

Edited January 21, 2018 by Gina

[tekkydave]

And I seem to remember you being slightly cynical about whether it was worth the extra money over the Ramps

 

[Gina]

Very true

[Gina]

Dave (tecky), have you used the Mesh Grid Compensation with 9 points (3x3 grid) as yet?  I saw your post of the result of a 4 point probe a while back but I haven't seen a 9 point one.  I ask because I'm having a problem with the 9 point 3x3 grid.  Only probing 6 points and not the first column.

[tekkydave]

Yes, using G29 via the Gcode console or the little dialog box top left of the screen. My config.g has:

M557 X50:250 Y40:240 S100:100             ; Define mesh grid (3x3)

It probes at X=50,150,250 and Y=40,140,240

The results graph should come up automatically at the end. If not select from drop-down next to mesh levelling button.

 

[Gina]

I have a smaller bed  (200x200 but printing area of 190x190) and using

M557 X15:175 Y15:175 S80          ; Define mesh grid

Giving probing points of 15,95,175 in X and Y.  But it only goes to and probes (95,15) (175,15) (175,95) (95, 95) (95,175) (175,175). ie.

no  yes  yes
no  yes  yes
no  yes  yes

It starts off at (15,15) after homing but doesn't probe it. 

Edited January 21, 2018 by Gina

[tekkydave]

See my comment in your thread. I think its to do with your probe offset.

[Stub Mandrel]

6 hours ago, tekkydave said:

Gap where wheels used to be:

You should be able to get away with just one idler, unless there isn't enough 'wrap' around the rear pulley with only one.

Two roles of idlers - maintaining tension and increasing the length of wrap around pulleys

[tekkydave]

6 minutes ago, Stub Mandrel said:

You should be able to get away with just one idler, unless there isn't enough 'wrap' around the rear pulley with only one.

Two roles of idlers - maintaining tension and increasing the length of wrap around pulleys

Yes maybe. I was aiming to make the wrap the same for each pulley.

[Gina]

Which slicer do you use with the Duet Dave?

[Stub Mandrel]

2 hours ago, tekkydave said:

Yes maybe. I was aiming to make the wrap the same for each pulley.

I do wonder if without the ldlers the back one would be prone to slipping.

[Gina]

Complicated, isn't it!